[27349] in Perl-Users-Digest
Perl-Users Digest, Issue: 9054 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Wed Mar 15 09:05:48 2006
Date: Wed, 15 Mar 2006 06:05:04 -0800 (PST)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Wed, 15 Mar 2006 Volume: 10 Number: 9054
Today's topics:
Re: A Problem With GD <tassilo.von.parseval@rwth-aachen.de>
Accessing package data through variable <a-brahme@ti.com>
Re: Can I skip tokens in RegExp backreferences? <invalid@earthlink.net.invalid>
Re: Can I skip tokens in RegExp backreferences? <uri@stemsystems.com>
Re: Can I skip tokens in RegExp backreferences? <invalid@earthlink.net.invalid>
Re: Can I skip tokens in RegExp backreferences? <invalid@earthlink.net.invalid>
Re: Can I skip tokens in RegExp backreferences? <invalid@earthlink.net.invalid>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Wed, 15 Mar 2006 10:37:30 +0100
From: "Tassilo v. Parseval" <tassilo.von.parseval@rwth-aachen.de>
Subject: Re: A Problem With GD
Message-Id: <47q5itFgsmpqU1@news.dfncis.de>
Also sprach robic0:
> But given the RGB function above, calling RGB(255,255,255) would be more appropriate.
> The difference is evals are mostly used, if its your purpose, to dynamically
> generate unknown code at runtime, then its evaluated. In the RGB case its a known form.
> In C/C++, macros are used for "substitution" by the pre-compiler. All instances of the
> macro are substituted for "real" code before compiling. Thats why there's always the
> perviable, "Beware of Macro's sideaffects" by certain documentation, since many C/C++
> constructs are macro's that are not intrinsics. For instance, long, short and byte
> are macro's.
As to all I know, this is utter nonsense. Do you have any documents
backing up that 'short' and 'long' are macros?
Tassilo
--
use bigint;
$n=71423350343770280161397026330337371139054411854220053437565440;
$m=-8,;;$_=$n&(0xff)<<$m,,$_>>=$m,,print+chr,,while(($m+=8)<=200);
------------------------------
Date: Wed, 15 Mar 2006 19:27:47 +0530
From: Amit Brahme <a-brahme@ti.com>
Subject: Accessing package data through variable
Message-Id: <dv96gt$h43$1@home.itg.ti.com>
Hi,
I want to know if perl can do following thing.
------------------------------------------------------------------------
I've a package and some variables defined in it, like below, in file
lets say "junk1.pm".
******************
package junk1;
$foo = "xyz";
$abc = "123";
******************
In my program I write a code like
******************
require "junk1.pm";
$myrf = "junk1";
print $junk1::foo;
******************
What I want is: instead of using
print $junk1::foo;
I want to use $myrf (which is defined as "junk1") to access variable
"foo" in package junk1.
I tried
print ${$myrf}::foo;
but perl gives error for this that it found barework foo. Is there any
way I can do something like this?
------------------------------------------------------------------------
Thanks and regards
Amit
------------------------------
Date: Wed, 15 Mar 2006 06:03:37 GMT
From: Someone Else <invalid@earthlink.net.invalid>
Subject: Re: Can I skip tokens in RegExp backreferences?
Message-Id: <Z6ORf.4368$k75.205@newsread3.news.atl.earthlink.net>
A. Sinan Unur wrote:
> Someone Else <invalid@earthlink.net.invalid> wrote in news:cSJRf.4199
> $sL2.327@newsread2.news.atl.earthlink.net:
>
>
>>What I want to do is to use a regular expression like:
>>
>> /([+-]\s*\d+)/;
[replacing part of your snip] but I don't want to capture the
\s* as part of $1.
>
>
> ...
>
>
>>What I am looking for is something like:
>>
>> /([+-](?:\s*)\d+)/;
[replacing more of your snip] but not quite. Not only don't I
want to capture the \s* in $2, but I want to exclude it from the
enclosing $1.
>
>
> #!/usr/bin/perl
>
> use strict;
> use warnings;
>
> my $s = '+ 42';
> $s =~ /([+-])\s*(\d+)/;
> print "$1$2\n";
[...]
> Why not state the precise problem instead of throwing variations at us?
