[22105] in Perl-Users-Digest
Perl-Users Digest, Issue: 4327 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Tue Dec 31 21:20:55 2002
Date: Tue, 31 Dec 2002 18:20:28 -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 Tue, 31 Dec 2002 Volume: 10 Number: 4327
Today's topics:
please! ls system call help 64.130.6.101 [joe@sirfsup.com]
Re: please! ls system call help (Tad McClellan)
Re: please! ls system call help <jurgenex@hotmail.com>
Re: please! ls system call help <family2@aracnet.com>
Re: please! ls system call help <jurgenex@hotmail.com>
Re: please! ls system call help (Tad McClellan)
Re: please! ls system call help (Tony Skelding)
Re: please! ls system call help <family2@aracnet.com>
Re: please! ls system call help <family2@aracnet.com>
Re: please! ls system call help <jurgenex@hotmail.com>
pod 2 info? <ryan@cardweb.com>
Re: pod 2 info? <ron@savage.net.au>
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@augustmail.com
Re: re splitting up a file <geoff.cox@blueyonder.co.uk>
Re: re splitting up a file <geoff.cox@blueyonder.co.uk>
Require only if required <mdudley@execonn.com>
Re: Require only if required (Anno Siegel)
Re: Require only if required <mdudley@execonn.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Mon, 30 Dec 2002 21:34:25 GMT
From: 64.130.6.101 [joe@sirfsup.com]
Subject: please! ls system call help
Message-Id: <BZ2Q9.68524$xp4.2499985@news1.telusplanet.net>
hi,
i just want to make an 'ls' system call on /home and put that in an array to use in the following program. How can I do this, please?
thanks,
joe
!/usr/bin/perl
# reads sendmail log files tells how much/from/date/to for all mail users on system
# orders by employee
# /main/
@employee_names=("","","","","","", "", "");
my @employee_names_copy = @employee_names;
my $first_object = make_hash->new("maillog.5");
my $array_ref = $first_object->return_array_object;
# my $list_ref = ${$first_object->return_list_object};
# from
my $from_array_ref = parse_from_hash(\@employee_names, $array_ref);
print "********************from**************************\n";
my @array = @$from_array_ref;
for ($j=0; $j <= $#array; $j++) {
print "&&&&&&& " . $array[$j]{name} . " sent out $array[$j]{from_count} messages.\n";
if ($array[$j]{from_count} > 0) {
print "the recipients were:\n";
for ($i=0; $i < $array[$j]{from_count}; $i++) {
print $i+1 . ") [" . $array[$j]{array_copy}[$i]{date} . "] ";
foreach ( @{$array[$j]{array_copy}[$i]{to_list}}) {
print $_ . " " ;
}
print "\n";
}
}
print "\n\n";
}
==================================
Poster's IP address: 64.130.6.101
Posted via http://nodevice.com
Linux Programmer's Site
------------------------------
Date: Mon, 30 Dec 2002 17:50:03 -0600
From: tadmc@augustmail.com (Tad McClellan)
Subject: Re: please! ls system call help
Message-Id: <slrnb11mtb.5jh.tadmc@magna.augustmail.com>
64.130.6.101 [joe@sirfsup.com] <64.130.6.101[joe@sirfsup.com]> wrote:
> i just want to make an 'ls' system call on /home and put that in an
> array to use in the following program. How can I do this, please?
perldoc -f system
Which will lead to:
my @fs_objects = `ls`;
or
my @fs_objects = qx/ls/;
But you do not need to do that. You can do it in native Perl:
opendir HOME, '/home' or die "could not open /home $!";
my @fs_objects = sort readdir HOME;
closedir HOME;
Or if you want only directories:
opendir HOME, '/home' or die "could not open /home $!";
my @dirs = sort grep -d "/home/$_", readdir HOME;
closedir HOME;
> !/usr/bin/perl
^^
^^ oops!
You should ask for all the help you can get:
#!/usr/bin/perl
use strict;
use warnings;
--
Tad McClellan SGML consulting
tadmc@augustmail.com Perl programming
Fort Worth, Texas
------------------------------
Date: Tue, 31 Dec 2002 00:42:07 GMT
From: "Jürgen Exner" <jurgenex@hotmail.com>
Subject: Re: please! ls system call help
Message-Id: <zJ5Q9.22601$ac.18962@nwrddc01.gnilink.net>
64.130.6.101 [joe@sirfsup.com] wrote:
> i just want to make an 'ls' system call on /home and put that in an
> array to use in the following program. How can I do this, please?
