free_mutant/lib/mutant/mutator/call.rb

module Mutant
  class Mutator
    # Class for mutations where messages are send to objects
    class Call < self

      handle(Rubinius::AST::Send)

    private

      # Return receiver AST node
      #
      # @return [Rubinius::AST::Node]
      #
      # @api private
      #
      def receiver
        node.receiver
      end

      # Return name of call
      #
      # @return [Symbol]
      #
      # @api private
      #
      def name
        node.name
      end

      # Check if receiver is self
      #
      # @return [true]
      #   returns true when receiver is a Rubinius::AST::Self node
      #
      # @return [false]
      #   return false otherwise
      #
      # @api private
      #
      def self?
        receiver.kind_of?(Rubinius::AST::Self)
      end

      # Emit mutation that replaces explicit send to self with implicit send to self
      # 
      # @example:
      #
      #   # This class does use Foo#a with explicitly specifing the receiver self.
      #   # But an implicit (privately) call should be used as there is no need for 
      #   # specifing en explicit receiver.
      #
      #   class Foo         # Mutation
      #     def print_a     # def print_a
      #       puts self.a   #   puts a
      #     end             # end
      #
      #     def a
      #       :bar
      #     end
      #   end
      #
      #   There will not be any exception so the mutant is not killed and such calls where
      #   implicit receiver should be used will be spotted.
      #
      # @return [undefined]
      #
      # @api private
      #
      def emit_implicit_self_receiver
        # FIXME: Edge case that is currently not very well undestood
        return if name == :block_given?
        return unless self?
        mutant = dup_node
        mutant.privately = true
        # TODO: Fix rubinius to allow this as an attr_accessor
        mutant.instance_variable_set(:@vcall_style, true)
        emit(mutant)
      end

      # Emit mutations
      #
      # @return [undefined]
      #
      # @api private
      #
      def dispatch
        emit_implicit_self_receiver
      end

      class SendWithArguments < Call
        
        handle(Rubinius::AST::SendWithArguments)

      private

        # Emut mutations
        #
        # @return [undefined]
        #
        # @api private
        #
        def dispatch
          super
        end
      end
    end
  end
end