anchor.diff:  // Identifiers
   Identifier
   	:	Letter LetterOrDigit*
  +	|	ContextIdentifier
  +	;
  +
  +ContextIdentifier
  +	: '$' Identifier
   	;
   
   fragment
   Letter
  -	:	[a-zA-Z]
  +	:	[a-zA-Z_]
   	;
   
   fragment
   LetterOrDigit
  -	:	[a-zA-Z0-9]
  +	:	[a-zA-Z0-9_]
   	;
   
   WS 
  
positive.code: 	;
  
  functionDeclaration
  	:	'function' Identifier formalParameters
  		(
  			functionBody
  			|
  			';'
  		)
  	;
  
  functionBody
  
negative.code: 
  fragment
  Digits
  	:	Digit+
  	;
  
  fragment
  