[22217] in Perl-Users-Digest
Perl-Users Digest, Issue: 4438 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Tue Jan 21 09:05:42 2003
Date: Tue, 21 Jan 2003 06:05:10 -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, 21 Jan 2003 Volume: 10 Number: 4438
Today's topics:
Re: abs. pathname <krahnj@acm.org>
ActivePerl 5.8 / MySQL / Apache Problem <alex@alexbanks.com>
Re: avoid chaos -or- "protected" writing <flavell@mail.cern.ch>
Re: Couple of Perl CGI problems (Helgi Briem)
Re: MAKE symbol missing (-)
Re: newbie perl pattern processing question (Anno Siegel)
Re: OO perl : object containing ref to other object (tî'pô)
Re: OO perl : object containing ref to other object <koos_pol@NO.nl.JUNK.compuware.MAIL.com>
Paragraph Mode <sjcole@hotmail.com>
Re: Paragraph Mode <koos_pol@NO.nl.JUNK.compuware.MAIL.com>
Re: Paragraph Mode <bernard.el-hagin@DODGE_THISlido-tech.net>
Re: Paragraph Mode <tassilo.parseval@post.rwth-aachen.de>
Re: Paragraph Mode <koos_pol@NO.nl.JUNK.compuware.MAIL.com>
Re: perl to post files to newsgroups??? <control153@NOSPAMyahoo.com>
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@augustmail.com
Re: Regex to find all words containing a single vowel? (Anno Siegel)
Re: Reverse Inheritance? (Anno Siegel)
Re: Reverse Inheritance? <ubl@schaffhausen.de>
Re: Reverse Inheritance? (Anno Siegel)
Re: Reverse Inheritance? (Ben Morrow)
Re: Reverse Inheritance? <ubl@schaffhausen.de>
Re: Reverse Inheritance? <ubl@schaffhausen.de>
Re: Reverse Inheritance? <ubl@schaffhausen.de>
Re: Starting with Perl <hazelbigfoot@gmx.net>
Still a little variable trouble. <spikey-wan@bigfoot.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Tue, 21 Jan 2003 12:30:57 GMT
From: "John W. Krahn" <krahnj@acm.org>
Subject: Re: abs. pathname
Message-Id: <3E2D3D31.EC61F10@acm.org>
Stephan Bressler wrote:
>
> my program is started somewhere in the directory tree (dir A). It takes a
> pathname of a file, either relativ or absolute.
>
> I'd like to convert the relativ pathname to an absolute pathname.
>
> Example:
> We're in dir /a/b/c and get ../x/foo.txt as filename. The function should
> return /a/b/x.
>
> BTW: It should be OS-independent.
use Cwd qw/abs_path/;
use File::Spec;
my $path = '../x/foo.txt';
my ( $volume, $directories, $file ) = File::Spec->splitpath( $path, -d $path );
print abs_path( $directories );
John
--
use Perl;
program
fulfillment
------------------------------
Date: Tue, 21 Jan 2003 12:04:29 -0000
From: "Alex Banks" <alex@alexbanks.com>
Subject: ActivePerl 5.8 / MySQL / Apache Problem
Message-Id: <3e2d374f$0$219$cc9e4d1f@news.dial.pipex.com>
Would be really grateful for any help with this... I've been surfing for
hours to try to find a similar case.
---
I used to run ActivePerl 5.6 with Apache on my Windows XP box just fine -
but since I installed ActivePerl 5.8 my old database scripts don't work.
They come back with this error:
[Tue Jan 21 11:51:24 2003] [error] [client 192.168.1.15]
install_driver(mysql) failed: Can't load
'C:/Perl/site/lib/auto/DBD/mysql/mysql.dll' for module DBD::mysql:
load_file:The specified module could not be found at
C:/Perl/lib/DynaLoader.pm line 229.
[Tue Jan 21 11:51:24 2003] [error] [client 192.168.1.15] at (eval 1) line 3
[Tue Jan 21 11:51:24 2003] [error] [client 192.168.1.15] Compilation failed
in require at (eval 1) line 3.
