anchor.diff:  or_expression:
   	unary_relationexpression ('&&' unary_relationexpression)*;
   
  -unary_relationexpression: ('!' unary_relationexpression)
  -	| relation_expression;
  +unary_relationexpression: '!'? relation_expression;
   
  -relation_expression: (add_expression relop add_expression)
  -	| add_expression;
  +relation_expression: add_expression (relop add_expression)*;
   
   relop: '<=' | '>=' | '==' | '!=' | '>' | '>';
   
  
positive.code: 
  WHILE: 'WHILE';
  
  INTEGER: ('+' | '-')? [1-9][0-9]*;
  
  ID: [a-zA-Z][a-z0-9A-Z_]*;
  
  STRINGLITERAL: '"' .*? '"';
  
  
negative.code: 
  addop: '-' | '+';
  
  term: factor (multop factor)*;
  
  multop: '*' | '/' | '%';
  
  factor: '(' simple_expression ')' | constant;
  
  constant:
  	integer
  	| TRUE
  	| FALSE
  	| 'next'
  