Rickard's Projects

This site hosts my projects.

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• blog My blog.
• rlworkbench Experimental language workbench based on rlmeta2.
• rlmeta2 New experiment with rlmeta.
• rlselect2 Rewrite of rlselect with a new approach to performance.
• projects2 Software to setup a code hosting platform. Powers this site.
• timeline A cross-platform application for displaying and navigating events on a timeline.
• garmin A tool to work with Garmin data.
• gittest A test project for Git.
• dotfiles My dotfiles.
• rlselect rlselect allows you to select a line interactively by searching. It works by reading input from stdin and printing the selected line to stdout. You can therefore use it to search anything, and it is up to you what to do with the selected line.

Recent events

2025-12-15 22:23 Rickard pushed to blog

commit 23be08c456f904d2b50f77e1a245dc63e77187bc
Author: Rickard Lindberg <rickard@rickardlindberg.me>
Date:   Mon Dec 15 22:23:09 2025 +0100

    New post maze math puzzles

diff --git a/posts/2025/12/15/maze-math-puzzles/post.md b/posts/2025/12/15/maze-math-puzzles/post.md
new file mode 100644
index 0000000..1b4725f
--- /dev/null
+++ b/posts/2025/12/15/maze-math-puzzles/post.md
@@ -0,0 +1,233 @@
+---
+date: 2025-12-15 22:18:00
+title: Maze Math Puzzles
+tags: aoc
+---
+
+<style type="text/css">
+pre { padding: 10px; }
+pre.highlight                    { background: #002b36; }
+pre.highlight                    { color: #93a1a1; }
+pre.highlight span.Meta          { color: #d33682; }
+pre.highlight span.Reserved      { color: #859900; }
+pre.highlight span.String        { color: #2aa198; }
+pre.highlight span.CharString    { color: #ffffff; }
+pre.highlight span.Escape        { color: #dc322f; }
+pre.highlight span.RuleName      { color: #268bd2; }
+pre.highlight span.VariableName  { color: #b58900; }
+</style>
+
+Inspired by [](post:2025/12/13/advent-of-code-2025/post.md), I wanted to make
+some kind of similar puzzle for my son. He usually takes some interest in me
+solving the problems. He even helped me program some solutions last year. But
+it mostly meant I told him what keys to press. Programming is a little hard.
+But he likes math.
+
+So I came up with an idea to generate maze math problems.
+
+Your task is to walk from start to end in a maze. You also carry a backpack
+with a number in it. That number is initially 1. When you cross another number
+on your way to the end, you add the number that you have in your backpack with
+the number you just encountered and put the result back in your backpack. When
+you cross an operator, it changes what operation you perform the next time you
+cross a number. The puzzle answer is the number that you have in your backpack
+when you reach the end.
+
+Here is the first puzzle that I generated that I had my son solve:
+
+<pre class="highlight">#########################################
+# <span class="Reserved">S</span>     #                               #
+#####   #   #############################
+#       #                               #
+#   #####   #########################   #
+#   #       #     <span class="RuleName">4</span>                     #
+#   #########   #####################   #
+#         <span class="VariableName">*</span>   <span class="RuleName">2</span> # <span class="VariableName">*</span>                 # <span class="VariableName">+</span> #
+#################   #########   #   #   #
+#     <span class="RuleName">3</span>             #           #   #   #
+#########   #########   #########   #   #
+# <span class="RuleName">4</span>     # <span class="VariableName">*</span>     #       #   #     <span class="VariableName">+</span> #   #
+#   #   #########   #####   #   #####   #
+#   #               #         <span class="RuleName">4</span> # <span class="RuleName">3</span>     #
+#   #############################   #####
+#     <span class="RuleName">2</span>                     #       # <span class="RuleName">2</span> #
+#########################   #   #####   #
+#     <span class="RuleName">3</span>               <span class="VariableName">+</span>     #     <span class="Escape">E</span>     #
+#   #################################   #
+#                                       #
+#########################################
+</pre>
+
+I had to explain the rules a few times before he got it. But then he was able
+to solve it. It was both a little challenging to remember the number in the
+backpack and to remember what operation to perform. The mazes don't seem to be
+too hard to solve right now. Perhaps I have done something wrong in the
+generation code? There are often few choices that you can make.
+
+Can you figure out the answer?
+
+The program that generates the mazes also helpfully shows the answer and the
+path from start to end:
+
+<pre class="highlight">Answer = <span class="RuleName">1</span><span class="RuleName">1</span>
+#########################################
+# <span class="Reserved">S</span>   <span class="Meta">.</span> #                               #
+#####   #   #############################
+# <span class="Meta">.</span>   <span class="Meta">.</span> #                               #
+#   #####   #########################   #
+# <span class="Meta">.</span> #       # <span class="Meta">.</span>   <span class="RuleName">4</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #
+#   #########   #####################   #
+# <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="VariableName">*</span>   <span class="RuleName">2</span> # <span class="VariableName">*</span>                 # <span class="VariableName">+</span> #
+#################   #########   #   #   #
+#     <span class="RuleName">3</span>             #           #   # <span class="Meta">.</span> #
+#########   #########   #########   #   #
+# <span class="RuleName">4</span>     # <span class="VariableName">*</span>     #       #   #     <span class="VariableName">+</span> # <span class="Meta">.</span> #
+#   #   #########   #####   #   #####   #
+#   #               #         <span class="RuleName">4</span> # <span class="RuleName">3</span>   <span class="Meta">.</span> #
+#   #############################   #####
+#     <span class="RuleName">2</span>                     # <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="RuleName">2</span> #
+#########################   #   #####   #
+#     <span class="RuleName">3</span>               <span class="VariableName">+</span>     # <span class="Meta">.</span>   <span class="Escape">E</span>     #
+#   #################################   #
+#                                       #
+#########################################
+</pre>
+
+Right now only numbers 1, 2, 3, and 4 are used and operators `+` and `*`. We
+can easily make the problems harder by adding bigger numbers and more
+operators.
+
+We can also get harder problems by generating mazes a few times at random. Here
+is one for example:
+
+<pre class="highlight">#########################################
+# <span class="Reserved">S</span>       <span class="RuleName">2</span> #                           #
+#########   #   #########   #############
+#       #   #   #       #     <span class="RuleName">3</span>         #
+#   #   #   #####   #   #############   #
+#   #   #   #       #         <span class="VariableName">+</span>   <span class="VariableName">*</span> # <span class="RuleName">4</span> #
+#   #   #   #   #################   #   #
+#   #   #       #               # <span class="RuleName">3</span> #   #
+#   #################   #####   #   #   #
+#         <span class="RuleName">2</span>         #   #       #       #
+#############   #   #####   #   #####   #
+#             <span class="RuleName">3</span> # <span class="VariableName">+</span>   <span class="RuleName">4</span>     #   #       #
+#   #############################   #####
+#                               #       #
+#############################   #####   #
+#                 <span class="VariableName">*</span>         #   #     <span class="RuleName">4</span> #
+#   #####################   #   #   #####
+#   # <span class="VariableName">*</span>                       <span class="VariableName">+</span> # <span class="Escape">E</span> #   #
+#   #############################   #   #
+#                                 <span class="RuleName">2</span>     #
+#########################################
+Answer = <span class="RuleName">3</span><span class="RuleName">6</span>
+#########################################
+# <span class="Reserved">S</span>   <span class="Meta">.</span>   <span class="RuleName">2</span> #                           #
+#########   #   #########   #############
+#       # <span class="Meta">.</span> #   # <span class="Meta">.</span>   <span class="Meta">.</span> #     <span class="RuleName">3</span>         #
+#   #   #   #####   #   #############   #
+#   #   # <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="VariableName">+</span>   <span class="VariableName">*</span> # <span class="RuleName">4</span> #
+#   #   #   #   #################   #   #
+#   #   # <span class="Meta">.</span>   <span class="Meta">.</span> #               # <span class="RuleName">3</span> #   #
+#   #################   #####   #   #   #
+#         <span class="RuleName">2</span>         #   #       # <span class="Meta">.</span>   <span class="Meta">.</span> #
+#############   #   #####   #   #####   #
+#             <span class="RuleName">3</span> # <span class="VariableName">+</span>   <span class="RuleName">4</span>     #   # <span class="Meta">.</span>   <span class="Meta">.</span> #
+#   #############################   #####
+#                               # <span class="Meta">.</span>   <span class="Meta">.</span> #
+#############################   #####   #
+#                 <span class="VariableName">*</span>         #   # <span class="Meta">.</span>   <span class="RuleName">4</span> #
+#   #####################   #   #   #####
+#   # <span class="VariableName">*</span>                       <span class="VariableName">+</span> # <span class="Escape">E</span> #   #
+#   #############################   #   #
+#                                 <span class="RuleName">2</span>     #
+#########################################
+</pre>
+
+And of course we can play around with larger size:
+
+<pre class="highlight">#################################################################################
+# <span class="Reserved">S</span>       <span class="VariableName">*</span>     #                       #           #                       #   #
+#############   #   #################   #   #####   #   #################   #   #
+#   #           #           #               #           #       #           # <span class="VariableName">+</span> #
+#   #   #################   #   #############################   #   #########   #
+#       #                   #   # <span class="RuleName">4</span>                         #   #   #           #
+#   #############   #   #########   #####################   #   #   #########   #
+# <span class="RuleName">3</span>         #       #   #                   #               #       #         <span class="RuleName">4</span> #
+#########   #   #########   #################   #############   #####   #########
+#       #   #                   #               #           #   #   #     <span class="RuleName">4</span>     #
+#####   #   #####################   #############   #########   #   #   #####   #
+#       #             <span class="VariableName">*</span>             #           #   #         <span class="RuleName">3</span> #       #       #
+#   #   #################################   #   #   #   #################   #####
+#   #       #                               #       #           #       #       #
+#   #####   #####################   #########################   #   #   #####   #
+#   #       #           #       #       #                   #   #   #           #
+#   #   #####   #####   #   #   #####   #   #####   #########   #   #############
+#   #           #   #       #     <span class="Escape">E</span> #       #       # <span class="VariableName">*</span>         #               #
+#   #############   #############   #########   #####   #####################   #
+#           #               #       #       # <span class="RuleName">2</span> #       #                       #
+#########   #   #############   #####   #   #   #   #########   #################
+#           #         <span class="VariableName">+</span>                 # <span class="RuleName">3</span>     #   #       #             <span class="VariableName">*</span>     #
+#   #####   #################################   #   #   #   #   #############   #
+#   #       #                               #   #       #   #   #           #   #
+#   #########   #########################   #############   #####   #####   #   #
+#     <span class="VariableName">*</span>         #                           #           #           #   #       #
+#   #############   #########################   #####   #############   #####   #
+#   #               #                   #       #                 <span class="RuleName">2</span>         #   #
+#####   #####   #####   #############   #   #####   #########   #############   #
+#     <span class="RuleName">3</span> #       #       #           #       #       #         <span class="RuleName">4</span> #               #
+#   #############   #####   #####   #########   #####   #########   #############
+#             <span class="RuleName">4</span>     # <span class="RuleName">3</span>     #   #             <span class="RuleName">2</span> #   # <span class="VariableName">+</span>     #       #           #
+#####################   #####   #################   #####   #   #####   #####   #
+#                       #               #         <span class="RuleName">2</span>         #           #       #
+#   #################################   #   #############################   #####
+# <span class="RuleName">2</span>                       <span class="VariableName">+</span> #           #                           #       #   #
+#########################   #   #################################   #   #####   #
+#                           #                                       #   #       #
+#   #################################################################   #####   #
+#                                                                             <span class="VariableName">+</span> #
+#################################################################################
+Answer = <span class="RuleName">5</span><span class="RuleName">0</span>
+#################################################################################
+# <span class="Reserved">S</span>   <span class="Meta">.</span>   <span class="VariableName">*</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #   #
+#############   #   #################   #   #####   #   #################   #   #
+#   # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #         <span class="Meta">.</span>   <span class="Meta">.</span> #     <span class="Meta">.</span>   <span class="Meta">.</span> #       # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="VariableName">+</span> #
+#   #   #################   #   #############################   #   #########   #
+# <span class="Meta">.</span>   <span class="Meta">.</span> #         <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #   # <span class="RuleName">4</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #   # <span class="Meta">.</span> #           #
+#   #############   #   #########   #####################   #   #   #########   #
+# <span class="RuleName">3</span>   <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span> #   # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>         # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span> #         <span class="RuleName">4</span> #
+#########   #   #########   #################   #############   #####   #########
+#       # <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>     # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #           # <span class="Meta">.</span> #   #     <span class="RuleName">4</span>     #
+#####   #   #####################   #############   #########   #   #   #####   #
+# <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="VariableName">*</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #           #   # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="RuleName">3</span> #       #       #
+#   #   #################################   #   #   #   #################   #####
+# <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span> #                               #       # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #       #       #
+#   #####   #####################   #########################   #   #   #####   #
+# <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span> #       #                   # <span class="Meta">.</span> #   #           #
+#   #   #####   #####   #   #   #####   #   #####   #########   #   #############
+# <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #   # <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Escape">E</span> #       #       # <span class="VariableName">*</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #               #
+#   #############   #############   #########   #####   #####################   #
+# <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #               #       #       # <span class="RuleName">2</span> # <span class="Meta">.</span>   <span class="Meta">.</span> #                       #
+#########   #   #############   #####   #   #   #   #########   #################
+# <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #         <span class="VariableName">+</span>                 # <span class="RuleName">3</span>     # <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span> #             <span class="VariableName">*</span>     #
+#   #####   #################################   #   #   #   #   #############   #
+# <span class="Meta">.</span> #       # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #   # <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span> #   # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #   #
+#   #########   #########################   #############   #####   #####   #   #
+# <span class="Meta">.</span>   <span class="VariableName">*</span>   <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #   # <span class="Meta">.</span>   <span class="Meta">.</span> #
+#   #############   #########################   #####   #############   #####   #
+#   # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>           <span class="RuleName">2</span>         # <span class="Meta">.</span> #
+#####   #####   #####   #############   #   #####   #########   #############   #
+# <span class="Meta">.</span>   <span class="RuleName">3</span> #       # <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span> #         <span class="RuleName">4</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #
+#   #############   #####   #####   #########   #####   #########   #############
+# <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="RuleName">4</span>   <span class="Meta">.</span> # <span class="RuleName">3</span>   <span class="Meta">.</span> #   # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="RuleName">2</span> #   # <span class="VariableName">+</span>     # <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #
+#####################   #####   #################   #####   #   #####   #####   #
+# <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #               #         <span class="RuleName">2</span>         # <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> # <span class="Meta">.</span>   <span class="Meta">.</span> #
+#   #################################   #   #############################   #####
+# <span class="RuleName">2</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="VariableName">+</span> #           #                           # <span class="Meta">.</span>   <span class="Meta">.</span> #   #
+#########################   #   #################################   #   #####   #
+# <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span> #                                       # <span class="Meta">.</span> #       #
+#   #################################################################   #####   #
+# <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>   <span class="Meta">.</span>       <span class="VariableName">+</span> #
+#################################################################################
+</pre>

commit dde5983d88ac9102f18f83b3a2c24ebc57f8b2f8
Author: Rickard Lindberg <rickard@rickardlindberg.me>
Date:   Mon Dec 15 22:05:08 2025 +0100

