[28376] in Perl-Users-Digest
Perl-Users Digest, Issue: 9740 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Tue Sep 19 09:05:55 2006
Date: Tue, 19 Sep 2006 06:05:06 -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 Tue, 19 Sep 2006 Volume: 10 Number: 9740
Today's topics:
Re: database connect: protect with exceptions? <filippo2991@virgilio.it>
Re: database connect: protect with exceptions? <1usa@llenroc.ude.invalid>
Re: How to find methods of Classes ? nkprajapati@gmail.com
Re: How to tie Perl script with cgi <joe@inwap.com>
Re: If...else and exit; <joe@inwap.com>
Re: Learning perl - for experienced programmers <john@castleamber.com>
Re: Learning perl - for experienced programmers <addinall@addinall.org>
Re: Learning perl - for experienced programmers <john@castleamber.com>
Re: Learning perl - for experienced programmers <robb@acm.org>
Re: Learning perl - for experienced programmers anno4000@radom.zrz.tu-berlin.de
Re: Learning perl - for experienced programmers cartercc@gmail.com
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@augustmail.com
Re: Preventing changes to a module's variables in mod_p <nobull67@gmail.com>
Re: Use of uninitialized value in print <nobull67@gmail.com>
where to put dclone <graham.removethis.t.wood@andthis.oracle.com>
Re: where to put dclone <someone@example.com>
Re: where to put dclone anno4000@radom.zrz.tu-berlin.de
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: 19 Sep 2006 02:50:29 -0700
From: "Filippo" <filippo2991@virgilio.it>
Subject: Re: database connect: protect with exceptions?
Message-Id: <1158659429.171967.51610@k70g2000cwa.googlegroups.com>
Tad McClellan ha scritto:
> my $DATABASE_SERVER = shift @ARGV;
> unless ( defined $DATABASE_SERVER ) {
> print STDOUT 'enter the database server name: ';
> $DATABASE_SERVER = <STDIN>;
> chomp $DATABASE_SERVER;
> }
thanks Tad but this isn't what I want: the unless clause accept any
value for DATABASE_SERVER. I want to try to connect and get the value
unless the connection is succeeded fine.
Thanks and best regards,
Filippo
------------------------------
Date: Tue, 19 Sep 2006 11:12:00 GMT
From: "A. Sinan Unur" <1usa@llenroc.ude.invalid>
Subject: Re: database connect: protect with exceptions?
Message-Id: <Xns984349447CFB8asu1cornelledu@127.0.0.1>
"Filippo" <filippo2991@virgilio.it> wrote in
news:1158659429.171967.51610@k70g2000cwa.googlegroups.com:
>
> Tad McClellan ha scritto:
>
>> my $DATABASE_SERVER = shift @ARGV;
>> unless ( defined $DATABASE_SERVER ) {
>> print STDOUT 'enter the database server name: ';
>> $DATABASE_SERVER = <STDIN>;
>> chomp $DATABASE_SERVER;
>> }
>
> thanks Tad but this isn't what I want:
So?
> the unless clause accept any value for DATABASE_SERVER. I want to try
> to connect
OK. Try to connect then ...
> and get the value unless the connection is succeeded fine.
What's stopping you?
You might want to read about what RaiseError => 1 does.
Sinan
--
A. Sinan Unur <1usa@llenroc.ude.invalid>
(remove .invalid and reverse each component for email address)
comp.lang.perl.misc guidelines on the WWW:
http://augustmail.com/~tadmc/clpmisc/clpmisc_guidelines.html
------------------------------
Date: 19 Sep 2006 03:23:23 -0700
From: nkprajapati@gmail.com
Subject: Re: How to find methods of Classes ?
Message-Id: <1158661403.902835.214280@i42g2000cwa.googlegroups.com>
Tad McClellan wrote:
> nkprajapati@gmail.com <nkprajapati@gmail.com> wrote:
>
> > I have 5 millions lines of source code, purely written in
> > c++. I want to find all the methods of some classes, used in code.
> ^^^^
> ^^^^
>
> So if a method is defined but never called it should not be reported?