[Tue Jan 21 11:51:24 2003] [error] [client 192.168.1.15] Perhaps a required
shared library or dll isn't installed where expected
The file c:\perl\site\lib\auto\DBD\mysql\mysql.dll exists. All other my Perl
scripts work fine except those that invoke a database connection. Apache
works fine - the webpages are served normally.
In case it helps, here's what I did to install:
- Download the ActivePerl 5.8 and Apache bundle from
http://theoryx5.uwinnipeg.ca/pub/other/.
- Stop and uninstall the old Apache service (apache -n apache -k stop THEN
apache -n apache -k uninstall)
- Rename my old directories C:\Apache --> C:\OldApache and C:\Perl -->
C:\OldPerl.
- Unpack the download and move directories to root - C:\Apache2 and C:\Perl
- Run the Perl configuration utility - c:\Perl\bin\perl configure.pl -
selecting all the default options.
- Modify the httpd.conf to point to my desired web and scripts folders.
- Install the new apache service (c:\apache2\bin\apache -n apache2 -k
install THEN c:\apache2\bin\apache -n apache2 -k start)
- Install the database modules ('c:\perl\bin\ppm' then 'install DBI' then
'install DBD-mysql')
- Quit all the programmes then restart my PC
------------------------------
Date: Tue, 21 Jan 2003 11:53:48 +0100
From: "Alan J. Flavell" <flavell@mail.cern.ch>
Subject: Re: avoid chaos -or- "protected" writing
Message-Id: <Pine.LNX.4.40.0301211149490.26821-100000@lxplus072.cern.ch>
On Jan 20, Michael Budash inscribed on the eternal scroll:
> In article <u9d6mr8v5u.fsf@wcl-l.bham.ac.uk>,
> Brian McCauley <nobull@mail.com> wrote:
>
> > There is no way you can produce a program (or an HTML document or
> > whatever) that when fed into a computer (about whuch you have only
> > public knowledge) will cause that computer to exhibit a prescribed
> > behaviour and yet at the same time prevent another person with access
> > to that program and the same public knowledge from being able to infer
> > that behaviour.
> >
> > This is the "perpetual motion machine" of computer programming.
> >
> > Get over it.
> >
> > This has nothing to do with Perl.
>
> true, but not very helpful.
Here from the sidelines, it looks to be potentially a lot more helpful
than your followup.
> rather insulting actually.
Those who feel insulted by their own current level of understanding
are unlikely to find Usenet a comfortable place.
> why bother replying at all?
Hmmm. Perhaps I better apply the principle of "least said, soonest
mended" at this point. Wouldn't you care to reconsider your position?
------------------------------
Date: Tue, 21 Jan 2003 11:07:37 GMT
From: helgi@decode.is (Helgi Briem)
Subject: Re: Couple of Perl CGI problems
Message-Id: <3e2d279b.1497340031@news.cis.dfn.de>
On 20 Jan 2003 19:11:59 -0800, kedaran0504@yahoo.com.au
(UmanS) wrote:
>First problem.
>I am submitting a field contains name and email address separated by
>"|" (Selected from a drop down list in a form)
>ex: Surname.Firstname|user@mydomain.com
>In the cgi script I assign this to a field and splitting this field
>into an array.
Do yourself a favour and allow warnings and strictures.
You would have this problem solved by now if you did.
use warnings; # -w on shebang line for old perls
use strict;
>$var1 =query->param('formfield1');
# formfield1 is a BAD name for a form field that seems
# to contain name and email address. Why concatenate
them into one form field anyway?
# $var1 is likewise an atrocious name for a variable.
my $name_email =query->param('NAME_EMAIL');
>@myarray = split ("|",$var1);
my ($name,$email) = split "|",$name_email;
>@myname = $myarray[0];
>@myaddr = $myarray[1];
>When I print $var1 it prints ok, but how can I print @myname or
>@myaddr. If say
>print $myname[0] it will print only the first letter.
You are making the individual elements into arrays
of letters. Not what you want.
>Second Problem.