    Fix bug in sorting code

diff --git a/blog.py b/blog.py
index b10f4c0..61634cf 100755
--- a/blog.py
+++ b/blog.py
@@ -324,7 +324,7 @@ class Posts:
         ul = Tag("ul")
         for post in sorted(
             self.by_id.values(),
-            key=lambda post: post.date,
+            key=lambda post: post.date.date,
             reverse=True
         ):
             li = Tag("li")

2025-12-15 07:27 Rickard pushed to rlworkbench

fatal: Invalid revision range 08b36fc69880c7b7e53b09492fb04a980bb6d929..ccd1cf99946300ef6fbf2e7db0c1beda98ccd654

2025-12-15 07:13 Rickard pushed to rlworkbench

fatal: Invalid revision range 13c31b3fd4b76279834bca34084fb2ba724a1289..08b36fc69880c7b7e53b09492fb04a980bb6d929

2025-12-14 14:21 Rickard pushed to blog

commit fedefd512f79347a931b2f075a36f8d5df2b9fd8
Author: Rickard Lindberg <rickard@rickardlindberg.me>
Date:   Sun Dec 14 14:21:14 2025 +0100

    Add aoc tag

diff --git a/posts/2025/12/13/advent-of-code-2025/post.md b/posts/2025/12/13/advent-of-code-2025/post.md
index 4994d11..604e5b9 100644
--- a/posts/2025/12/13/advent-of-code-2025/post.md
+++ b/posts/2025/12/13/advent-of-code-2025/post.md
@@ -1,7 +1,7 @@
 ---
 date: 2025-12-14 14:20:00
 title: Advent of Code 2025
-tags: rlworkbench,c
+tags: rlworkbench,c,aoc
 ---
 
 <style type="text/css">

2025-12-14 14:20 Rickard pushed to blog

commit 9ecacb38906777388e05c6deeccdb477602c0288
Author: Rickard Lindberg <rickard@rickardlindberg.me>
Date:   Sun Dec 14 14:20:50 2025 +0100

