[antlr-interest] Context-Sensitive Follow Sets.. Bug?

Andrey Desyatov andrey.desyatov at gmail.com
Fri Oct 1 10:21:23 PDT 2010


Thanks, Jim for fast reply.

I can't give you any info about the grammar from May thread.
But in my grammar (the second link:
http://www.antlr.org/pipermail/antlr-interest/2010-September/039764.html)
I can see the same behavior (described at the link location).
Definitions for Identifier, WS, Comments and so on are typical
(according to the book "The Definitive ANTLR Reference: Building
domain-specific languages").
Could you have a look on my grammar and the problem?

Kind regards,
Andrey

2010/10/1 Jim Idle <jimi at temporal-wave.com>:
>
>
>> -----Original Message-----
>> From: Andrey Desyatov [mailto:andrey.desyatov at gmail.com]
>> Sent: Friday, October 01, 2010 9:28 AM
>> To: Jim Idle
>> Cc: antlr-interest at antlr.org
>> Subject: Re: [antlr-interest] Context-Sensitive Follow Sets.. Bug?
>>
>> Sorry, Jim for the confusing question.
>> I've tried to continue thread from May with subject "Context-Sensitive
>> Follow Sets.. Bug?"
>> (http://www.antlr.org/pipermail/antlr-interest/2010-May/038776.html),
>> but without success (it was my second post to mailing list and I couldn't
>> understand how to continue any thread).
>
> I had to remove the many stars from the grammar to see what it was:
>
> start: animal (AND acClass)? service EOF;
>
> animal: (DOG | CAT );
>
> service: (HARDWARE | SOFTWARE) ;
>
> AND: 'and';
>
> DOG: 'dog';
>
> CAT: 'cat';
>
> HARDWARE: 'hardware';
>
>
> SOFTWARE: 'software';
>
> acClass
> @init*
> {
>        System.out.println(computeContextSensitiveRuleFOLLOW().toString());
> }
> :
> ;
>
> And the OP says:
>
>
> Testing this grammar, with let's say input:
> "*dog and software*",
> the result in the console is:
> "{4, 7, 8}" (which stands for tokens {THE, HARDWARE, SOFTWARE}),
>
> However, the grammar given does not have a token for THE, or a specification
> for WS, or a grammar xzy;
>
> so the grammar is incomplete. I suspect that there is a problem with the
> grammar and not the followsets. If someone can give a complete example, then
> I can look at it
>
> Jim
>
>
>
>>
>> Description of my problem I've given in another thread:
>> http://www.antlr.org/pipermail/antlr-interest/2010-
>> September/039764.html.
>>
>
>
>
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