>
>
> > Can any one help me out how to go ahead ?
>
>
> The first step would be to get a C++ parser.
>
>
> --
> Tad McClellan SGML consulting
> tadmc@augustmail.com Perl programming
> Fort Worth, Texas
Finally, I managed to write a perl script.....
Fortunately..code was so simply written that made scripting very
easy...
I am handling normal delacalaration, construction declaration and
pointer declaration..
#!/usr/bin/perl
sub process($)
{
my($filename) = @_;
open(FILE, $filename) or die("Unable to open file");
@data = <FILE>;
close(FILE);
foreach $line (@data)
{
# declaration with new
if( ($line =~
m/([a-zA-Z0-9._%-]+)\s+=\s+new\s+\(*\s*$eachclass/))
{
$var = $1;
foreach $line2 (@data)
{
if($line2 =~ m/$var->([a-zA-Z0-9]+\([A-Za-z0-9._%-]*\))/)
{
print HANDLE "\t",$1, "\n";
}
}
}
# normal delcaration
elsif ($line =~ m/$eachclass\s+([a-zA-Z0-9]+);/)
{
$var = $1;
foreach $line2 (@data)
{
if($line2 =~
m/$var\.([a-zA-Z0-9]+\([A-Za-z0-9._%-]*\))/)
{
print HANDLE "\t",$1, "\n";
}
}
}
#pointer delcaration
elsif ($line =~ m/$eachclass\s*\*\s*([a-zA-Z0-9]+)\s*;/)
{
$var = $1;
foreach $line2 (@data)
{
if($line2 =~ m/$var->([a-zA-Z0-9]+\([A-Za-z0-9._%-]*\))/)
{
print HANDLE "\t",$1, "\n";
}
}
}
#normal declaration but with constuction
elsif ($line =~ m/$eachclass\s+([a-zA-Z0-9]+)\s*\(*/)
{
#print"\n...................";
#
$var = $1;
foreach $line2 (@data)
{
if($line2 =~
m/$var\.([a-zA-Z0-9]+\([A-Za-z0-9._%-]*\))/)
{
print HANDLE "\t",$1, "\n";
}
}
}
}
}
sub recurse($) {
my($path) = @_;
$path .= '/' if($path !~ /\/$/);
for my $eachFile (glob($path.'*')) {
if( -d $eachFile) {
recurse($eachFile);
} else {
if($eachFile =~ m/[a-zA-Z0-9]\.cpp/)
{
process($eachFile);
}
}
}
}
sub classname($) {
open(FILE1, "rw.txt") or die("Unable to open file");
@data1 = <FILE1>;
close(FILE1);
foreach $line (@data1)
{
print $line;
$eachclass = $line;
chomp($eachclass);
chop($eachclass);
$eachclass =~ s/\s+$//;
$outfile = $eachclass;
open(HANDLE, ">$outfile");
recurse("./");
close(HANDLE);
}
}
classname("some");
------------------------------
Date: Tue, 19 Sep 2006 01:21:05 -0700
From: Joe Smith <joe@inwap.com>
Subject: Re: How to tie Perl script with cgi
Message-Id: <rMidnUfkdZU3NZLYnZ2dnUVZ_v-dnZ2d@comcast.com>
Vinay Nagrik wrote:
> I am just introduced to Perl and written my first program. I need to
> fire it through a cgi script.
> Could someone tell me how to tie two programs together so that when I
> send a post request through uri, my script gets fired.
1) Install perl on your computer.
2) Install a web server on your computer.
3) Configure the web server to allow CGI execution.
4) Put your CGI script where the web server will see it.
5) Write some HTML that has form that does a POST to your script.
6) Hit the form with your browser.
As you can see, none of those steps are on-topic for this newsgroup.
That's why you were told to "Ask in some webserver configuration group."
