[23987] in Perl-Users-Digest
Perl-Users Digest, Issue: 6188 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Fri Feb 27 09:05:42 2004
Date: Fri, 27 Feb 2004 06:05:06 -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 Fri, 27 Feb 2004 Volume: 10 Number: 6188
Today's topics:
Re: Coderef usage in complex data structures <kz15@earthling.net>
Re: Comments requested: brief summary of Perl <bik.mido@tiscalinet.it>
Re: Double Jump Box Redirection <matthew.garrish@sympatico.ca>
Re: How to access filehandle through globref? <usenet@morrow.me.uk>
Re: How to access filehandle through globref? <jill_krugman@yahoo.com>
Re: How to access filehandle through globref? <usenet@morrow.me.uk>
Re: OOP <tore@aursand.no>
Re: OOP <mirod@xmltwig.com>
Re: Parsing Word Doc files <ouellmi@videotron.ca>
Persisten TCP Connection for Win32 <sammie-nospam@greatergreen.com>
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@augustmail.com
Regexp problem <nomail_nospam@nopain.nopain.com>
Re: Regexp problem <krahnj@acm.org>
Re: Regexp problem <usenet@morrow.me.uk>
Re: Regexp problem <nomail_nospam@nopain.nopain.com>
Re: return multiple arrays from functions <tassilo.parseval@rwth-aachen.de>
Re: return multiple arrays from functions (Ross Clement)
Re: Using glob() in a PAR executable (WAS: Replacing a <usenet@morrow.me.uk>
using sed from with a perl script (Jack Penarth)
Re: using sed from with a perl script <josef.moellers@fujitsu-siemens.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Fri, 27 Feb 2004 14:16:00 +0100
From: "kz" <kz15@earthling.net>
Subject: Re: Coderef usage in complex data structures
Message-Id: <YyH%b.618$YG4.5787@news.uswest.net>
"Tad McClellan" <tadmc@augustmail.com> wrote in message
news:slrnc3s0gj.3hl.tadmc@magna.augustmail.com...
>
[snip]
>
> It looks to me like the docs for strict.pm are
incomplete|misleading|wrong.
>
>
> perldoc strict
>
> "strict refs"
> ...
> There is one exception to this rule:
>
> $bar = \&{'foo'};
> &$bar;
>
>
> The docs do not provide a specification for the exception, only
> an example of an exception.
>
> The example has no runtime-ness in the symbol, so you could
> reasonably conclude that the exception is only at compile-time,
> while it looks like we are seeing runtime stuff being excepted...
>
>
> --
> Tad McClellan SGML consulting
> tadmc@augustmail.com Perl programming
> Fort Worth, Texas
...at least this is what below snippet would suggest when run on XP and ASPN
631, both runtime and compile-time stuff are excepted.
What would be the correct/expected behaviour of Perl?
Side question: why does this manpage (and lots of others as well) still
suggest calling a sub with &? Is there any difference between &$bar and
$bar->()?
I have done some RTFM but still ... which FM should I believe?
use strict;
use warnings;
my $num = "01";
my $bar = \&{"sub_".$num};
my $baz = \&{"sub_02"};
print "before...\n";
$bar->();
$baz->();
print "after...\n";
exit 0;
sub sub_01 {
print "I am inside sub_01...\n";
}
sub sub_02 {
print "I am inside sub_02...\n";
}
Cheers,
Zoltan
------------------------------
Date: Fri, 27 Feb 2004 12:27:20 +0100
From: Michele Dondi <bik.mido@tiscalinet.it>
Subject: Re: Comments requested: brief summary of Perl
Message-Id: <m6au30hrbeljpvv3mkpad27eaf8o43meoc@4ax.com>
On 23 Feb 2004 22:33:37 -0800, adamba@gte.net (Adam Barr) wrote:
>The file is at
>
>http://www.proudlyserving.com/language/perl.pdf
Some more cmts...
| Perl uses the term list to describe an ordered collection of scalars. An array is a variable that
| contains a list, so the terms "array" and "list" are often thought of as being the same.
