[antlr-interest] Reg Multi-line comments

[Gokulakannan Somasundaram]

Hi David-Sarah Hopwood,
                     Sorry i missed your post and failed to reply.
                     Yes this solution works well in Java. But the problem
is that i am trying to do in C++(C), and this is not possible there. So i am
introducing the state information with the  Nevertheless, it is a very
thoughtful solution and thanks for helping me out.

Thanks,
Gokul.


On Fri, Jul 17, 2009 at 11:03 AM, David-Sarah Hopwood <
david-sarah at jacaranda.org> wrote:

> Gokulakannan Somasundaram wrote:
> > Actually there is a comment like this before the source code of the
> > function.
> >
> >     /** A more general version of getRuleInvocationStack where you can
> >      *  pass in, for example, a RecognitionException to get it's rule
> >      *  stack trace.  This routine is shared with all recognizers, hence,
> >      *  static.
> >      *
> >      *  TODO: move to a utility class or something; weird having lexer
> call
> >      *  this */
> >     public static List getRuleInvocationStack(Throwable e,
> >                                               String recognizerClassName)
> >
> >
> > It more or less sounds to me that lexer should not call this.
>
> The recipe in section 10.2 of 'The Definitive ANTLR Reference' does so,
> therefore it's a supported API, not internal. Moving it would break all
> lexers using that recipe.
>
> Calling the static version of this method rather than the instance
> version (with no arguments) is correct: if you don't obtain the stack
> from the RecognitionException that is passed to getErrorMessage, then
> the relevent lexer rule will no longer be on the current stack in some
> cases.
>
> > When i observe
> > the source code, i see that your approach may not be possible, because
> the
> > token to be tried out never gets saved anywhere. But let me check this.
>
> It is possible because the implementation uses a stack trace to determine
> which lexer methods were on the call stack when the RecognitionException
> was thrown, and so no explicit state is needed. In any case, I tested this
> code before posting; it works.
>
> --
> David-Sarah Hopwood  ⚥  http://davidsarah.livejournal.com
>
>
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