[31477] in Perl-Users-Digest
Perl-Users Digest, Issue: 2729 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Fri Dec 18 06:09:37 2009
Date: Fri, 18 Dec 2009 03:09:04 -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, 18 Dec 2009 Volume: 11 Number: 2729
Today's topics:
Re: Closing a DBI instance <tim@johnsons-web.com>
Re: Closing a DBI instance <hjp-usenet2@hjp.at>
Re: Creating an alias to an existing hash (from a hash <ben@morrow.me.uk>
Re: Creating an alias to an existing hash (from a hash <ruben@mrbrklyn.com>
Re: Opening a file with case-insensitive name <john@castleamber.com>
Re: perl compile failure <ben@morrow.me.uk>
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@seesig.invalid
Re: split and lc or \L in one statement <uri@StemSystems.com>
WWW::Mechanize <nathanabu@gmail.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Thu, 17 Dec 2009 23:13:12 -0600
From: Tim Johnson <tim@johnsons-web.com>
Subject: Re: Closing a DBI instance
Message-Id: <slrnhim2oa.hbs.tim@bart.johnson.com>
On 2009-12-17, Jochen Lehmeier <OJZGSRPBZVCX@spammotel.com> wrote:
> On Thu, 17 Dec 2009 22:13:16 +0100, Tim Johnson <tim@johnsons-web.com>
> wrote:
>
>> Neither am I. At least I have enough to rule out.
>
> I assume that the perl processes started by your cron actually end (i.e.,
> are not listed by "ps" anymore), and you still run out of connections in
> MySQL.
Correct.
> I see two possible sources for your problem:
>
> a) You are creating many connections in a perl script, not just one, and
> thus running out because they are not Garbage Collected quickly enough
> (for whatever reason).
And maybe there is some sort of unintended recursive process?
> b) Your processes end, but still MySQL thinks the connections are open. I
> do not know if the architecture of MySQL allows this to happen, since I
> use Oracle (and there this is impossible, as the DB cleans up connections
> when the underlying TCP/IP connection goes down, which is guaranteed by
> the OS when the process stops).
>
> Here's a test for you to rule out b): write a little test script which
> only opens one DBI connection and then sleeps for a long time. Start it,
> and then kill it with SIGKILL (kill -9). This will kill it without it
> being able to close the connection in a controlled manner, i.e., the
> DESTROY will certainly not run. I'd try this first, because it's very
> simple and straightforward.
>
> If you do that a lot of times, and do not run out of MySQL connections,
> then you know that b) cannot be the case. Then it's time to rule out a),
> i.e., take a very good look at your scripts. Maybe one script opens
> mulitple connections and does not free them (because it stores them in a
> hash or whatever).
Good advice. I'm using this as an archive for our perl programmer to
review when he gets back..
thanks
--
Tim
tim@johnsons-web.com
http://www.akwebsoft.com
------------------------------
Date: Fri, 18 Dec 2009 07:54:09 +0100
From: "Peter J. Holzer" <hjp-usenet2@hjp.at>
Subject: Re: Closing a DBI instance
Message-Id: <slrnhim9oh.10j.hjp-usenet2@hrunkner.hjp.at>
On 2009-12-17 17:13, Tim Johnson <tim@johnsons-web.com> wrote:
> On 2009-12-17, Ben Morrow <ben@morrow.me.uk> wrote:
>> Quoth tim@johnsons-web.com:
>>>
>>> Thanks for that Ben. Can you think of any syntax or system factors
>>> that might prevent the destructor from being triggered?
>>
>> Do you have reason to believe it isn't being?
>> One thing that can cause
> A large number of perl scripts are being run as by cron jobs some once
> per hour others even more frequently. The mysql server has to be restarted
> frequently because MAX_CONNECTIONS is surpassed. One thing that I have
> suspected is that connections are not being properly closed. Thus
> the code inventory.
The connection is closed when the client exits - there is nothing the
client can do to prevent that. So I think you are barking up the wrong
tree. You should check which clients are running when you get near
MAX_CONNECTIONS. Are any of them hung? Can you distribute them better
over time? If the problem happens at unpredictable time, dumping the
output of "mysqladmin processlist" and "lsof" into a file every few
minutes can help you reconstruct what happened just before the problem
occured. (And then you can write a perl script to analyze the data, to
get back on topic)
hp
------------------------------
Date: Thu, 17 Dec 2009 23:52:44 +0000
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: Creating an alias to an existing hash (from a hash reference)
Message-Id: <crsqv6-8np1.ln1@osiris.mauzo.dyndns.org>
Quoth "jl_post@hotmail.com" <jl_post@hotmail.com>:
>
> Recently I was reviewing someone's Perl code and I saw that his
> code used a few global variables that were set and accessed by several
> functions. Since I am not a fan of global variables, I edited the
> code to get rid of all but one of them.
