Use and improve child nameing for send mutator

lib/mutant/mutator/node.rb

@@ -43,15 +43,19 @@ module Mutant
 
       # Define remaining children
       #
-      # @param [Fixnum] from_index
+      # @param [Array<Symbol>] names
       #
       # @return [undefined]
       #
       # @api private
       #
-      def self.define_remaining_children(from_index)
+      def self.define_remaining_children(names)
+        define_method(:remaining_children_with_index) do
+          children.each_with_index.drop(names.length)
+        end
+
         define_method(:remaining_children) do
-          children[from_index..-1]
+          children.drop(names.length)
         end
       end
       private_class_method :define_remaining_children
@@ -66,7 +70,7 @@ module Mutant
         names.each_with_index do |name, index|
           define_named_child(name, index)
         end
-        define_remaining_children(names.length)
+        define_remaining_children(names)
       end
       private_class_method :children
 

lib/mutant/mutator/node/send.rb

@@ -7,8 +7,9 @@ module Mutant
 
         handle(:send)
 
-        RECEIVER_INDEX, SELECTOR_INDEX = 0, 1
-        ARGUMENTS_INDEX                = 2..-1.freeze
+        children :receiver, :selector
+
+        alias_method :arguments, :remaining_children
 
       private
 
@@ -23,6 +24,16 @@ module Mutant
             run(Binary)
             return
           end
+          normal_dispatch
+        end
+
+        # Perform normal, non special case dispatch
+        #
+        # @return [undefined]
+        #
+        # @api private
+        #
+        def normal_dispatch
           emit(receiver) if receiver
           mutate_receiver
           emit_argument_propagation
@@ -52,8 +63,7 @@ module Mutant
         def mutate_arguments
           return if arguments.empty?
           emit_self(receiver, selector)
-          children.each_index do |index|
-            next if index <= SELECTOR_INDEX
+          remaining_children_with_index.each do |node, index|
             mutate_child(index)
             delete_child(index)
           end
@@ -79,7 +89,7 @@ module Mutant
         def mutate_receiver
           return unless receiver
           emit_implicit_self
-          mutate_child(RECEIVER_INDEX)
+          emit_receiver_mutations
         end
 
         # Emit implicit self mutation
@@ -90,41 +100,10 @@ module Mutant
         #
         def emit_implicit_self
           if receiver.type == :self and !KEYWORDS.include?(selector)
-            emit_child_update(RECEIVER_INDEX, nil)
+            emit_receiver(nil)
           end
         end
 
-        # Return receiver
-        #
-        # @return [Parser::Node::AST]
-        #
-        # @api private
-        #
-        def receiver
-          children[RECEIVER_INDEX]
-        end
-
-        # Return selector
-        #
-        # @return [Symbol]
-        #
-        # @api private
-        #
-        def selector
-          children[SELECTOR_INDEX]
-        end
-
-        # Return arguments
-        #
-        # @return [Array<Parser::AST::Node>]
-        #
-        # @api private
-        #
-        def arguments
-          children[ARGUMENTS_INDEX]
-        end
-        memoize :arguments
-
       end # Send
     end # Node
   end # Mutator

lib/mutant/mutator/node/send/binary.rb

@@ -6,7 +6,7 @@ module Mutant
         # Mutator for sends that correspond to a binary operator
         class Binary < self
 
-          RIGHT_INDEX = SELECTOR_INDEX+1
+          children :left, :operator, :right
 
         private
 
@@ -17,10 +17,10 @@ module Mutant
           # @api private
           #
           def dispatch
-            emit(receiver)
-            mutate_child(RECEIVER_INDEX) # left
-            mutate_child(RIGHT_INDEX)
-            emit(arguments.first)
+            emit(left)
+            emit_left_mutations
+            emit(right)
+            emit_right_mutations
           end
 
         end # Binary