Bison derivation order

Hi I'm using bison for a school project, but I'm having an problem i got the next rules:

callsubrotina : callfunction | callprocedure;

callprocedure: 
        T_IDENTIFICADOR
        {identifier_check( GOTO, $1, TIPO_PROCEDIMENTO );} 
    |   T_IDENTIFICADOR  T_PARENTESE_E listaexpressoes T_PARENTESE_D
        {identifier_check( GOTO, $1, TIPO_PROCEDIMENTO );} 
    ;

callfunction: 
        T_IDENTIFICADOR
        {identifier_check( LD_VAR, $1, TIPO_FUNCAO );} 
    |   T_IDENTIFICADOR  T_PARENTESE_E lis开发者_运维百科taexpressoes T_PARENTESE_D
        {identifier_check( LD_VAR, $1, TIPO_FUNCAO );} ;

The problem is bison always goes to "callprocedure" even if this trigger an error. How can I force it to check both the rules? Or how I can create a rule to treat properly?

PS: Sorry for the bad English folks.

Since the syntax of the a 'callprocedure' and a 'callfunction' is identical in the rules shown, there is no way for Bison (or any other analogous tool) to distinguish between them.

You must have a conceptual difference - maybe a procedure returns no value and a function does return a value. But unless there is some syntactic way to identify that a particular call belongs to a function and not to a procedure, you will always get the first written rule executed. You should also be getting a warning about an unused rule.

One possibility: if your functions and procedures must be declared before they can be called, so you can tell whether a given name belongs to a function or procedure, then you could modify the lexical analyzer to say 'this is a FUNCTION NAME' and 'that is a PROCEDURE NAME', and then the grammar could be:

callsobrotina: callprocedure | callfunction ;

callprocedure:
        T_PROCEDURE_NAME
    |   T_PROCEDURE_NAME T_PARETESE_E listaexpressoes T_PARENTES_D
    ;

callfunction:
        T_FUNCTION_NAME
    |   T_FUNCTION_NAME T_PARETESE_E listaexpressoes T_PARENTES_D
    ;