>I am sumitting a Text type field through a web form that may contains
>(' single quot character) and when my perl cgi script submit this to
>the oracle database oracle interprets it as a terminator. SO I am
>coverting the single quots to double quots. But the problem is I am
>using
>$string = ~/\'/\"/; but this changes only the first occurance only.
I don't believe you. If you separate the = and the ~ with a
space like that, you will get a syntax error. Copy and
paste code, don't retype.
You want the /g modifier to make the substitutionn global.
Change that to:
$string =~ s/'/"/g;
--
Regards, Helgi Briem
helgi AT decode DOT is
------------------------------
Date: 21 Jan 2003 05:11:50 -0800
From: cbdeja@my-deja.com (-)
Subject: Re: MAKE symbol missing
Message-Id: <611952a3.0301210511.33b30ff2@posting.google.com>
Got it.
Something had set
MAKEFLAGS=r
in my environment which tells make NOT to read its default makefile in
/usr/share/lib/make/make.rules
This file sets up (among other thinks) the assignment MAKE=make
and that's why my build was losing it!
cbdeja@my-deja.com (-) wrote in message news:<611952a3.0301170715.7e913f2b@posting.google.com>...
> I'm trying to build perl 5.6.1 on Solaris 2.8 in 64 bit mode. All
> seems fine until:
>
> Run make depend now? [y]
> sh ./makdepend MAKE=
> ./makdepend: clist: not found
> Searching for .c files
> ..... <several "Finding depandancies" lines> .....
> ./makedepend: shlist: not found
> Searching for .SH files...
> Updating makefile...
> test -s perlmain.c && touch perlmain.c
> *** Error code 1 (ignored)
> cd x2p; depend
> sh: depend: not found
> *** Error code 1
> make: fatal error: command failed for target `depend'
>
>
> It seems to start going wrong because the second line should end in
> MAKE=make and not simply MAKE=
>
> Subsequent errors occur because there is no longer a MAKE symbol, so
> the line
>
> cd x2p; depend
>
> should read
>
> cd x2p;make depend
>
> and so on.
>
> I thought that make was supposed to always set MAKE=make and so should
> never be lost as in the above.
>
> Does anyone know what is going wrong here?
>
> P.S. I've just tried building it again, but have set an environment
> variable MAKE=make in my shell before building. This seems to have
> worked, but it should not be necessary. Perhaps there is a bug in the
> perl installation scripts?
>
> Thanks
>
> Colin
------------------------------
Date: 21 Jan 2003 11:07:54 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: newbie perl pattern processing question
Message-Id: <b0j9ma$f96$1@mamenchi.zrz.TU-Berlin.DE>
Sol Linderstein <slinderstein@yahoo.com> wrote in comp.lang.perl.misc:
> Hi,
>
> I'm not new to programming but I am new to perl. Here's what I want to
> do.
> I have a text file with lines of HTML with special embedded tags in
> it. I want to parse each line of the file and process the tags. A line
> of the input file might look like this:
>
> <A HREF="blahblahblah?id=<<var id>>">blah</A>
>
> or like this:
>
> <INPUT TYPE="HIDDEN" NAME="<<var foo>>" VALUE="<<var bar>>">
>
> So, what I want to do is find the chunks of text surrounded by << >>
> and then process the stuff inside of the double angle brackets,
> replacing the << >> and the stuff inside of it with what my code will
> compute then printing out the processed line. There might be multiple
> of these patterns on each line.
Simple pattern matching is not enough to parse HTML, except under
the most restrictive circumstances. Use HTML::Parser to parse
HTML.
Anno
------------------------------
Date: Tue, 21 Jan 2003 14:53:57 +0200
From: "Teh (tî'pô)" <teh@mindless.com>
Subject: Re: OO perl : object containing ref to other object
Message-Id: <7cgq2vkaqci58olsl3q7n5m51seobeq6hc@4ax.com>
Koos Pol bravely attempted to attach 55 electrodes of knowledge
to the nipples of comp.lang.perl.misc by saying:
>Teh (tî'pô) wrote (Monday 20 January 2003 17:35):
>>> $self->name($name); # methods and variables prefer lower case
>> ^^^^^^^^
>> Says who? it's a matter of taste and has nothing to do with the OP
>> problem.
