anchor.diff:  
   forUpdate
   	:	expressionList
  -	;
  -	
  -blockStatement
  -	:	localVariableDeclarationStatement
  -	|	statement
  -	; 
  +	;	
   
   // expressions
   parExpression
  
positive.code: 	;
  
  block
  	:	LBRACE blockStatement* RBRACE
  	;
  
  localVariableDeclarationStatement
  	:	localVariableDeclaration SEMI
  	;
  
  localVariableDeclaration
  	:	nonConstVariableDeclaration
  	|	constVariableDeclaration
  	;
  
  nonConstVariableDeclaration
  	:	VAR Identifier ASSIGN expression
  	;
  
  constVariableDeclaration
  	:	CONST nonConstVariableDeclaration
  	;
  	
  formalParameter
  
negative.code: script
  	:	functionDeclaration*
  	;
  	
  localVariableDeclaration
  	:	VAR Identifier ASSIGN expression
  	;
  
  functionDeclaration
  	:	FUNCTION Identifier formalParameters functionBody
  