    Advent of Code 2025

diff --git a/posts/2025/12/13/advent-of-code-2025/aoc20251-parser-only.meta b/posts/2025/12/13/advent-of-code-2025/aoc20251-parser-only.meta
new file mode 100644
index 0000000..0669e1a
--- /dev/null
+++ b/posts/2025/12/13/advent-of-code-2025/aoc20251-parser-only.meta
@@ -0,0 +1,14 @@
+main = instruction* !.;
+
+instruction = 
+    | left
+    | right
+    ;
+
+left[Reserved] = 'L' number '\n';
+
+right[RuleName] = 'R' number '\n';
+
+number = digit digit*;
+
+digit = '0'-'9';
diff --git a/posts/2025/12/13/advent-of-code-2025/aoc20251.meta b/posts/2025/12/13/advent-of-code-2025/aoc20251.meta
new file mode 100644
index 0000000..f843124
--- /dev/null
+++ b/posts/2025/12/13/advent-of-code-2025/aoc20251.meta
@@ -0,0 +1,54 @@
+main = instruction*:xs !. -> {
+    $dialSize
+    >dialSize { "100" }
+    "#include <stdio.h>\n"
+    "typedef struct {\n" >
+        "unsigned int positive_offset;\n"
+        "unsigned int partial;\n"
+        "unsigned int complete;\n"
+    < "} Turn;\n"
+    "static Turn turns[] = {\n" >
+        xs
+    < "};\n"
+    "static unsigned int number_of_turns = " xs.count ";\n"
+    "int main(void) {\n" >
+        "unsigned int dial_position = 50;\n"
+        "unsigned int times_ended_at_zero = 0;\n"
+        "unsigned int times_at_zero = 0;\n"
+        "unsigned int turn_index;\n"
+        "unsigned int partial_counter;\n"
+        "for(turn_index=0; turn_index<number_of_turns; turn_index++) {\n" >
+            "for(partial_counter=0; partial_counter<turns[turn_index].partial; partial_counter++) {\n" >
+                "dial_position += turns[turn_index].positive_offset;\n"
+                "dial_position %= " <dialSize ";\n"
+                "if (dial_position == 0) {\n" >
+                    "times_at_zero += 1;\n"
+                < "}\n"
+            < "}\n"
+            "if (dial_position == 0) {\n" >
+                "times_ended_at_zero += 1;\n"
+            < "}\n"
+            "times_at_zero += turns[turn_index].complete;\n"
+        < "}\n"
+        "printf(\"Part 1: %d\\n\", times_ended_at_zero);\n"
+        "printf(\"Part 2: %d\\n\", times_at_zero);\n"
+        "return 0;\n"
+    < "}\n"
+};
+
+instruction = 
+    | left:x -> { x }
+    | right:x -> { x }
+    ;
+
+left[Reserved] = 'L' number:x '\n' -> {
+    "{" <dialSize "-1, " x "%" <dialSize ", " x "/" <dialSize "},\n"
+};
+
+right[RuleName] = 'R' number:x '\n' -> {
+    "{1, " x "%" <dialSize ", " x "/" <dialSize "},\n"
+};
+
+number = digit digit*;
+
+digit = '0'-'9';
diff --git a/posts/2025/12/13/advent-of-code-2025/example.aoc20251 b/posts/2025/12/13/advent-of-code-2025/example.aoc20251
new file mode 100644
index 0000000..53287c7
--- /dev/null
+++ b/posts/2025/12/13/advent-of-code-2025/example.aoc20251
@@ -0,0 +1,10 @@
+L68
+L30
+R48
+L5
+R60
+L55
+L1
+L99
+R14
+L82
diff --git a/posts/2025/12/13/advent-of-code-2025/example_aoc20251.c b/posts/2025/12/13/advent-of-code-2025/example_aoc20251.c
new file mode 100644
index 0000000..f426d74
--- /dev/null
+++ b/posts/2025/12/13/advent-of-code-2025/example_aoc20251.c
@@ -0,0 +1,42 @@
+#include <stdio.h>
+typedef struct {
+    unsigned int positive_offset;
+    unsigned int partial;
+    unsigned int complete;
+} Turn;
+static Turn turns[] = {
+    {100-1, 68%100, 68/100},
+    {100-1, 30%100, 30/100},
+    {1, 48%100, 48/100},
+    {100-1, 5%100, 5/100},
+    {1, 60%100, 60/100},
+    {100-1, 55%100, 55/100},
+    {100-1, 1%100, 1/100},
+    {100-1, 99%100, 99/100},
+    {1, 14%100, 14/100},
+    {100-1, 82%100, 82/100},
+};
+static unsigned int number_of_turns = 10;
+int main(void) {
+    unsigned int dial_position = 50;
+    unsigned int times_ended_at_zero = 0;
+    unsigned int times_at_zero = 0;
+    unsigned int turn_index;
+    unsigned int partial_counter;
+    for(turn_index=0; turn_index<number_of_turns; turn_index++) {
+        for(partial_counter=0; partial_counter<turns[turn_index].partial; partial_counter++) {
+            dial_position += turns[turn_index].positive_offset;
+            dial_position %= 100;
+            if (dial_position == 0) {
+                times_at_zero += 1;
+            }
+        }
+        if (dial_position == 0) {
+            times_ended_at_zero += 1;
+        }
+        times_at_zero += turns[turn_index].complete;
+    }
+    printf("Part 1: %d\n", times_ended_at_zero);
+    printf("Part 2: %d\n", times_at_zero);
+    return 0;
+}
diff --git a/posts/2025/12/13/advent-of-code-2025/interesting.c b/posts/2025/12/13/advent-of-code-2025/interesting.c
new file mode 100644
index 0000000..51b48c5
--- /dev/null
+++ b/posts/2025/12/13/advent-of-code-2025/interesting.c
@@ -0,0 +1,13 @@
+static Turn turns[] = {
+    {100-1, 68%100, 68/100},
+    {100-1, 30%100, 30/100},
+    {1, 48%100, 48/100},
+    {100-1, 5%100, 5/100},
+    {1, 60%100, 60/100},
+    {100-1, 55%100, 55/100},
+    {100-1, 1%100, 1/100},
+    {100-1, 99%100, 99/100},
+    {1, 14%100, 14/100},
+    {100-1, 82%100, 82/100},
+};
+static unsigned int number_of_turns = 10;
diff --git a/posts/2025/12/13/advent-of-code-2025/post.md b/posts/2025/12/13/advent-of-code-2025/post.md
new file mode 100644
index 0000000..4994d11
--- /dev/null
+++ b/posts/2025/12/13/advent-of-code-2025/post.md
@@ -0,0 +1,666 @@
+---
+date: 2025-12-14 14:20:00
+title: Advent of Code 2025
+tags: rlworkbench,c
+---
+
+<style type="text/css">
+pre { padding: 10px; }
+pre.highlight                    { background: #002b36; }
+pre.highlight                    { color: #93a1a1; }
+pre.highlight span.Meta          { color: #d33682; }
+pre.highlight span.Reserved      { color: #859900; }
+pre.highlight span.String        { color: #2aa198; }
+pre.highlight span.CharString    { color: #ffffff; }
+pre.highlight span.Escape        { color: #dc322f; }
+pre.highlight span.RuleName      { color: #268bd2; }
+pre.highlight span.VariableName  { color: #b58900; }
+</style>
+
+**Warning: This blog post contains spoilers. If you don't want any insights
+into this years' puzzles, stop reading now.**
+
+I couldn't resist participating in [Advent of Code](https://adventofcode.com)
+this year either.
+
+Usually I challenge myself by solving the puzzles in some new kind of way.
+This year I decided to take a meta approach. What does that mean?
+
+In my [last
+newsletter](https://buttondown.com/rickardlindberg/archive/november-2025-can-rlworkbench-replace-vim/),
+I wrote about my new project, rlworkbench, where I try to build a [language
+workbench](https://en.wikipedia.org/wiki/Language_workbench). What is that?
+What am I trying to build?
+
+The way I think about it is that rlworkbench should be a text editor that is
+aware of the language of the text that is being edited. That awareness can give
+you syntax highlighting for example. But it can also give you more if it knows
+more about the language. For example, there might be an editor operation to
+expand the selection. If the cursor is inside a function, expanding the
+selection might select the whole function. Because the editor is aware of the
+language, it knows where the function starts and ends. Furthermore, defining
+the languages that rlworkbench knows about should be easy. And the norm should
+be to create many small domain specific languages. And when you define a
+language, it not only gives you editor support, but you can also define how
+that language should be compiled or translated.
+
+How does that relate to Advent of Code?
+
+Think of every day's puzzle input as its own language. The input is the
+program. Your job is to write a parser and code generator for that language.
+The parser provides editor support and the code generator compiles the puzzle
+input into something that can be executed. Because rlworkbench is written
+in C, and because I want to practice writing more C, I chose to make all code
+generators output C code.
+
+So the general shape of my solutions this year looked something like this:
+
+1. Write a parser for day X in the meta language of rlworkbench
+2. Write a code generator that transforms the input of day X into a C program
+3. Compile and run that C program
+4. Watch it print solutions for part 1 and part 2
+
+Since you usually don't edit the puzzle input, it is a bit contrived to see it
+as a language. But, hey, I wanted to experiment.
+
+Let's walk through day 1 in a bit of detail to show my process this year. Then
+I will continue with some highlights from each day.
+
+## Day 1
+
+The example input for [day 1](https://adventofcode.com/2025/day/1) looks like
+this:
+
+    L68
+    L30
+    R48
+    L5
+    R60
+    L55
+    L1
+    L99
+    R14
+    L82
+
+It is a sequence of instructions for how to rotate a dial.
+
+Here is a parser for this language, written in the meta language of
+rlworkbench:
+
+<pre class="highlight"><span class="RuleName">m</span><span class="RuleName">a</span><span class="RuleName">i</span><span class="RuleName">n</span> = <span class="RuleName">i</span><span class="RuleName">n</span><span class="RuleName">s</span><span class="RuleName">t</span><span class="RuleName">r</span><span class="RuleName">u</span><span class="RuleName">c</span><span class="RuleName">t</span><span class="RuleName">i</span><span class="RuleName">o</span><span class="RuleName">n</span><span class="Reserved">*</span> <span class="Reserved">!</span><span class="Reserved">.</span>;
+
+<span class="RuleName">i</span><span class="RuleName">n</span><span class="RuleName">s</span><span class="RuleName">t</span><span class="RuleName">r</span><span class="RuleName">u</span><span class="RuleName">c</span><span class="RuleName">t</span><span class="RuleName">i</span><span class="RuleName">o</span><span class="RuleName">n</span> =
+    <span class="Reserved">|</span> <span class="RuleName">l</span><span class="RuleName">e</span><span class="RuleName">f</span><span class="RuleName">t</span>
+    <span class="Reserved">|</span> <span class="RuleName">r</span><span class="RuleName">i</span><span class="RuleName">g</span><span class="RuleName">h</span><span class="RuleName">t</span>
+    ;
+
+<span class="RuleName">l</span><span class="RuleName">e</span><span class="RuleName">f</span><span class="RuleName">t</span>[<span class="Meta">R</span><span class="Meta">e</span><span class="Meta">s</span><span class="Meta">e</span><span class="Meta">r</span><span class="Meta">v</span><span class="Meta">e</span><span class="Meta">d</span>] = <span class="CharString">'</span><span class="CharString">L</span><span class="CharString">'</span> <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> <span class="CharString">'</span><span class="Escape">\</span><span class="Escape">n</span><span class="CharString">'</span>;
+
+<span class="RuleName">r</span><span class="RuleName">i</span><span class="RuleName">g</span><span class="RuleName">h</span><span class="RuleName">t</span>[<span class="Meta">R</span><span class="Meta">u</span><span class="Meta">l</span><span class="Meta">e</span><span class="Meta">N</span><span class="Meta">a</span><span class="Meta">m</span><span class="Meta">e</span>] = <span class="CharString">'</span><span class="CharString">R</span><span class="CharString">'</span> <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> <span class="CharString">'</span><span class="Escape">\</span><span class="Escape">n</span><span class="CharString">'</span>;
+
+<span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> = <span class="RuleName">d</span><span class="RuleName">i</span><span class="RuleName">g</span><span class="RuleName">i</span><span class="RuleName">t</span> <span class="RuleName">d</span><span class="RuleName">i</span><span class="RuleName">g</span><span class="RuleName">i</span><span class="RuleName">t</span><span class="Reserved">*</span>;
+
+<span class="RuleName">d</span><span class="RuleName">i</span><span class="RuleName">g</span><span class="RuleName">i</span><span class="RuleName">t</span> = <span class="CharString">'</span><span class="CharString">0</span><span class="CharString">'</span>-<span class="CharString">'</span><span class="CharString">9</span><span class="CharString">'</span>;
+</pre>
+
+The meta language can describe other languages. Hence the word meta. (It is
+highly influenced by [META II](https://en.wikipedia.org/wiki/META_II).)
+
+The parsing begins at `main`. Here we say that the input is a sequence of
+`instruction` followed by the end of file. The end of file is detected by
+matching "not anything".
+
+Next we say that an `instruction` can either be `left` or `right` (checked in
+that order). They are matched by checking for the character `L`/`R` followed by
+a `number` and a newline. The `Reserved` and `RuleName` are names of highlight
+groups that should be used for the match.
+
+Then finally a `number` is one ore more `digit`. And a `digit` is any
+character in the range 0-9.
+
+Now that we have a parser for this language, we can open the input file in
+rlworkbench and it will highlight it like this:
+
+<pre class="highlight"><span class="Reserved">L</span><span class="Reserved">6</span><span class="Reserved">8</span><span class="Reserved">
+</span><span class="Reserved">L</span><span class="Reserved">3</span><span class="Reserved">0</span><span class="Reserved">
+</span><span class="RuleName">R</span><span class="RuleName">4</span><span class="RuleName">8</span><span class="RuleName">
+</span><span class="Reserved">L</span><span class="Reserved">5</span><span class="Reserved">
+</span><span class="RuleName">R</span><span class="RuleName">6</span><span class="RuleName">0</span><span class="RuleName">
+</span><span class="Reserved">L</span><span class="Reserved">5</span><span class="Reserved">5</span><span class="Reserved">
+</span><span class="Reserved">L</span><span class="Reserved">1</span><span class="Reserved">
+</span><span class="Reserved">L</span><span class="Reserved">9</span><span class="Reserved">9</span><span class="Reserved">
+</span><span class="RuleName">R</span><span class="RuleName">1</span><span class="RuleName">4</span><span class="RuleName">
+</span><span class="Reserved">L</span><span class="Reserved">8</span><span class="Reserved">2</span><span class="Reserved">
+</span></pre>
+
+Pretty cool. The highlighting can help you gain insight into the data. For
+example, you could quite quickly see the distribution of left and right turns.
+
+How can we make this run? Let's augment the parser with code generation
+instructions:
+
+<pre class="highlight"><span class="RuleName">m</span><span class="RuleName">a</span><span class="RuleName">i</span><span class="RuleName">n</span> = <span class="RuleName">i</span><span class="RuleName">n</span><span class="RuleName">s</span><span class="RuleName">t</span><span class="RuleName">r</span><span class="RuleName">u</span><span class="RuleName">c</span><span class="RuleName">t</span><span class="RuleName">i</span><span class="RuleName">o</span><span class="RuleName">n</span><span class="Reserved">*</span><span class="Reserved">:</span><span class="VariableName">x</span><span class="VariableName">s</span> <span class="Reserved">!</span><span class="Reserved">.</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> {
+    $dialSize
+    &gt;dialSize { <span class="String">&quot;</span><span class="String">1</span><span class="String">0</span><span class="String">0</span><span class="String">&quot;</span> }
+    <span class="String">&quot;</span><span class="String">#</span><span class="String">i</span><span class="String">n</span><span class="String">c</span><span class="String">l</span><span class="String">u</span><span class="String">d</span><span class="String">e</span><span class="String"> </span><span class="String">&lt;</span><span class="String">s</span><span class="String">t</span><span class="String">d</span><span class="String">i</span><span class="String">o</span><span class="String">.</span><span class="String">h</span><span class="String">&gt;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+    <span class="String">&quot;</span><span class="String">t</span><span class="String">y</span><span class="String">p</span><span class="String">e</span><span class="String">d</span><span class="String">e</span><span class="String">f</span><span class="String"> </span><span class="String">s</span><span class="String">t</span><span class="String">r</span><span class="String">u</span><span class="String">c</span><span class="String">t</span><span class="String"> </span><span class="String">{</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span> &gt;
+        <span class="String">&quot;</span><span class="String">u</span><span class="String">n</span><span class="String">s</span><span class="String">i</span><span class="String">g</span><span class="String">n</span><span class="String">e</span><span class="String">d</span><span class="String"> </span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String"> </span><span class="String">p</span><span class="String">o</span><span class="String">s</span><span class="String">i</span><span class="String">t</span><span class="String">i</span><span class="String">v</span><span class="String">e</span><span class="String">_</span><span class="String">o</span><span class="String">f</span><span class="String">f</span><span class="String">s</span><span class="String">e</span><span class="String">t</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+        <span class="String">&quot;</span><span class="String">u</span><span class="String">n</span><span class="String">s</span><span class="String">i</span><span class="String">g</span><span class="String">n</span><span class="String">e</span><span class="String">d</span><span class="String"> </span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String"> </span><span class="String">p</span><span class="String">a</span><span class="String">r</span><span class="String">t</span><span class="String">i</span><span class="String">a</span><span class="String">l</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+        <span class="String">&quot;</span><span class="String">u</span><span class="String">n</span><span class="String">s</span><span class="String">i</span><span class="String">g</span><span class="String">n</span><span class="String">e</span><span class="String">d</span><span class="String"> </span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String"> </span><span class="String">c</span><span class="String">o</span><span class="String">m</span><span class="String">p</span><span class="String">l</span><span class="String">e</span><span class="String">t</span><span class="String">e</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+    &lt; <span class="String">&quot;</span><span class="String">}</span><span class="String"> </span><span class="String">T</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+    <span class="String">&quot;</span><span class="String">s</span><span class="String">t</span><span class="String">a</span><span class="String">t</span><span class="String">i</span><span class="String">c</span><span class="String"> </span><span class="String">T</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String"> </span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String">s</span><span class="String">[</span><span class="String">]</span><span class="String"> </span><span class="String">=</span><span class="String"> </span><span class="String">{</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span> &gt;
