anchor.diff:  		'=' expression(&exp)	 { assign(var,exp); }
   	;
   
  -lineinputstmt { int var,intv; }
  +lineinputstmt { int var; int intv; }
   	: 	LINESYM
   		[ INPUTSYM
   	  	  semiprompt		 { setchannel(-1); }
  
positive.code: 		]
  	    ;
  	
  swapstmt { int var1,var2; }
  	: SWAPSYM
  	  variable(&var1)
  	  ','
  
negative.code: 	: variable(&var)	{ readelm(var); }
  	;
  
  lsetstmt { int var; int exp; }
  	:	LSETSYM variable(&var) '=' expression(&exp)
  				{ notyetimpl(); }
  	;
  