[antlr-interest] Grammar help

[Brian Catlin]

(Brian slaps head again), "Duh!"  Sigh.  Sometimes, I really wonder whether
I'm overpaid ;-}

You fixed it!

Thank you very much for your help!!

 -Brian


-----Original Message-----
From: antlr-interest-bounces at antlr.org
[mailto:antlr-interest-bounces at antlr.org] On Behalf Of Bart Kiers
Sent: Tuesday, March 16, 2010 15:33
To: antlr-interest at antlr.org
Subject: Re: [antlr-interest] Grammar help

On Tue, Mar 16, 2010 at 8:10 AM, Brian Catlin <BrianC at sannas.org> wrote:

> While that gets rid of those warnings (why don't the warnings print a 
> reasonable line number?  I would call that a BUG),


Note that the '!' is a valid operator inside your grammar, ANTLR just
assumes that you're building trees. So, you're not doing anything wrong.
But, yes, a warning with the line number of the improper use of rewrite
operators would be nice.


 On Tue, Mar 16, 2010 at 8:10 AM, Brian Catlin <BrianC at sannas.org> wrote:

> the fundamental problem
> of being able to parse (or otherwise capture the file name) still exists.
>
> Any ideas?
>

The error message is telling that your FILE_NAME is ambiguous. When matching
one or more characters from:

~('|' | '<' | '>' | '*' | '?')+

then line breaks will also be matched, yet after that, the following could
be matched:

('\r'? '\n')

which has already been "eaten" by the previous part of your rule. You could
fix that by adding line breaks to that first part of your rule, like this:

FILE_NAME    :  ~('|' | '<' | '>' | '*' | '?'| '\r' | '\n')+ (('\r'? '\n') |
EOF);

Regards,

Bart.

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