+        <span class="VariableName">x</span><span class="VariableName">s</span>
+    &lt; <span class="String">&quot;</span><span class="String">}</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+    <span class="String">&quot;</span><span class="String">s</span><span class="String">t</span><span class="String">a</span><span class="String">t</span><span class="String">i</span><span class="String">c</span><span class="String"> </span><span class="String">u</span><span class="String">n</span><span class="String">s</span><span class="String">i</span><span class="String">g</span><span class="String">n</span><span class="String">e</span><span class="String">d</span><span class="String"> </span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String"> </span><span class="String">n</span><span class="String">u</span><span class="String">m</span><span class="String">b</span><span class="String">e</span><span class="String">r</span><span class="String">_</span><span class="String">o</span><span class="String">f</span><span class="String">_</span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String">s</span><span class="String"> </span><span class="String">=</span><span class="String"> </span><span class="String">&quot;</span> <span class="VariableName">x</span><span class="VariableName">s</span>.count <span class="String">&quot;</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+    <span class="String">&quot;</span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String"> </span><span class="String">m</span><span class="String">a</span><span class="String">i</span><span class="String">n</span><span class="String">(</span><span class="String">v</span><span class="String">o</span><span class="String">i</span><span class="String">d</span><span class="String">)</span><span class="String"> </span><span class="String">{</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span> &gt;
+        <span class="String">&quot;</span><span class="String">u</span><span class="String">n</span><span class="String">s</span><span class="String">i</span><span class="String">g</span><span class="String">n</span><span class="String">e</span><span class="String">d</span><span class="String"> </span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String"> </span><span class="String">d</span><span class="String">i</span><span class="String">a</span><span class="String">l</span><span class="String">_</span><span class="String">p</span><span class="String">o</span><span class="String">s</span><span class="String">i</span><span class="String">t</span><span class="String">i</span><span class="String">o</span><span class="String">n</span><span class="String"> </span><span class="String">=</span><span class="String"> </span><span class="String">5</span><span class="String">0</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+        <span class="String">&quot;</span><span class="String">u</span><span class="String">n</span><span class="String">s</span><span class="String">i</span><span class="String">g</span><span class="String">n</span><span class="String">e</span><span class="String">d</span><span class="String"> </span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String"> </span><span class="String">t</span><span class="String">i</span><span class="String">m</span><span class="String">e</span><span class="String">s</span><span class="String">_</span><span class="String">e</span><span class="String">n</span><span class="String">d</span><span class="String">e</span><span class="String">d</span><span class="String">_</span><span class="String">a</span><span class="String">t</span><span class="String">_</span><span class="String">z</span><span class="String">e</span><span class="String">r</span><span class="String">o</span><span class="String"> </span><span class="String">=</span><span class="String"> </span><span class="String">0</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+        <span class="String">&quot;</span><span class="String">u</span><span class="String">n</span><span class="String">s</span><span class="String">i</span><span class="String">g</span><span class="String">n</span><span class="String">e</span><span class="String">d</span><span class="String"> </span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String"> </span><span class="String">t</span><span class="String">i</span><span class="String">m</span><span class="String">e</span><span class="String">s</span><span class="String">_</span><span class="String">a</span><span class="String">t</span><span class="String">_</span><span class="String">z</span><span class="String">e</span><span class="String">r</span><span class="String">o</span><span class="String"> </span><span class="String">=</span><span class="String"> </span><span class="String">0</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+        <span class="String">&quot;</span><span class="String">u</span><span class="String">n</span><span class="String">s</span><span class="String">i</span><span class="String">g</span><span class="String">n</span><span class="String">e</span><span class="String">d</span><span class="String"> </span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String"> </span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String">_</span><span class="String">i</span><span class="String">n</span><span class="String">d</span><span class="String">e</span><span class="String">x</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+        <span class="String">&quot;</span><span class="String">u</span><span class="String">n</span><span class="String">s</span><span class="String">i</span><span class="String">g</span><span class="String">n</span><span class="String">e</span><span class="String">d</span><span class="String"> </span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String"> </span><span class="String">p</span><span class="String">a</span><span class="String">r</span><span class="String">t</span><span class="String">i</span><span class="String">a</span><span class="String">l</span><span class="String">_</span><span class="String">c</span><span class="String">o</span><span class="String">u</span><span class="String">n</span><span class="String">t</span><span class="String">e</span><span class="String">r</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+        <span class="String">&quot;</span><span class="String">f</span><span class="String">o</span><span class="String">r</span><span class="String">(</span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String">_</span><span class="String">i</span><span class="String">n</span><span class="String">d</span><span class="String">e</span><span class="String">x</span><span class="String">=</span><span class="String">0</span><span class="String">;</span><span class="String"> </span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String">_</span><span class="String">i</span><span class="String">n</span><span class="String">d</span><span class="String">e</span><span class="String">x</span><span class="String">&lt;</span><span class="String">n</span><span class="String">u</span><span class="String">m</span><span class="String">b</span><span class="String">e</span><span class="String">r</span><span class="String">_</span><span class="String">o</span><span class="String">f</span><span class="String">_</span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String">s</span><span class="String">;</span><span class="String"> </span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String">_</span><span class="String">i</span><span class="String">n</span><span class="String">d</span><span class="String">e</span><span class="String">x</span><span class="String">+</span><span class="String">+</span><span class="String">)</span><span class="String"> </span><span class="String">{</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span> &gt;
+            <span class="String">&quot;</span><span class="String">f</span><span class="String">o</span><span class="String">r</span><span class="String">(</span><span class="String">p</span><span class="String">a</span><span class="String">r</span><span class="String">t</span><span class="String">i</span><span class="String">a</span><span class="String">l</span><span class="String">_</span><span class="String">c</span><span class="String">o</span><span class="String">u</span><span class="String">n</span><span class="String">t</span><span class="String">e</span><span class="String">r</span><span class="String">=</span><span class="String">0</span><span class="String">;</span><span class="String"> </span><span class="String">p</span><span class="String">a</span><span class="String">r</span><span class="String">t</span><span class="String">i</span><span class="String">a</span><span class="String">l</span><span class="String">_</span><span class="String">c</span><span class="String">o</span><span class="String">u</span><span class="String">n</span><span class="String">t</span><span class="String">e</span><span class="String">r</span><span class="String">&lt;</span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String">s</span><span class="String">[</span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String">_</span><span class="String">i</span><span class="String">n</span><span class="String">d</span><span class="String">e</span><span class="String">x</span><span class="String">]</span><span class="String">.</span><span class="String">p</span><span class="String">a</span><span class="String">r</span><span class="String">t</span><span class="String">i</span><span class="String">a</span><span class="String">l</span><span class="String">;</span><span class="String"> </span><span class="String">p</span><span class="String">a</span><span class="String">r</span><span class="String">t</span><span class="String">i</span><span class="String">a</span><span class="String">l</span><span class="String">_</span><span class="String">c</span><span class="String">o</span><span class="String">u</span><span class="String">n</span><span class="String">t</span><span class="String">e</span><span class="String">r</span><span class="String">+</span><span class="String">+</span><span class="String">)</span><span class="String"> </span><span class="String">{</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span> &gt;
+                <span class="String">&quot;</span><span class="String">d</span><span class="String">i</span><span class="String">a</span><span class="String">l</span><span class="String">_</span><span class="String">p</span><span class="String">o</span><span class="String">s</span><span class="String">i</span><span class="String">t</span><span class="String">i</span><span class="String">o</span><span class="String">n</span><span class="String"> </span><span class="String">+</span><span class="String">=</span><span class="String"> </span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String">s</span><span class="String">[</span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String">_</span><span class="String">i</span><span class="String">n</span><span class="String">d</span><span class="String">e</span><span class="String">x</span><span class="String">]</span><span class="String">.</span><span class="String">p</span><span class="String">o</span><span class="String">s</span><span class="String">i</span><span class="String">t</span><span class="String">i</span><span class="String">v</span><span class="String">e</span><span class="String">_</span><span class="String">o</span><span class="String">f</span><span class="String">f</span><span class="String">s</span><span class="String">e</span><span class="String">t</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+                <span class="String">&quot;</span><span class="String">d</span><span class="String">i</span><span class="String">a</span><span class="String">l</span><span class="String">_</span><span class="String">p</span><span class="String">o</span><span class="String">s</span><span class="String">i</span><span class="String">t</span><span class="String">i</span><span class="String">o</span><span class="String">n</span><span class="String"> </span><span class="String">%</span><span class="String">=</span><span class="String"> </span><span class="String">&quot;</span> &lt;dialSize <span class="String">&quot;</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+                <span class="String">&quot;</span><span class="String">i</span><span class="String">f</span><span class="String"> </span><span class="String">(</span><span class="String">d</span><span class="String">i</span><span class="String">a</span><span class="String">l</span><span class="String">_</span><span class="String">p</span><span class="String">o</span><span class="String">s</span><span class="String">i</span><span class="String">t</span><span class="String">i</span><span class="String">o</span><span class="String">n</span><span class="String"> </span><span class="String">=</span><span class="String">=</span><span class="String"> </span><span class="String">0</span><span class="String">)</span><span class="String"> </span><span class="String">{</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span> &gt;
+                    <span class="String">&quot;</span><span class="String">t</span><span class="String">i</span><span class="String">m</span><span class="String">e</span><span class="String">s</span><span class="String">_</span><span class="String">a</span><span class="String">t</span><span class="String">_</span><span class="String">z</span><span class="String">e</span><span class="String">r</span><span class="String">o</span><span class="String"> </span><span class="String">+</span><span class="String">=</span><span class="String"> </span><span class="String">1</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+                &lt; <span class="String">&quot;</span><span class="String">}</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+            &lt; <span class="String">&quot;</span><span class="String">}</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+            <span class="String">&quot;</span><span class="String">i</span><span class="String">f</span><span class="String"> </span><span class="String">(</span><span class="String">d</span><span class="String">i</span><span class="String">a</span><span class="String">l</span><span class="String">_</span><span class="String">p</span><span class="String">o</span><span class="String">s</span><span class="String">i</span><span class="String">t</span><span class="String">i</span><span class="String">o</span><span class="String">n</span><span class="String"> </span><span class="String">=</span><span class="String">=</span><span class="String"> </span><span class="String">0</span><span class="String">)</span><span class="String"> </span><span class="String">{</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span> &gt;
+                <span class="String">&quot;</span><span class="String">t</span><span class="String">i</span><span class="String">m</span><span class="String">e</span><span class="String">s</span><span class="String">_</span><span class="String">e</span><span class="String">n</span><span class="String">d</span><span class="String">e</span><span class="String">d</span><span class="String">_</span><span class="String">a</span><span class="String">t</span><span class="String">_</span><span class="String">z</span><span class="String">e</span><span class="String">r</span><span class="String">o</span><span class="String"> </span><span class="String">+</span><span class="String">=</span><span class="String"> </span><span class="String">1</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+            &lt; <span class="String">&quot;</span><span class="String">}</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+            <span class="String">&quot;</span><span class="String">t</span><span class="String">i</span><span class="String">m</span><span class="String">e</span><span class="String">s</span><span class="String">_</span><span class="String">a</span><span class="String">t</span><span class="String">_</span><span class="String">z</span><span class="String">e</span><span class="String">r</span><span class="String">o</span><span class="String"> </span><span class="String">+</span><span class="String">=</span><span class="String"> </span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String">s</span><span class="String">[</span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String">_</span><span class="String">i</span><span class="String">n</span><span class="String">d</span><span class="String">e</span><span class="String">x</span><span class="String">]</span><span class="String">.</span><span class="String">c</span><span class="String">o</span><span class="String">m</span><span class="String">p</span><span class="String">l</span><span class="String">e</span><span class="String">t</span><span class="String">e</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+        &lt; <span class="String">&quot;</span><span class="String">}</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+        <span class="String">&quot;</span><span class="String">p</span><span class="String">r</span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String">f</span><span class="String">(</span><span class="Escape">\</span><span class="Escape">&quot;</span><span class="String">P</span><span class="String">a</span><span class="String">r</span><span class="String">t</span><span class="String"> </span><span class="String">1</span><span class="String">:</span><span class="String"> </span><span class="String">%</span><span class="String">d</span><span class="Escape">\</span><span class="Escape">\</span><span class="String">n</span><span class="Escape">\</span><span class="Escape">&quot;</span><span class="String">,</span><span class="String"> </span><span class="String">t</span><span class="String">i</span><span class="String">m</span><span class="String">e</span><span class="String">s</span><span class="String">_</span><span class="String">e</span><span class="String">n</span><span class="String">d</span><span class="String">e</span><span class="String">d</span><span class="String">_</span><span class="String">a</span><span class="String">t</span><span class="String">_</span><span class="String">z</span><span class="String">e</span><span class="String">r</span><span class="String">o</span><span class="String">)</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+        <span class="String">&quot;</span><span class="String">p</span><span class="String">r</span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String">f</span><span class="String">(</span><span class="Escape">\</span><span class="Escape">&quot;</span><span class="String">P</span><span class="String">a</span><span class="String">r</span><span class="String">t</span><span class="String"> </span><span class="String">2</span><span class="String">:</span><span class="String"> </span><span class="String">%</span><span class="String">d</span><span class="Escape">\</span><span class="Escape">\</span><span class="String">n</span><span class="Escape">\</span><span class="Escape">&quot;</span><span class="String">,</span><span class="String"> </span><span class="String">t</span><span class="String">i</span><span class="String">m</span><span class="String">e</span><span class="String">s</span><span class="String">_</span><span class="String">a</span><span class="String">t</span><span class="String">_</span><span class="String">z</span><span class="String">e</span><span class="String">r</span><span class="String">o</span><span class="String">)</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+        <span class="String">&quot;</span><span class="String">r</span><span class="String">e</span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String"> </span><span class="String">0</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+    &lt; <span class="String">&quot;</span><span class="String">}</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+};
