[antlr-interest] Fixing grammar rule with trailing optional token
Terence Parr
parrt at jguru.com
Fri Jan 17 15:16:04 PST 2003
On Friday, January 17, 2003, at 02:50 PM, angryal2000
<angryal2000 at yahoo.ca> wrote:
> I am having difficulty trying to fix the following rule:
>
> data_type: FLOAT (OPENBRACKET INTEGER CLOSEBRACKET)? ;
>
> FLOAT="float";
> OPENBRACKET='(';
> CLOSEBRACKET=')';
> INTEGER=('0'..'9')+;
>
> e.g.
> "float" is accept by the rule data_type
> as is
> "float(23)"
>
>
> i know my rule is wrong, i am just not sure how to go about fixing it.
> any ideas? thanks.
We'll need more data to help. For example, is float(23) legal as a
data_type or not? Are you getting a nondeterminism warning? I suspect
that whoever is calling data_type can also match (... afterwards and
you are getting a warning. Is that it?
Terence
--
Co-founder, http://www.jguru.com
Creator, ANTLR Parser Generator: http://www.antlr.org
Lecturer in Comp. Sci., University of San Francisco
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