anchor.diff:  
   // binary addition/subtraction (level 3)
   additiveExpression
  -	:	multiplicativeExpression ((PLUS^ | MINUS^) multiplicativeExpression)*
  +	:	multiplicativeExpression (options{warnWhenFollowAmbig=false;} : (PLUS^ | MINUS^) multiplicativeExpression)*
   	;
   
   
  
positive.code: postfixExpression
  	:	primaryExpression // start with a primary
  
  		(	// qualified id (id.id.id.id...) -- build the name
  			DOT^
  			( (typeArguments[false])?
  			  ( IDENT
  
negative.code: 	;
  
  lambdaBody
  	:	(options{generateAmbigWarnings=false;}: expression 
  	|	statement)
  	;
  inferredParameterList
  	:	IDENT (COMMA IDENT)*
  