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From: Peter J. Holzer on 24 Apr 2010 15:04
On 2010-04-24 18:45, C.DeRykus <derykus(a)gmail.com> wrote:
> On Apr 24, 8:53�am, "freesof...(a)gmail.com" <freesof...(a)gmail.com>
> wrote:
>> Thanks for the pointer to the perldoc section! I tried this suggestion
>> in that section and I did not get the newline problem:
[...]
>> my $parser = Parse::RecDescent->new($grammar);
>>
>> open(IN,"data.txt") or die "Cannot open data.txt";
>> my $var = do { local $/; <IN> };
>> defined $parser->start($var) or die "Didn't match anything";
[...]
> And you don't really need to slurp:
>
> while (<IN>)
> {
> defined $parser->start($_)
> or die "Didn't match anything";
> }

That parses every line separately which is in general not the same as
parsing a whole file.

hp
From: C.DeRykus on 24 Apr 2010 18:11
On Apr 24, 12:04 pm, "Peter J. Holzer" <hjp-usen...(a)hjp.at> wrote:
> On 2010-04-24 18:45, C.DeRykus <dery...(a)gmail.com> wrote:
>
> [...]
> > And you don't really need to slurp:
>
> > while (<IN>)
> > {
> >         defined $parser->start($_)
> >               or die "Didn't match anything";
> > }
>
> That parses every line separately which is in general not the same as
> parsing a whole file.
>

Right, a simple example like the OP's, doesn't but even
a slightly more complex grammar could. For instance, if
the grammar required a blank line too:


start: identifier(s) blank

identifier : /\S+/
{ print $item[1],"\n"; }

blank: /^$/
{ print "blank...\n"; }


Then, you'd need to slurp... I think.

--
Charles DeRykus
From: freesoft12 on 29 Apr 2010 18:44

I can't slurp as my orig grammar has a hierarchy to it (meaning that
the identifiers belong to a group and that group belongs to another
etc). I only used a small example to post. I will have to slurp the
whole file rather than passing in every line.

Regards
John
From: freesoft12 on 29 Apr 2010 18:45
Thanks for the tip! I will try it out.

Regards
John

From: Uri Guttman on 29 Apr 2010 19:42
>>>>> "fc" == freesoft12(a)gmail com <freesoft12(a)gmail.com> writes:

fc> I can't slurp as my orig grammar has a hierarchy to it (meaning that
fc> the identifiers belong to a group and that group belongs to another
fc> etc). I only used a small example to post. I will have to slurp the
fc> whole file rather than passing in every line.

that makes no sense as that is what slurping is - reading in the whole
file at one time into an array or scalar. sometimes parsing is much
easier and faster when the entire file is in a scalar. since P::RD can't
parse incrementally it does better when you slurp. and yes, slurping is
the technical term! check out File::Slurp for more.

uri

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