[27048] in Perl-Users-Digest
Perl-Users Digest, Issue: 8957 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Wed Feb 15 09:05:36 2006
Date: Wed, 15 Feb 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 Feb 2006 Volume: 10 Number: 8957
Today's topics:
Re: Arrays <christoph.lamprecht.no.spam@web.de>
Merging sparse arrays <samwyse@gmail.com>
Re: Merging sparse arrays (Anno Siegel)
Re: Modules <1usa@llenroc.ude.invalid>
Re: Modules <josef.moellers@fujitsu-siemens.com>
Re: Modules <1usa@llenroc.ude.invalid>
Re: The inverse problem: generate all instances of a re <someone@example.com>
Re: The inverse problem: generate all instances of a re <josef.moellers@fujitsu-siemens.com>
Re: The inverse problem: generate all instances of a re <1usa@llenroc.ude.invalid>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Wed, 15 Feb 2006 14:06:23 +0100
From: Ch Lamprecht <christoph.lamprecht.no.spam@web.de>
Subject: Re: Arrays
Message-Id: <dsv90f$28g$1@online.de>
Frank J. Russo wrote:
> Jim, Thanks, that is the most inspired view and what I was looking for.
> And I appreciate you not flaming me.
>
> I have tried a number of thing but not all of them worked. This is the
> better way to get to where I want to be.
>
> Followup question: I am feverishly going thru my books / notes / and
> documentation but have not located how do I write to a file and read in from
> a file a HASH?
>
perldoc Storable
HTH, Christoph
--
perl -e "print scalar reverse q/ed.enilno@ergn.l.hc/"
------------------------------
Date: Wed, 15 Feb 2006 12:55:48 GMT
From: Samwyse <samwyse@gmail.com>
Subject: Merging sparse arrays
Message-Id: <oxFIf.30309$F_3.6888@newssvr29.news.prodigy.net>
I have two arrays of equal length that contain null values. I want one
array with fewer nulls. This almost works:
push @t, shift(@f).shift(@g) while scalar @f;
except that every once in a while both arrays have values in the same
slot. This won't work at all:
push @t, shift(@f)||shift(@g) while scalar @f;
because the || operator short-circuits. Can anyone do this in one line,
or do I need do it the hard way:
while (scalar @f) {
($a, $b) = (shift(@f), shift(@g));
push @t, $a || $b;
}
------------------------------
Date: 15 Feb 2006 13:52:18 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: Merging sparse arrays
Message-Id: <dsvbmi$i0q$1@mamenchi.zrz.TU-Berlin.DE>
Samwyse <samwyse@gmail.com> wrote in comp.lang.perl.misc:
> I have two arrays of equal length that contain null values. I want one
> array with fewer nulls. This almost works:
>
> push @t, shift(@f).shift(@g) while scalar @f;
>
> except that every once in a while both arrays have values in the same
> slot. This won't work at all:
>
> push @t, shift(@f)||shift(@g) while scalar @f;
>
> because the || operator short-circuits. Can anyone do this in one line,
> or do I need do it the hard way:
>
> while (scalar @f) {
> ($a, $b) = (shift(@f), shift(@g));
> push @t, $a || $b;
> }
One way:
my @t = map shift @g || $_, @f;
That consumes @g but leaves @f intact.
Anno
--
If you want to post a followup via groups.google.com, don't use
the broken "Reply" link at the bottom of the article. Click on
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"Reply" at the bottom of the article headers.
------------------------------
Date: Wed, 15 Feb 2006 12:14:54 GMT
From: "A. Sinan Unur" <1usa@llenroc.ude.invalid>
Subject: Re: Modules
Message-Id: <Xns976B49D44B6CBasu1cornelledu@127.0.0.1>
<b_wayne@freeguestforum.com> wrote in
news:tFBIf.13$r76.1503315@news.salzburg-online.at:
> I am new with programming in perl. I was wondering, if there is an
> archive with perl modules which can be downloaded and used as well as
> a description of the functionalities of the modules.
Your question is frequently asked. You are expected to read the FAQ list
before posting:
perldoc -q module
Sinan
PS: Does this also count as a SAQ?
--
A. Sinan Unur <1usa@llenroc.ude.invalid>
(reverse each component and remove .invalid for email address)
comp.lang.perl.misc guidelines on the WWW:
http://mail.augustmail.com/~tadmc/clpmisc/clpmisc_guidelines.html
------------------------------
Date: Wed, 15 Feb 2006 14:01:00 +0100
From: Josef Moellers <josef.moellers@fujitsu-siemens.com>
Subject: Re: Modules
Message-Id: <dsv84n$vo0$1@nntp.fujitsu-siemens.com>
A. Sinan Unur wrote:
> <b_wayne@freeguestforum.com> wrote in
> news:tFBIf.13$r76.1503315@news.salzburg-online.at:=20
>=20
>=20
>>I am new with programming in perl. I was wondering, if there is an
>>archive with perl modules which can be downloaded and used as well as
>>a description of the functionalities of the modules.
>=20
>=20
> Your question is frequently asked. You are expected to read the FAQ lis=
t=20
> before posting:
>=20
> perldoc -q module
>=20
> Sinan
>=20
> PS: Does this also count as a SAQ?
It comes close, as it has "perl" and "archive", but not "comprehensive"=20
and "network".