-Joe
------------------------------
Date: Tue, 19 Sep 2006 01:01:59 -0700
From: Joe Smith <joe@inwap.com>
Subject: Re: If...else and exit;
Message-Id: <a8adnXAoY-GuOZLYnZ2dnUVZ_vCdnZ2d@comcast.com>
MattJ83 wrote:
> I would like the code to exit if it can't find FASTSEARCH or
> conflicting. I would also like it to exit if it can't find 'inversions'
What do you mean?
Do you want to abort and not read two.log if "FASTSEARCH"
or "conflicting" is not found in the first file? Just check
at the bottom of the loop that reads each file.
If you want to exit if it can't find "FASTSEARCH" or "conflicting"
in any of the files, then what you've got already does that.
It reads through each file until EOF, and stops when there
are no more files.
You'll need to rephrase your request for us to understand it.
-Joe
------------------------------
Date: 19 Sep 2006 07:08:00 GMT
From: John Bokma <john@castleamber.com>
Subject: Re: Learning perl - for experienced programmers
Message-Id: <Xns984315B384414castleamber@130.133.1.4>
"robb@acm.org" <robb@acm.org> wrote:
> Remember, the post this quote was in response to was
"Plus, with Java,
you can easily run javadoc and get something in a standard format.
There's probably something like that for Perl, but it's not a part of
the core language."
- pod does generate something in a standard format
- pod is part of Perl
Hence my reply:
"AFAIK it is, it's called POD. And AFAIK it was there before Java was born
:-)"
Instead of trying to "remember" to what I replied and making things up to
look good, look it actually up.
Furthermore, you somehow seem to be impressed by the ability of javadoc to
use the method signature (amongst other) to generate some bare
"documentation". If a Java programmer followed only worst practices, how
useful is this? (rhetorical question).
--
John Experienced Perl programmer: http://castleamber.com/
Perl help, tutorials, and examples: http://johnbokma.com/perl/
------------------------------
Date: 19 Sep 2006 00:15:58 -0700
From: "addinall" <addinall@addinall.org>
Subject: Re: Learning perl - for experienced programmers
Message-Id: <1158650158.827180.142400@e3g2000cwe.googlegroups.com>
John Bokma wrote:
> merlyn@stonehenge.com (Randal L. Schwartz) wrote:
>
> > In fact, the number of companies looking for good Perl programmers
> > who *do* have a clue about maintenance has been steadily increasing
> > over the past few years... I'm even hearing reports that there AREN'T
> > ENOUGH PERL PROGRAMMERS. Go figure.
>
> Thanks Randal, that's very encouraging news :-) Some people keep telling
> me that I will soon get into problems as a programmer focussing mainly on
> Perl. This got me worried enough to consider learning a "popular" language
> like C# or PHP (yikes). I decided to settle for a "non-popular" one in the
> end (I guess Python can be called that) *and* improve my Perl skills
> (currently reading HOP) and your reply makes me happy :-).
Nothing wrong with PHP! I have done a few largish jobs for Telco's
using Perl to handle IO from RADIUS, IOS, LDAP and other secret
underworld places and present the results via SSH to another server
running PHP scripts/Web applications. Shrug, horses for courses.
Perl is neat, I love it to death. PHP has it's uses, bloody fast
in putting together a slick GUI.
Cheers,
Mark.
>
> --
> John Experienced Perl programmer: http://castleamber.com/
>
> Perl help, tutorials, and examples: http://johnbokma.com/perl/
------------------------------
Date: 19 Sep 2006 07:19:57 GMT
From: John Bokma <john@castleamber.com>
Subject: Re: Learning perl - for experienced programmers
Message-Id: <Xns984317BA7F5E7castleamber@130.133.1.4>
"addinall" <addinall@addinall.org> wrote:
> Nothing wrong with PHP!
There is a lot wrong with PHP :-) It's getting better though. But it also
suffers from the same problem I saw with Perl when it was "hot": most
hosting providers offer version 4, not 5.
--
John Experienced Perl programmer: http://castleamber.com/
Perl help, tutorials, and examples: http://johnbokma.com/perl/
------------------------------
Date: 19 Sep 2006 00:32:09 -0700
From: "robb@acm.org" <robb@acm.org>
Subject: Re: Learning perl - for experienced programmers
Message-Id: <1158651129.516962.131240@i3g2000cwc.googlegroups.com>
John Bokma wrote:
>
> Instead of trying to "remember" to what I replied and making things up to
> look good, look it actually up.