+
+<span class="RuleName">i</span><span class="RuleName">n</span><span class="RuleName">s</span><span class="RuleName">t</span><span class="RuleName">r</span><span class="RuleName">u</span><span class="RuleName">c</span><span class="RuleName">t</span><span class="RuleName">i</span><span class="RuleName">o</span><span class="RuleName">n</span> =
+    <span class="Reserved">|</span> <span class="RuleName">l</span><span class="RuleName">e</span><span class="RuleName">f</span><span class="RuleName">t</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> }
+    <span class="Reserved">|</span> <span class="RuleName">r</span><span class="RuleName">i</span><span class="RuleName">g</span><span class="RuleName">h</span><span class="RuleName">t</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> }
+    ;
+
+<span class="RuleName">l</span><span class="RuleName">e</span><span class="RuleName">f</span><span class="RuleName">t</span>[<span class="Meta">R</span><span class="Meta">e</span><span class="Meta">s</span><span class="Meta">e</span><span class="Meta">r</span><span class="Meta">v</span><span class="Meta">e</span><span class="Meta">d</span>] = <span class="CharString">'</span><span class="CharString">L</span><span class="CharString">'</span> <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="CharString">'</span><span class="Escape">\</span><span class="Escape">n</span><span class="CharString">'</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> {
+    <span class="String">&quot;</span><span class="String">{</span><span class="String">&quot;</span> &lt;dialSize <span class="String">&quot;</span><span class="String">-</span><span class="String">1</span><span class="String">,</span><span class="String"> </span><span class="String">&quot;</span> <span class="VariableName">x</span> <span class="String">&quot;</span><span class="String">%</span><span class="String">&quot;</span> &lt;dialSize <span class="String">&quot;</span><span class="String">,</span><span class="String"> </span><span class="String">&quot;</span> <span class="VariableName">x</span> <span class="String">&quot;</span><span class="String">/</span><span class="String">&quot;</span> &lt;dialSize <span class="String">&quot;</span><span class="String">}</span><span class="String">,</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+};
+
+<span class="RuleName">r</span><span class="RuleName">i</span><span class="RuleName">g</span><span class="RuleName">h</span><span class="RuleName">t</span>[<span class="Meta">R</span><span class="Meta">u</span><span class="Meta">l</span><span class="Meta">e</span><span class="Meta">N</span><span class="Meta">a</span><span class="Meta">m</span><span class="Meta">e</span>] = <span class="CharString">'</span><span class="CharString">R</span><span class="CharString">'</span> <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="CharString">'</span><span class="Escape">\</span><span class="Escape">n</span><span class="CharString">'</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> {
+    <span class="String">&quot;</span><span class="String">{</span><span class="String">1</span><span class="String">,</span><span class="String"> </span><span class="String">&quot;</span> <span class="VariableName">x</span> <span class="String">&quot;</span><span class="String">%</span><span class="String">&quot;</span> &lt;dialSize <span class="String">&quot;</span><span class="String">,</span><span class="String"> </span><span class="String">&quot;</span> <span class="VariableName">x</span> <span class="String">&quot;</span><span class="String">/</span><span class="String">&quot;</span> &lt;dialSize <span class="String">&quot;</span><span class="String">}</span><span class="String">,</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+};
+
+<span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> = <span class="RuleName">d</span><span class="RuleName">i</span><span class="RuleName">g</span><span class="RuleName">i</span><span class="RuleName">t</span> <span class="RuleName">d</span><span class="RuleName">i</span><span class="RuleName">g</span><span class="RuleName">i</span><span class="RuleName">t</span><span class="Reserved">*</span>;
+
+<span class="RuleName">d</span><span class="RuleName">i</span><span class="RuleName">g</span><span class="RuleName">i</span><span class="RuleName">t</span> = <span class="CharString">'</span><span class="CharString">0</span><span class="CharString">'</span>-<span class="CharString">'</span><span class="CharString">9</span><span class="CharString">'</span>;
+</pre>
+
+In the meta language, we can add semantic actions to rules with the ` -> { ...
+}` syntax. It specifies what should be generated when this rule is matched. We
+can bind sub matches to variables using the `<expression>:<name>` syntax.
+
+When we generate code for the example, we get this C program:
+
+<pre class="highlight"><span class="CharString">#</span><span class="CharString">i</span><span class="CharString">n</span><span class="CharString">c</span><span class="CharString">l</span><span class="CharString">u</span><span class="CharString">d</span><span class="CharString">e</span><span class="CharString"> </span><span class="CharString">&lt;</span><span class="CharString">s</span><span class="CharString">t</span><span class="CharString">d</span><span class="CharString">i</span><span class="CharString">o</span><span class="CharString">.</span><span class="CharString">h</span><span class="CharString">&gt;</span><span class="CharString">
+</span><span class="VariableName">t</span><span class="VariableName">y</span><span class="VariableName">p</span><span class="VariableName">e</span><span class="VariableName">d</span><span class="VariableName">e</span><span class="VariableName">f</span> <span class="VariableName">s</span><span class="VariableName">t</span><span class="VariableName">r</span><span class="VariableName">u</span><span class="VariableName">c</span><span class="VariableName">t</span> {
+    <span class="VariableName">u</span><span class="VariableName">n</span><span class="VariableName">s</span><span class="VariableName">i</span><span class="VariableName">g</span><span class="VariableName">n</span><span class="VariableName">e</span><span class="VariableName">d</span> <span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> positive_offset;
+    <span class="VariableName">u</span><span class="VariableName">n</span><span class="VariableName">s</span><span class="VariableName">i</span><span class="VariableName">g</span><span class="VariableName">n</span><span class="VariableName">e</span><span class="VariableName">d</span> <span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> partial;
+    <span class="VariableName">u</span><span class="VariableName">n</span><span class="VariableName">s</span><span class="VariableName">i</span><span class="VariableName">g</span><span class="VariableName">n</span><span class="VariableName">e</span><span class="VariableName">d</span> <span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> complete;
+} Turn;
+<span class="VariableName">s</span><span class="VariableName">t</span><span class="VariableName">a</span><span class="VariableName">t</span><span class="VariableName">i</span><span class="VariableName">c</span> Turn turns[] = {
+    {<span class="String">1</span><span class="String">0</span><span class="String">0</span>-<span class="String">1</span>, <span class="String">6</span><span class="String">8</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">6</span><span class="String">8</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span><span class="String">0</span><span class="String">0</span>-<span class="String">1</span>, <span class="String">3</span><span class="String">0</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">3</span><span class="String">0</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span>, <span class="String">4</span><span class="String">8</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">4</span><span class="String">8</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span><span class="String">0</span><span class="String">0</span>-<span class="String">1</span>, <span class="String">5</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">5</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span>, <span class="String">6</span><span class="String">0</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">6</span><span class="String">0</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span><span class="String">0</span><span class="String">0</span>-<span class="String">1</span>, <span class="String">5</span><span class="String">5</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">5</span><span class="String">5</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span><span class="String">0</span><span class="String">0</span>-<span class="String">1</span>, <span class="String">1</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">1</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span><span class="String">0</span><span class="String">0</span>-<span class="String">1</span>, <span class="String">9</span><span class="String">9</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">9</span><span class="String">9</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span>, <span class="String">1</span><span class="String">4</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">1</span><span class="String">4</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span><span class="String">0</span><span class="String">0</span>-<span class="String">1</span>, <span class="String">8</span><span class="String">2</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">8</span><span class="String">2</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+};
+<span class="VariableName">s</span><span class="VariableName">t</span><span class="VariableName">a</span><span class="VariableName">t</span><span class="VariableName">i</span><span class="VariableName">c</span> <span class="VariableName">u</span><span class="VariableName">n</span><span class="VariableName">s</span><span class="VariableName">i</span><span class="VariableName">g</span><span class="VariableName">n</span><span class="VariableName">e</span><span class="VariableName">d</span> <span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> number_of_turns = <span class="String">1</span><span class="String">0</span>;
+<span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> main(<span class="VariableName">v</span><span class="VariableName">o</span><span class="VariableName">i</span><span class="VariableName">d</span>) {
+    <span class="VariableName">u</span><span class="VariableName">n</span><span class="VariableName">s</span><span class="VariableName">i</span><span class="VariableName">g</span><span class="VariableName">n</span><span class="VariableName">e</span><span class="VariableName">d</span> <span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> dial_position = <span class="String">5</span><span class="String">0</span>;
+    <span class="VariableName">u</span><span class="VariableName">n</span><span class="VariableName">s</span><span class="VariableName">i</span><span class="VariableName">g</span><span class="VariableName">n</span><span class="VariableName">e</span><span class="VariableName">d</span> <span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> times_ended_at_zero = <span class="String">0</span>;
+    <span class="VariableName">u</span><span class="VariableName">n</span><span class="VariableName">s</span><span class="VariableName">i</span><span class="VariableName">g</span><span class="VariableName">n</span><span class="VariableName">e</span><span class="VariableName">d</span> <span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> times_at_zero = <span class="String">0</span>;
+    <span class="VariableName">u</span><span class="VariableName">n</span><span class="VariableName">s</span><span class="VariableName">i</span><span class="VariableName">g</span><span class="VariableName">n</span><span class="VariableName">e</span><span class="VariableName">d</span> <span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> turn_index;
+    <span class="VariableName">u</span><span class="VariableName">n</span><span class="VariableName">s</span><span class="VariableName">i</span><span class="VariableName">g</span><span class="VariableName">n</span><span class="VariableName">e</span><span class="VariableName">d</span> <span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> partial_counter;
+    <span class="Reserved">f</span><span class="Reserved">o</span><span class="Reserved">r</span>(turn_index=<span class="String">0</span>; turn_index&lt;number_of_turns; turn_index++) {
+        <span class="Reserved">f</span><span class="Reserved">o</span><span class="Reserved">r</span>(partial_counter=<span class="String">0</span>; partial_counter&lt;turns[turn_index].partial; partial_counter++) {
+            dial_position += turns[turn_index].positive_offset;
+            dial_position %= <span class="String">1</span><span class="String">0</span><span class="String">0</span>;
+            <span class="Reserved">i</span><span class="Reserved">f</span> (dial_position == <span class="String">0</span>) {
+                times_at_zero += <span class="String">1</span>;
+            }
+        }
+        <span class="Reserved">i</span><span class="Reserved">f</span> (dial_position == <span class="String">0</span>) {
+            times_ended_at_zero += <span class="String">1</span>;
+        }
+        times_at_zero += turns[turn_index].complete;
+    }
+    printf(<span class="String">&quot;</span><span class="String">P</span><span class="String">a</span><span class="String">r</span><span class="String">t</span><span class="String"> </span><span class="String">1</span><span class="String">:</span><span class="String"> </span><span class="String">%</span><span class="String">d</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>, times_ended_at_zero);
+    printf(<span class="String">&quot;</span><span class="String">P</span><span class="String">a</span><span class="String">r</span><span class="String">t</span><span class="String"> </span><span class="String">2</span><span class="String">:</span><span class="String"> </span><span class="String">%</span><span class="String">d</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>, times_at_zero);
+    <span class="Reserved">r</span><span class="Reserved">e</span><span class="Reserved">t</span><span class="Reserved">u</span><span class="Reserved">r</span><span class="Reserved">n</span> <span class="String">0</span>;
+}
+</pre>
+
+So the majority of the code generation is outputting static C code. The most
+"dynamic" part is this:
+
+<pre class="highlight"><span class="VariableName">s</span><span class="VariableName">t</span><span class="VariableName">a</span><span class="VariableName">t</span><span class="VariableName">i</span><span class="VariableName">c</span> Turn turns[] = {
+    {<span class="String">1</span><span class="String">0</span><span class="String">0</span>-<span class="String">1</span>, <span class="String">6</span><span class="String">8</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">6</span><span class="String">8</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span><span class="String">0</span><span class="String">0</span>-<span class="String">1</span>, <span class="String">3</span><span class="String">0</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">3</span><span class="String">0</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span>, <span class="String">4</span><span class="String">8</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">4</span><span class="String">8</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span><span class="String">0</span><span class="String">0</span>-<span class="String">1</span>, <span class="String">5</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">5</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span>, <span class="String">6</span><span class="String">0</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">6</span><span class="String">0</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span><span class="String">0</span><span class="String">0</span>-<span class="String">1</span>, <span class="String">5</span><span class="String">5</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">5</span><span class="String">5</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span><span class="String">0</span><span class="String">0</span>-<span class="String">1</span>, <span class="String">1</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">1</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span><span class="String">0</span><span class="String">0</span>-<span class="String">1</span>, <span class="String">9</span><span class="String">9</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">9</span><span class="String">9</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span>, <span class="String">1</span><span class="String">4</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">1</span><span class="String">4</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+    {<span class="String">1</span><span class="String">0</span><span class="String">0</span>-<span class="String">1</span>, <span class="String">8</span><span class="String">2</span>%<span class="String">1</span><span class="String">0</span><span class="String">0</span>, <span class="String">8</span><span class="String">2</span>/<span class="String">1</span><span class="String">0</span><span class="String">0</span>},