But there are some subtle differences between an array and a list, so
that it may be useful to check:
perldoc -q "What is the difference between a list and an array?"
| An entire list is referenced by preceding the name with @. If a list is included in another list,
^^^^^^^^^^^^^^
Ahem! That is an array, see above...
| As a shortcut for lists of strings, you can use qw (the letter q followed by the letter w):
^^^^^^^
Of "words"!
i.e. ('foo bar', 'bar foo') for example is a list of strings, but you
*can't* use qw{} as a shortcut to specify it...
| Access to elements in an array uses 0-based indexing, and supports negative numbers to
| indicate counting back from the end. When indexing into an array, the list name is preceded with
| $, not @, except for certain circumstances which we won't get into:
When accessing a single element of an array by means of its index, the
*array* name is preceded with [...] (with no exception).
| Consistent with being one less than the size of the array, $#arrayname will be –1 for an
| array that has an empty list.
Stylistic note: why not "empty array"?!?
| When a program is invoked, the list @ARGV contains the command-line parameters that were
| passed to it:
| $firstarg = shift @ARGV;
^^^^^^^^^^^
Also in this case, as in many others, Perl tries to provide you with a
simplified syntax by choosing for you suitable defaults in order to
achieve a DWIM effect, so it may be worth mentioning that shift() is
just like shift(@ARGV) outside of the body of a sub. This idiom is
used very frequently in Perl programs.
BTW: somewhere above you said that you would have stuck to the
convention of explicitly using parentheses for functions args. FWIW:
it is MHO that it is much better not to adhere strictly to this
program...
| There can be only one value for a given key; it is replaced if a new value is assigned.
| The entire contents of a hash are referred to by precending the name with %. The functions
| keys() and values() return lists of the keys and values of a hash:
| $machinenames = keys %iphash;
| $ipaddrs = values %iphash;
This is perfectly legal, but I guess you don't want e.g. $machinenames
to hold the number of machines. You want
@machinenames = keys %iphash;
@ipaddrs = values %iphash;
instead!
| Perl supports else and elsif (note the spelling) blocks after if statements:
| if ($command = "sort") {
| do_sort();
| } elsif ($command = "print") {
| do_print();
| } else {
| invalid_command();
| }
I think you want
if ($command eq "sort") {
...
} elsif ($command eq "print") {
| There are also until loops, which execute as long as their test is false (while and until
| are related the same way as if and unless), and also do/while and do/until loops.
There is also [...] a smart mechanism to emulate other languages'
do/while, do/until loops by means of the 'do' "function"/flow control
statement and a special "coordination" with loop modifiers.
Please note:
while (<>) { print }
^^^^ ^
Parentheses are necessary, semicolon is not (although stylistically
recommended);
do { $_ ||= 'foo'; print } while <>;
^^^
Parentheses are not required, semicolon is.
| Perl allows if, unless, while, until, and foreach to be written as "modifiers" to
| expressions, which can be easier to read in some cases:
| $x += 1 unless $x > 100;
| print $_ foreach (1..10);
| This is just a reordering of the traditional way. In particular, the conditional is still evaluated
| before the code is executed, even though it is to the right of it. With foreach written as a
^^^^^^
unless with do BLOCK, as seen above!
| enclosing the handle between < and > and assigning the result to a variable. In scalar context a
^^^^^^^^^^^^^^
| file handle returns the next line of a file, or undef when end-of-file is reached; in scalar context it
^^^^^^^^^^^^^^
| returns every line of the file. Thus, you can loop through a file either with:
(In addition to what others pointed out...) Ahem!!
| foreach (<STDIN>) { # list context
| process($_);
| }
Now that I come to think of it, and OT WRT this context, it may be
worth mentioning that foreach is just an alias to for...
Well, time to go once again... seeya next time!!
Michele
--
you'll see that it shouldn't be so. AND, the writting as usuall is
fantastic incompetent. To illustrate, i quote:
- Xah Lee trolling on clpmisc,
"perl bug File::Basename and Perl's nature"
------------------------------
Date: Fri, 27 Feb 2004 08:09:21 -0500
From: "Matt Garrish" <matthew.garrish@sympatico.ca>
Subject: Re: Double Jump Box Redirection
Message-Id: <2kH%b.20183$253.1259573@news20.bellglobal.com>
"Martien Verbruggen" <mgjv@tradingpost.com.au> wrote in message
news:slrnc3thh3.8k7.mgjv@verbruggen.comdyn.com.au...
