One Rule object stores all alternative patterns

lib/imbecile/parser.rb

@@ -3,9 +3,8 @@ class Imbecile
   class Parser
 
     def initialize(tokens, rules)
-      start_rules = rules.select {|rule| rule.name == "Start"}
-      start_items = start_rules.map do |rule|
-        Item.new(rule, 0)
+      start_items = rules["Start"].patterns.map do |pattern|
+        Item.new(pattern, 0)
       end
       start_item_set = ItemSet.new(start_items)
       start_item_set.close!

lib/imbecile/parser/item.rb

@@ -3,24 +3,24 @@ class Imbecile
 
     class Item
 
-      attr_reader :rule
+      attr_reader :pattern
       attr_reader :position
 
-      def initialize(rule, position)
-        @rule = rule
+      def initialize(pattern, position)
+        @pattern = pattern
         @position = position
       end
 
       def next_component
-        @rule.components[@position]
+        @pattern.components[@position]
       end
 
       def hash
-        [@rule, @position].hash
+        [@pattern, @position].hash
       end
 
       def ==(other)
-        @rule == other.rule && @position == other.position
+        @pattern == other.pattern && @position == other.position
       end
 
       def eql?(other)
@@ -28,9 +28,9 @@ class Imbecile
       end
 
       def closed_items
-        if @rule.components[@position].is_a?(Array)
-          @rule.components[@position].map do |rule|
-            Item.new(rule, 0)
+        if @pattern.components[@position].is_a?(Rule)
+          @pattern.components[@position].patterns.map do |pattern|
+            Item.new(pattern, 0)
           end
         else
           []

lib/imbecile/rule.rb

@@ -2,16 +2,30 @@ class Imbecile
 
   class Rule
 
+    class Pattern
+
+      attr_reader :components
+
+      attr_reader :code
+
+      def initialize(components, code)
+        @components = components
+        @code = code
+      end
+
+    end
+
     attr_reader :name
 
-    attr_reader :components
+    attr_reader :patterns
 
-    attr_reader :code
-
-    def initialize(name, rule_components, code)
+    def initialize(name)
       @name = name
-      @components = rule_components
-      @code = code
+      @patterns = []
+    end
+
+    def add_pattern(components, code)
+      @patterns << Pattern.new(components, code)
     end
 
   end