Re: Usage of C++ parser with C++ flex scanner

[Michael Brandt]

Hi,

2006/5/23, Toly Kournik <address@hidden>:
> I'm trying to integrate generated C++ Bison parser with generated C++
> Flex scanner.
> The goal is to do it without generated code intervention.
> There are several questions:
> 1. How can I cause generated Parser::parse() method to call
> Lexer::yylex() instead of yylex() ?

You could try the following (untestet). Write a global yylex-Function
that is called from bison. Use the bison directive %lex-param to pass
your Flexer:

%lex-param {MyFlexLexer* lexer}

Then call the lexer->yylex() method from this function:

int yylex(MyFlexLexer* lexer) {
  return lexer->yylex();
}

When you have more arguments use more %lex-params and just pass them
through the global yylex-Function.

> 2. How can I tell Lexer::yylex() to receive parameters?

in your derived class from yyFlexLexer declare the yylex-Function as
you like it:

class MyFlexLexer : public yyFlexLexer {
// ...
  public:
     int yylex(int foo, std::string& bar);
// ...
}

then redefine YY_DECL to  MyFlexLexer::yylex(int foo, std::string& bar);

Regards,
Michael