--=20
Josef M=F6llers (Pinguinpfleger bei FSC)
If failure had no penalty success would not be a prize
-- T. Pratchett
------------------------------
Date: Wed, 15 Feb 2006 13:03:08 GMT
From: "A. Sinan Unur" <1usa@llenroc.ude.invalid>
Subject: Re: Modules
Message-Id: <Xns976B520169C17asu1cornelledu@127.0.0.1>
Josef Moellers <josef.moellers@fujitsu-siemens.com> wrote in
news:dsv84n$vo0$1@nntp.fujitsu-siemens.com:
> A. Sinan Unur wrote:
>> <b_wayne@freeguestforum.com> wrote in
>> news:tFBIf.13$r76.1503315@news.salzburg-online.at:
>>
>>
>>>I am new with programming in perl. I was wondering, if there is an
>>>archive with perl modules which can be downloaded and used as well as
>>>a description of the functionalities of the modules.
>>
>>
>> Your question is frequently asked. You are expected to read the FAQ
>> list before posting:
>>
>> perldoc -q module
>>
>> Sinan
>>
>> PS: Does this also count as a SAQ?
>
> It comes close, as it has "perl" and "archive", but not
> "comprehensive" and "network".
But it also has "module" which is the only word needed to find the
answer ;-)
Sinan
--
A. Sinan Unur <1usa@llenroc.ude.invalid>
(reverse each component and remove .invalid for email address)
comp.lang.perl.misc guidelines on the WWW:
http://mail.augustmail.com/~tadmc/clpmisc/clpmisc_guidelines.html
------------------------------
Date: Wed, 15 Feb 2006 11:50:15 GMT
From: "John W. Krahn" <someone@example.com>
Subject: Re: The inverse problem: generate all instances of a regexp
Message-Id: <XzEIf.2438$jh5.1857@edtnps84>
Andrei Alexandrescu (See Website For Email) wrote:
> I wonder how this could be done elegantly. Given a regular expression
> $re, write a function Generate($) that returns a list of all possible
> strings that could match $re. If the set is infinite, die with an error
> message.
>
> For example, if $re = '(debug|release)/progname\.(c|h)', Generate($re)
> should return four strings:
>
> 'debug/progname.c'
> 'debug/progname.h'
> 'release/progname.c'
> 'release/progname.h'
>
> If, on the other hand, $re = '(debug/release)/.*\.(c|h)' then
> Generate($re) should die.
That is not infinite, unless you know of a file system that can use infinitely
large file names.
John
--
use Perl;
program
fulfillment
------------------------------
Date: Wed, 15 Feb 2006 13:50:37 +0100
From: Josef Moellers <josef.moellers@fujitsu-siemens.com>
Subject: Re: The inverse problem: generate all instances of a regexp
Message-Id: <dsv7ht$uhu$1@nntp.fujitsu-siemens.com>
Andrei Alexandrescu (See Website For Email) wrote:
> I wonder how this could be done elegantly. Given a regular expression=20
> $re, write a function Generate($) that returns a list of all possible=20
> strings that could match $re. If the set is infinite, die with an error=
=20
> message.
>=20
> For example, if $re =3D '(debug|release)/progname\.(c|h)', Generate($re=
)=20
> should return four strings:
>=20
> 'debug/progname.c'
> 'debug/progname.h'
> 'release/progname.c'
> 'release/progname.h'
You do know, that your re would also match all strings that have=20
arbitrary pre- and postfix strings, such as
adebug/progname.c
bdebug/progname.c
cdebug/progname.c
=2E..
debug/progname.ca
debug/progname.cb
debug/progname.cc
=2E..
To name but a few ;-)
If you anchor your pattern, then you'r more safe:
$re =3D '^(debug|release)/progname\.(c|h)$'
Not being an expert in these trings, if you could somehow get a dfa for=20
your re, then you could recursively walk through the graph and construct =
what you want.
Josef
--=20
Josef M=F6llers (Pinguinpfleger bei FSC)
If failure had no penalty success would not be a prize
-- T. Pratchett
------------------------------
Date: Wed, 15 Feb 2006 13:01:22 GMT
From: "A. Sinan Unur" <1usa@llenroc.ude.invalid>
Subject: Re: The inverse problem: generate all instances of a regexp
Message-Id: <Xns976B51B502C40asu1cornelledu@127.0.0.1>
"Andrei Alexandrescu (See Website For Email)"
<SeeWebsiteForEmail@moderncppdesign.com> wrote in
news:Iupuns.1J37@beaver.cs.washington.edu:
> I wonder how this could be done elegantly.
Hmmm ... Please don't bury your question in the subject line.
Subject: The inverse problem: generate all instances of a regexp
> Given a regular expression $re, write a function Generate($) that
> returns a list of all possible strings that could match $re. If the
> set is infinite, die with an error message.
The YAPE::Regex modules might be of some help:
#!/usr/bin/perl
use strict;
use warnings;
use YAPE::Regex::Explain;
my $one = qr{(debug|release)/progname\.(c|h)};
my $two = qr{(debug/release)/.*\.(c|h)};
print YAPE::Regex::Explain->new($one)->explain, "\n",
YAPE::Regex::Explain->new($two)->explain, "\n";
> Any ideas on how to do that in a clever manner? (The only way that I
> think of is to parse $re and use recursion etc.)
I have to wonder, however, why you want to do this. There might be
another, more appropriate solution to the real problem you are trying to
solve.
Sinan
--
A. Sinan Unur <1usa@llenroc.ude.invalid>
(reverse each component and remove .invalid for email address)
comp.lang.perl.misc guidelines on the WWW:
http://mail.augustmail.com/~tadmc/clpmisc/clpmisc_guidelines.html
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
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End of Perl-Users Digest V10 Issue 8957
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