> On 26 Feb 2004 18:23:34 -0800,
> Kenton <kenton_mcleod@hotmail.com> wrote:
>
> > So that leave me with pearl.
>
> This newsgroup is called comp.lang.perl.misc. I find it interesting
> that you succeeded in posting to this group without realising that the
> language does not have an 'a' in its name.
>
> Besides that, in web-related programming JavaScript and Perl are
> generally used for two very different things. JavaScript is most
> commonly used for client-side scripting, and Perl for server-side
> programming.
>
> I'd say, from the utterly vague description that you give, that
> JavaScript would probably be what you want.
>
> One of the groups in the comp.infosystems.www.* hierarchy can probably
> help you further.
>
Or good old comp.lang.javascript...
Matt
------------------------------
Date: Fri, 27 Feb 2004 05:12:02 +0000 (UTC)
From: Ben Morrow <usenet@morrow.me.uk>
Subject: Re: How to access filehandle through globref?
Message-Id: <c1mjj2$2o6$1@wisteria.csv.warwick.ac.uk>
J Krugman <jill_krugman@yahoo.com> wrote:
> In <c1lrlf$g0a$3@wisteria.csv.warwick.ac.uk> Ben Morrow <usenet@morrow.me.uk> writes:
>
> >*{*$x}{IO}
>
> Thanks! I can retrieve the contents of the filehandle slot with
> *{*$x}{IO}, but it looks like Perl won't let me assign to it. It
> complains with "Can't modify glob elem in scalar assignment". Is
> there any way to set the filehandle slot through a typeglob ref?
s/through a typeglob ref//;
No. You definitely have an X-Y problem here: what are you trying to achieve?
> P.S. Is this documented anywhere?
The *foo{THING} syntax is documented in perlref.
Ben
--
don't get my sympathy hanging out the 15th floor. you've changed the locks 3
times, he still comes reeling though the door, and soon he'll get to you, teach
you how to get to purest hell. you do it to yourself and that's what really
hurts is you do it to yourself just you, you and noone else ** ben@morrow.me.uk
------------------------------
Date: Fri, 27 Feb 2004 10:27:24 +0000 (UTC)
From: J Krugman <jill_krugman@yahoo.com>
Subject: Re: How to access filehandle through globref?
Message-Id: <c1n62c$o3$1@reader2.panix.com>
In <c1mjj2$2o6$1@wisteria.csv.warwick.ac.uk> Ben Morrow <usenet@morrow.me.uk> writes:
>J Krugman <jill_krugman@yahoo.com> wrote:
>> In <c1lrlf$g0a$3@wisteria.csv.warwick.ac.uk> Ben Morrow <usenet@morrow.me.uk> writes:
>>
>> >*{*$x}{IO}
>>
>> Thanks! I can retrieve the contents of the filehandle slot with
>> *{*$x}{IO}, but it looks like Perl won't let me assign to it. It
>> complains with "Can't modify glob elem in scalar assignment". Is
>> there any way to set the filehandle slot through a typeglob ref?
>s/through a typeglob ref//;
>No.
OK, how do you do it through if you have the typeglob, not just a
reference to it?
>You definitely have an X-Y problem here: what are you trying to achieve?
I'm trying to find a way to temporarily reassign DB::OUT in perldb.
Everything I've tried has failed...
The reason I want to reassign DB::OUT is that I want to capture
the output of certain perldb commands (e.g. x or V) to a file.
jill
P.S. "X-Y problem"???
------------------------------
Date: Fri, 27 Feb 2004 10:59:31 +0000 (UTC)
From: Ben Morrow <usenet@morrow.me.uk>
Subject: Re: How to access filehandle through globref?
Message-Id: <c1n7uj$g8q$1@wisteria.csv.warwick.ac.uk>
J Krugman <jill_krugman@yahoo.com> wrote:
> In <c1mjj2$2o6$1@wisteria.csv.warwick.ac.uk> Ben Morrow <usenet@morrow.me.uk> writes:
> >J Krugman <jill_krugman@yahoo.com> wrote:
> >> In <c1lrlf$g0a$3@wisteria.csv.warwick.ac.uk> Ben Morrow <usenet@morrow.me.uk> writes:
> >>
> >> >*{*$x}{IO}
> >>
> >> Thanks! I can retrieve the contents of the filehandle slot with
> >> *{*$x}{IO}, but it looks like Perl won't let me assign to it. It
> >> complains with "Can't modify glob elem in scalar assignment". Is
> >> there any way to set the filehandle slot through a typeglob ref?