Good work :).
> The remaining global variable was a hash. I proceded to edit the
> code so that the functions took a hash reference as an input
> argument. So previously, the code looked something like:
<snip>
>
> In the function definitions themselves, I added code to read in the
> input arguments, like this:
>
> sub f
> {
> my ($hashRef) = @_;
> .
> .
> .
> }
>
> However, all the functions still referred to %hash (which at this
> point was no longer visible to the functions). So I figured I had to
> change all instances of "$hash{...}" to "$hashRef->{...}".
>
> But then I thought: Could there be another way that doesn't
> involve changing all those instances in each function? I'd like to do
> something similar to what C++ allows with references:
use Data::Alias;
sub f {
my ($hashRef) = @_;
alias my %hash = %$hashref;
...;
}
I'm rather fond of D::A, for exactly this reason.
<snip>
> I thought of using typeglobs, like this:
>
> local *hash = $hashRef;
>
> which would allow %hash to be used as if it were a real hash, all the
> while reading and writing from the hash that $hashRef points to.
>
> However, since his code had "use strict;" in effect, "perl -c"
> responded with:
>
> Variable "%hash" is not imported at ...
>
> So I declared %hash the line before with "my", like this:
>
> my %hash;
> local *hash = $hashRef;
>
> That didn't work; although it compiled just fine, %hash was empty.
Typeglobs always refer to package globals. Lexicals don't live in
typeglobs, so you need a module like Data::Alias to do the aliasing
magic for you.
> So then I changed it to be declared with "our" instead of "my", like
> this:
>
> our %hash;
> local *hash = $hashRef;
>
> and that worked. From then on in that function, every instance of
> %hash pointed back to the passed-in %hash (that was passed in as a
> reference).
>
> However, I'm a little concerned with the usage of "our". That has
> the effect of creating a package variable named %hash (separate from
> the lexical), which can be accessed from anywhere in the package. Is
> this a good idea to do?
Absolutely not. This variable is now *more* global than the file-scoped
'my %hash' you started with. In particular, if you have an 'our %hash'
in another sub, it will refer to the *same* variable.
A rule of thumb is that 'our' variables, like named subs, should always
appear at file scope, not inside a function.
> ...or should I just bite the bullet and change all the instances of
> %hash in the functions to hash references?
Some might consider D::A obscure. If you think you need to please such
people, you will have to do the find-and-replace. (With a decent editor
it shouldn't be difficult.)
> P.S. Incidentally, the generated Perl code that find2perl creates
> uses this typeglob approach to create aliases named $name, $dir, and
> $prune.
Yes. find2perl is *very* old, and predates the invention of 'my'.
Playing fancy tricks with typeglobs was entirely standard in Perl 4, as
there was often no alternative.
Ben
------------------------------
Date: Fri, 18 Dec 2009 02:54:53 +0000 (UTC)
From: Ruben Safir <ruben@mrbrklyn.com>
Subject: Re: Creating an alias to an existing hash (from a hash reference)
Message-Id: <hgeqtt$933$5@reader1.panix.com>
On Thu, 17 Dec 2009 14:52:16 -0800, jl_post@hotmail.com wrote:
> Hi,
>
> Recently I was reviewing someone's Perl code and I saw that his
> code used a few global variables that were set and accessed by several
> functions. Since I am not a fan of global variables, I edited the code
> to get rid of all but one of them.
>
> (For the record, his code used "strict" and "warnings".)
>
> The remaining global variable was a hash. I proceded to edit the
> code so that the functions took a hash reference as an input argument.
> So previously, the code looked something like:
>
> my %hash;
>
> {
> f1();
> f2();
> f3();
> f4();
> }
>
> sub f1 { ... }
> sub f2 { ... }
> sub f3 { ... }
> sub f4 { ... }
>
> (This is a simplification.)
>
> I changed those lines to something like:
>
> sub f1 { ... }
> sub f2 { ... }
> sub f3 { ... }
> sub f4 { ... }
>
> {
> my %hash;
>
> f1(\%hash);
> f2(\%hash);
> f3(\%hash);
> f4(\%hash);
> }
It would probably be better to just use an object.
>
> In the function definitions themselves, I added code to read in the
> input arguments, like this:
>
> sub f
> {
> my ($hashRef) = @_;
> .
> .
> .
> }
>
> However, all the functions still referred to %hash (which at this
> point was no longer visible to the functions). So I figured I had to
> change all instances of "$hash{...}" to "$hashRef->{...}".
