From: Minero Aoki <aamine@...>
Date: 2004-02-28T22:23:25+09:00
Subject: Re: [RACC] Multiple entry points?

Hi,

  In mail "[RACC] Multiple entry points?"
    Carlos <angus@quovadis.com.ar> wrote:

> imagine I have a parser like this:
> 
> program: PROGRAM name '{' statements '}' { ... }
>   ;
> 
> statements: statement { ... }
>           | statements statement { ... }
>   ;
> 
> statement: ...
> 
> and I want to parse a single statement. How I can tell the parser to
> start at 'statement' and return?

Use dummy token.

  targets: PARSE_PROGRAM program        /* PARSE_PROGRAM is a dummy token */
         | PARSE_STATEMENT statement    /* PARSE_STATEMENT is a dummy token */
         ;

  program: ....

  statement: ....

When you want to parse "program", a lexer returns PARSE_PROGRAM at first.
When you want to parse "statement", a lexer returns PARSE_STATEMENT at first.


Regards,
Minero Aoki