>
> >s/through a typeglob ref//;
>
> >No.
>
> OK, how do you do it through if you have the typeglob, not just a
> reference to it?
Sorry, I seem to have confused you... the intention was that you cannot
assign to the filehandle slot at all, whether through a typeglob ref or
not.
> >You definitely have an X-Y problem here: what are you trying to achieve?
>
> I'm trying to find a way to temporarily reassign DB::OUT in perldb.
> Everything I've tried has failed...
>
> The reason I want to reassign DB::OUT is that I want to capture
> the output of certain perldb commands (e.g. x or V) to a file.
open my $SAVE_DBOUT, '>&=', DB::OUT;
open DB::OUT, '>', 'file';
...
open DB::OUT, '>&=', $SAVE_DBOUT;
If you're not using 5.8 you'll need to change those to
open my $SAVE_DBOUT, '>&=' . fileno DB::OUT;
.
> P.S. "X-Y problem"???
This a common expression here... it means 'you asked how to do X, but
you're actually trying to do Y and X is not the way to go about it'. The
implication is that we'll be better able to help you if you tell us what
Y is.
Ben
--
perl -e'print map {/.(.)/s} sort unpack "a2"x26, pack "N"x13,
qw/1632265075 1651865445 1685354798 1696626283 1752131169 1769237618
1801808488 1830841936 1886550130 1914728293 1936225377 1969451372
2047502190/' # ben@morrow.me.uk
------------------------------
Date: Fri, 27 Feb 2004 07:16:57 +0100
From: Tore Aursand <tore@aursand.no>
Subject: Re: OOP
Message-Id: <pan.2004.02.27.03.51.54.914644@aursand.no>
On Thu, 26 Feb 2004 22:27:49 +0000, JC wrote:
> I'm familiar with OOP, and I use it in VB, but I don't have that talent
> in PERL. For example, I write a good bit of code, using syntax like:
> if($FORM{'calculate_shipping'} eq "") {
> &show_calc_shipping;
> }
> else {
> $ship_data = &calc_shipping;
> }
Are you decoding CGI data manually? You really should use the CGI module
for that kind of work.
And don't call sub-routines with a '&' unless you really know what you're
doing.
> That's easy, but I don't understand the following:
> $rateReqEl->setAttribute('USERID', 'xxxxxxxx');
> $rateReqEl->setAttribute('PASSWORD', 'xxxxxxxx');
> $rateReqDoc->appendChild($rateReqEl); $
'$rateReqEl' and '$rateReqDoc' are objects, while the part after the '->'
is the object's method.
Check out the OOP documentation for more details;
perldoc perlboot
perldoc perltoot
--
Tore Aursand <tore@aursand.no>
"First, God created idiots. That was just for practice. Then He created
school boards." -- Mark Twain
------------------------------
Date: Fri, 27 Feb 2004 13:49:34 +0100
From: Michel Rodriguez <mirod@xmltwig.com>
Subject: Re: OOP
Message-Id: <c1n905$sdu$1@news-reader2.wanadoo.fr>
JC wrote:
> [...] I don't understand the following:
> $rateReqEl->setAttribute('USERID', 'xxxxxxxx');
> $rateReqEl->setAttribute('PASSWORD', 'xxxxxxxx');
> $rateReqDoc->appendChild($rateReqEl); $
>
> Even my CGI book doesn't talk like that. Where's a good place to learn
> this dialect? I need to interact with the USPS servers, and this is how
> their documents tell me to query (using Perl XML parser and libwww-perl).
Once you have learned the basics of OO Perl, you will need to understand
what this specific piece of code does: setAttribute and appendChild look
very much like methods from the XML::DOM module. $rateReqEl is an
XML::DOM::Element and $rateReqDoc is an XML::DOM::Document.