I think I did state the precise question at the outset (although
you snipped much of the relevant part). It's a question of Perl
syntax and semantics, not of whether the problem can be
addressed in other ways. There are obvious workarounds. I
mentioned one, to distinguish workarounds from the underlying
question. You seem to have reproduced a few variants of that
workaround.
My question remains whether Perl regular expressions provide a
clean way to capture the "[+-]" and "\d+" of "/([+-]\s*\d+)/" in
$1, without capturing the "\s*".
-- David
To make invalid valid, reverse the letters
------------------------------
Date: Wed, 15 Mar 2006 01:29:18 -0500
From: Uri Guttman <uri@stemsystems.com>
Subject: Re: Can I skip tokens in RegExp backreferences?
Message-Id: <x7wtew43wh.fsf@mail.sysarch.com>
no.
uri
--
Uri Guttman ------ uri@stemsystems.com -------- http://www.stemsystems.com
--Perl Consulting, Stem Development, Systems Architecture, Design and Coding-
Search or Offer Perl Jobs ---------------------------- http://jobs.perl.org
------------------------------
Date: Wed, 15 Mar 2006 06:31:44 GMT
From: Someone Else <invalid@earthlink.net.invalid>
Subject: Re: Can I skip tokens in RegExp backreferences?
Message-Id: <kxORf.4374$k75.1559@newsread3.news.atl.earthlink.net>
Rick Scott wrote:
> (Someone Else <invalid@earthlink.net.invalid> uttered:)
>
>>What I am looking for is something like:
>>
>> /([+-](?:\s*)\d+)/;
>>
>>but not quite. Not only don't I want to capture the \s* in $2,
>>but I want to exclude it from the enclosing $1.
>>
>>Any ideas?
>>
>>...it's still easy to use:
>>
>> @a = /\s*([+-])\s*(\d+)/g;
>>
>>and then concatenate every pair of entries in @a.
>
>
> That's exactly the solution I was about to suggest -- capture two
> groups, then concatenate them.
[...]
> Have you tried and benchmarked this simpler solution yet? Looking for
> more efficient ways to do things is always laudable, but until you
> know whether or not your solution is intractably slow, you don't
> really know whether or not you actually have a problem worth solving.
I'm already using the simple solution (and it runs just fine),
but it's ugly when mixed into the larger parsing problem. It's
mostly just an issue I never ran into before, although it looks
like a natural thing to want to do. I couldn't find a clean way
to handle it, so I thought I'd ask.
> Cheers,
> Rick
And cheers to you.
-- David
To make invalid valid, reverse the letters
------------------------------
Date: Wed, 15 Mar 2006 06:38:04 GMT
From: Someone Else <invalid@earthlink.net.invalid>
Subject: Re: Can I skip tokens in RegExp backreferences?
Message-Id: <gDORf.4375$k75.3703@newsread3.news.atl.earthlink.net>
Dr.Ruud wrote:
> Someone Else schreef:
>
>
>>What I want to do is to use a regular expression like:
>>
>> /([+-]\s*\d+)/;
>>
>>to parse some fairly complicated algebraic expressions; but I
>>don't want to capture the \s* as part of $1. [...]
>>it's still easy to use:
>>
>> @a = /\s*([+-])\s*(\d+)/g;
>>
>>and then concatenate every pair of entries in @a. But as I said,
>>the real application is much more complicated.
>
>
> If that second approach is not feasible, and I can't guess why not, than
> you'd better add a step:
> 1. remove all meaningless whitespace etc.
> s/([+-])[[:blank:]]+(\d)/$1$2/g;
> 2. do the captures
Yes, there are several perfectly servicable workarounds. I was
just wondering whether it could be done directly. It would be a
lot cleaner (in the context of the larger parsing problem) if
there were a way.
> But my real advise is to use Yacc/Lex, because then you can convert 40
> MB in a few seconds.
Now that _would_ be overkill (:-).
-- David
To make invalid valid, reverse the letters
------------------------------
Date: Wed, 15 Mar 2006 06:56:42 GMT
From: Someone Else <invalid@earthlink.net.invalid>
Subject: Re: Can I skip tokens in RegExp backreferences?
Message-Id: <KUORf.12644$S25.10011@newsread1.news.atl.earthlink.net>
Uri Guttman wrote:
> no.
>
> uri
I suspected as much, but thanks for confirming it.
-- David
To make invalid valid, reverse the letters
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>
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End of Perl-Users Digest V10 Issue 9054
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