On Mon, 23 Jun 2003, [EMAIL PROTECTED] wrote:
> 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.
Could I ask you to please condense your example grammar to the
smallest unit that exhibits a bug?
I think your definition of zoekVraag doesn't work:
> zoekVraag:
> basisZoekVraag (operator basisZoekVraag)(s)
Parse::RecDescent grammars work better with two-part recursive
definitions; see below for how your grammar could work (I shortened it
for the example, but it should be clear how to do your whole grammar).
The $return actions make debugging easier. You could also do
<autotree>.
I'm not sure why your Criteria rule has the /\D/ match, it works fine
without it on your example text and with it you'll miss some data. \D
will match just one non-digit character (also non-space unless you
override your skip); is that what you really want?
There is no need to quote ' characters in a regular expression (the
zoekString rule).
HTH
Ted
#!/usr/bin/perl -w
use strict;
use Parse::RecDescent;
use Data::Dumper;
#$::RD_TRACE=100;
my $grammar = q{
# Criteria:zoekVraag /\D/
Criteria: zoekVraag(s)
zoekVraag:
basisZoekVraag | compoundZV | <error>
compoundZV: operator zoekVraag { $return = { operator => $item{operator}, zv =>
$item{zoekVraag} }; 1; }
basisZoekVraag:
mediumZoekVraag | onderwerpZoekVraag
|
<error>
onderwerpZoekVraag:
'topic=' zoekString { $return = { topic => $item{zoekString} }; 1; }
mediumZoekVraag:
'medium=' zoekString { $return = { medium => $item{zoekString} }; 1; }
operator:
/or|and/
|
<error>
zoekString: /'[a-zA-Z:\. ]+'/
};
my $parser = new Parse::RecDescent($grammar);
undef $/;
my $text = "medium='d' or medium='f' and topic='t'";
my $result = $parser->Criteria($text);
print Dumper($result);