+};
+<span class="VariableName">s</span><span class="VariableName">t</span><span class="VariableName">a</span><span class="VariableName">t</span><span class="VariableName">i</span><span class="VariableName">c</span> <span class="VariableName">u</span><span class="VariableName">n</span><span class="VariableName">s</span><span class="VariableName">i</span><span class="VariableName">g</span><span class="VariableName">n</span><span class="VariableName">e</span><span class="VariableName">d</span> <span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> number_of_turns = <span class="String">1</span><span class="String">0</span>;
+</pre>
+
+The code generator transforms the input into a data structure in C that is easy
+to work with.  We could have generated just this part and then written the rest
+of the C code outside the meta language. It wouldn't exactly work in this case
+because the `dialSize` is used as a variable in the meta language. But we could
+have generated a constant in C with this value. But for the purposes of this
+year's Advent of Code puzzles, I chose to write all C code in the meta
+language. The meta language is implemented in itself and it generates more
+complicated C code than this example. So writing C code in the meta language
+code generation part is an actual use case and if it's not easy to do, we
+should make it easier.  After all, we are in complete control of how the meta
+language works.
+
+I actually struggled to solve day 1. Not because of the new approach with meta
+and not because of C which is a new language for me. The main struggle I had
+was that I didn't want to do the inner loop at first. I thought it would be too
+wasteful. And then I couldn't get all arithmetic right. I actually looked up
+other solutions for part 2. Then I decided to just implement the inner loop and
+it worked fine.
+
+From today's puzzle, I also learned that the `%` operator works differently in
+C and Python.
+
+In C:
+
+     7 % 5 => 2
+    -7 % 5 => -2
+
+In Python:
+
+     7 % 5 => 2
+    -7 % 5 => 3
+
+Furthermore I learned that the behavior in C89 could differ between
+implementations if negative operators are used. That's why I wanted to use
+unsigned numbers in my implementation. Because those I could reason about.
+
+## Day 2
+
+I got to practice string manipulation code in C. Like this for example. Nice!
+
+<pre class="highlight"><span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> eq(<span class="VariableName">c</span><span class="VariableName">h</span><span class="VariableName">a</span><span class="VariableName">r</span>* one, <span class="VariableName">c</span><span class="VariableName">h</span><span class="VariableName">a</span><span class="VariableName">r</span>* two, size_t len) {
+    <span class="Reserved">w</span><span class="Reserved">h</span><span class="Reserved">i</span><span class="Reserved">l</span><span class="Reserved">e</span> (len &gt; <span class="String">0</span>) {
+        <span class="Reserved">i</span><span class="Reserved">f</span> (*one != *two) {
+            <span class="Reserved">r</span><span class="Reserved">e</span><span class="Reserved">t</span><span class="Reserved">u</span><span class="Reserved">r</span><span class="Reserved">n</span> <span class="String">0</span>;
+        };
+        one++;
+        two++;
+        len--;
+    }
+    <span class="Reserved">r</span><span class="Reserved">e</span><span class="Reserved">t</span><span class="Reserved">u</span><span class="Reserved">r</span><span class="Reserved">n</span> <span class="String">1</span>;
+}
+</pre>
+
+## Day 3
+
+This was probably one of the more fun days for me because I was able to solve
+the puzzle almost entirely in the meta language. Here is the solution for part
+1:
+
+<pre class="highlight"><span class="RuleName">m</span><span class="RuleName">a</span><span class="RuleName">i</span><span class="RuleName">n</span> = <span class="RuleName">b</span><span class="RuleName">a</span><span class="RuleName">n</span><span class="RuleName">k</span><span class="RuleName">2</span><span class="Reserved">*</span><span class="Reserved">:</span><span class="VariableName">x</span><span class="VariableName">s</span> <span class="Reserved">!</span><span class="Reserved">.</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> {
+    <span class="String">&quot;</span><span class="String">#</span><span class="String">i</span><span class="String">n</span><span class="String">c</span><span class="String">l</span><span class="String">u</span><span class="String">d</span><span class="String">e</span><span class="String"> </span><span class="String">&lt;</span><span class="String">s</span><span class="String">t</span><span class="String">d</span><span class="String">i</span><span class="String">o</span><span class="String">.</span><span class="String">h</span><span class="String">&gt;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+    <span class="String">&quot;</span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String"> </span><span class="String">m</span><span class="String">a</span><span class="String">i</span><span class="String">n</span><span class="String">(</span><span class="String">v</span><span class="String">o</span><span class="String">i</span><span class="String">d</span><span class="String">)</span><span class="String"> </span><span class="String">{</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span> &gt;
+        <span class="String">&quot;</span><span class="String">p</span><span class="String">r</span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String">f</span><span class="String">(</span><span class="Escape">\</span><span class="Escape">&quot;</span><span class="String">P</span><span class="String">a</span><span class="String">r</span><span class="String">t</span><span class="String"> </span><span class="String">1</span><span class="String">:</span><span class="String"> </span><span class="String">%</span><span class="String">l</span><span class="String">d</span><span class="Escape">\</span><span class="Escape">\</span><span class="String">n</span><span class="Escape">\</span><span class="Escape">&quot;</span><span class="String">,</span><span class="String"> </span><span class="String">(</span><span class="String">l</span><span class="String">o</span><span class="String">n</span><span class="String">g</span><span class="String"> </span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String">)</span><span class="String">(</span><span class="String">0</span><span class="String">&quot;</span> <span class="VariableName">x</span><span class="VariableName">s</span> <span class="String">&quot;</span><span class="String">)</span><span class="String">)</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+        <span class="String">&quot;</span><span class="String">r</span><span class="String">e</span><span class="String">t</span><span class="String">u</span><span class="String">r</span><span class="String">n</span><span class="String"> </span><span class="String">0</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+    &lt; <span class="String">&quot;</span><span class="String">}</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+};
+
+<span class="RuleName">b</span><span class="RuleName">a</span><span class="RuleName">n</span><span class="RuleName">k</span><span class="RuleName">2</span> = <span class="RuleName">j</span><span class="RuleName">o</span><span class="RuleName">l</span><span class="RuleName">t</span><span class="RuleName">a</span><span class="RuleName">g</span><span class="RuleName">e</span><span class="RuleName">2</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span><span class="Reserved">*</span> <span class="CharString">'</span><span class="Escape">\</span><span class="Escape">n</span><span class="CharString">'</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="String">&quot;</span><span class="String"> </span><span class="String">+</span><span class="String"> </span><span class="String">&quot;</span> <span class="VariableName">x</span> };
+
+<span class="RuleName">j</span><span class="RuleName">o</span><span class="RuleName">l</span><span class="RuleName">t</span><span class="RuleName">a</span><span class="RuleName">g</span><span class="RuleName">e</span><span class="RuleName">2</span> =
+    <span class="Reserved">|</span> <span class="RuleName">n</span><span class="RuleName">i</span><span class="RuleName">n</span><span class="RuleName">e</span><span class="Reserved">:</span><span class="VariableName">x</span>  <span class="RuleName">j</span><span class="RuleName">o</span><span class="RuleName">l</span><span class="RuleName">t</span><span class="RuleName">a</span><span class="RuleName">g</span><span class="RuleName">e</span><span class="RuleName">1</span><span class="Reserved">:</span><span class="VariableName">y</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> <span class="VariableName">y</span> }
+    <span class="Reserved">|</span> <span class="RuleName">e</span><span class="RuleName">i</span><span class="RuleName">g</span><span class="RuleName">h</span><span class="RuleName">t</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="RuleName">j</span><span class="RuleName">o</span><span class="RuleName">l</span><span class="RuleName">t</span><span class="RuleName">a</span><span class="RuleName">g</span><span class="RuleName">e</span><span class="RuleName">1</span><span class="Reserved">:</span><span class="VariableName">y</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> <span class="VariableName">y</span> }
+    <span class="Reserved">|</span> <span class="RuleName">s</span><span class="RuleName">e</span><span class="RuleName">v</span><span class="RuleName">e</span><span class="RuleName">n</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="RuleName">j</span><span class="RuleName">o</span><span class="RuleName">l</span><span class="RuleName">t</span><span class="RuleName">a</span><span class="RuleName">g</span><span class="RuleName">e</span><span class="RuleName">1</span><span class="Reserved">:</span><span class="VariableName">y</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> <span class="VariableName">y</span> }
+    <span class="Reserved">|</span> <span class="RuleName">s</span><span class="RuleName">i</span><span class="RuleName">x</span><span class="Reserved">:</span><span class="VariableName">x</span>   <span class="RuleName">j</span><span class="RuleName">o</span><span class="RuleName">l</span><span class="RuleName">t</span><span class="RuleName">a</span><span class="RuleName">g</span><span class="RuleName">e</span><span class="RuleName">1</span><span class="Reserved">:</span><span class="VariableName">y</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> <span class="VariableName">y</span> }
+    <span class="Reserved">|</span> <span class="RuleName">f</span><span class="RuleName">i</span><span class="RuleName">v</span><span class="RuleName">e</span><span class="Reserved">:</span><span class="VariableName">x</span>  <span class="RuleName">j</span><span class="RuleName">o</span><span class="RuleName">l</span><span class="RuleName">t</span><span class="RuleName">a</span><span class="RuleName">g</span><span class="RuleName">e</span><span class="RuleName">1</span><span class="Reserved">:</span><span class="VariableName">y</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> <span class="VariableName">y</span> }
+    <span class="Reserved">|</span> <span class="RuleName">f</span><span class="RuleName">o</span><span class="RuleName">u</span><span class="RuleName">r</span><span class="Reserved">:</span><span class="VariableName">x</span>  <span class="RuleName">j</span><span class="RuleName">o</span><span class="RuleName">l</span><span class="RuleName">t</span><span class="RuleName">a</span><span class="RuleName">g</span><span class="RuleName">e</span><span class="RuleName">1</span><span class="Reserved">:</span><span class="VariableName">y</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> <span class="VariableName">y</span> }
+    <span class="Reserved">|</span> <span class="RuleName">t</span><span class="RuleName">h</span><span class="RuleName">r</span><span class="RuleName">e</span><span class="RuleName">e</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="RuleName">j</span><span class="RuleName">o</span><span class="RuleName">l</span><span class="RuleName">t</span><span class="RuleName">a</span><span class="RuleName">g</span><span class="RuleName">e</span><span class="RuleName">1</span><span class="Reserved">:</span><span class="VariableName">y</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> <span class="VariableName">y</span> }
+    <span class="Reserved">|</span> <span class="RuleName">t</span><span class="RuleName">w</span><span class="RuleName">o</span><span class="Reserved">:</span><span class="VariableName">x</span>   <span class="RuleName">j</span><span class="RuleName">o</span><span class="RuleName">l</span><span class="RuleName">t</span><span class="RuleName">a</span><span class="RuleName">g</span><span class="RuleName">e</span><span class="RuleName">1</span><span class="Reserved">:</span><span class="VariableName">y</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> <span class="VariableName">y</span> }
+    <span class="Reserved">|</span> <span class="RuleName">o</span><span class="RuleName">n</span><span class="RuleName">e</span><span class="Reserved">:</span><span class="VariableName">x</span>   <span class="RuleName">j</span><span class="RuleName">o</span><span class="RuleName">l</span><span class="RuleName">t</span><span class="RuleName">a</span><span class="RuleName">g</span><span class="RuleName">e</span><span class="RuleName">1</span><span class="Reserved">:</span><span class="VariableName">y</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> <span class="VariableName">y</span> }
+    ;
+
+<span class="RuleName">j</span><span class="RuleName">o</span><span class="RuleName">l</span><span class="RuleName">t</span><span class="RuleName">a</span><span class="RuleName">g</span><span class="RuleName">e</span><span class="RuleName">1</span> =
+    <span class="Reserved">|</span> <span class="RuleName">n</span><span class="RuleName">i</span><span class="RuleName">n</span><span class="RuleName">e</span><span class="Reserved">:</span><span class="VariableName">x</span>  <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> }
+    <span class="Reserved">|</span> <span class="RuleName">e</span><span class="RuleName">i</span><span class="RuleName">g</span><span class="RuleName">h</span><span class="RuleName">t</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> }
+    <span class="Reserved">|</span> <span class="RuleName">s</span><span class="RuleName">e</span><span class="RuleName">v</span><span class="RuleName">e</span><span class="RuleName">n</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> }
+    <span class="Reserved">|</span> <span class="RuleName">s</span><span class="RuleName">i</span><span class="RuleName">x</span><span class="Reserved">:</span><span class="VariableName">x</span>   <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> }
+    <span class="Reserved">|</span> <span class="RuleName">f</span><span class="RuleName">i</span><span class="RuleName">v</span><span class="RuleName">e</span><span class="Reserved">:</span><span class="VariableName">x</span>  <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> }
+    <span class="Reserved">|</span> <span class="RuleName">f</span><span class="RuleName">o</span><span class="RuleName">u</span><span class="RuleName">r</span><span class="Reserved">:</span><span class="VariableName">x</span>  <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> }
+    <span class="Reserved">|</span> <span class="RuleName">t</span><span class="RuleName">h</span><span class="RuleName">r</span><span class="RuleName">e</span><span class="RuleName">e</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> }
+    <span class="Reserved">|</span> <span class="RuleName">t</span><span class="RuleName">w</span><span class="RuleName">o</span><span class="Reserved">:</span><span class="VariableName">x</span>   <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> }
+    <span class="Reserved">|</span> <span class="RuleName">o</span><span class="RuleName">n</span><span class="RuleName">e</span><span class="Reserved">:</span><span class="VariableName">x</span>   <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> }
+    ;
+
+<span class="RuleName">n</span><span class="RuleName">i</span><span class="RuleName">n</span><span class="RuleName">e</span>  = <span class="Reserved">&amp;</span><span class="CharString">'</span><span class="CharString">9</span><span class="CharString">'</span> <span class="RuleName">h</span><span class="RuleName">i</span><span class="RuleName">t</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> } <span class="Reserved">|</span> <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> <span class="RuleName">n</span><span class="RuleName">i</span><span class="RuleName">n</span><span class="RuleName">e</span><span class="Reserved">:</span><span class="VariableName">x</span>  <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> };
