FromNand2Tetris: Try using a custom HDL lexer.

_config.yml

@@ -225,3 +225,6 @@ jekyll-archives:
   permalinks:
     tag: /tags/:name/
     category: /categories/:name/
+
+plugins:
+  - rouge

_plugins/rouge/hdl.rb

@@ -0,0 +1,41 @@
+module Rouge
+  module Lexers
+    class HDLCustom < RegexLexer
+      tag 'hdlcustom'
+      filenames '*.hdl'
+      mimetypes 'text/x-hdl'
+
+      # Keywords
+      keywords = %w(
+        CHIP IN OUT BUILTIN PARTS
+      )
+
+      # Built-in gates
+      builtins = %w(
+        Nand And Or Not Xor Mux DMux
+        Add16 Inc16 ALU Register RAM8 RAM64
+      )
+
+      # Pin directions and types
+      pins = %w(in out)
+
+      state :root do
+        rule %r(//.*), Comment::Single
+        rule %r(/\*), Comment::Multiline, :comment
+        rule %r/\b(#{keywords.join('|')})\b/, Keyword
+        rule %r/\b(#{builtins.join('|')})\b/, Name::Builtin
+        rule %r/\b(#{pins.join('|')})\b/, Keyword::Pseudo
+        rule %r/[a-zA-Z_]\w*/, Name::Variable
+        rule %r/\d+/, Num
+        rule %r/[\[\]\(\)\{\},;=]/, Punctuation
+        rule %r/\s+/, Text::Whitespace
+      end
+
+      state :comment do
+        rule %r/\*\//, Comment::Multiline, :pop!
+        rule %r/[^\*]+/, Comment::Multiline
+        rule %r/\*/, Comment::Multiline
+      end
+    end
+  end
+end

_posts/2024-08-30-FromNand2Tetris.md

@@ -55,7 +55,7 @@ and division of two integers, etc. It is a simple and elegant design.
 
 Here is my implementation in less than twenty lines of HDL code:
 
-```verilog
+```hdlcustom
  * ALU (Arithmetic Logic Unit):
  * Computes out = one of the following functions:
  *                0, 1, -1,