>
>
>To be honest, I can't point the exact location. But it is hidden somewhere
>in the docs. Package names with initial caps, variables and the like lc,
>hidden/system like stuff with a leading _. It is not only a matter of taste
>but also a matter of being able to visually interpret the code without
>actually reading the code. This leads to more transparent code and less
>errors.
Cool, I've been using _ for "private" methods and members without
knowing it's the accepted thing to do ;o)
Sorry I was a bit snappy, I saw three people answering a post, all
saying that valid syntax isn't and not dealing with the real problem
and I was a bit annoyed.
It's true that it's easier if everyone sticks to one coding style but
it's not likely to happen. I think it's OK to say "BTW most people
write $obj->{member} and not ${$obj}{member}" but not make it the main
part of the post.
------------------------------
Date: Tue, 21 Jan 2003 14:51:13 +0100
From: Koos Pol <koos_pol@NO.nl.JUNK.compuware.MAIL.com>
Subject: Re: OO perl : object containing ref to other object
Message-Id: <newscache$d5h29h$ald$1@news.emea.compuware.com>
Teh (tî'pô) wrote (Tuesday 21 January 2003 13:53):
> Koos Pol bravely attempted to attach 55 electrodes of knowledge
> to the nipples of comp.lang.perl.misc by saying:
>>To be honest, I can't point the exact location. But it is hidden somewhere
>>in the docs. Package names with initial caps, variables and the like lc,
>>hidden/system like stuff with a leading _. It is not only a matter of
>>taste but also a matter of being able to visually interpret the code
>>without actually reading the code. This leads to more transparent code and
>>less errors.
>
> Cool, I've been using _ for "private" methods and members without
> knowing it's the accepted thing to do ;o)
Intuitivity at it's best :-)
> Sorry I was a bit snappy, I saw three people answering a post, all
> saying that valid syntax isn't and not dealing with the real problem
> and I was a bit annoyed.
You have a point here. I should better have examined the OP's complete code.
Cheers,
--
KP
------------------------------
Date: Tue, 21 Jan 2003 12:39:40 -0000
From: "Steve C" <sjcole@hotmail.com>
Subject: Paragraph Mode
Message-Id: <1043152503.588469@ananke.eclipse.net.uk>
Hi Folks,
I'm currently working my way through the "Llama" book which was recommended
in this NG. So far I'm very impressed - so thank you for the advice.
Anyway to the point - I'm adapting a script which was supplied with Exim
(written by Philip Hazel).
He talks about reading <STDIN> in 'Paragraph Mode'
There is no mention of this in Llama - What does this actually mean, and is
there a more "technically correct" term for this 'paragraph mode' ??
Many thanks
Steve.
------------------------------
Date: Tue, 21 Jan 2003 13:47:05 +0100
From: Koos Pol <koos_pol@NO.nl.JUNK.compuware.MAIL.com>
Subject: Re: Paragraph Mode
Message-Id: <newscache$h6e29h$okd$1@news.emea.compuware.com>
Steve C wrote (Tuesday 21 January 2003 13:39):
> Anyway to the point - I'm adapting a script which was supplied with Exim
> (written by Philip Hazel).
> He talks about reading <STDIN> in 'Paragraph Mode'
> There is no mention of this in Llama - What does this actually mean, and
> is there a more "technically correct" term for this 'paragraph mode' ??
>
> Many thanks
>
> Steve.
My guess is it is the standard mode. I.e. reading one line (paragraph) at a
time:
while (<STDIN>) {
print $_;
}
Read "perldoc perlvar" on $| for a variation.
--
KP
------------------------------
Date: Tue, 21 Jan 2003 14:01:32 +0100
From: Bernard El-Hagin <bernard.el-hagin@DODGE_THISlido-tech.net>
Subject: Re: Paragraph Mode
Message-Id: <8sgq2v452lf27bucujeupic9joosp28ugq@4ax.com>
On Tue, 21 Jan 2003 13:47:05 +0100, Koos Pol
<koos_pol@NO.nl.JUNK.compuware.MAIL.com> wrote:
>Steve C wrote (Tuesday 21 January 2003 13:39):
>
>> Anyway to the point - I'm adapting a script which was supplied with Exim
>> (written by Philip Hazel).
