Build Lexer and Parser tables upon construction

lib/propane/lexer.rb

@@ -1,48 +1,13 @@
 class Propane
   class Lexer
 
+    attr_reader :state_table
+    attr_reader :transition_table
+    attr_reader :mode_table
+
     def initialize(grammar)
       @grammar = grammar
-    end
-
-    def build_tables
-      @modes = @grammar.patterns.group_by do |pattern|
-        pattern.mode
-      end.transform_values do |patterns|
-        {dfa: DFA.new(patterns)}
-      end
-      @modes.each_with_index do |(mode_name, mode_info), index|
-        mode_info[:id] = index
-      end
-      transition_table = []
-      state_table = []
-      mode_table = []
-      @modes.each do |mode_name, mode_info|
-        state_table_offset = state_table.size
-        mode_table << {
-          state_table_offset: state_table_offset,
-        }
-        states = mode_info[:dfa].enumerate
-        states.each do |state, id|
-          token = state.accepts && state.accepts.token && state.accepts.token.id
-          code_id = state.accepts && state.accepts.code_id && state.accepts.code_id
-          state_table << {
-            transition_table_index: transition_table.size,
-            n_transitions: state.transitions.size,
-            accepts: !!state.accepts,
-            token: token,
-            code_id: code_id,
-          }
-          state.transitions.each do |transition|
-            transition_table << {
-              first: transition.code_point_range.first,
-              last: transition.code_point_range.last,
-              destination: states[transition.destination] + state_table_offset,
-            }
-          end
-        end
-      end
-      [transition_table, state_table, mode_table]
+      build_tables!
     end
 
     # Get ID for a mode.
@@ -58,5 +23,46 @@ class Propane
       end
     end
 
+    private
+
+    def build_tables!
+      @modes = @grammar.patterns.group_by do |pattern|
+        pattern.mode
+      end.transform_values do |patterns|
+        {dfa: DFA.new(patterns)}
+      end
+      @modes.each_with_index do |(mode_name, mode_info), index|
+        mode_info[:id] = index
+      end
+      @state_table = []
+      @transition_table = []
+      @mode_table = []
+      @modes.each do |mode_name, mode_info|
+        state_table_offset = @state_table.size
+        @mode_table << {
+          state_table_offset: state_table_offset,
+        }
+        states = mode_info[:dfa].enumerate
+        states.each do |state, id|
+          token = state.accepts && state.accepts.token && state.accepts.token.id
+          code_id = state.accepts && state.accepts.code_id && state.accepts.code_id
+          @state_table << {
+            transition_table_index: @transition_table.size,
+            n_transitions: state.transitions.size,
+            accepts: !!state.accepts,
+            token: token,
+            code_id: code_id,
+          }
+          state.transitions.each do |transition|
+            @transition_table << {
+              first: transition.code_point_range.first,
+              last: transition.code_point_range.last,
+              destination: states[transition.destination] + state_table_offset,
+            }
+          end
+        end
+      end
+    end
+
   end
 end

lib/propane/parser.rb

@@ -2,6 +2,10 @@ class Propane
 
   class Parser
 
+    attr_reader :state_table
+    attr_reader :shift_table
+    attr_reader :reduce_table
+
     def initialize(grammar, rule_sets, log)
       @grammar = grammar
       @rule_sets = rule_sets
@@ -33,12 +37,15 @@ class Propane
 
       build_reduce_actions!
       write_log!
+      build_tables!
     end
 
-    def build_tables
-      shift_table = []
-      state_table = []
-      reduce_table = []
+    private
+
+    def build_tables!
+      @state_table = []
+      @shift_table = []
+      @reduce_table = []
       @item_sets.each do |item_set|
         shift_entries = item_set.following_symbols.map do |following_symbol|
           state_id =
@@ -65,20 +72,17 @@ class Propane
           else
             []
           end
-        state_table << {
-          shift_index: shift_table.size,
+        @state_table << {
+          shift_index: @shift_table.size,
           n_shifts: shift_entries.size,
-          reduce_index: reduce_table.size,
+          reduce_index: @reduce_table.size,
           n_reduces: reduce_entries.size,
         }
-        shift_table += shift_entries
-        reduce_table += reduce_entries
+        @shift_table += shift_entries
+        @reduce_table += reduce_entries
       end
-      [state_table, shift_table, reduce_table]
     end
 
-    private
-
     def process_item_set(item_set)
       item_set.following_symbols.each do |following_symbol|
         unless following_symbol.name == "$EOF"