Is there anything wrong with the information given in "perldoc -f system"
[...] This is
*not* what you want to use to capture the output from a command,
for that you should use [...]
or in "perldoc -q output"?
" Why can't I get the output of a command with system()?"
However, the real question in why are you using an external command to begin
with.
'opendir' and 'readdir' are more Perlish, don't require an external process,
and are even portable.
jue
------------------------------
Date: Mon, 30 Dec 2002 18:51:10 -0600
From: Abernathey Family <family2@aracnet.com>
Subject: Re: please! ls system call help
Message-Id: <3E10E9FE.4CA63048@aracnet.com>
64.130.6.101, [joe@sirfsup.com] wrote:
>
> hi,
> i just want to make an 'ls' system call on /home and put that in an array to use in the following program. How can I do this, please?
> thanks,
> joe
> !/usr/bin/perl
> # reads sendmail log files tells how much/from/date/to for all mail users on system
> # orders by employee
> # /main/
--snip--
#!/usr/bin/perl -w
my @dir_contents = 'ls -1';
or
my @dir_contents = system("ls -1") == 0 or die "cannot access: $?";
------------------------------
Date: Tue, 31 Dec 2002 03:43:59 GMT
From: "Jürgen Exner" <jurgenex@hotmail.com>
Subject: Re: please! ls system call help
Message-Id: <3o8Q9.26768$Jb.16049@nwrddc02.gnilink.net>
Abernathey Family wrote:
> 64.130.6.101, [joe@sirfsup.com] wrote:
>>
>> hi,
>> i just want to make an 'ls' system call on /home and put that in an
>> array to use in the following program. How can I do this, please?
> my @dir_contents = 'ls -1';
This will create an array with the first element containing the literal text
'ls -1'
In how far does it address the OPs question?
> or
> my @dir_contents = system("ls -1") == 0 or die "cannot access: $?";
I might have messed up priorities, but I think this will assign a value of
zero to the first element of @dir_content (unless "system" fails in which
case we "die" anyway).
In which way is this related to the OPs problem?
jue
------------------------------
Date: Mon, 30 Dec 2002 21:56:51 -0600
From: tadmc@augustmail.com (Tad McClellan)
Subject: Re: please! ls system call help
Message-Id: <slrnb125c3.67l.tadmc@magna.augustmail.com>
Abernathey Family <family2@aracnet.com> wrote:
> 64.130.6.101, [joe@sirfsup.com] wrote:
>> i just want to make an 'ls' system call on /home and put that in an array
> my @dir_contents = 'ls -1';
>
> or
>
> my @dir_contents = system("ls -1") == 0 or die "cannot access: $?";
Neither one of those will work.
--
Tad McClellan SGML consulting
tadmc@augustmail.com Perl programming
Fort Worth, Texas
------------------------------
Date: 31 Dec 2002 08:32:38 -0800
From: tony@skelding.co.uk (Tony Skelding)
Subject: Re: please! ls system call help
Message-Id: <a78026a1.0212310832.6ef54c17@posting.google.com>
64.130.6.101 [joe@sirfsup.com] wrote in message news:<BZ2Q9.68524$xp4.2499985@news1.telusplanet.net>...
> hi,
> i just want to make an 'ls' system call on /home and put that in an array to use in the following program. How can I do this, please?
> thanks,
> joe
> !/usr/bin/perl
> # reads sendmail log files tells how much/from/date/to for all mail users on system
> # orders by employee
> # /main/
>
> @employee_names=("","","","","","", "", "");
> my @employee_names_copy = @employee_names;
> my $first_object = make_hash->new("maillog.5");
> my $array_ref = $first_object->return_array_object;
> # my $list_ref = ${$first_object->return_list_object};
> # from
> my $from_array_ref = parse_from_hash(\@employee_names, $array_ref);
> print "********************from**************************\n";
> my @array = @$from_array_ref;
> for ($j=0; $j <= $#array; $j++) {
> print "&&&&&&& " . $array[$j]{name} . " sent out $array[$j]{from_count} messages.\n";
> if ($array[$j]{from_count} > 0) {
> print "the recipients were:\n";
> for ($i=0; $i < $array[$j]{from_count}; $i++) {
> print $i+1 . ") [" . $array[$j]{array_copy}[$i]{date} . "] ";
> foreach ( @{$array[$j]{array_copy}[$i]{to_list}}) {
> print $_ . " " ;
> }
> print "\n";
> }
> }
> print "\n\n";
> }
>
>
>
> ==================================
> Poster's IP address: 64.130.6.101
> Posted via http://nodevice.com
> Linux Programmer's Site
glob '/home/*'
------------------------------
Date: Tue, 31 Dec 2002 16:59:23 -0600
From: Abernathey Family <family2@aracnet.com>
Subject: Re: please! ls system call help
Message-Id: <3E12214B.93482498@aracnet.com>
Abernathey Family wrote:
>
> 64.130.6.101, [joe@sirfsup.com] wrote:
> >
> > hi,
> > i just want to make an 'ls' system call on /home and put that in an array to use in the following program. How can I do this, please?
> > thanks,
> > joe
> > !/usr/bin/perl
> > # reads sendmail log files tells how much/from/date/to for all mail users on system
> > # orders by employee
> > # /main/
> --snip--
> #!/usr/bin/perl -w
>
> my @dir_contents = 'ls -1';
>
> or
>
> my @dir_contents = system("ls -1") == 0 or die "cannot access: $?";
By the way, sometimes the call must be explicit, like:
my @dir_contents = `/bin/ls -1`;
------------------------------
Date: Tue, 31 Dec 2002 17:02:14 -0600
From: Abernathey Family <family2@aracnet.com>
Subject: Re: please! ls system call help
Message-Id: <3E1221F6.F92B630E@aracnet.com>
Without glancing at the screen, Tad McClellan wrote 6 words:
>
> Abernathey Family <family2@aracnet.com> wrote:
> > 64.130.6.101, [joe@sirfsup.com] wrote:
>
> >> i just want to make an 'ls' system call on /home and put that in an array
>
> > my @dir_contents = 'ls -1';
> >
> > or
> >
> > my @dir_contents = system("ls -1") == 0 or die "cannot access: $?";
>
> Neither one of those will work.
--snip--
Both work fine.
------------------------------
Date: Wed, 01 Jan 2003 02:04:52 GMT
From: "Jürgen Exner" <jurgenex@hotmail.com>
Subject: Re: please! ls system call help
Message-Id: <81sQ9.14791$Xc.5334@nwrddc04.gnilink.net>
Abernathey Family wrote:
>>> i just want to make an 'ls' system call on /home and put that in an
>>> array to use in the following program.
> By the way, sometimes the call must be explicit, like:
> my @dir_contents = `/bin/ls -1`;
Yep, this is the first variation you posted that will actually work.
jue
------------------------------
Date: Mon, 30 Dec 2002 12:49:27 -0500
From: Ryan <ryan@cardweb.com>
Subject: pod 2 info?
Message-Id: <JG%P9.21$ap1.16528@news.abs.net>
Is there any easy way to convert pod to info or texinfo files, or even
latex or man to texinfo, as perl comes with pod2latex and pod2man utilities?
I cannot find any good way of converting from these different formats.
I don't want to have to maintain separate documents; what do other
people do?
Thanks,
Ryan
------------------------------
Date: Tue, 31 Dec 2002 09:32:10 +1100
From: "Ron Savage" <ron@savage.net.au>
Subject: Re: pod 2 info?
Message-Id: <auqhjc$2eoo$1@arachne.labyrinth.net.au>
"Ryan" <ryan@cardweb.com> wrote in message
news:JG%P9.21$ap1.16528@news.abs.net...
> Is there any easy way to convert pod to info or texinfo files, or even
> latex or man to texinfo, as perl comes with pod2latex and pod2man
utilities?
>
> I cannot find any good way of converting from these different formats.
> I don't want to have to maintain separate documents; what do other
> people do?
Ryan
Good question.
Personally, I write in POD format, and use the Pod::POM module and my script
fancy-pom2.pl to convert to HTML.
Yep, that's it - no other formats supported. People have browsers, right? So
HTML is sufficient.
Ron Savage
http://savage.net.au/index.html
------------------------------
Date: Tue, 31 Dec 2002 08:04:45 -0600
From: tadmc@augustmail.com
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.2 $)
Message-Id: <6KecnZa0a5JgPoyjXTWcow@august.net>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
- Do not provide too much information
- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
- Asking a question easily answered by a cursory doc search
- Asking for emailed answers
- Beware of saying "doesn't work"
- Sending a "stealth" Cc copy
Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($Revision: 1.2 $)
This newsgroup, commonly called clpmisc, is a technical newsgroup
intended to be used for discussion of Perl related issues (except job
postings), whether it be comments or questions.
As you would expect, clpmisc discussions are usually very technical in
nature and there are conventions for conduct in technical newsgroups
going somewhat beyond those in non-technical newsgroups.
This article describes things that you should, and should not, do to
increase your chances of getting an answer to your Perl question. It is
available in POD, HTML and plain text formats at:
http://mail.augustmail.com/~tadmc/clpmisc.shtml
For more information about netiquette in general, see the "Netiquette
Guidelines" at:
http://andrew2.andrew.cmu.edu/rfc/rfc1855.html
A note to newsgroup "regulars":
Please do not use the existence of these guidelines as a
"license to flame" or other meanness. It is possible that
a poster is not aware of the things discussed here. Let's
give them the benefit of the doubt, and just help them learn
how to post, rather than assume that they do know and are
being the "bad kind" of Lazy.
A note about technical terms used here:
In this document, we use words like "must" and "should" in the
very precise sense that they're used in technical conversation
(such as you're likely to encounter in this newsgroup). When
we say that you *must* do something, we mean that if you don't
do that something, then it's very unlikely that you're going to
get much benefit from using this group. We're not trying to boss
you around; we're just trying to convey the point without using
a lot of words.
Do *NOT* send email to the maintainer of these guidelines. It will be
discarded unread. The guidelines belong to the newsgroup so all
discussion should appear in the newsgroup. I am just the secretary that
writes down the consensus of the group.
Before posting to comp.lang.perl.misc
Must
This section describes things that you *must* do before posting to
clpmisc, in order to maximize your chances of getting meaningful replies
to your inquiry and to avoid getting flamed for being lazy and trying to
have others do your work.
The perl distribution includes documentation that is copied to your hard
drive when you install perl. Also installed is a program for looking
things up in that (and other) documentation named 'perldoc'.
You should either find out where the docs got installed on your system,
or use perldoc to find them for you. Type "perldoc perldoc" to learn how
to use perldoc itself. Type "perldoc perl" to start reading Perl's
standard documentation.
Check the Perl Frequently Asked Questions (FAQ)
Checking the FAQ before posting is required in Big 8 newsgroups in
general, there is nothing clpmisc-specific about this requirement.
You are expected to do this in nearly all newsgroups.
You can use the "-q" switch with perldoc to do a word search of the
questions in the Perl FAQs.
Check the other standard Perl docs (*.pod)
The perl distribution comes with much more documentation than is
available for most other newsgroups, so in clpmisc you should also
see if you can find an answer in the other (non-FAQ) standard docs
before posting.
It is *not* required, or even expected, that you actually *read* all of
Perl's standard docs, only that you spend a few minutes searching them
before posting.
Try doing a word-search in the standard docs for some words/phrases
taken from your problem statement or from your very carefully worded
"Subject:" header.
Really Really Should
This section describes things that you *really should* do before posting
to clpmisc.
Lurk for a while before posting
This is very important and is expected regardless of what newsgroup
you are visiting. Lurking means to simply monitor a newsgroup for a
period of time until you become very familiar with local customs.
Think of a newsgroup as foreign culture. Each newsgroup has its own
specific customs and rituals. Get to know those customs and rituals
well before you participate. This will help you to avoid
embarrassing social situations. Consider yourself to be a foreigner
at first!
Search a Usenet archive
There are tens of thousands of Perl programmers. It is very likely
that your question has already been asked (and answered). See if you
can find where it has already been answered.
One such searchable archive is:
http://groups.google.com/advanced_group_search
If You Like
This section describes things that you *can* do before posting to
clpmisc.
Check Other Resources
You may want to check in books or on web sites to see if you can
find the answer to your question.
But you need to consider the source of such information: there are a
lot of very poor Perl books and web sites, and several good ones
too, of course.
Posting to comp.lang.perl.misc
There can be 200 messages in clpmisc in a single day. Nobody is going to
read every article. They must decide somehow which articles they are
going to read, and which they will skip.
Your post is in competition with 199 other posts. You need to "win"
before a person who can help you will even read your question.
These sections describe how you can help keep your article from being
one of the "skipped" ones.
Is there a better place to ask your question?
Question should be about Perl, not about the application area
It can be difficult to separate out where your problem really is,
but you should make a conscious effort to post to the most
applicable newsgroup. That is, after all, where you are the most
likely to find the people who know how to answer your question.
Being able to "partition" a problem is an essential skill for
effectively troubleshooting programming problems. If you don't get
that right, you end up looking for answers in the wrong places.
It should be understood that you may not know that the root of your
problem is not Perl-related (the two most frequent ones are CGI and
Operating System related), so off-topic postings will happen from
time to time. Be gracious when someone helps you find a better place
to ask your question by pointing you to a more applicable newsgroup.
How to participate (post) in the clpmisc community
Carefully choose the contents of your Subject header
You have 40 precious characters of Subject to win out and be one of
the posts that gets read. Don't waste them. Take care while
composing them, they are the key that opens the door to getting an
answer.
Spend them indicating what aspect of Perl others will find if they
should decide to read your article.
Do not spend them indicating "experience level" (guru, newbie...).
Do not spend them pleading (please read, urgent, help!...).
Do not spend them on non-Subjects (Perl question, one-word
Subject...)
For more information on choosing a Subject see "Choosing Good
Subject Lines":
http://www.perl.com/CPAN-local/authors/Dean_Roehrich/subjects.post
Part of the beauty of newsgroup dynamics, is that you can contribute
to the community with your very first post! If your choice of
Subject leads a fellow Perler to find the thread you are starting,
then even asking a question helps us all.
Use an effective followup style
When composing a followup, quote only enough text to establish the
context for the comments that you will add. Always indicate who
wrote the quoted material. Never quote an entire article. Never
quote a .signature (unless that is what you are commenting on).
Intersperse your comments *following* the sections of quoted text
that your comments apply to. Failure to do this is called "Jeopardy"
posting because the answer comes before the question.
Reversing the chronology of the dialog makes it much harder to
understand (some folks won't even read it if written in that style).
For more information on quoting style, see:
http://www.geocities.com/nnqweb/nquote.html
Speak Perl rather than English, when possible
Perl is much more precise than natural language. Saying it in Perl
instead will avoid misunderstanding your question or problem.
Do not say: I have variable with "foo\tbar" in it.
Instead say: I have $var = "foo\tbar", or I have $var = 'foo\tbar',
or I have $var = <DATA> (and show the data line).
Ask perl to help you
You can ask perl itself to help you find common programming mistakes
by doing two things: enable warnings (perldoc warnings) and enable
"strict"ures (perldoc strict).
You should not bother the hundreds/thousands of readers of the
newsgroup without first seeing if a machine can help you find your
problem. It is demeaning to be asked to do the work of a machine. It
will annoy the readers of your article.
You can look up any of the messages that perl might issue to find
out what the message means and how to resolve the potential mistake
(perldoc perldiag). If you would like perl to look them up for you,
you can put "use diagnostics;" near the top of your program.
Do not re-type Perl code
Use copy/paste or your editor's "import" function rather than
attempting to type in your code. If you make a typo you will get
followups about your typos instead of about the question you are
trying to get answered.
Provide enough information
If you do the things in this item, you will have an Extremely Good
chance of getting people to try and help you with your problem!
These features are a really big bonus toward your question winning
out over all of the other posts that you are competing with.
First make a short (less than 20-30 lines) and *complete* program
that illustrates the problem you are having. People should be able
to run your program by copy/pasting the code from your article. (You
will find that doing this step very often reveals your problem
directly. Leading to an answer much more quickly and reliably than
posting to Usenet.)
Describe *precisely* the input to your program. Also provide example
input data for your program. If you need to show file input, use the
__DATA__ token (perldata.pod) to provide the file contents inside of
your Perl program.
Show the output (including the verbatim text of any messages) of
your program.
Describe how you want the output to be different from what you are
getting.
If you have no idea at all of how to code up your situation, be sure
to at least describe the 2 things that you *do* know: input and
desired output.
Do not provide too much information
Do not just post your entire program for debugging. Most especially
do not post someone *else's* entire program.
Do not post binaries, HTML, or MIME
clpmisc is a text only newsgroup. If you have images or binaries
that explain your question, put them in a publically accessible
place (like a Web server) and provide a pointer to that location. If
you include code, cut and paste it directly in the message body.
Don't attach anything to the message. Don't post vcards or HTML.
Many people (and even some Usenet servers) will automatically filter
out such messages. Many people will not be able to easily read your
post. Plain text is something everyone can read.
Social faux pas to avoid
The first two below are symptoms of lots of FAQ asking here in clpmisc.
It happens so often that folks will assume that it is happening yet
again. If you have looked but not found, or found but didn't understand
the docs, say so in your article.
Asking a Frequently Asked Question
It should be understood that you may have missed the applicable FAQ
when you checked, which is not a big deal. But if the Frequently
Asked Question is worded similar to your question, folks will assume
that you did not look at all. Don't become indignant at pointers to
the FAQ, particularly if it solves your problem.
Asking a question easily answered by a cursory doc search
If folks think you have not even tried the obvious step of reading
the docs applicable to your problem, they are likely to become
annoyed.
If you are flamed for not checking when you *did* check, then just
shrug it off (and take the answer that you got).
Asking for emailed answers
Emailed answers benefit one person. Posted answers benefit the
entire community. If folks can take the time to answer your
question, then you can take the time to go get the answer in the
same place where you asked the question.
It is OK to ask for a *copy* of the answer to be emailed, but many
will ignore such requests anyway. If you munge your address, you
should never expect (or ask) to get email in response to a Usenet
post.
Ask the question here, get the answer here (maybe).
Beware of saying "doesn't work"
This is a "red flag" phrase. If you find yourself writing that,
pause and see if you can't describe what is not working without
saying "doesn't work". That is, describe how it is not what you
want.
Sending a "stealth" Cc copy
A "stealth Cc" is when you both email and post a reply without
indicating *in the body* that you are doing so.
Be extra cautious when you get upset
Count to ten before composing a followup when you are upset
This is recommended in all Usenet newsgroups. Here in clpmisc, most
flaming sub-threads are not about any feature of Perl at all! They
are most often for what was seen as a breach of netiquette. If you
have lurked for a bit, then you will know what is expected and won't
make such posts in the first place.
But if you get upset, wait a while before writing your followup. I
recommend waiting at least 30 minutes.
Count to ten after composing and before posting when you are upset
After you have written your followup, wait *another* 30 minutes
before committing yourself by posting it. You cannot take it back
once it has been said.
AUTHOR
Tad McClellan <tadmc@augustmail.com> and many others on the
comp.lang.perl.misc newsgroup.
------------------------------
Date: Mon, 30 Dec 2002 16:56:56 GMT
From: Geoff Cox <geoff.cox@blueyonder.co.uk>
Subject: Re: re splitting up a file
Message-Id: <klu01voe7m3vck642medhf963s1pktg5kt@4ax.com>
Tad,
thanks for the explanations.
Cheers
Geoff
------------------------------
Date: Mon, 30 Dec 2002 17:13:50 GMT
From: Geoff Cox <geoff.cox@blueyonder.co.uk>
Subject: Re: re splitting up a file
Message-Id: <llv01v0g317ib5m5ltr4410nsana47idf9@4ax.com>
Bart,
thanks for the inproved version.
Cheers
Geoff
------------------------------
Date: Tue, 31 Dec 2002 15:44:19 -0500
From: Marshall Dudley <mdudley@execonn.com>
Subject: Require only if required
Message-Id: <3E1201A3.65CDD959@execonn.com>
I have a program that is about 100,000 lines long, including all the
files required by the main script. I am looking at ways to speed it up,
and have noticed that all the library files that may be required
anywhere in the program or libraries, are preloaded by requiring them at
the start of the script, thus bloating the memory requirements, and
wasting cpu on unneeded compilations.
