[antlr-interest] Choosing token
Terence Parr
parrt at cs.usfca.edu
Fri May 11 09:34:53 PDT 2007
On May 11, 2007, at 9:19 AM, Johannes Luber wrote:
> Stefan Chrobot wrote:
>> Hello!
>>
>> Is there a way other than reordering the rules to tell ANTLRv3 to
>> prefer
>> token BOOLEAN instead of IDENTIFIER?
>>
>> grammar Test;
>>
>> start : BOOLEAN
>> | IDENTIFIER;
>>
>> IDENTIFIER
>> : ('a'..'z'|'A'..'Z'|'0'..'9')+;
>>
>> BOOLEAN : 'true' | 'false';
>
> Yes. Look at
> <http://www.antlr.org/wiki/display/ANTLR3/Quick+Starter+on+Parser
> +Grammars+-+No+Past+Experience+Required>
> in the "How to define tokens" section for more information.
I'm not sure Johannes (excellent) tutorial says it explicitly: the
order in which you define lexical rules gives the priority. Put
BOOLEAN before IDENTIFIER. :)
Ter
More information about the antlr-interest
mailing list