>
> But then I thought: Could there be another way that doesn't
> involve changing all those instances in each function? I'd like to do
> something similar to what C++ allows with references:
>
> int cat = 5;
> int & dog = cat;
> // Now every change made to dog will be // reflected in cat, and
> vice-versa.
>
> The idea of creating a new variable named %hash came to mind:
>
> sub f
> {
> my ($hashRef) = @_;
> my %hash = %$hashRef;
> .
> .
> .
> }
>
> but that would create a completely new copy of the original %hash (using
> extra memory),
Oh.. - why do you say that?
> and any changes made to the copy would have to be copied
> back to the original be returning from the function, like this:
>
> %$hashRef = %hash;
>
> I thought of using typeglobs, like this:
>
> local *hash = $hashRef;
>
> which would allow %hash to be used as if it were a real hash, all the
> while reading and writing from the hash that $hashRef points to.
>
> However, since his code had "use strict;" in effect, "perl -c"
> responded with:
>
> Variable "%hash" is not imported at ...
>
> So I declared %hash the line before with "my", like this:
>
> my %hash;
> local *hash = $hashRef;
>
> That didn't work; although it compiled just fine, %hash was empty.
> So then I changed it to be declared with "our" instead of "my", like
> this:
>
> our %hash;
> local *hash = $hashRef;
>
> and that worked. From then on in that function, every instance of %hash
> pointed back to the passed-in %hash (that was passed in as a reference).
>
> However, I'm a little concerned with the usage of "our". That has
> the effect of creating a package variable named %hash (separate from the
> lexical), which can be accessed from anywhere in the package. Is this a
> good idea to do?
>
> In other words, if I need to create an alias for a variable, is it
> a good idea to do something like this:
>
> our %dog;
> local *dog = \%ENV;
> # Now %dog and %ENV are the same:
> # any changes made to %dog will
> # affect %ENV, and vice-versa.
>
> or is there a better way to do this?
>
> ...or should I just bite the bullet and change all the instances of
> %hash in the functions to hash references?
>
> Any thoughts, advice, and ideas are welcome.
>
> -- Jean-Luc
>
> P.S. Incidentally, the generated Perl code that find2perl creates uses
> this typeglob approach to create aliases named $name, $dir, and $prune.
------------------------------
Date: Thu, 17 Dec 2009 18:13:05 -0600
From: John Bokma <john@castleamber.com>
Subject: Re: Opening a file with case-insensitive name
Message-Id: <87eimtf8by.fsf@castleamber.com>
Brian Wakem <no@email.com> writes:
> John Bokma wrote:
>>
>> I would suggest to read all files in /home/mydomain/, lowercase all
>> entries, and match it with the lowercase version of $filename.
>
> One potential gotcha here is that lowercasing all the files in the dir could
> leave you with more than 1 file with the same name. What is the OP going
> to do then I wonder?
Oops, very good point.
--
John Bokma
Read my blog: http://johnbokma.com/
Hire me (Perl/Python): http://castleamber.com/
------------------------------
Date: Thu, 17 Dec 2009 23:43:22 +0000
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: perl compile failure
Message-Id: <q9sqv6-8np1.ln1@osiris.mauzo.dyndns.org>
Quoth Ruben Safir <ruben@mrbrklyn.com>:
> On Thu, 17 Dec 2009 21:33:15 +0000, Ruben Safir wrote:
> > On Thu, 17 Dec 2009 20:43:51 +0000, Ben Morrow wrote:
> >> Quoth Ruben Safir <ruben@mrbrklyn.com>:
> >>> It seems that the perl 5.10.1 won't compile on my system with is a new
> >>> opensuse 11.2
> >>>
> >>> Its dieing on this line
> >>>
> >>> make[1]: Entering directory `/home/ruben/Downloads/perl-5.10.1/ext/
> >>> ODBM_File'
> >>> Skip ../../lib/ODBM_File.pm (unchanged) ../../miniperl "-I../../lib"
> >>> "-I../../lib" ../../lib/ExtUtils/xsubpp - noprototypes -typemap
> >>> ../../lib/ExtUtils/typemap -typemap typemap ODBM_File.xs >
> >>> ODBM_File.xsc && mv ODBM_File.xsc ODBM_File.c gcc -c -D_REENTRANT
> >>> -D_GNU_SOURCE -fno-strict-aliasing -pipe -fstack- protector
> >>> -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -O2
> >>> -DVERSION=\"1.07\" -DXS_VERSION=\"1.07\" -fPIC "-I../.." ODBM_File.c
> >>> ODBM_File.xs: In function ‘XS_ODBM_File_DESTROY’: ODBM_File.xs:124:
> >>> error: too few arguments to function ‘dbmclose’ make[1]: ***
> >>> [ODBM_File.o] Error 1
> >>> make[1]: Leaving directory `/home/ruben/Downloads/perl-5.10.1/ext/
> >>> ODBM_File'
> >>> Unsuccessful make(ext/ODBM_File): code=512 at make_ext.pl line 360.