The program is somewhat of a cpu hog, and I am trying to speed it up.
So what I need to do is only load the library routines if they are
needed. Unfortunately, a library routine may contain a number of
different subroutines, and may get called in a number of places, in the
main script or in another library routine. Thus keeping up with if a
library has been loaded or not, and only loading it if needed is
somewhat tricky, and in itself will consume cpu.
So I hit on the idea of putting every subroutine name that is in any
required file in the main program. Each of these looks something like
this:
sub text {
require "./library/textfile.pl";
&text;
}
Then, do not do any requires up front.
So basically, only if the "text" routine gets called will the
textfile.pl get loaded, and then only if it has not already been loaded
via a call already to text or another subroutine that is in the file.
This seems to work when I test it, when the file is required, the old
pointer to the text subroutine is overwritten by the new pointer from
the required file.
My question is, am I missing something? Is there any reason I should
not, or cannot do this? Will it get me into trouble at any point?
Thanks,
Marshall
------------------------------
Date: 31 Dec 2002 21:54:08 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: Require only if required
Message-Id: <aut3m0$pgb$2@mamenchi.zrz.TU-Berlin.DE>
Marshall Dudley <mdudley@execonn.com> wrote in comp.lang.perl.misc:
> I have a program that is about 100,000 lines long, including all the
> files required by the main script. I am looking at ways to speed it up,
> and have noticed that all the library files that may be required
> anywhere in the program or libraries, are preloaded by requiring them at
> the start of the script, thus bloating the memory requirements, and
> wasting cpu on unneeded compilations.
Looks like a clear-cut case for "autouse". You can say
use autouse 'Module' => qw(func1 func2);
instead of
use Module qw(func1 func2);
The "autouse" line doesn't load "Module", but arranges for "Module"
to be loaded the first time func1() or func2() is called. This works
along similar lines as those you sketched in the part I snipped, but
it's tried and tested.
See "perldoc autouse" for the details and some limitations.
Anno
------------------------------
Date: Tue, 31 Dec 2002 16:30:10 -0500
From: Marshall Dudley <mdudley@execonn.com>
Subject: Re: Require only if required
Message-Id: <3E120C62.7E8AA25C@execonn.com>
Thanks. Learn something new every day. You would think after writing perl for
the the last 4 years I would already know that. :<
Marshall
Anno Siegel wrote:
> Marshall Dudley <mdudley@execonn.com> wrote in comp.lang.perl.misc:
> > I have a program that is about 100,000 lines long, including all the
> > files required by the main script. I am looking at ways to speed it up,
> > and have noticed that all the library files that may be required
> > anywhere in the program or libraries, are preloaded by requiring them at
> > the start of the script, thus bloating the memory requirements, and
> > wasting cpu on unneeded compilations.
>
> Looks like a clear-cut case for "autouse". You can say
>
> use autouse 'Module' => qw(func1 func2);
>
> instead of
>
> use Module qw(func1 func2);
>
> The "autouse" line doesn't load "Module", but arranges for "Module"
> to be loaded the first time func1() or func2() is called. This works
> along similar lines as those you sketched in the part I snipped, but
> it's tried and tested.
>
> See "perldoc autouse" for the details and some limitations.
>
> Anno
------------------------------
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>
Administrivia:
The Perl-Users Digest is a retransmission of the USENET newsgroup
comp.lang.perl.misc. For subscription or unsubscription requests, send
the single line:
subscribe perl-users
or:
unsubscribe perl-users
to almanac@ruby.oce.orst.edu.
To submit articles to comp.lang.perl.announce, send your article to
clpa@perl.com.
To request back copies (available for a week or so), send your request
to almanac@ruby.oce.orst.edu with the command "send perl-users x.y",
where x is the volume number and y is the issue number.
For other requests pertaining to the digest, send mail to
perl-users-request@ruby.oce.orst.edu. Do not waste your time or mine
sending perl questions to the -request address, I don't have time to
answer them even if I did know the answer.
------------------------------
End of Perl-Users Digest V10 Issue 4327
***************************************
