[26274] in Perl-Users-Digest
Perl-Users Digest, Issue: 8456 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Mon Sep 26 06:05:35 2005
Date: Mon, 26 Sep 2005 03:05:05 -0700 (PDT)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Mon, 26 Sep 2005 Volume: 10 Number: 8456
Today's topics:
Re: complete manual and reference <joe@inwap.com>
Re: FAQ 4.42 How can I tell whether a certain element i <segraves_f13@mindspring.com>
How do I get more-detailed directory info? <bogus.address@no.spam.com>
print @{1} versus print @{11} <fishfry@your-mailbox.com>
Re: print @{1} versus print @{11} <tassilo.von.parseval@rwth-aachen.de>
Re: Script for migrating HTML tree into a single direct <panam@nospam.com>
Re: script to run the program <joe@inwap.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Sun, 25 Sep 2005 23:59:23 -0700
From: Joe Smith <joe@inwap.com>
Subject: Re: complete manual and reference
Message-Id: <VJmdnfSJ-v_QAareRVn-tg@comcast.com>
nobody wrote:
> where can i get a complete manual and a complete reference for understanding
> perl language?
Start -> Programs -> ActivePerl -> Documentation
has the same info as
http://aspn.activestate.com/ASPN/Perl/Reference/
In other words, install perl on your computer and you will have
the documentation on your hard drive.
-Joe
------------------------------
Date: Mon, 26 Sep 2005 02:07:47 GMT
From: "Bill Segraves" <segraves_f13@mindspring.com>
Subject: Re: FAQ 4.42 How can I tell whether a certain element is contained in a list or array?
Message-Id: <TJIZe.4215$QE1.770@newsread2.news.atl.earthlink.net>
<axel@white-eagle.invalid.uk> wrote in message
news:v6DZe.7097$fl6.6646@fe2.news.blueyonder.co.uk...
> Bill Segraves <segraves_f13@mindspring.com> wrote:
> > "John Bokma" <john@castleamber.com> wrote in message
>
> >> Write? Does it have to be in Perl? There is plenty of Wiki software
etc.
> >> out there, probably not written in Perl, but I don't care about that.
The
> >> OS I use is not written in Perl either :-)
>
> > OTOH, there is at least one that *is* written in Perl, e.g.,
>
> > http://c2.com/cgi/wiki?QuickiWiki
> > http://c2.com/cgi/wiki?ClusterWiki
> > http://www.wiki.org/
>
> >> So what are the next steps to have a Perl wiki? Especially for the FAQ
> >> part?
>
> > 1. Download and install QuickiWiki.
> > 2. Write a script to extract Usenet clpm postings from the PerlFAQ
server
> > into Wiki format.
>
Somehow the smiley face I put with my suggestion was dropped. Sorry you
missed the subtle point, e.g.,
"Please let us know when you have it up and running, John. ;-)"
OTOH, I may have misread the context of John's remarks, thinking the issue
was about *if* a Perl FAQ *could* be implemented as a Wiki, rather that *if*
such a Perl FAQ *should* be implemented. I was already aware that a well
established process for ongoing development of the Perl FAQ is already in
place, e.g., see http://faq.perl.org/.
> And then decide both on a political and technical level how and when the
> actual FAQ would be updated; or *if* changes would be fed back in or
should
> the Wiki version would just develop separately as an additional resource.
>
> Axel
>
Quite so, Axel. I was just trying to answer the questions posed by John
Bokma. Whether such a FAQ *should* be done is another issue, as you have
stated.
The only issue I have with your statement is that the phrase "And then"
should be replaced with "First,".
Cheers.
--
Bill Segraves
------------------------------
Date: Mon, 26 Sep 2005 09:47:13 GMT
From: "Robbie Hatley" <bogus.address@no.spam.com>
Subject: How do I get more-detailed directory info?
Message-Id: <BsPZe.406$Y_5.123@newssvr11.news.prodigy.com>
Greetings, group. This is the first time I've posted here,
or in any Perl-related forum for that matter. I'm a rank
beginner at Perl. I'm trying to teaching myself the language
from reading books (incl. one with a camel on the cover, and
one with a llama; not that anyone here would recongize those,
of course), trying my own Perl hacks, and struggling
with compiler errror messages.
The training program I'm currently trying to write is a
duplicate-file finding/removing program. A rather elaborate
program when written in C++. An engineer friend told me it
would be much simpler in Perl. I had to tell him, "Cool, but
I don't know Perl". He seemed offended and said "Your loss.".
So... pasted below is my first (incomplete) attempt at writing
a real Perl program.
I have hundreds of questions about Perl, but for now I'll
ask this group just two questions:
1:
How do I get a more-detailed directory listing than is offered
by the readdir function? Is their any way to goad that
function into coughing-up file-type (file or directory or link),
size in bytes, mod-time, mod-date, attribtutes, etc.? Or do I
have to use some other approach to get that data?
2:
Is there a better way to emulate the C++ concept of a "list of
structs" than what I'm doing below? (I'm using an array of refs
to hashes.)
Here's my program at it's current state of development:
################################################################################
##########
# dedup3.perl
# Duplicate file finding/erasing program.
# Written by Robbie Hatley, as a "learn Perl" excercise.
# Plan: Recursively decend directory tree starting from current working
directory,
# and make a master list of all files encountered on this branch. Order the
list by size.
# Within each size group, compare each file, from left to right, to all the
files to
# its right. If a duplicate pair is found, alert user and get user input. Give
user
# these choices:
# 1. Erase left file
# 2. Erase right file
# 3. Ignore this pair of duplicate files and move to next
# 4. Quit
# If user elects to delete a file, delete it, then move to next duplicate file
pair.
################################################################################
##########
use strict;
use warnings;
use Cwd;
# Not valid Perl; how do I do this???
# struct FileRecord
# {
# std::string Date;
# std::string Time;
# std::string Type;
# long int Size;
# std::string Attr;
# std::string Name;
# };
#
# std::list<rhdir::FileRecord> FileList;
#
# TODO: How do I extract size, mod-time, mod-date, type (file or dir),
# attributes, etc. and store in an array of structs (or Perl equiv)???
#
# Try an array of hashes?
my $CurDir = getcwd();
print "CWD = ", $CurDir, "\n";
opendir(Dot, ".") or die "Can\'t open the directory!!!";
my @LocalFiles;
my $FileName;
my $FileRecord;
while ($FileName=readdir(Dot))
{
$FileRecord=
{
"Date" => "Unknown",
"Time" => "Unknown",
"Type" => "Unknown",
"Size" => 42,
"Attr" => "Unknown",
"Name" => $FileName
};
push @LocalFiles, $FileRecord;
}
closedir(Dot);
foreach $FileRecord (@LocalFiles)
{
print($$FileRecord{"Name"}, "\n");
}
--
Cheers,
Robbie Hatley
Tustin, CA, USA
email: lonewolfintj at pacbell dot net
web: home dot pacbell dot net slant earnur slant
------------------------------
Date: Sun, 25 Sep 2005 21:53:32 -0700
From: fishfry <fishfry@your-mailbox.com>
Subject: print @{1} versus print @{11}
Message-Id: <fishfry-3FCA59.21533225092005@comcast.dca.giganews.com>
Can someone please explain this result?
print @{1}
compiles but doesn't print anything.
@{11}
throws "Can't use string ("11") as an ARRAY ref while "strict refs" in
use"
This one's really got me going. Perl 5.8.7.
------------------------------
Date: Mon, 26 Sep 2005 09:13:24 +0200
From: "Tassilo v. Parseval" <tassilo.von.parseval@rwth-aachen.de>
Subject: Re: print @{1} versus print @{11}
Message-Id: <slrndjf7sk.ra.tassilo.von.parseval@localhost.localdomain>
Also sprach fishfry:
> Can someone please explain this result?
>
> print @{1}
>
> compiles but doesn't print anything.
>
> @{11}
>
> throws "Can't use string ("11") as an ARRAY ref while "strict refs" in
> use"
>
> This one's really got me going. Perl 5.8.7.
This is a bit obscure and probably due to the special nature of the
digit variables ($1, $2...). You get an idea when you use B::Deparse to
see that for perl those two things are treated differently in a subtle
manner:
ethan@ethan:~$ perl -MO=Deparse -e 'print @{1}'
print @1;
-e syntax OK
ethan@ethan:~$ perl -MO=Deparse -e 'print @{11}'
print @{11;};
-e syntax OK
@{1} is condensed into @1. Strictures don't warn on certain symbols that
are always global and live in package main::. These are variables with
digits and punctuation as name (so you are always allowed to use e.g.
$`, @`, %` etc., even $²).
@{11} however is @{11;} which is a symbolic reference. That means the
block {...} is executed and whatever is returned is turned into a string
and taken as the name of the variable. These (also called soft
references) are disallowed when "strict 'refs'" are in effect.
Having said that, this different treatment of @{1} and @{11} is a bug
IMO.
Tassilo
--
use bigint;
$n=71423350343770280161397026330337371139054411854220053437565440;
$m=-8,;;$_=$n&(0xff)<<$m,,$_>>=$m,,print+chr,,while(($m+=8)<=200);
------------------------------
Date: Mon, 26 Sep 2005 09:13:12 +0200
From: Pan Am <panam@nospam.com>
Subject: Re: Script for migrating HTML tree into a single directory ?
Message-Id: <1127718782.dec091df8ad9e40ce5405a7cc5f29972@teranews>
On Fri, 23 Sep 2005 13:13:35 -0400, Stan Brown wrote:
> Frankly, that statement stuns me. Or are you using some "hosting
> service" that will wrap your actual pages in a lot of ads and
> Javascript and similar crap?
not really... having very limited needs I use a free service: no
ads, limited space, single directory. Very basic, but ok for me.
> It would be hard to do, unless you can guarantee up front that
> different directories don't contain files with the same names.
> But really, Web hosting isn't expensive these days, and any
> "service" that limits you to a single directory is targeted at the
> lower end. Since you have enough pages that you want a script because
> hand editing is too cumbersome, you're really much better off with a
> better host.
The script could prefix filenames to avoid duplications...
Yet, if I cannot find it around I will look into paid services.
Thank you,
SJ
------------------------------
Date: Mon, 26 Sep 2005 00:33:20 -0700
From: Joe Smith <joe@inwap.com>
Subject: Re: script to run the program
Message-Id: <A-mdna_sWerfOareRVn-tA@comcast.com>
Josef Moellers wrote:
> a wrote:
>
>> I need to run a program that need input at run time.
>> Is it possible to simulate this by perl?
>
> It depends.
> You can open a pipe to the program and send the input through the pipe
> (beware of buffering):
> open(DST, '|', $program);
> print DST "Input\n";
>
> Or look at Perl/Expect.
For interactive use (where a line of input depends on something that
was output previously), a PTY-based solution (such as Expect.pm)
is the way to go.
http://search.cpan.org/author/DJERIUS/Expect-Simple-0.02/Simple.pm
-Joe
------------------------------
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 8456
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