From 2122ca02fe5b6c5eb372b01619e41c7d57d8553a Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Wed, 23 Jun 2021 23:15:02 -0400
Subject: [PATCH] Start generating lexer states and transitions

---
 assets/parser.d.erb      | 29 +++++++++++++++++++++++++++++
 lib/imbecile/regex/fa.rb | 25 ++++++++++++++-----------
 2 files changed, 43 insertions(+), 11 deletions(-)

diff --git a/assets/parser.d.erb b/assets/parser.d.erb
index 4bcca7e..7c9e4fd 100644
--- a/assets/parser.d.erb
+++ b/assets/parser.d.erb
@@ -10,4 +10,33 @@ class <%= classname %>
         TOKEN_<%= token.c_name %>,
 <% end %>
     }
+
+    private struct Transition
+    {
+        uint first;
+        uint last;
+        uint dest;
+    }
+
+    private struct LexerState
+    {
+        Transition[] transitions;
+        size_t accepts;
+    }
+
+    private static const LexerState lexer_states[] = [
+<% lexer_dfa.enumerate.each do |state, index| %>
+        LexerState([
+<%   state.transitions.each do |transition| %>
+                Transition(<%= transition.code_point_range.first %>, <%= transition.code_point_range.last %>, <%= lexer_dfa.enumerate[transition.destination] %>),
+<%   end %>
+            ],
+<%   if state.accepts %>
+            <%= state.accepts.id %>,
+<%   else %>
+            cast(size_t)-1,
+<%   end %>
+            ),
+<% end %>
+    ];
 }
diff --git a/lib/imbecile/regex/fa.rb b/lib/imbecile/regex/fa.rb
index 1115cac..afe2017 100644
--- a/lib/imbecile/regex/fa.rb
+++ b/lib/imbecile/regex/fa.rb
@@ -39,19 +39,22 @@ module Imbecile
       end
 
       def enumerate
-        id = 0
-        states = {}
-        visit = lambda do |state|
-          unless states.include?(state)
-            id += 1
-            states[state] = id
-            state.transitions.each do |transition|
-              visit[transition.destination]
+        @_enumerated ||=
+          begin
+            id = 0
+            states = {}
+            visit = lambda do |state|
+              unless states.include?(state)
+                id += 1
+                states[state] = id
+                state.transitions.each do |transition|
+                  visit[transition.destination]
+                end
+              end
             end
+            visit[@start_state]
+            states
           end
-        end
-        visit[@start_state]
-        states
       end
 
     end