As XML::DOM should be installed on your system you can do a perldoc
XML::DOM or man XML::DOM to read the docs for the module. Alternatively
you can read it at http://search.cpan.org/dist/XML-DOM/ (where you can
also download the latest version of the module)
It is possible that your code uses XML::LibXML instead of XML::DOM
(which would be a good thing as XML::LibXML is more recent and a lot
more powerful), as it has the same methods (they come straight out of
the DOM) in which case look at http://search.cpan.org/dist/XML-LibXML
You can tell which module your code use by searching for use XML::DOM or
use XML::LibXML.
--
Michel Rodriguez
Perl & XML
http://www.xmltwig.com
------------------------------
Date: Fri, 27 Feb 2004 08:17:10 -0500
From: "Michele Ouellet" <ouellmi@videotron.ca>
Subject: Re: Parsing Word Doc files
Message-Id: <1rH%b.31531$qe5.761256@wagner.videotron.net>
>> Can someone refer me to one somewhere or give me a hint about the
structure of such files? Thanks!
The format is proprietary and liable to change at any time. If you are
running under Windows, your best bet is probably to use OLE ( for instance,
the Win32::OLE module in the ActiveState Perl distribution ). You then need
to study the Word object model for the manipulations you want to perform; VB
code can generally found and adapted to your needs.
If you are not running under Windows, you might find something in
SourceForge, not necessarily in Perl, though.
Mich¨¨le.
------------------------------
Date: Fri, 27 Feb 2004 00:12:26 -0800
From: "Brad Walton" <sammie-nospam@greatergreen.com>
Subject: Persisten TCP Connection for Win32
Message-Id: <RMednQqIM9J6ZqPdRVn-hg@comcast.com>
I am trying to setup a persistent TCP connection between 2 Perl scripts
(using IO::Socket::INET). I have attempted establishing a pipe, but when the
server-side is broken, then connection will not re-establish. This seems to
work ok on Linux, but not Windows.
Client Code (from package):
---------------------------------------------
use strict;
use warnings;
use Storable qw(nstore_fd);
use IO::Socket::INET;
my $socket;
$SIG{PIPE} = sub {$socket = undef};
... declare some globals ...
#=========================================
# sconnect
#
# Sets up persistent connection
#=========================================
sub sconnect {
my $rv;
$rv = IO::Socket::INET->new( PeerAddr => $_stats_ip, PeerPort =>
$_stats_port, Proto => "tcp", Type => SOCK_STREAM);
return $rv;
}
#======================================
# stats_connect
#
# send single-line data
#======================================
sub stats_connect ($) {
my $stats_data = shift;
return if (!$_doing_stats);
my %PACKET = ();
$PACKET{'data'}{'type'} = $stats_data;
if (!$socket) { $socket = sconnect(); }
nstore_fd(\%PACKET, $socket) if ($socket);
return;
}
---------------------------------------------
Server Code
---------------------------------------------
use strict;
use warnings;
use Storable qw(fd_retrieve);
use IO::Socket::INET;
... declare some globals ...
my $server = IO::Socket::INET->new( LocalPort => $CONFIG{'fb port'},
Type => SOCK_STREAM,
Reuse => 1,
Listen => 10 ) # or SOMAXCONN
or die "Couldn't start server on port $CONFIG{'fb port'}: $!\n";
print " Initialized and ready to collect data\n";
print "--------------------------------------------------------------\n";
while (my $client = $server->accept()) {
eval {
while (my %PACKET = %{ fd_retrieve $client }) {
... do stuff ...
}
}
}
---------------------------------------------
Thanks for any help!
Brad
------------------------------
Date: Fri, 27 Feb 2004 02:22:02 -0600
From: tadmc@augustmail.com
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.5 $)
Message-Id: <tbCdnYA7Tv23Y6PdRVn-hw@august.net>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
- Do not provide too much information
- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
- Asking a question easily answered by a cursory doc search
- Asking for emailed answers
- Beware of saying "doesn't work"
- Sending a "stealth" Cc copy
Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($Revision: 1.5 $)
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://mail.augustmail.com/~tadmc/clpmisc.shtml
For more information about netiquette in general, see the "Netiquette
Guidelines" at:
http://andrew2.andrew.cmu.edu/rfc/rfc1855.html
A note to newsgroup "regulars":
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: Fri, 27 Feb 2004 11:00:31 +0000 (UTC)
From: kj <nomail_nospam@nopain.nopain.com>
Subject: Regexp problem
Message-Id: <c1n80f$11t$1@reader2.panix.com>
I want to remove from a (variable) string any character whose ascii
code is greater than 127, along with any whitespace preceding it.
