Forwarded on behalf of Ron D. Smith
------- Forwarded message follows -------
To: "Peter van der Kamp" <[EMAIL PROTECTED]>
Subject: Re: Matching subrules
Date sent: Mon, 23 Jun 2003 10:02:32 -0700
From: "Ron D. Smith" <[EMAIL PROTECTED]>
I'm not sure why you are confused, particularly with
tracing on. You
are asking for a 'Criteria' which is a 'zoekVraag
/\D/'
You then give it your string which CORRECTLY parses:
"medium='d' or medium='f' a"
This is obviously a zoekVraag followed by a non-
digit.
Your grammar clearly does not preclude extra stuff
at the end of the
string and you do not specify that the string must
be completely
consumed.
I don't know what you want but there are at least
two ways to get your
grammar to fail. The first is the non-digit regx,
which does not
specify that you have nothing after the non-digit.
Criteria:zoekVraag /\D\b/
will force the non-digit to be a single character.
This does not
necessarily generate the nice error messages you
might like but does
return undef. You also might make the following
modification:
Criteria:zoekVraag /\D/ /^\Z/
This will also fail. The two suggestions are, of
course, not mutually
exclusive.
What was important about the trace was not what it
*parsed*, but WHAT
IT LEFT OVER. What you seem to be objecting to was
that it did not
try and consume the entire input, but you never told
it that it had
to.
On Monday, Jun 23, 2003 "Peter van der Kamp" said:
> I'm wondering why my grammar (see hereafter) accepts
> the following input:
> medium='d' or medium='f' ant topic='t'
>
> while it should raise an error on 'ant'.
> With tracing enabled you can see that it really does
> something with 'ant', except raising an error.
>
> Peter van der Kamp
>
>
> use Parse::RecDescent;
> #$::RD_TRACE=100;
>
> my $grammar = q{
> Criteria:zoekVraag /\D/
>
> zoekVraag:
> basisZoekVraag (operator basisZoekVraag)(s)
> |
> <error>
>
> basisZoekVraag:
> mediumZoekVraag
> |
> onderwerpZoekVraag
> |
> titelZoekVraag
> |
> auteurZoekVraag
> |
> periodZoekVraag
> |
> <error>
>
> mediumZoekVraag:
> 'medium=' zoekString
>
> onderwerpZoekVraag:
> 'topic=' zoekString
>
> titelZoekVraag:
> 'title=' zoekString
>
> auteurZoekVraag:
> 'author=' zoekString
>
> periodZoekVraag:
> rangePeriodZoekVraag
> |
> singlePeriodZoekVraag
>
> singlePeriodZoekVraag:
> 'p=' cijfers
>
> rangePeriodZoekVraag:
> 'p=' cijfers '-' cijfers
> |
> 'p=' '-' cijfers
> |
> 'p=' cijfers '-'
>
> operator:
> /or|and/
> |
> <error>
>
> zoekString: /\'[a-zA-Z:\. ]+\'/
> cijfers: /[0-9]{4}/
> };
>
> my $parser = new Parse::RecDescent($grammar);
> undef $/;
> my $text = <STDIN>;
> #print Data::Dumper->Dump([$parser-
> >Criteria($text)]);
> $result = $parser->Criteria($text);
>
>
--
Intel, Corp.
5000 W. Chandler Blvd.
Chandler, AZ 85226
--
Intel, Corp.
5000 W. Chandler Blvd.
Chandler, AZ 85226
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