>> He talks about reading <STDIN> in 'Paragraph Mode'
>> There is no mention of this in Llama - What does this actually mean, and
>> is there a more "technically correct" term for this 'paragraph mode' ??
>>
>> Many thanks
>>
>> Steve.
>
>
>My guess is it is the standard mode. I.e. reading one line (paragraph) at a
>time:
How do you arrive at the conclusion that a paragraph is the same as a
line? It could be, but usually isn't. Paragraph mode is when the data
is read one paragraph at a time, not one line at a time.
> while (<STDIN>) {
> print $_;
> }
>
>
>Read "perldoc perlvar" on $| for a variation.
Why should the OP read about the $| variable? It has nothing to do
with paragraph mode? Did you mean the $/ variable?
To the OP - paragraph mode is when the special variable $/ is set to
"\n\n". For example, if the input is:
aaa
bbb
ccc
ddd
eee
fff
ggg
hhh
then in paragraph mode ($/ = "\n\n") there are 2 records while in the
default mode ($/ = "\n") there are 9 (each line being a record).
Cheers,
Bernard
--
echo 42|perl -pe '$#="Just another Perl hacker,"'
------------------------------
Date: 21 Jan 2003 13:19:56 GMT
From: "Tassilo v. Parseval" <tassilo.parseval@post.rwth-aachen.de>
Subject: Re: Paragraph Mode
Message-Id: <b0jhds$9h2$1@nets3.rz.RWTH-Aachen.DE>
Also sprach Steve C:
> Hi Folks,
> I'm currently working my way through the "Llama" book which was recommended
> in this NG. So far I'm very impressed - so thank you for the advice.
>
> Anyway to the point - I'm adapting a script which was supplied with Exim
> (written by Philip Hazel).
> He talks about reading <STDIN> in 'Paragraph Mode'
> There is no mention of this in Llama - What does this actually mean, and is
> there a more "technically correct" term for this 'paragraph mode' ??
I thought it would be mentioned in perlvar, under $/, but it's not very
clear there either.
It means setting $/ to either "" or "\n\n". Both are some sort of
paragraph modes, albeit slightly different. Consider a text like this:
-1- this is a line
-2- this is another line
-3-
-4- a newline above
-5-
-6-
-7- two newlines above
If $/ eq "": The first read using <> will return line 1 and 2. The
second read will give you line 4 and the third read will return line 7.
If $/ eq "\n\n": The first read will return line 1 and 2, the second
read line 4 and the third read line 6 AND 7.
The difference is that "\n\n" will take one blank line as the delimiter for
paragraphs and anything following this blank line (including blank
lines) up to the next empty line is a paragraph. In case of "" one or
more consecutive empty lines are the separators for paragraphs and they
wont show up in the data returned.
Tassilo
--
$_=q!",}])(tsuJ[{@"tnirp}3..0}_$;//::niam/s~=)]3[))_$-3(rellac(=_$({
pam{rekcahbus;})(rekcah{lrePbus;})(lreP{rehtonabus;})(rehtona{tsuJbus!;
$_=reverse;s/sub/(reverse"bus").chr(32)/xge;tr~\n~~d;eval;
------------------------------
Date: Tue, 21 Jan 2003 14:45:40 +0100
From: Koos Pol <koos_pol@NO.nl.JUNK.compuware.MAIL.com>
Subject: Re: Paragraph Mode
Message-Id: <newscache$4wg29h$7ld$1@news.emea.compuware.com>
Bernard El-Hagin wrote (Tuesday 21 January 2003 14:01):
> On Tue, 21 Jan 2003 13:47:05 +0100, Koos Pol
> <koos_pol@NO.nl.JUNK.compuware.MAIL.com> wrote:
>
>>Steve C wrote (Tuesday 21 January 2003 13:39):
>>
>>> Anyway to the point - I'm adapting a script which was supplied with Exim
>>> (written by Philip Hazel).
