anchor.diff:  		|	OR
   		)
   		expression	# BinaryExpression
  -	|	(NormalIdentifier | PropertyIdentifier) 
  +	|	<assoc=right> expression QUESTION expression COLON expression		# TernaryOpExpression
  +	|	<assoc=right> (NormalIdentifier | PropertyIdentifier) 
   		Operator=(
   			ASSIGN
   		|	MUL_ASSIGN 
  
positive.code: 	|	Literal						# LiteralExpression
  	|	NormalIdentifier			        # NormalIdentifierExpression
  	|	PropertyIdentifier					# PropertyIdentifierExpression
  	|	(NormalIdentifier|PropertyIdentifier) Operator=(INC|DEC)		# PostIncDecExpression
  	|	Operator=(
  			SUB
  
negative.code: 		|	SUB_ASSIGN
  		)
  		expression  # AssignmentExpression
  	;
  	
  /*
  