[32239] in Perl-Users-Digest
Perl-Users Digest, Issue: 3504 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Fri Sep 23 06:09:31 2011
Date: Fri, 23 Sep 2011 03:09:11 -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 Fri, 23 Sep 2011 Volume: 11 Number: 3504
Today's topics:
'use warnings' vs the -w flag <news@lawshouse.org>
Re: 'use warnings' vs the -w flag <RedGrittyBrick@spamweary.invalid>
Re: defined $var <rweikusat@mssgmbh.com>
Re: defined $var <tzz@lifelogs.com>
Re: defined $var <jurgenex@hotmail.com>
Re: defined $var <rweikusat@mssgmbh.com>
Getting Perl to print out error messages <laredotornado@zipmail.com>
Re: Getting Perl to print out error messages <rweikusat@mssgmbh.com>
Re: Getting Perl to print out error messages <nospam-abuse@ilyaz.org>
Re: Getting Perl to print out error messages <news@lawshouse.org>
Re: Getting Perl to print out error messages <jurgenex@hotmail.com>
Re: Getting Perl to print out error messages sln@netherlands.com
Re: Getting Perl to print out error messages <nospam-abuse@ilyaz.org>
pipe gzip error <nospam.gravitalsun@hotmail.com.nospam>
Re: pipe gzip error <rweikusat@mssgmbh.com>
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@seesig.invalid
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Fri, 23 Sep 2011 10:53:55 +0100
From: Henry Law <news@lawshouse.org>
Subject: 'use warnings' vs the -w flag
Message-Id: <vOqdnbudcLGpyuHTnZ2dnUVZ8vSdnZ2d@giganews.com>
In another thread, Ilya Zakharevich said:
> `use warnings' should be better restricted to coding
> packages. Use the "standard" boilerplate
>
> #!/usr/bin/perl -w
> use strict;
>
And remarked that this had been discussed many times before in this
group. I must say that this guidance shakes my faith in my Perl skills:
so deeply imbedded in my consciousness is the use of warnings and strict
that I mutter "use strict, use warnings" as I switch off my alarm clock
in the morning ...
I've googled c.l.p.m. to find these dicussions but the phrase "use
warnings" and the letter w are ubiquitous and I can't find a sensible
search string. Could someone point me to a source where I can read up
and find out actually what is best to do?
perldoc warnings and perldoc perllexwarn seem to me to make the case
quite comprehensively for "use warnings" rather than -w, on the grounds
of flexibility if nothing else; but Ilya says that at least some of this
is plain wrong. What's a coder to do?
--
Henry Law Manchester, England
------------------------------
Date: Fri, 23 Sep 2011 11:00:59 +0100
From: RedGrittyBrick <RedGrittyBrick@spamweary.invalid>
Subject: Re: 'use warnings' vs the -w flag
Message-Id: <4e7c58da$0$2923$fa0fcedb@news.zen.co.uk>
On 23/09/2011 10:53, Henry Law wrote:
> In another thread, Ilya Zakharevich said:
>
>> `use warnings' should be better restricted to coding
>> packages. Use the "standard" boilerplate
>>
>> #!/usr/bin/perl -w
>> use strict;
>>
>
> And remarked that this had been discussed many times before in this
> group. I must say that this guidance shakes my faith in my Perl skills:
> so deeply imbedded in my consciousness is the use of warnings and strict
> that I mutter "use strict, use warnings" as I switch off my alarm clock
> in the morning ...
>
> I've googled c.l.p.m. to find these dicussions but the phrase "use
> warnings" and the letter w are ubiquitous and I can't find a sensible
> search string. Could someone point me to a source where I can read up
> and find out actually what is best to do?
>
> perldoc warnings and perldoc perllexwarn seem to me to make the case
> quite comprehensively for "use warnings" rather than -w, on the grounds
> of flexibility if nothing else; but Ilya says that at least some of this
> is plain wrong. What's a coder to do?
>
I don't recall exactly, but I think it reflects a difference of opinion
about whether you want to enable warnings for your own code only or for
other people's code too - particularly for code in the standard modules .