>>> He talks about reading <STDIN> in 'Paragraph Mode'
>>> There is no mention of this in Llama - What does this actually mean, and
>>> is there a more "technically correct" term for this 'paragraph mode' ??
>>>
>>> Many thanks
>>>
>>> Steve.
>>
>>
>>My guess is it is the standard mode. I.e. reading one line (paragraph) at
>>a time:
>
>
> How do you arrive at the conclusion that a paragraph is the same as a
> line?
As said, that is my guess. Usually paragraphs ar chunks of text (multiple
sentences) seperated by a blank line.
> It could be, but usually isn't. Paragraph mode is when the data
> is read one paragraph at a time, not one line at a time.
>
>
>> while (<STDIN>) {
>> print $_;
>> }
>>
>>
>>Read "perldoc perlvar" on $| for a variation.
>
>
> Why should the OP read about the $| variable? It has nothing to do
> with paragraph mode? Did you mean the $/ variable?
Darn, ofcourse... Absolutely!
> To the OP - paragraph mode is when the special variable $/ is set to
> "\n\n". For example, if the input is:
>
>
> aaa
> bbb
> ccc
> ddd
>
> eee
> fff
> ggg
> hhh
>
>
> then in paragraph mode ($/ = "\n\n") there are 2 records while in the
> default mode ($/ = "\n") there are 9 (each line being a record).
Are those paragraphs? I thought these were sections. But there could be a
I18N issue here. In my dictionany an "alinea" (nl) translates to
"paragraph" (en). In Dutch terminoloy an "alinea" (paragraph) is a small
chunk of multi-sentence text. Those thingies that start with a small
indentation. The Dutch "paragraaf" translates to "section". And that would
be a larger chunk of text (multiple "alineas") seperated by a blank line.
Hence the confusion ofcourse.
May be the OP could clarify if he's interested in alinegraphs or perhaps
parections? :-)
Cheers,
--
KP
------------------------------
Date: Tue, 21 Jan 2003 14:03:43 GMT
From: ocd <control153@NOSPAMyahoo.com>
Subject: Re: perl to post files to newsgroups???
Message-Id: <Xns930A5CA951F7Acontrol153NOSPAMyaho@167.206.3.2>
thanks tintin
i have used that to post simple messages but i would like to post files
which is much more complicated ...
please help ..
------------------------------
Date: Tue, 21 Jan 2003 07:25:03 -0600
From: tadmc@augustmail.com
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.3 $)
Message-Id: <cs-dnYeC6oWy17CjXTWcrg@august.net>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
- Do not provide too much information
- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
- Asking a question easily answered by a cursory doc search
- Asking for emailed answers
- Beware of saying "doesn't work"
- Sending a "stealth" Cc copy
Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($Revision: 1.3 $)
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
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This article describes things that you should, and should not, do to
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available in POD, HTML and plain text formats at:
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For more information about netiquette in general, see the "Netiquette
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A note to newsgroup "regulars":
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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
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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.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* each section of quoted text to
which they relate. Unappreciated followup styles are referred to as
"Jeopardy" (because the answer comes before the question), or
"TOFU".
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: 21 Jan 2003 11:56:28 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: Regex to find all words containing a single vowel?
Message-Id: <b0jchc$f96$3@mamenchi.zrz.TU-Berlin.DE>
Martin <mrennix@totalise.co.uk> wrote in comp.lang.perl.misc:
> "Janek Schleicher" <bigj@kamelfreund.de> wrote in message
> news:<pan.2003.01.20.22.09.55.52492@kamelfreund.de>...
[...]
> > print join "\n",
> > ($string =~ /(\b [^aeiou\s]* [aeiou] [^aeiou\s]* \b)/gix);
>
> This works great, and I actually understand it! But, why does it need
> to be given the x modifier (for extended regexes)? Which features are
> available only when the x modifier is used?
>
> I guess I need to buy a book!
That may be a good idea, but a book is not necessary to read about
Perl's core features. These are all in the documentation that comes
with Perl. For the /x modifier, see "perldoc perlre".
Anno
------------------------------
Date: 21 Jan 2003 11:25:41 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: Reverse Inheritance?