>
You're right. I'm sorry - you did say that POD would produce
"something" from obfuscated perl code, and I'm sure it would.
My only beef is that this "something" wouldn't be useful, and I
wouldn't present POD as being the same as Javadoc when talking to a
newbie.
> Furthermore, you somehow seem to be impressed by the ability of javadoc to
> use the method signature (amongst other) to generate some bare
> "documentation".
You betcha! An interlinked set of docs showing all inheritance
relationships, class names, methods and their parameters, exceptions
thrown, interfaces implemented, class and object variables.... all
from the raw self-documenting source code without any human-written
comments. It's a great embodiment of lazyness as a virtue. In my
experience, most people would find that pretty impressive.
------------------------------
Date: 19 Sep 2006 08:19:37 GMT
From: anno4000@radom.zrz.tu-berlin.de
Subject: Re: Learning perl - for experienced programmers
Message-Id: <4n9ngpF9b2sjU1@news.dfncis.de>
John W. Kennedy <jwkenne@attglobal.net> wrote in comp.lang.perl.misc:
> anno4000@radom.zrz.tu-berlin.de wrote:
> > For many years, COBOL was the *only* tool for certain IO-heavy and
> > table-oriented tasks that come up in financial and administrative
> > computing. At least it was the only COmmon Business Oriented
> > Language and claimed to be specially fit for these purposes. People
> > believed it and developed large code bases in COBOL. In reality,
> > the FORTRAN of the day would have worked as well, if not better.
>
> No, it wouldn't have, lacking, as it did (just off the top of my head):
> decorated numeric output,
> record I/O,
> fixed-point arithmetic, and
> even the most primitive string manipulation.
Okay, the lack of records (what is record I/O?) is serious. Other
features could be supported by library routines.
Anno
------------------------------
Date: 19 Sep 2006 06:00:35 -0700
From: cartercc@gmail.com
Subject: Re: Learning perl - for experienced programmers
Message-Id: <1158670835.562143.172650@m73g2000cwd.googlegroups.com>
Randal L. Schwartz wrote:
> cartercc> In my job, I use ColdFusion, Perl, and Java. Each language has its
> cartercc> good uses and bad uses. Perl is very good for one off scripts of
> cartercc> less than 25 - 50 lines. In fact, it's very, very good for that. If
> cartercc> you're dealing with an application of 100 lines or more that will
> cartercc> stick around for a while, I'd run like hell from Perl. (Within the
> cartercc> past year, I inherited a great mass of Perl scripts, around 70 or
> cartercc> so, each containing 500 or more lines of code, and it's absolutely
> cartercc> not maintainable, nor maintained. As it breaks, we are rewriting in
> cartercc> something else.)
> It's a good thing Amazon.com and Ticketmaster haven't hired you, or the people
> who worked at your company before you. Contrary to your experience, they're
> finding that Perl *does* scale as well as any other language, *provided* you
> treat it as a grown-up language.
For the record, the code base I inherited dates from around 1994, and
was initially written for Perl 4. It was a one man operation, who was a
tenured faculty member with his degree in EE. Tom didn't believe in
deleting code, or library routines, or modules, but believed in keeping
them all around, in most cases not even commenting the old ones out.
His revision history looks like this: 1, 2, 5, 8, 12, 14, 16, 19, 24,
25. In one case, it literally took us three weeks to discover where a
variable was initialized. It came from a module three directories over!
Tom was a bright guy and was continually learning and improving, which
meant that we had a real mix of styles and quality. He died tragically
young, and about a year later, after his code started breaking, I and
another fellow were asked to review Tom's code and fix it. We read
through it for about 12 weeks, and decided it was an impossible task,
so we started rewriting it in Java.