--
RGB
------------------------------
Date: Wed, 21 Sep 2011 13:53:41 +0100
From: Rainer Weikusat <rweikusat@mssgmbh.com>
Subject: Re: defined $var
Message-Id: <87aa9yys2y.fsf@sapphire.mobileactivedefense.com>
"George Mpouras" <nospam.gravitalsun@hotmail.com.nospam> writes:
> "Jurgen Exner" <jurgenex@hotmail.com> wrote in message
> news:scaj77t2ol08r3okdo0cof2bk73k96t6ga@4ax.com...
>> "George Mpouras" <nospam.gravitalsun@hotmail.com.nospam> wrote:
>>>why this give errors ?
>>>
>>>use strict;
>>>use warnings;
>>>#my $var=1;
>>>unless (defined $var) {die "variable \$var is undefined\n"}
>>>print $var;
>>
>> Because you didn't declare $var.
>>
>> "defined()" is about the value of a variable, it has nothing to do with
>> the existence i.e. declaration of a variable.
>>
>> jue
>
> Ok , then what about the existence ?!
'Existence' doesn't figure here. The variable will spring into
existence upon first use. But when strict 'vars' is being used
(IMO, generally a good idea) then a declaration (our $var) is required
in order to inform the compiler that this variable is actually
supposed to exist.
I suggest to discuss the theory that what hasn't been declared cannot
possibly exist with a customs officer in suitable situation in order
to gain some inside into the meaning of the term 'declaration'.
------------------------------
Date: Wed, 21 Sep 2011 12:32:59 -0500
From: Ted Zlatanov <tzz@lifelogs.com>
Subject: Re: defined $var
Message-Id: <87hb45hkc4.fsf@lifelogs.com>
On Wed, 21 Sep 2011 12:32:50 +0300 "George Mpouras" <nospam.gravitalsun@hotmail.com.nospam> wrote:
GM> "Jurgen Exner" <jurgenex@hotmail.com> wrote in message
GM> news:scaj77t2ol08r3okdo0cof2bk73k96t6ga@4ax.com...
>> "George Mpouras" <nospam.gravitalsun@hotmail.com.nospam> wrote:
>>> why this give errors ?
>>>
>>> use strict;
>>> use warnings;
>>> #my $var=1;
>>> unless (defined $var) {die "variable \$var is undefined\n"}
>>> print $var;
>>
>> Because you didn't declare $var.
>>
>> "defined()" is about the value of a variable, it has nothing to do with
>> the existence i.e. declaration of a variable.
GM> Ok , then what about the existence ?!
You can use Devel::Symdump to look at the full list of declared scalars,
arrays, and hashes, for any scope, including $main.
Ted
------------------------------
Date: Wed, 21 Sep 2011 17:12:37 -0700
From: Jürgen Exner <jurgenex@hotmail.com>
Subject: Re: defined $var
Message-Id: <82vk7790lhn9iulclrt1t9eqbjosd6r6f9@4ax.com>
"George Mpouras" <nospam.gravitalsun@hotmail.com.nospam> wrote:
>"Jurgen Exner" <jurgenex@hotmail.com> wrote in message
>> "defined()" is about the value of a variable, it has nothing to do with
>> the existence i.e. declaration of a variable.
>
>Ok , then what about the existence ?!
What about it?
There are programming languages where a variable is created
automatically on first use. Perl is such a language.
However this methodology has been frowned upon for a long time since it
leads to many hard to find errors where a user simply misspelled a
variable. Therefore 'use strict' alters this behaviour and enforces a
declaration before you can use the variable(*).
jue
*: somewhat simplified, there are a few exceptions
------------------------------
Date: Thu, 22 Sep 2011 11:23:25 +0100
From: Rainer Weikusat <rweikusat@mssgmbh.com>
Subject: Re: defined $var
Message-Id: <87fwjoq3j6.fsf@sapphire.mobileactivedefense.com>
Jürgen Exner <jurgenex@hotmail.com> writes:
> "George Mpouras" <nospam.gravitalsun@hotmail.com.nospam> wrote:
>>"Jurgen Exner" <jurgenex@hotmail.com> wrote in message
>>> "defined()" is about the value of a variable, it has nothing to do with
>>> the existence i.e. declaration of a variable.
>>
>>Ok , then what about the existence ?!
>
> What about it?
> There are programming languages where a variable is created
> automatically on first use. Perl is such a language.