Message-Id: <b0janl$f96$2@mamenchi.zrz.TU-Berlin.DE>
Ben Morrow <mauzo@mimosa.csv.warwick.ac.uk> wrote in comp.lang.perl.misc:
> eval "require $backend";
> $@ and die $@;
I'd rather avoid string eval here and write
require "$backend.pm";
Anno
------------------------------
Date: Tue, 21 Jan 2003 13:01:30 +0100
From: Malte Ubl <ubl@schaffhausen.de>
Subject: Re: Reverse Inheritance?
Message-Id: <b0jg2q$rbs$1@news.dtag.de>
Anno Siegel wrote:
> Ben Morrow <mauzo@mimosa.csv.warwick.ac.uk> wrote in comp.lang.perl.misc:
>
>
>> eval "require $backend";
>> $@ and die $@;
>
>
> I'd rather avoid string eval here and write
>
> require "$backend.pm";
Just out of curiosity: Why?
->malte
------------------------------
Date: 21 Jan 2003 12:23:19 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: Reverse Inheritance?
Message-Id: <b0je3n$f96$4@mamenchi.zrz.TU-Berlin.DE>
Malte Ubl <ubl@schaffhausen.de> wrote in comp.lang.perl.misc:
> Anno Siegel wrote:
> > Ben Morrow <mauzo@mimosa.csv.warwick.ac.uk> wrote in comp.lang.perl.misc:
> >
> >
> >> eval "require $backend";
> >> $@ and die $@;
> >
> >
> > I'd rather avoid string eval here and write
> >
> > require "$backend.pm";
>
> Just out of curiosity: Why?
Well, string eval is a potentially dangerous operation and requires
careful checking of the string(s) involved. So it's a stumbling block
in the way of anyone reading the program.
Also, it is huge overkill to start another interpreter run just
to load a module. While efficiency is no concern in this case,
it is good engineering to do things with as little expenditure
as possible.
Anno
------------------------------
Date: Tue, 21 Jan 2003 12:25:40 +0000 (UTC)
From: mauzo@ux-ma160-6.csv.warwick.ac.uk (Ben Morrow)
Subject: Re: Reverse Inheritance?
Message-Id: <b0je84$6t6$1@wisteria.csv.warwick.ac.uk>
anno4000@lublin.zrz.tu-berlin.de (Anno Siegel) wrote:
>Ben Morrow <mauzo@mimosa.csv.warwick.ac.uk> wrote in comp.lang.perl.misc:
>
>> eval "require $backend";
>> $@ and die $@;
>
>I'd rather avoid string eval here and write
>
> require "$backend.pm";
So would I, except that it doesn't work :).
You would need to convert ::s into directory separators, which (although it
could be done portably with File::Spec) I think is worth a small string eval
to avoid.
I feel that the fact that require "Foo::Bar" (sans .pm) doesn't DWIM is a
shame...
Ben
------------------------------
Date: Tue, 21 Jan 2003 13:56:33 +0100
From: Malte Ubl <ubl@schaffhausen.de>
Subject: Re: Reverse Inheritance?
Message-Id: <b0jja2$hu9$1@news.dtag.de>
Ben Morrow wrote:
> anno4000@lublin.zrz.tu-berlin.de (Anno Siegel) wrote:
>
>>Ben Morrow <mauzo@mimosa.csv.warwick.ac.uk> wrote in comp.lang.perl.misc:
>>
>>
>>> eval "require $backend";
>>> $@ and die $@;
>>
>>I'd rather avoid string eval here and write
>>
>> require "$backend.pm";
>
>
> So would I, except that it doesn't work :).
> You would need to convert ::s into directory separators, which (although it
> could be done portably with File::Spec) I think is worth a small string eval
> to avoid.
> I feel that the fact that require "Foo::Bar" (sans .pm) doesn't DWIM is a
> shame...
As far as I know, you don't have to do it portably "Foo/Bar.pm" will
always work in require (Not totally sure though).
I guess the nicest way to do this is the UNIVERSAL::require module;
however that one does the eval trick, too, so it won't save you the
extra interpreter run.