The only regexp I can think of to do this with is the abominable:
/\s*(.)/ord($1) > 127 ? '' : $1/eg
Is there a better way?
Thanks!
kj
------------------------------
Date: Fri, 27 Feb 2004 11:07:31 GMT
From: "John W. Krahn" <krahnj@acm.org>
Subject: Re: Regexp problem
Message-Id: <403F24EB.F9F384A3@acm.org>
kj wrote:
>
> I want to remove from a (variable) string any character whose ascii
> code is greater than 127,
Anything greater than 127 is not ASCII.
> along with any whitespace preceding it.
> The only regexp I can think of to do this with is the abominable:
>
> /\s*(.)/ord($1) > 127 ? '' : $1/eg
>
> Is there a better way?
s/\s*[^[:ascii:]]+//g;
John
--
use Perl;
program
fulfillment
------------------------------
Date: Fri, 27 Feb 2004 11:05:19 +0000 (UTC)
From: Ben Morrow <usenet@morrow.me.uk>
Subject: Re: Regexp problem
Message-Id: <c1n89f$g8q$2@wisteria.csv.warwick.ac.uk>
kj <nomail_nospam@nopain.nopain.com> wrote:
>
> I want to remove from a (variable) string any character whose ascii
> code is greater than 127, along with any whitespace preceding it.
> The only regexp I can think of to do this with is the abominable:
>
> /\s*(.)/ord($1) > 127 ? '' : $1/eg
>
> Is there a better way?
There *are* no characters whose ASCII codes are greater than 127, so
this will do what you want:
s/\s*[^[:ascii:]]//g;
Ben
--
'Deserve [death]? I daresay he did. Many live that deserve death. And some die
that deserve life. Can you give it to them? Then do not be too eager to deal
out death in judgement. For even the very wise cannot see all ends.'
ben@morrow.me.uk
------------------------------
Date: Fri, 27 Feb 2004 11:42:11 +0000 (UTC)
From: kj <nomail_nospam@nopain.nopain.com>
Subject: Re: Regexp problem
Message-Id: <c1naei$1k9$1@reader2.panix.com>
In <c1n80f$11t$1@reader2.panix.com> kj <nomail_nospam@nopain.nopain.com> writes:
>I want to remove from a (variable) string any character whose ascii
>code is greater than 127, along with any whitespace preceding it.
>The only regexp I can think of to do this with is the abominable:
> /\s*(.)/ord($1) > 127 ? '' : $1/eg
Oops. Make that s/(\s*(\S))/ord($2) > 127 ? '' : $2/eg
It's just as bad.
>Is there a better way?
>Thanks!
>kj
------------------------------
Date: 27 Feb 2004 07:55:10 GMT
From: "Tassilo v. Parseval" <tassilo.parseval@rwth-aachen.de>
Subject: Re: return multiple arrays from functions
Message-Id: <c1mt4u$pp6$1@nets3.rz.RWTH-Aachen.DE>
Also sprach Uri Guttman:
>>>>>> "t4" == thumb 42 <thumb_42@yahoo.com> writes:
>
> t4> I generally happen to *like* &func() in part because it's what
> t4> I've always used. (The other reason is that it makes it a little
> t4> more obvious that I'm calling a subroutine and not a method or
> t4> perl builtin)
>
> and it makes your code look like a perl4 kiddie coder wrote it. just
> because you are used to it doesn't defend your use of it. and how can it
> be confused with a method? there is NO object nor -> there. and
> confusing it with a perl function is rare since you should KNOW most of
> the perl function names and not use a sub name that would be confused
> with them.
>
> any more weak defenses?
Consistency. Look at how you create references for instance:
*GLOB => \*GLOB
$scalar => \$scalar
@ary => \@ary
%hash => \%hash
When using the ampersand, this table can be completed to
&func => \&func
Every data-type (and functions in Perl can be considered a type as well)
has a special sigil so why not keep using it with functions, too? Not
that I'd be using ampersands on function calls, but then I don't see a
problem when others do.
