anchor.diff:  multDivExpr : atom        ( multDiv^        atom)* ;
   
   
  - addMin : '+'|'-' ;
  -multDiv : '*'|'/' ;
  -   comp : '<'|'>'|'<='|'>='|'='|'<>' ;
  -    and : '&' ;
  -     or : '|' ;
  - assign : ':=' ;
  +addMin  : PLUS|MINUS ;
  +multDiv : MULT|DIV ;
  +  comp  : SUP|INF|SUP_EQ|INF_EQ|EQ|DIFF ;
  +   and  : AND ;
  +    or  : OR ;
  +assign  : ASSIGNE ;
  
positive.code: tokens {
    INSTRUCTIONS; LET; WHILE; FOR; IF; BREAK; RETURN;
    DECLARATIONS; VAR_DECLARATION; FUNC_DECLARATION; PARAMS; PARAM;
    EXPR; ASSIGNE; OR; AND; COMP; MULT; ADD;
    FUNC_CALL; ARGS; STR; INT; NEG; NIL;
  }
  
  
negative.code: 
  
  args
    : '(' (expr (',' expr)*)? ')'                                                 -> ^(FUNC_CALL ^(ARGS expr*))
    ;
  
  
  