->malte
--
srand 108641088; print chr int rand 256 for qw<J A P H>
------------------------------
Date: Tue, 21 Jan 2003 14:01:05 +0100
From: Malte Ubl <ubl@schaffhausen.de>
Subject: Re: Reverse Inheritance?
Message-Id: <b0jjij$j02$1@news.dtag.de>
Anno Siegel wrote:
> Well, string eval is a potentially dangerous operation and requires
> careful checking of the string(s) involved. So it's a stumbling block
> in the way of anyone reading the program.
>
> Also, it is huge overkill to start another interpreter run just
> to load a module. While efficiency is no concern in this case,
> it is good engineering to do things with as little expenditure
> as possible.
While I think string eval is OK if the value comes from a lookup table
or something similar, the efficiency is a good point. I have written a
big mod_perl based MVC system that does 2 evals on every request to load
the required Views/Models on demand, because I figured it'd come for
free. Gotta change that.
Thx,
->malte
------------------------------
Date: Tue, 21 Jan 2003 14:46:42 +0100
From: Malte Ubl <ubl@schaffhausen.de>
Subject: Re: Reverse Inheritance?
Message-Id: <b0jm81$56n$1@news.dtag.de>
Malte Ubl wrote:
> As far as I know, you don't have to do it portably "Foo/Bar.pm" will
> always work in require (Not totally sure though).
Ignore this.
> I guess the nicest way to do this is the UNIVERSAL::require module;
> however that one does the eval trick, too, so it won't save you the
> extra interpreter run.
Tools::Load
is even better. In fact it is a great module, deserves to be part of the
standard dist. The Tools namespace seems a little awkward, like
My::Collection::Of::What::I::Considered::Useful::Load
->malte
------------------------------
Date: Tue, 21 Jan 2003 13:15:52 +0100
From: Jens Hoehne <hazelbigfoot@gmx.net>
Subject: Re: Starting with Perl
Message-Id: <3E2D39F8.FBE164ED@gmx.net>
Hello Brian,
Brian Smart wrote:
>
> Hello All,
> Thanks for comments, I am now over the first hurdle. I have installed Perl
> on my computer and can run my script from the command line and get the
> desired result.
Thats good.
> Any comments on how to move forward with learning the language would be
> appreciated.
Learning Perl? Or cgi programming? For the first I would recommend a
look at "Learning Perl" by Randal L. Schwartz and Tom Phoenix -
sometimes referred as Llama book. Note that by now you have the
complete and definite documentation on your harddrive - type 'perldoc -q
book' and see what I mean.
Your tofu style posting indicates, that you should also take a look at
the excellent "posting guidelines" which are posted here weekly. It
takes a few minutes to read them but this can save you hours of
embarrassment and worse.
Regards,
Jens
------------------------------
Date: Tue, 21 Jan 2003 12:10:27 -0000
From: "Richard S Beckett" <spikey-wan@bigfoot.com>
Subject: Still a little variable trouble.
Message-Id: <b0jdd7$o50$1@newshost.mot.com>
Hello World!
I'm still having a little trouble with variables.
My script uses Tk.
When you click on the 'Help' menu item, it invokes the help subroutine.
In the help subroutine, I define the main help window, with...
my $help_window = $main_window -> Toplevel (etc...
Into this window I put some buttons, that call subroutines, and a ROText
widget, again defined with my.
my $text_area = $help_window -> ROText (etc...
When you press a button, it calls another subroutine, that should put text
into the ROText widget, but because I've defined the ROText widget inside
the help sub, with my, when the text insertion routines get called, I get an
error:
Global symbol "$text_area" requires explicit package name...
The easy way would be to replace 'my $text_area =...' in the subroutine with
'$text_area = ...', and put a 'my $text;' at the beginning of my script, but
surely that defeats the object of the way that variables work in perl?
I suppose I could define my buttons as -command => \&text_sub ($text_area),
but again, I think that's messy.
How should I do this, properly?
Thanks.
R.
------------------------------
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:
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------------------------------
End of Perl-Users Digest V10 Issue 4438
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