> However this methodology has been frowned upon for a long time since it
> leads to many hard to find errors where a user simply misspelled a
> variable. Therefore 'use strict' alters this behaviour and enforces
> a declaration before you can use the variable(*).
[rw@sapphire]~ $perl -we '$a = 1'
Name "main::a" used only once: possible typo at -e line 1.
But that's - at best - as unreliable as relying on strict to catch
accidental misspellings. That's something the computer cannot ever do
because doing so requires both understanding the meaning of the
executed code and knowing what effect the program was supposed to
produce.
------------------------------
Date: Wed, 21 Sep 2011 09:20:13 -0700 (PDT)
From: laredotornado <laredotornado@zipmail.com>
Subject: Getting Perl to print out error messages
Message-Id: <032575a9-b308-4c0f-8e3a-fc99598f4be5@u3g2000yqb.googlegroups.com>
Hi,
I'm using ACtivePerl 5.12.4 on Windows 7. How do I get Perl to print
out run time error messages? I have this at the top of my script ...
use warnings;
use strict;
but making a call like this ...
$baseTestDir = File::Spec->catfile($data{'myco.checkout.dir'},
$data{'selenium.myco.test.root'});
causes script execution to exit without printing out why (I was able
to pinpoint the failure point by putting in a bunch of print
statements). If I add "use File::Spec" at the top, execution occurs
past that line, but it would be great if Perl just told me why things
failed.
Any help is appreciated, - Dave
------------------------------
Date: Wed, 21 Sep 2011 18:35:03 +0100
From: Rainer Weikusat <rweikusat@mssgmbh.com>
Subject: Re: Getting Perl to print out error messages
Message-Id: <877h51sss8.fsf@sapphire.mobileactivedefense.com>
laredotornado <laredotornado@zipmail.com> writes:
> I'm using ACtivePerl 5.12.4 on Windows 7. How do I get Perl to print
> out run time error messages? I have this at the top of my script ...
>
> use warnings;
> use strict;
>
> but making a call like this ...
>
> $baseTestDir = File::Spec->catfile($data{'myco.checkout.dir'},
> $data{'selenium.myco.test.root'});
>
> causes script execution to exit without printing out why (I was able
> to pinpoint the failure point by putting in a bunch of print
> statements). If I add "use File::Spec" at the top, execution occurs
> past that line, but it would be great if Perl just told me why things
> failed.
NB: I don't Windows.
How where you running the script? When I try the same here, I get
[rw@sapphire]/tmp $perl a.pl
Can't locate object method "catfile" via package "File::Spec" (perhaps you forgot to load "File::Spec"?) at a.pl line 3.
------------------------------
Date: Wed, 21 Sep 2011 22:00:09 +0000 (UTC)
From: Ilya Zakharevich <nospam-abuse@ilyaz.org>
Subject: Re: Getting Perl to print out error messages
Message-Id: <slrnj7knj9.8pa.nospam-abuse@panda.math.berkeley.edu>
On 2011-09-21, laredotornado <laredotornado@zipmail.com> wrote:
> Hi,
>
> I'm using ACtivePerl 5.12.4 on Windows 7. How do I get Perl to print
> out run time error messages? I have this at the top of my script ...
>
> use warnings;
> use strict;
Do not. `use warnings' should be better restricted to coding
packages. Use the "standard" boilerplate
#!/usr/bin/perl -w
use strict;
(but this was discussed many times here...).
Hope this helps,
Ilya
------------------------------
Date: Wed, 21 Sep 2011 23:59:06 +0100
From: Henry Law <news@lawshouse.org>
Subject: Re: Getting Perl to print out error messages
Message-Id: <gdudnYHXc6ig8efTnZ2dnUVZ8vednZ2d@giganews.com>
On 21/09/11 23:00, Ilya Zakharevich wrote:
> Do not. `use warnings' should be better restricted to coding
> packages. Use the "standard" boilerplate
>
> #!/usr/bin/perl -w
> use strict;
>
> (but this was discussed many times here...).
So would it be a good idea, therefore, to have the documentation changed
to reflect this "good practice"? Currently it says
> The use warnings pragma [is]... a more flexible alternative for both the command line flag -w ...