> >>> make: *** [lib/auto/ODBM_File/ODBM_File.so] Error 2
> >>>
> >>>
> >>> in the ODBM module. Any clues on a fix?
> >>
> >> Well, if you don't need ODBM then just re-Configure perl and omit ODBM
> >> from the list of extensions to build. Make sure you start in a clean
> >> directory, or remove Policy.sh before starting.
> >>
> >> Otherwise: where are you getting your <dbm.h> from? dbmclose should be
> >> int dbmclose(void); if you have some GDBM passthrough with a different
> >> prototype that isn't going to work.
> >>
> >> You could also take this question to perl5-porters@perl.org, which is
> >> the list for discussing perl development (as opposed to Perl
> >> development).
> >
> > I don't know where the dbm is coming or going to.
The easiest way to find out is:
- rebuild with ODBM_File included, and wait for it to fail,
- cd to the ext/ODBM_File directory,
- type 'make ODBM_File.i',
- search through ODBM_File.i for 'dbm.h', and check the full path,
- find out where you got that file from (ask rpm, perhaps).
> Actually, I'm wondering if this might be why CPAN is failing. Does it
> use a Berkleys Database to keep track of modules?
ODBM is not the same as Berkely DB. The normal Perl interface to bdb is
DB_File, though there is a more complete BerkelyDB module on CPAN.
I seriously doubt CPAN.pm uses ODBM_File. If anything, it might use
dbmopen/AnyDBM_File, but since that will choose ODBM *last* of the
available options it's unlikely it would end up using it.
Unless you have some code that asks for ODBM_File specifically, I'd just
build a perl without it. I'm fairly certain all you'd end up with is a
compatibility layer from some other DBM library (probably GDBM) anyway.
Ben
------------------------------
Date: Fri, 18 Dec 2009 02:13:26 -0600
From: tadmc@seesig.invalid
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
Message-Id: <Y_CdnSq5f-k7pLbWnZ2dnUVZ_sCdnZ2d@giganews.com>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
- Do not provide too much information
- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
- Asking a question easily answered by a cursory doc search
- Asking for emailed answers
- Beware of saying "doesn't work"
- Sending a "stealth" Cc copy
Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
This newsgroup, commonly called clpmisc, is a technical newsgroup
intended to be used for discussion of Perl related issues (except job
postings), whether it be comments or questions.
As you would expect, clpmisc discussions are usually very technical in
nature and there are conventions for conduct in technical newsgroups
going somewhat beyond those in non-technical newsgroups.
The article at:
http://www.catb.org/~esr/faqs/smart-questions.html
describes how to get answers from technical people in general.
This article describes things that you should, and should not, do to
increase your chances of getting an answer to your Perl question. It is
available in POD, HTML and plain text formats at:
http://www.rehabitation.com/clpmisc.shtml
For more information about netiquette in general, see the "Netiquette
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 that they do
know and are being the "bad kind" of Lazy.
A note about technical terms used here:
In this document, we use words like "must" and "should" 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_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 and many others on the comp.lang.perl.misc newsgroup.
--
Tad McClellan
email: perl -le "print scalar reverse qq/moc.liamg\100cm.j.dat/"
------------------------------
Date: Thu, 17 Dec 2009 23:30:47 -0500
From: "Uri Guttman" <uri@StemSystems.com>
Subject: Re: split and lc or \L in one statement
Message-Id: <874ono3nuw.fsf@quad.sysarch.com>
>>>>> "MG" == Marc Girod <marc.girod@gmail.com> writes:
MG> On Dec 17, 11:57 am, Thomas Glanzmann <tho...@glanzmann.de> wrote:
>> my ($snummer, $maschinenname, $prozess) = (split(/;_,?/))[0,1,14];
>> $snummer = lc($snummer);
>> $maschinenname = lc($maschinenname);
MG> my ($snummer, $maschinenname, $prozess) =
MG> grep{$_ = $c++<2 ? lc : $_}(split(/;_,?/))[0,1,14];
that should be map. grep won't return the value if it is false and maybe
the split results has a null string in there.
also $c is undeclared and could be set to something other than 0 by
other code. so this is longer and noisier than it has to be.
uri
--
Uri Guttman ------ uri@stemsystems.com -------- http://www.sysarch.com --
----- Perl Code Review , Architecture, Development, Training, Support ------
--------- