anchor.diff:  	language  = "Python";
   }
   
  +
   class atermLexer extends Lexer;
   
   tokens {
  
positive.code: }
  
  // Whitespace -- ignored
  WS	: ( ' ' | '\t' | '\f' )+ { $setType(SKIP); }
  	| ( '\r' ('\n')? | '\n') { $newline; $setType(SKIP); }
  	;
  
  REAL_OR_INT	
  
negative.code: 		{ res = elms }
  	| LPAREN args=aterms RPAREN
  		{ res = self.factory.makeAppl(self.factory.makeStr(""), args) }
  	| 
  		cname:CONS
  			{ res = self.factory.makeStr(cname.getText()) }
  		( LPAREN args=aterms RPAREN
  			{ res = self.factory.makeAppl(res, args) }
  		|
  			{ res = self.factory.makeAppl(res) }
  		)
  	|
  		( vname:VAR
  			{ res = self.factory.makeVar(vname.getText()) }
  