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Re: stupid format question
From: |
Tim Van Holder |
Subject: |
Re: stupid format question |
Date: |
28 Feb 2003 11:07:04 +0100 |
On Thu, 2003-02-27 at 23:07, Urdaneta, Alfonso E (N-Summitt
Technologies) wrote:
> I have an IEEE language definition that looks like so:
>
> noun-field:
> { noun |
> noun-name } [ "USING" label-identifier ];
>
> now my first thought is that in bisonland this would look like so (I have
> omitted dependencies)
>
> noun_field:
> { noun | noun_name }
> | noun_field USING_TOKEN label_identifier
> ;
Don't use recursion if you don't want a sequence.
The rules below should do what you want (I am assuming the [] around the
USING clause mean that it is optional; if not, drop the 'optional_'
prefix from the rule, and remove its 'empty' part).
noun_field
: noun_or_noun_name optional_using_label
;
noun_or_noun_name
: noun
| noun_name
;
optional_using_label
: /* empty */
| USING_TOKEN label_identifier
;
--
Tim Van Holder <address@hidden>