I confess that I am confused.
--
Henry Law Manchester, England
------------------------------
Date: Wed, 21 Sep 2011 17:18:18 -0700
From: Jürgen Exner <jurgenex@hotmail.com>
Subject: Re: Getting Perl to print out error messages
Message-Id: <nhvk77poo8n9gj7dvs9pooppjp4f1fika6@4ax.com>
laredotornado <laredotornado@zipmail.com> wrote:
>I'm using ACtivePerl 5.12.4 on Windows 7. How do I get Perl to print
>out run time error messages? I have this at the top of my script ...
>
>use warnings;
>use strict;
>
>but making a call like this ...
>
> $baseTestDir = File::Spec->catfile($data{'myco.checkout.dir'},
>$data{'selenium.myco.test.root'});
>
>causes script execution to exit without printing out why (I was able
>to pinpoint the failure point by putting in a bunch of print
>statements). If I add "use File::Spec" at the top, execution occurs
>past that line, but it would be great if Perl just told me why things
>failed.
>
>Any help is appreciated, - Dave
I cannot reproduce your problem. After declaring the obvious variables I
am getting
Can't locate object method "catfile" via package "File::Spec" (perhaps
you forgot to load "File::Spec"?) at C:\tmp\t.pl line 6.
That message seems to be self-explanatory to me.
jue
------------------------------
Date: Wed, 21 Sep 2011 22:43:04 -0700
From: sln@netherlands.com
Subject: Re: Getting Perl to print out error messages
Message-Id: <75il775vr5mphg66l1bg14p5nfi294bj38@4ax.com>
On Wed, 21 Sep 2011 09:20:13 -0700 (PDT), laredotornado <laredotornado@zipmail.com> wrote:
>Hi,
>
>I'm using ACtivePerl 5.12.4 on Windows 7. How do I get Perl to print
>out run time error messages? I have this at the top of my script ...
>
>use warnings;
>use strict;
>
>but making a call like this ...
>
> $baseTestDir = File::Spec->catfile($data{'myco.checkout.dir'},
>$data{'selenium.myco.test.root'});
>
>causes script execution to exit without printing out why (I was able
>to pinpoint the failure point by putting in a bunch of print
>statements). If I add "use File::Spec" at the top, execution occurs
>past that line, but it would be great if Perl just told me why things
>failed.
>
>Any help is appreciated, - Dave
Its possible your STDERR output is not going to the console.
I can reproduce your dificulty by redirecting STDERR to a file then
calling the File::Spec->catfile() function.
I'm not the greatest I/O expert and don't know windows 7 that well,
is it possible a shell can redirect STDERR, or maybe in your program or
some module your program loads?
Try this. I redirected STDERR to a file then trapped the system error.
-sln
###############
# test.pl
###############
use strict;
use warnings;
my ($baseTestDir, %data);
# Close stderr, reopen it to a text file:
close STDERR;
open STDERR, '>', 'stderr.txt' or die "$!";
# Trap runtime exceptions in eval {} block:
eval {
# This should cause system to die();
$baseTestDir = File::Spec->catfile($data{'myco.checkout.dir'},
$data{'selenium.myco.test.root'});
};
# See if eval trapped an error,
# if so, print it out to STDERR (really to file 'stderr.txt')
$@ && print STDERR "$@\n";
# Print a message to STDOUT
print "All!\n";
# Test that die() sends a message to STDERR (really to file 'stderr.txt')
die "Done!";
__END__
--------------------------------
From the command line:
c:\temp>perl test.pl
All!
c:\temp>type stderr.txt
Can't locate object method "catfile" via package "File::Spec" (perhaps you forgo
t to load "File::Spec"?) at uu.pl line 16.
Done! at uu.pl line 32.
c:\temp>
------------------------------
Date: Fri, 23 Sep 2011 00:57:45 +0000 (UTC)
From: Ilya Zakharevich <nospam-abuse@ilyaz.org>
Subject: Re: Getting Perl to print out error messages
Message-Id: <slrnj7nmc9.luv.nospam-abuse@panda.math.berkeley.edu>
On 2011-09-21, Henry Law <news@lawshouse.org> wrote:
>> Do not. `use warnings' should be better restricted to coding
>> packages. Use the "standard" boilerplate
>>
>> #!/usr/bin/perl -w
>> use strict;
>>
>> (but this was discussed many times here...).