It's a style issue and not a technical one (the often quoted
side-effects of the ampersand really don't count since they wont get
into the way). And now that we are talking about matters of taste, the
old Latin saying "De gustibus non est disputandum" comes to my mind.
Tassilo
--
$_=q#",}])!JAPH!qq(tsuJ[{@"tnirp}3..0}_$;//::niam/s~=)]3[))_$-3(rellac(=_$({
pam{rekcahbus})(rekcah{lrePbus})(lreP{rehtonabus})!JAPH!qq(rehtona{tsuJbus#;
$_=reverse,s+(?<=sub).+q#q!'"qq.\t$&."'!#+sexisexiixesixeseg;y~\n~~dddd;eval
------------------------------
Date: 27 Feb 2004 03:40:04 -0800
From: clemenr@wmin.ac.uk (Ross Clement)
Subject: Re: return multiple arrays from functions
Message-Id: <e5b5d377.0402270340.67940fc9@posting.google.com>
Tore Aursand <tore@aursand.no> wrote in message news:<pan.2004.02.26.09.38.14.947243@aursand.no>...
> On Thu, 26 Feb 2004 01:15:08 -0800, Ross Clement wrote:
> >> What's the problem with this, except that you don't want to call your
> >> function with a '&'?
>
> > No problem that I know of, just wondering if there was a better way.
>
> It would be truly interesting to hear from you what you mean would be a
> better way? I can't think of a better way;
Erm, no I can't think of a better way.
But, I don't know everything there is to know about Perl.
If I already knew of a better way, then there wouldn't have been any
point in my posting the question to the group.
Cheers,
Ross-c
------------------------------
Date: Fri, 27 Feb 2004 05:15:50 +0000 (UTC)
From: Ben Morrow <usenet@morrow.me.uk>
Subject: Re: Using glob() in a PAR executable (WAS: Replacing a text in multiple files with regular expressions)
Message-Id: <c1mjq6$2o6$2@wisteria.csv.warwick.ac.uk>
jl_post@hotmail.com (J. Romano) wrote:
>
> When a glob() function is encountered in a Perl script, ActiveState
> Perl will run the "perlglob.exe" executable using the backtick
> operator.
As of 5.6 this is no longer true, and the File::Glob module is used on
all platforms.
Ben
--
Musica Dei donum optimi, trahit homines, trahit deos. |
Musica truces molit animos, tristesque mentes erigit. | ben@morrow.me.uk
Musica vel ipsas arbores et horridas movet feras. |
------------------------------
Date: 27 Feb 2004 04:24:21 -0800
From: jackpenarth@aol.com (Jack Penarth)
Subject: using sed from with a perl script
Message-Id: <f27d1c90.0402270424.39a88f5b@posting.google.com>
I use a perl scrip to parse fixed-length field database outputs into
.csv files. I regularly use a back-ticked sed command to do stuff
after perl has finished with the file ('cos I am not that good with
perl yet!). I have a need to remove the last line of these files and I
thought that the following line would work:
`sed '$d' file.csv > file.csvnew`
But it doesn't. Am I missing something obvious here?
TIA
Jack
------------------------------
Date: Fri, 27 Feb 2004 13:31:07 +0100
From: Josef =?iso-8859-1?Q?M=F6llers?= <josef.moellers@fujitsu-siemens.com>
Subject: Re: using sed from with a perl script
Message-Id: <403F388B.28F17C44@fujitsu-siemens.com>
Jack Penarth wrote:
> =
> I use a perl scrip to parse fixed-length field database outputs into
> .csv files. I regularly use a back-ticked sed command to do stuff
> after perl has finished with the file ('cos I am not that good with
> perl yet!). I have a need to remove the last line of these files and I
> thought that the following line would work:
> =
> `sed '$d' file.csv > file.csvnew`
> =
> But it doesn't. Am I missing something obvious here?
You should have enabled warnings:
Name "main::d" used only once: possible typo at ./pp line 2.
Use of uninitialized value in concatenation (.) at ./pp line 2.
Try
`sed '\$d' file.csv > file.csvnew`
Josef
-- =
Josef M=F6llers (Pinguinpfleger bei FSC)
If failure had no penalty success would not be a prize
-- T. Pratchett
------------------------------
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 6188
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