It's not my purpose to rate one language as 'better' than another. I'm
a database manaber for a large public university, and most days I write
some Perl. I can do some wonderful things in just a few lines of code
(as could Tom), and people use the term 'magic fingers' when talking
about our work product. That shouldn't surprise you at all.
HOWEVER, I still maintain that Java is much, much better than Perl for
a large project. The very things that Perl programmers don't like about
it, like static typing, single inheritance, access modifiers, etc.,
enforce a strictness that Perl doesn't. Additionally, Java compiles to
bytecode, and I've not had a problem running class files on different
systems. With Perl, I've found that I need to code for the target
system. Programs written for Windows will run on Linux, but some
programs written on Linux will not, repeat, not, run on Windows.
I made an analogy earilier, Java is like a deuce and a half, while Perl
is like a sports car. Perl can do things that are difficult or
(virtually) impossible in Java, and Java can do things that are
difficult or (virtually) impossible in Perl. They are different
languages, with different strengths and different weaknesses.
Personally, I find them both useful. Further, I think if you were
sitting in my chair and faced with my responsibilities, you would agree
with me.
One final note. I teach a course in OO programming. Java IMO is a
perfectly horrible language to teach programming, the reason is that it
answers questions a beginning student doesn't know to ask. Once a
student has figured out how to program, Java is a delight to use. Its
object model is structured, clear, unambiguous, and straight forward.
Perl's object model, by contrast, is a mess. Tom was beginning to use
OO Perl for the last two or three years, and I guess he was doing OJT,
but I don't even think he could remember from app to app how and why
he set some class variables. Blame the programmer (you would be
justified in doing so), but share a small part of the blame with the
language.
> In fact, the number of companies looking for good Perl programmers
> who *do* have a clue about maintenance has been steadily increasing
> over the past few years... I'm even hearing reports that there AREN'T
> ENOUGH PERL PROGRAMMERS. Go figure.
I keep an eye on dice.com. If you search for Perl, you see admin and
web jobs, but few for Perl developers in general. Search for Java, and
you get plenty of general programming results. Java jobs: 14217; Perl
jobs: 4780 - a 3 to 1 ratio.
> Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
> <merlyn@stonehenge.com> <URL:http://www.stonehenge.com/merlyn/>
> Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
> See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!
On a personal note, I've been a fan of yours from LP 1. This is the
first time I've had any contact with you, and I want to say that you've
done a first class job with LP and also with LPORM. Thank you for what
you've done, and may you long continue to evangelize and educate.
All the best, Charles Carter.
------------------------------
Date: 19 Sep 2006 07:22:06 GMT
From: tadmc@augustmail.com
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.6 $)
Message-Id: <450f9a9e$0$47254$ae4e5890@news.nationwide.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: 1.6 $)
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.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":
Do not use these guidelines as a "license to flame" or other
meanness. It is possible that a poster is unaware of things
discussed here. Give them the benefit of the doubt, and just
help them learn how to post, rather than assume
A note about technical terms used here:
In this document, we use words like "must" and "should" as
they're used in technical conversation (such as you will
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 unlikely that you will benefit much from this group.
We're not bossing you around; we're making the point without
lots 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 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_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.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 <tadmc@augustmail.com> and many others on the
comp.lang.perl.misc newsgroup.
------------------------------
Date: 19 Sep 2006 05:19:44 -0700
From: "Brian McCauley" <nobull67@gmail.com>
Subject: Re: Preventing changes to a module's variables in mod_perl
Message-Id: <1158668384.102308.129420@m7g2000cwm.googlegroups.com>
anno4000@radom.zrz.tu-berlin.de wrote:
> Brian McCauley <nobull67@gmail.com> wrote in comp.lang.perl.misc:
> >
> > You'd probably get more informative errors with
> >
> > sub Readonly::croak {
> > require Carp;
> > goto &Carp::carp;
> > }
> >
> > The problem with this approach is it breaks any other uses of Readonly
> > that are going on in other modules that anyone who happens to use your
> > module is also using.