+<span class="RuleName">e</span><span class="RuleName">i</span><span class="RuleName">g</span><span class="RuleName">h</span><span class="RuleName">t</span> = <span class="Reserved">&amp;</span><span class="CharString">'</span><span class="CharString">8</span><span class="CharString">'</span> <span class="RuleName">h</span><span class="RuleName">i</span><span class="RuleName">t</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> } <span class="Reserved">|</span> <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> <span class="RuleName">e</span><span class="RuleName">i</span><span class="RuleName">g</span><span class="RuleName">h</span><span class="RuleName">t</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> };
+<span class="RuleName">s</span><span class="RuleName">e</span><span class="RuleName">v</span><span class="RuleName">e</span><span class="RuleName">n</span> = <span class="Reserved">&amp;</span><span class="CharString">'</span><span class="CharString">7</span><span class="CharString">'</span> <span class="RuleName">h</span><span class="RuleName">i</span><span class="RuleName">t</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> } <span class="Reserved">|</span> <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> <span class="RuleName">s</span><span class="RuleName">e</span><span class="RuleName">v</span><span class="RuleName">e</span><span class="RuleName">n</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> };
+<span class="RuleName">s</span><span class="RuleName">i</span><span class="RuleName">x</span>   = <span class="Reserved">&amp;</span><span class="CharString">'</span><span class="CharString">6</span><span class="CharString">'</span> <span class="RuleName">h</span><span class="RuleName">i</span><span class="RuleName">t</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> } <span class="Reserved">|</span> <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> <span class="RuleName">s</span><span class="RuleName">i</span><span class="RuleName">x</span><span class="Reserved">:</span><span class="VariableName">x</span>   <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> };
+<span class="RuleName">f</span><span class="RuleName">i</span><span class="RuleName">v</span><span class="RuleName">e</span>  = <span class="Reserved">&amp;</span><span class="CharString">'</span><span class="CharString">5</span><span class="CharString">'</span> <span class="RuleName">h</span><span class="RuleName">i</span><span class="RuleName">t</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> } <span class="Reserved">|</span> <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> <span class="RuleName">f</span><span class="RuleName">i</span><span class="RuleName">v</span><span class="RuleName">e</span><span class="Reserved">:</span><span class="VariableName">x</span>  <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> };
+<span class="RuleName">f</span><span class="RuleName">o</span><span class="RuleName">u</span><span class="RuleName">r</span>  = <span class="Reserved">&amp;</span><span class="CharString">'</span><span class="CharString">4</span><span class="CharString">'</span> <span class="RuleName">h</span><span class="RuleName">i</span><span class="RuleName">t</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> } <span class="Reserved">|</span> <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> <span class="RuleName">f</span><span class="RuleName">o</span><span class="RuleName">u</span><span class="RuleName">r</span><span class="Reserved">:</span><span class="VariableName">x</span>  <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> };
+<span class="RuleName">t</span><span class="RuleName">h</span><span class="RuleName">r</span><span class="RuleName">e</span><span class="RuleName">e</span> = <span class="Reserved">&amp;</span><span class="CharString">'</span><span class="CharString">3</span><span class="CharString">'</span> <span class="RuleName">h</span><span class="RuleName">i</span><span class="RuleName">t</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> } <span class="Reserved">|</span> <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> <span class="RuleName">t</span><span class="RuleName">h</span><span class="RuleName">r</span><span class="RuleName">e</span><span class="RuleName">e</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> };
+<span class="RuleName">t</span><span class="RuleName">w</span><span class="RuleName">o</span>   = <span class="Reserved">&amp;</span><span class="CharString">'</span><span class="CharString">2</span><span class="CharString">'</span> <span class="RuleName">h</span><span class="RuleName">i</span><span class="RuleName">t</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> } <span class="Reserved">|</span> <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> <span class="RuleName">t</span><span class="RuleName">w</span><span class="RuleName">o</span><span class="Reserved">:</span><span class="VariableName">x</span>   <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> };
+<span class="RuleName">o</span><span class="RuleName">n</span><span class="RuleName">e</span>   = <span class="Reserved">&amp;</span><span class="CharString">'</span><span class="CharString">1</span><span class="CharString">'</span> <span class="RuleName">h</span><span class="RuleName">i</span><span class="RuleName">t</span><span class="Reserved">:</span><span class="VariableName">x</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> } <span class="Reserved">|</span> <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> <span class="RuleName">o</span><span class="RuleName">n</span><span class="RuleName">e</span><span class="Reserved">:</span><span class="VariableName">x</span>   <span class="Reserved">-</span><span class="Reserved">&gt;</span> { <span class="VariableName">x</span> };
+
+<span class="RuleName">h</span><span class="RuleName">i</span><span class="RuleName">t</span>[<span class="Meta">E</span><span class="Meta">s</span><span class="Meta">c</span><span class="Meta">a</span><span class="Meta">p</span><span class="Meta">e</span>] = <span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span>;
+
+<span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> = <span class="CharString">'</span><span class="CharString">1</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">2</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">3</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">4</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">5</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">6</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">7</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">8</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">9</span><span class="CharString">'</span>;
+</pre>
+
+And the cool thing is, that this also highlights the answer for each line:
+
+<pre class="highlight"><span class="Escape">9</span><span class="Escape">8</span>7654321111111
+<span class="Escape">8</span>1111111111111<span class="Escape">9</span>
+2342342342342<span class="Escape">7</span><span class="Escape">8</span>
+818181<span class="Escape">9</span>1111<span class="Escape">2</span>111
+</pre>
+
+The generated C code just performs the addition:
+
+<pre class="highlight"><span class="CharString">#</span><span class="CharString">i</span><span class="CharString">n</span><span class="CharString">c</span><span class="CharString">l</span><span class="CharString">u</span><span class="CharString">d</span><span class="CharString">e</span><span class="CharString"> </span><span class="CharString">&lt;</span><span class="CharString">s</span><span class="CharString">t</span><span class="CharString">d</span><span class="CharString">i</span><span class="CharString">o</span><span class="CharString">.</span><span class="CharString">h</span><span class="CharString">&gt;</span><span class="CharString">
+</span><span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> main(<span class="VariableName">v</span><span class="VariableName">o</span><span class="VariableName">i</span><span class="VariableName">d</span>) {
+    printf(<span class="String">&quot;</span><span class="String">P</span><span class="String">a</span><span class="String">r</span><span class="String">t</span><span class="String"> </span><span class="String">1</span><span class="String">:</span><span class="String"> </span><span class="String">%</span><span class="String">l</span><span class="String">d</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>, (<span class="VariableName">l</span><span class="VariableName">o</span><span class="VariableName">n</span><span class="VariableName">g</span> <span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span>)(<span class="String">0</span> + <span class="String">9</span><span class="String">8</span> + <span class="String">8</span><span class="String">9</span> + <span class="String">7</span><span class="String">8</span> + <span class="String">9</span><span class="String">2</span>));
+    <span class="Reserved">r</span><span class="Reserved">e</span><span class="Reserved">t</span><span class="Reserved">u</span><span class="Reserved">r</span><span class="Reserved">n</span> <span class="String">0</span>;
+}
+</pre>
+
+I was able to solve part 2 in the same way, but it required me to create
+`joltage12` to `joltage1` because you can not parameterize the recursion depth
+in meta. But here is what it looks like when run on the example:
+
+<pre class="highlight"><span class="Escape">9</span><span class="Escape">8</span><span class="Escape">7</span><span class="Escape">6</span><span class="Escape">5</span><span class="Escape">4</span><span class="Escape">3</span><span class="Escape">2</span><span class="Escape">1</span><span class="Escape">1</span><span class="Escape">1</span><span class="Escape">1</span>111
+<span class="Escape">8</span><span class="Escape">1</span><span class="Escape">1</span><span class="Escape">1</span><span class="Escape">1</span><span class="Escape">1</span><span class="Escape">1</span><span class="Escape">1</span><span class="Escape">1</span><span class="Escape">1</span><span class="Escape">1</span>111<span class="Escape">9</span>
+23<span class="Escape">4</span>2<span class="Escape">3</span><span class="Escape">4</span><span class="Escape">2</span><span class="Escape">3</span><span class="Escape">4</span><span class="Escape">2</span><span class="Escape">3</span><span class="Escape">4</span><span class="Escape">2</span><span class="Escape">7</span><span class="Escape">8</span>
+<span class="Escape">8</span>1<span class="Escape">8</span>1<span class="Escape">8</span>1<span class="Escape">9</span><span class="Escape">1</span><span class="Escape">1</span><span class="Escape">1</span><span class="Escape">1</span><span class="Escape">2</span><span class="Escape">1</span><span class="Escape">1</span><span class="Escape">1</span>
+</pre>
+
+Also note how numbers are parsed:
+
+<pre class="highlight"><span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> = <span class="CharString">'</span><span class="CharString">1</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">2</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">3</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">4</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">5</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">6</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">7</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">8</span><span class="CharString">'</span><span class="Reserved">|</span><span class="CharString">'</span><span class="CharString">9</span><span class="CharString">'</span>;
+</pre>
+
+This was the only way to do it in the meta language before. But I added support
+for character ranges. So the preferred way to write this now is this:
+
+<pre class="highlight"><span class="RuleName">n</span><span class="RuleName">u</span><span class="RuleName">m</span><span class="RuleName">b</span><span class="RuleName">e</span><span class="RuleName">r</span> = <span class="CharString">'</span><span class="CharString">1</span><span class="CharString">'</span>-<span class="CharString">'</span><span class="CharString">9</span><span class="CharString">'</span>;
+</pre>
+
+It is faster and it reads better. So one idea I had with solving Advent of Code
+using rlworkbench was that I can improve it with feedback from real usage. Here
+is one example.
+
+## Day 4
+
+This day I got to practice parsing grids i meta and practice how to represent
+them in C for easy access. Here is part of the parsing code:
+
+<pre class="highlight"><span class="RuleName">g</span><span class="RuleName">r</span><span class="RuleName">i</span><span class="RuleName">d</span> = <span class="RuleName">r</span><span class="RuleName">o</span><span class="RuleName">w</span><span class="Reserved">*</span><span class="Reserved">:</span><span class="VariableName">x</span><span class="VariableName">s</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> {
+    $rowCount
+    $colCount
+    <span class="String">&quot;</span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String"> </span><span class="String">p</span><span class="String">a</span><span class="String">p</span><span class="String">e</span><span class="String">r</span><span class="String">_</span><span class="String">r</span><span class="String">o</span><span class="String">l</span><span class="String">l</span><span class="String">s</span><span class="String">[</span><span class="String">&quot;</span> &lt;rowCount <span class="String">&quot;</span><span class="String">]</span><span class="String">[</span><span class="String">&quot;</span> &lt;colCount <span class="String">&quot;</span><span class="String">]</span><span class="String"> </span><span class="String">=</span><span class="String"> </span><span class="String">{</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span> &gt;
+        <span class="VariableName">x</span><span class="VariableName">s</span>
+    &lt; <span class="String">&quot;</span><span class="String">}</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+    <span class="String">&quot;</span><span class="String">i</span><span class="String">n</span><span class="String">t</span><span class="String"> </span><span class="String">c</span><span class="String">a</span><span class="String">n</span><span class="String">_</span><span class="String">b</span><span class="String">e</span><span class="String">_</span><span class="String">r</span><span class="String">e</span><span class="String">m</span><span class="String">o</span><span class="String">v</span><span class="String">e</span><span class="String">d</span><span class="String">[</span><span class="String">&quot;</span> &lt;rowCount <span class="String">&quot;</span><span class="String">]</span><span class="String">[</span><span class="String">&quot;</span> &lt;colCount <span class="String">&quot;</span><span class="String">]</span><span class="String">;</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+    &gt;rowCount { W[1] }
+    &gt;colCount { W[2] }
+};
+
+<span class="RuleName">r</span><span class="RuleName">o</span><span class="RuleName">w</span> = <span class="RuleName">c</span><span class="RuleName">e</span><span class="RuleName">l</span><span class="RuleName">l</span><span class="Reserved">*</span><span class="Reserved">:</span><span class="VariableName">x</span><span class="VariableName">s</span> <span class="CharString">'</span><span class="Escape">\</span><span class="Escape">n</span><span class="CharString">'</span> <span class="Reserved">-</span><span class="Reserved">&gt;</span> {
+    #inc(W[1] 1)
+    #max(W[2] <span class="VariableName">x</span><span class="VariableName">s</span>.len)
+    <span class="String">&quot;</span><span class="String">{</span><span class="String">&quot;</span> <span class="VariableName">x</span><span class="VariableName">s</span> <span class="String">&quot;</span><span class="String">}</span><span class="String">,</span><span class="Escape">\</span><span class="Escape">n</span><span class="String">&quot;</span>
+};
+</pre>
+
+And here is what it generates:
+
+<pre class="highlight"><span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> paper_rolls[<span class="String">1</span><span class="String">0</span>][<span class="String">1</span><span class="String">0</span>] = {
+    {<span class="String">0</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">0</span>, },
+    {<span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">1</span>, },
+    {<span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">1</span>, },
+    {<span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">0</span>, },
+    {<span class="String">1</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">1</span>, },
+    {<span class="String">0</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, },
+    {<span class="String">0</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, },
+    {<span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, },
+    {<span class="String">0</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">0</span>, },
+    {<span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">1</span>, <span class="String">0</span>, <span class="String">1</span>, <span class="String">0</span>, },
+};
+<span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> can_be_removed[<span class="String">1</span><span class="String">0</span>][<span class="String">1</span><span class="String">0</span>];
+</pre>
+
+I think the meta language would benefit from some better mechanism to keep
+track of rows and columns. The `W[x]` mechanism is a hacky way to somewhat work
+with counters. But it is not very nice. I though about adding implicit counters
+for the star-operator. Maybe this is an example to revisit later to try to
+improve meta.
+
+I also learned that local variables in C are not automatically initialized to
+0. I got some random behavior because of it. Yey C! Furthermore it seems that
+[the compiler can not always fully detect
+it](https://stackoverflow.com/questions/74672374/gcc-not-warning-of-uninitialized-local-variable).
+
+## Day 5
+
+This puzzle included some fun with ranges. Instead of thinking of every number
+in a range, compute with ranges instead. I think there was a similar puzzle
+last year. It was satisfying to figure out.
+
+## Day 6
+
+This puzzle was not a very good fit for meta. Or at least part 2 wasn't.
+Meta works well only if you can parse character by character. Not column wise.
+I ended up writing another meta program to rotate the input text. That is,
+turning this:
+
+    123 328  51 64
+     45 64  387 23
+      6 98  215 314
+    *   +   *   +
+
+Into this:
+
+    *  1
+      42
+     653
+
+    +963
+     842
+       8
+
+    *23
+     185
+     571
