From e432f62b055d0211c47db2d839692a67d554b943 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Mon, 13 Mar 2023 21:56:18 -0400
Subject: [PATCH] Add UserCodeID struct to represent user code IDs

---
 assets/parser.d.erb  | 47 +++++++++++++++++++++++++++++++++++++-------
 lib/propane/lexer.rb |  2 --
 2 files changed, 40 insertions(+), 9 deletions(-)

diff --git a/assets/parser.d.erb b/assets/parser.d.erb
index 9db579d..637ac45 100644
--- a/assets/parser.d.erb
+++ b/assets/parser.d.erb
@@ -45,12 +45,12 @@ class <%= @classname %>
             return Token(count);
         }
 
-        bool is_valid()
+        bool is_valid() const
         {
             return token < count;
         }
 
-        bool is_invalid()
+        bool is_invalid() const
         {
             return !is_valid();
         }
@@ -190,12 +190,41 @@ class <%= @classname %>
             uint destination;
         }
 
+        private struct UserCodeID
+        {
+            enum count = <%= (@grammar.patterns.map(&:code_id).compact.max || -1) + 1%>;
+            uint user_code_id;
+            alias user_code_id this;
+
+            @disable this();
+
+            this(uint user_code_id)
+            {
+                this.user_code_id = user_code_id;
+            }
+
+            static UserCodeID invalid()
+            {
+                return UserCodeID(count);
+            }
+
+            bool is_valid() const
+            {
+                return user_code_id < count;
+            }
+
+            bool is_invalid() const
+            {
+                return !is_valid();
+            }
+        }
+
         private struct State
         {
             uint transition_table_index;
             uint n_transitions;
             uint token;
-            uint code_id;
+            UserCodeID code_id;
         }
 
         private struct Mode
@@ -215,7 +244,11 @@ class <%= @classname %>
             State(<%= state_table_entry[:transition_table_index] %>u,
                   <%= state_table_entry[:n_transitions] %>u,
                   <%= state_table_entry[:token] %>u,
-                  <%= state_table_entry[:code_id] %>u),
+<%   if state_table_entry[:code_id] %>
+                  UserCodeID(<%= state_table_entry[:code_id] %>u)),
+<%   else %>
+                  UserCodeID.invalid()),
+<%   end %>
 <% end %>
         ];
 
@@ -284,7 +317,7 @@ class <%= @classname %>
          * @return Token ID to accept, or _TOKEN_COUNT if the user code does
          *   not explicitly return a token.
          */
-        private uint user_code(uint code_id, string match, Result * result)
+        private uint user_code(UserCodeID code_id, string match, Result * result)
         {
             switch (code_id)
             {
@@ -316,7 +349,7 @@ class <%= @classname %>
             if (match_info.accepting_state != null)
             {
                 uint token_to_accept = match_info.accepting_state.token;
-                if (match_info.accepting_state.code_id != 0xFFFF_FFFFu)
+                if (match_info.accepting_state.code_id.is_valid())
                 {
                     uint user_code_token = user_code(match_info.accepting_state.code_id, m_input[m_input_position..(m_input_position + match_info.length)], &result);
                     /* A return of _TOKEN_COUNT from user_code() means
@@ -386,7 +419,7 @@ class <%= @classname %>
                         }
                         current_state = dest;
                         if ((states[current_state].token != _TOKEN_COUNT) ||
-                            (states[current_state].code_id != 0xFFFF_FFFFu))
+                            (states[current_state].code_id.is_valid()))
                         {
                             attempt_match_info.accepting_state = &states[current_state];
                             *match_info = attempt_match_info;
diff --git a/lib/propane/lexer.rb b/lib/propane/lexer.rb
index 96c2a6f..472d0f8 100644
--- a/lib/propane/lexer.rb
+++ b/lib/propane/lexer.rb
@@ -37,8 +37,6 @@ class Propane
           code_id =
             if state.accepts && state.accepts.code_id
               state.accepts.code_id
-            else
-              0xFFFF_FFFF
             end
           state_table << {
             transition_table_index: transition_table.size,