>
> The substitution can be localized to a block or file:
>
> local *Readonly::croak = sub {
> require Carp;
> goto &Carp::carp;
> };
No! local() is dynamically scoped not lexical. Changes made with
local() are _not_ localized to a block or file but to a stack frame
(and subframes thereof).
Anyhow, even if it where lexical it would help the OP since he wants to
control the behaviour of complex data structures returned by his
modules when code outwith his control tries to modify them.
------------------------------
Date: 19 Sep 2006 05:22:54 -0700
From: "Brian McCauley" <nobull67@gmail.com>
Subject: Re: Use of uninitialized value in print
Message-Id: <1158668574.133156.152750@h48g2000cwc.googlegroups.com>
Mumia W. wrote:
> Down below, $total is undefined when you print it because it was never
> assigned up above.
Further evidence to support this comes from the fact that the stament
immediately before the assignment to $total would also emit a warning
and the user never mentioned this.
------------------------------
Date: Tue, 19 Sep 2006 12:02:33 +0100
From: Graham Wood <graham.removethis.t.wood@andthis.oracle.com>
Subject: where to put dclone
Message-Id: <LqQPg.31$ql6.288@news.oracle.com>
I have a function that accepts an array reference as an argument and
returns 2 array references. I'm "dclone"ing the references so that when
I call the function again I'm not using the same references again. As in ...
=========================================================
($ref1,$ref2)=return_2_refs($input_ref1);
$ref3=dclone($ref1);
$ref4=dclone($ref2);
($ref5,$ref6)=return_2_refs($input_ref2);
=========================================================
Can anyone tell me how to incorporate the dclone into this line:
($ref1,$ref2)=return_2_refs($input_ref1);
So that I don't have to create the extra $ref3 and $ref4?
I tried ($ref1,$ref2)=dclone(return_2_refs($input_ref1));
but that gave me nothing in $ref1.
Thanks in advance
Graham
------------------------------
Date: Tue, 19 Sep 2006 12:11:25 GMT
From: "John W. Krahn" <someone@example.com>
Subject: Re: where to put dclone
Message-Id: <N7RPg.24589$Lb5.8083@edtnps89>
Graham Wood wrote:
> I have a function that accepts an array reference as an argument and
> returns 2 array references. I'm "dclone"ing the references so that when
> I call the function again I'm not using the same references again. As in
> ...
> =========================================================
>
> ($ref1,$ref2)=return_2_refs($input_ref1);
> $ref3=dclone($ref1);
> $ref4=dclone($ref2);
>
> ($ref5,$ref6)=return_2_refs($input_ref2);
> =========================================================
>
> Can anyone tell me how to incorporate the dclone into this line:
> ($ref1,$ref2)=return_2_refs($input_ref1);
>
> So that I don't have to create the extra $ref3 and $ref4?
( $ref1, $ref2 ) = map dclone( $_ ), return_2_refs( $input_ref1 );
John
--
use Perl;
program
fulfillment
------------------------------
Date: 19 Sep 2006 12:17:25 GMT
From: anno4000@radom.zrz.tu-berlin.de
Subject: Re: where to put dclone
Message-Id: <4na5elF9eokqU1@news.dfncis.de>
Graham Wood <graham.removethis.t.wood@andthis.oracle.com> wrote in comp.lang.perl.misc:
> I have a function that accepts an array reference as an argument and
> returns 2 array references. I'm "dclone"ing the references so that when
> I call the function again I'm not using the same references again. As in ...
I don't think that's necessary. If it is, there's probably something
wrong with the sub return_2_refs(). Unfortunately you aren't showing
the code.
> =========================================================
>
> ($ref1,$ref2)=return_2_refs($input_ref1);
> $ref3=dclone($ref1);
> $ref4=dclone($ref2);
>
> ($ref5,$ref6)=return_2_refs($input_ref2);
> =========================================================
>
> Can anyone tell me how to incorporate the dclone into this line:
> ($ref1,$ref2)=return_2_refs($input_ref1);
( $ref1, $ref2) = map dclone( $_), return_2_refs($input_ref2);
should do that (untested).
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>
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------------------------------
End of Perl-Users Digest V10 Issue 9740
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