>
> So would it be a good idea, therefore, to have the documentation changed
> to reflect this "good practice"? Currently it says
>
>> The use warnings pragma [is]... a more flexible alternative for both the command line flag -w ...
> I confess that I am confused.
No wonder. This piece of documentation is plain wrong (alas, the same as
most of Perl docs nowadays). AFAIK, one cannot reconstruct the
effects of -w by `use warnings'.
BTW, (I expect that) the majority of bugs caught by -w won't be caught
by `use warnings'. I did not test the OP's problem, but it might be
in this category.
Hope this helps,
Ilya
------------------------------
Date: Thu, 22 Sep 2011 12:22:00 +0300
From: "George Mpouras" <nospam.gravitalsun@hotmail.com.nospam>
Subject: pipe gzip error
Message-Id: <j5eumb$10kb$1@news.ntua.gr>
Any one knows why I am getting this "Illegal seek" error ?
use strict;
use warnings;
my $fh;
open $fh, '| /bin/gzip --force --quiet > "/tmp/akuro1.1316680468"' or warn
"oups: $^E\n";
print "problem *$?* *$^E* *$!*\n";
close $fh;
------------------------------
Date: Thu, 22 Sep 2011 11:32:13 +0100
From: Rainer Weikusat <rweikusat@mssgmbh.com>
Subject: Re: pipe gzip error
Message-Id: <878vpgq34i.fsf@sapphire.mobileactivedefense.com>
"George Mpouras" <nospam.gravitalsun@hotmail.com.nospam> writes:
> Any one knows why I am getting this "Illegal seek" error ?
>
> use strict;
> use warnings;
> my $fh;
> open $fh, '| /bin/gzip --force --quiet > "/tmp/akuro1.1316680468"' or warn
> "oups: $^E\n";
> print "problem *$?* *$^E* *$!*\n";
> close $fh;
That's because of an lseek performed by some library routine with
the failure apparently considered to be harmless. Generally, a
specific value of errno aka $! is not an indication that 'an error
occurred' on its own: This is only the case when 'an error occurred'
was specifically signalled to the code calling a 'system routine'.
And that's not the case with the code above.
------------------------------
Date: Fri, 23 Sep 2011 02:23:31 -0500
From: tadmc@seesig.invalid
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
Message-Id: <fK-dnaKyaPturuHTnZ2dnUVZ5rydnZ2d@giganews.com>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
- Do not provide too much information
- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
- Asking a question easily answered by a cursory doc search
- Asking for emailed answers
- Beware of saying "doesn't work"
- Sending a "stealth" Cc copy
Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
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.
The article at:
http://www.catb.org/~esr/faqs/smart-questions.html
describes how to get answers from technical people in general.
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://www.rehabitation.com/clpmisc.shtml
For more information about netiquette in general, see the "Netiquette
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http://andrew2.andrew.cmu.edu/rfc/rfc1855.html
A note to newsgroup "regulars":
Do not use these guidelines as a "license to flame" or other
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A note about technical terms used here:
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Do *NOT* send email to the maintainer of these guidelines. It will be
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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 expected in all newsgroups. Lurking means
to monitor a newsgroup for a period to become familiar with local
customs. Each newsgroup has specific customs and rituals. Knowing
these before you participate will help 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_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
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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.cpan.org/authors/id/D/DM/DMR/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* each section of quoted text to
which they relate. Unappreciated followup styles are referred to as
"top-posting", "Jeopardy" (because the answer comes before the
question), or "TOFU" (Text Over, Fullquote Under).
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://web.presby.edu/~nnqadmin/nnq/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 and many others on the comp.lang.perl.misc newsgroup.
--
Tad McClellan
email: perl -le "print scalar reverse qq/moc.liamg\100cm.j.dat/"
The above message is a Usenet post.
I don't recall having given anyone permission to use it on a Web site.
------------------------------
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:
To submit articles to comp.lang.perl.announce, send your article to
clpa@perl.com.
Back issues are available via anonymous ftp from
ftp://cil-www.oce.orst.edu/pub/perl/old-digests.
#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 V11 Issue 3504
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