+
+    +326
+    134
+    4
+
+Which I could then parse for part 2. But the whole thing became very
+complicated.
+
+## Day 7
+
+In this puzzle I accidentally used an `integer` instead of a `long`. The
+program worked fine on the example but produced garbage for the real input.
+Luckily I found out why quite quickly. I'm used to bignums in Python which
+never overflow. So I gained some more C experience the hard way.
+
+## Day 8
+
+Brute force worked fine. Maybe thanks to the speed of C? Is there a more clever
+way?
+
+I watched [Advent of Code 2025 Day 8 Jonathan
+Paulson](https://www.youtube.com/watch?v=Gd4-LOBfA88) and learned that union
+find is probably an algorithm to look up for this.
+
+I also avoided doing sorting in C here. The problem was that I needed to get
+the three largest things in an array. I solved it by finding the largest through
+linear search, and then setting that value to 0. Then I could do that three
+time to get the three largest things at the expense of "removing" them from the
+array. This was fine for this solution. But investigating more elegant solutions
+to this in C is something that I might want to do. There is `qsort` in the
+standard library. But what if modifying the array is not desirable? Copy the
+whole array and then sort? Another thing I though about was to write a function
+that found the largest thing that is smaller than X. In each iteration I could
+pass the previous value. But I would have to do something special for the
+initial case.
+
+## Day 9
+
+I used the [Point in
+polygon](https://en.wikipedia.org/wiki/Point_in_polygon) that I learned about
+last year. It shows that you get better at Advent of Code when you do more
+advent of code. Surprise!
+
+I got the correct result for part 2, but took it took ~6 minutes. Can I
+improve?
+
+I searched YouTube and found that coordinate compression might be something to
+look into.
+
+## Day 10
+
+Today's puzzle was a little more complex to parse. So it was fun to use meta.
+
+The actual algorithm took a long time for me to code. Partly because I
+struggled with arrays in C. I learned that they are copied when copying structs
+(not treated as pointers). More resources on this that I found useful:
+
+* [Are Array Members Deeply Copied?](https://www.geeksforgeeks.org/c/are-array-members-deeply-copied/)
+* [Assign one struct to another in C](https://stackoverflow.com/questions/2302351/assign-one-struct-to-another-in-c)
+* [I'm getting "Invalid Initializer", what am I doing wrong?](https://stackoverflow.com/questions/11043313/im-getting-invalid-initializer-what-am-i-doing-wrong)
+
+I implemented a pop function by returning the first element and moving all
+elements in the array left:
+
+<pre class="highlight">LightsState pop_lights_state(LightsStates* fringe) {
+    LightsState state;
+    <span class="VariableName">i</span><span class="VariableName">n</span><span class="VariableName">t</span> i;
+    assert(fringe-&gt;used &gt; <span class="String">0</span>);
+    state = fringe-&gt;states[<span class="String">0</span>];
+    fringe-&gt;used--;
+    <span class="Reserved">f</span><span class="Reserved">o</span><span class="Reserved">r</span> (i=<span class="String">0</span>; i&lt;fringe-&gt;used; i++) {
+        fringe-&gt;states[i] = fringe-&gt;states[i+<span class="String">1</span>];
+    }
+    <span class="Reserved">r</span><span class="Reserved">e</span><span class="Reserved">t</span><span class="Reserved">u</span><span class="Reserved">r</span><span class="Reserved">n</span> state;
+}
+</pre>
+
+In Python these sort of functions are just available. So it was fun to practice
+implementing them with more primitive data types.
+
+I didn't manage to solve part 2 of today's puzzle. When my attempt just took
+forever, I assumed that you had to do something more clever. Most likely
+involving more math and solving some kind of equation. That was not for me. Not
+this year at least.
+
+## Day 11
+
+I had solved a similar problem in previous years. So I found the solution to
+this one quite straight forward. But once again I struggled to implement it in
+C.  Being at this lower level is so much less convenient. But some things are
+actually easier here. So this was good practice.
+
+## Day 12
+
+I was so excited about today.
+
+I started by writing a highlighter for boards:
+
+<pre class="highlight"><span class="RuleName">m</span><span class="RuleName">a</span><span class="RuleName">i</span><span class="RuleName">n</span> = <span class="RuleName">c</span><span class="RuleName">h</span><span class="RuleName">a</span><span class="RuleName">r</span><span class="Reserved">*</span> <span class="Reserved">!</span><span class="Reserved">.</span>;
+
+<span class="RuleName">c</span><span class="RuleName">h</span><span class="RuleName">a</span><span class="RuleName">r</span> =
+    <span class="Reserved">|</span> <span class="RuleName">h</span><span class="RuleName">a</span><span class="RuleName">s</span><span class="RuleName">h</span>
+    <span class="Reserved">|</span> <span class="RuleName">p</span><span class="RuleName">i</span><span class="RuleName">e</span><span class="RuleName">c</span><span class="RuleName">e</span><span class="RuleName">O</span><span class="RuleName">n</span><span class="RuleName">e</span>
+    <span class="Reserved">|</span> <span class="RuleName">p</span><span class="RuleName">i</span><span class="RuleName">e</span><span class="RuleName">c</span><span class="RuleName">e</span><span class="RuleName">T</span><span class="RuleName">w</span><span class="RuleName">o</span>
+    <span class="Reserved">|</span> <span class="RuleName">p</span><span class="RuleName">i</span><span class="RuleName">e</span><span class="RuleName">c</span><span class="RuleName">e</span><span class="RuleName">T</span><span class="RuleName">h</span><span class="RuleName">r</span><span class="RuleName">e</span><span class="RuleName">e</span>
+    <span class="Reserved">|</span> <span class="RuleName">p</span><span class="RuleName">i</span><span class="RuleName">e</span><span class="RuleName">c</span><span class="RuleName">e</span><span class="RuleName">F</span><span class="RuleName">o</span><span class="RuleName">u</span><span class="RuleName">r</span>
+    <span class="Reserved">|</span> <span class="RuleName">p</span><span class="RuleName">i</span><span class="RuleName">e</span><span class="RuleName">c</span><span class="RuleName">e</span><span class="RuleName">F</span><span class="RuleName">i</span><span class="RuleName">v</span><span class="RuleName">e</span>
+    <span class="Reserved">|</span> <span class="RuleName">p</span><span class="RuleName">i</span><span class="RuleName">e</span><span class="RuleName">c</span><span class="RuleName">e</span><span class="RuleName">S</span><span class="RuleName">i</span><span class="RuleName">x</span>
+    <span class="Reserved">|</span> <span class="Reserved">.</span>
+    ;
+
+<span class="RuleName">h</span><span class="RuleName">a</span><span class="RuleName">s</span><span class="RuleName">h</span>[<span class="Meta">M</span><span class="Meta">e</span><span class="Meta">t</span><span class="Meta">a</span>] = <span class="CharString">'</span><span class="CharString">#</span><span class="CharString">'</span>;
+
+<span class="RuleName">p</span><span class="RuleName">i</span><span class="RuleName">e</span><span class="RuleName">c</span><span class="RuleName">e</span><span class="RuleName">O</span><span class="RuleName">n</span><span class="RuleName">e</span>[<span class="Meta">R</span><span class="Meta">e</span><span class="Meta">s</span><span class="Meta">e</span><span class="Meta">r</span><span class="Meta">v</span><span class="Meta">e</span><span class="Meta">d</span>]     = <span class="CharString">'</span><span class="CharString">A</span><span class="CharString">'</span> <span class="Reserved">|</span> <span class="CharString">'</span><span class="CharString">0</span><span class="CharString">'</span>;
+<span class="RuleName">p</span><span class="RuleName">i</span><span class="RuleName">e</span><span class="RuleName">c</span><span class="RuleName">e</span><span class="RuleName">T</span><span class="RuleName">w</span><span class="RuleName">o</span>[<span class="Meta">S</span><span class="Meta">t</span><span class="Meta">r</span><span class="Meta">i</span><span class="Meta">n</span><span class="Meta">g</span>]       = <span class="CharString">'</span><span class="CharString">B</span><span class="CharString">'</span> <span class="Reserved">|</span> <span class="CharString">'</span><span class="CharString">1</span><span class="CharString">'</span>;
+<span class="RuleName">p</span><span class="RuleName">i</span><span class="RuleName">e</span><span class="RuleName">c</span><span class="RuleName">e</span><span class="RuleName">T</span><span class="RuleName">h</span><span class="RuleName">r</span><span class="RuleName">e</span><span class="RuleName">e</span>[<span class="Meta">C</span><span class="Meta">h</span><span class="Meta">a</span><span class="Meta">r</span><span class="Meta">S</span><span class="Meta">t</span><span class="Meta">r</span><span class="Meta">i</span><span class="Meta">n</span><span class="Meta">g</span>] = <span class="CharString">'</span><span class="CharString">C</span><span class="CharString">'</span> <span class="Reserved">|</span> <span class="CharString">'</span><span class="CharString">2</span><span class="CharString">'</span>;
+<span class="RuleName">p</span><span class="RuleName">i</span><span class="RuleName">e</span><span class="RuleName">c</span><span class="RuleName">e</span><span class="RuleName">F</span><span class="RuleName">o</span><span class="RuleName">u</span><span class="RuleName">r</span>[<span class="Meta">E</span><span class="Meta">s</span><span class="Meta">c</span><span class="Meta">a</span><span class="Meta">p</span><span class="Meta">e</span>]      = <span class="CharString">'</span><span class="CharString">D</span><span class="CharString">'</span> <span class="Reserved">|</span> <span class="CharString">'</span><span class="CharString">3</span><span class="CharString">'</span>;
+<span class="RuleName">p</span><span class="RuleName">i</span><span class="RuleName">e</span><span class="RuleName">c</span><span class="RuleName">e</span><span class="RuleName">F</span><span class="RuleName">i</span><span class="RuleName">v</span><span class="RuleName">e</span>[<span class="Meta">R</span><span class="Meta">u</span><span class="Meta">l</span><span class="Meta">e</span><span class="Meta">N</span><span class="Meta">a</span><span class="Meta">m</span><span class="Meta">e</span>]    = <span class="CharString">'</span><span class="CharString">E</span><span class="CharString">'</span> <span class="Reserved">|</span> <span class="CharString">'</span><span class="CharString">4</span><span class="CharString">'</span>;
+<span class="RuleName">p</span><span class="RuleName">i</span><span class="RuleName">e</span><span class="RuleName">c</span><span class="RuleName">e</span><span class="RuleName">S</span><span class="RuleName">i</span><span class="RuleName">x</span>[<span class="Meta">V</span><span class="Meta">a</span><span class="Meta">r</span><span class="Meta">i</span><span class="Meta">a</span><span class="Meta">b</span><span class="Meta">l</span><span class="Meta">e</span><span class="Meta">N</span><span class="Meta">a</span><span class="Meta">m</span><span class="Meta">e</span>] = <span class="CharString">'</span><span class="CharString">F</span><span class="CharString">'</span> <span class="Reserved">|</span> <span class="CharString">'</span><span class="CharString">5</span><span class="CharString">'</span>;
+</pre>
+
+My idea was that I would be able to more easily debug how my algorithm placed
+blocks on the grid. And it kind of worked. After a lot of coding on the
+algorithm (which again was difficult for me in C) I had something that produced
+states like this:
+
+<pre class="highlight"><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span>..<span class="String">1</span><span class="CharString">2</span>..<span class="CharString">2</span>..<span class="CharString">2</span>..<span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="RuleName">4</span>.<span class="RuleName">4</span><span class="RuleName">4</span>.<span class="RuleName">4</span>..<span class="VariableName">5</span>....
+..<span class="Reserved">0</span>..<span class="Reserved">0</span>.<span class="String">1</span><span class="String">1</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="Escape">3</span><span class="Escape">3</span>.<span class="Escape">3</span><span class="Escape">3</span>.<span class="Escape">3</span><span class="Escape">3</span>.<span class="RuleName">4</span><span class="RuleName">4</span><span class="RuleName">4</span><span class="RuleName">4</span><span class="RuleName">4</span><span class="RuleName">4</span>.<span class="VariableName">5</span><span class="VariableName">5</span>....
+<span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="String">1</span><span class="String">1</span><span class="String">1</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span>.<span class="Escape">3</span><span class="Escape">3</span>.<span class="Escape">3</span><span class="Escape">3</span>.<span class="Escape">3</span><span class="Escape">3</span><span class="RuleName">4</span>.<span class="RuleName">4</span><span class="RuleName">4</span>.<span class="RuleName">4</span><span class="VariableName">5</span><span class="VariableName">5</span><span class="VariableName">5</span>....
+<span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span>.<span class="String">1</span><span class="String">1</span><span class="CharString">2</span>..<span class="CharString">2</span>..<span class="CharString">2</span>..<span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="RuleName">4</span>.<span class="RuleName">4</span><span class="RuleName">4</span>.<span class="RuleName">4</span>..<span class="VariableName">5</span>....
+..<span class="Reserved">0</span>..<span class="Reserved">0</span><span class="String">1</span><span class="String">1</span><span class="String">1</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="Escape">3</span><span class="Escape">3</span>.<span class="Escape">3</span><span class="Escape">3</span>.<span class="Escape">3</span><span class="Escape">3</span>.<span class="RuleName">4</span><span class="RuleName">4</span><span class="RuleName">4</span><span class="RuleName">4</span><span class="RuleName">4</span><span class="RuleName">4</span>.<span class="VariableName">5</span><span class="VariableName">5</span>....
+<span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span>.<span class="String">1</span><span class="String">1</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span>.<span class="Escape">3</span><span class="Escape">3</span>.<span class="Escape">3</span><span class="Escape">3</span>.<span class="Escape">3</span><span class="Escape">3</span><span class="RuleName">4</span>.<span class="RuleName">4</span><span class="RuleName">4</span>.<span class="RuleName">4</span><span class="VariableName">5</span><span class="VariableName">5</span><span class="VariableName">5</span>....
+<span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="Reserved">0</span><span class="String">1</span><span class="String">1</span><span class="String">1</span><span class="CharString">2</span>..<span class="CharString">2</span>..<span class="CharString">2</span>..<span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="Escape">3</span><span class="RuleName">4</span>.<span class="RuleName">4</span><span class="RuleName">4</span>.<span class="RuleName">4</span>..<span class="VariableName">5</span>....
+..<span class="Reserved">0</span>..<span class="Reserved">0</span>.<span class="String">1</span><span class="String">1</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="CharString">2</span><span class="Escape">3</span><span class="Escape">3</span>.<span class="Escape">3</span><span class="Escape">3</span>.<span class="Escape">3</span><span class="Escape">3</span>.<span class="RuleName">4</span><span class="RuleName">4</span><span class="RuleName">4</span><span class="RuleName">4</span><span class="RuleName">4</span><span class="RuleName">4</span>.<span class="VariableName">5</span><span class="VariableName">5</span>....
+</pre>
+
+So far, so good. But my search seemed to take forever. I wanted to introduce
+caching to see if it would help. But after ~5 hours of struggling with C, I
+couldn't do it. I actually switched to Python. Implemented roughly the same
+that I had in C and was able to add caching. I think at least. But it still
+took forever.
+
+That's when I decided to quit. This was it for me this year.
+
+I looked up solutions for day 12 on the Internet and found that searching (as I
+was attempting) was probably not the right way to go. Although, I found one
+solution that was similar to what I tried to do: [ShuvraneelMitra |
+Advent-of-Code-2025-CPP | Day
+12](https://github.com/ShuvraneelMitra/Advent-of-Code-2025-CPP/blob/main/Day%2012/Day12_P1.cpp).
+
+I don't have a good intuition for when a computation is going to take too long.
+I tried to do something clever in day 1 to avoid unnecessary work. And I tried
+to brute force day 12. So that's maybe something that I should practice more
+next year. Analyse the problem and think about if a solution would be feasible.
+And if not, think of other ways to attack the problem.
+
+## Summary
+
+This year was fun.
+
+I got to improve rlworkbench and meta with input from real world usage.
+
+I got to practice writing more C code and learned some things the hard way.
+
+I got ideas for algorithms to look up (maybe for next year) and new areas of C
+to explore.
+
+But now I'm done. I'm glad it is over. Now I can get back to all the things I
+neglected during the last 12 days.

2025-12-14 13:33 Rickard pushed to rlworkbench

fatal: Invalid revision range 14b7949fa8c6b23f0cbdfca293934d1d0c4b7b6c..13c31b3fd4b76279834bca34084fb2ba724a1289

2025-12-13 21:32 Rickard pushed to rlworkbench

fatal: Invalid revision range e7e50a6eeba626d5b721f5c796a5246171deba85..14b7949fa8c6b23f0cbdfca293934d1d0c4b7b6c

2025-12-13 18:16 Rickard pushed to rlworkbench

fatal: Invalid revision range c2d1c28a4355b38c63ee0f75ca5ce249fbbe2a81..e7e50a6eeba626d5b721f5c796a5246171deba85

2025-12-13 16:13 Rickard pushed to rlworkbench

fatal: Invalid revision range e0e0078a243ab6d81b95b2838e731dfb50c5fabb..c2d1c28a4355b38c63ee0f75ca5ce249fbbe2a81

2025-12-13 15:52 Rickard pushed to rlworkbench

fatal: Invalid revision range 57b81b367aa1ffdd6eff1667229fbad172b18f68..e0e0078a243ab6d81b95b2838e731dfb50c5fabb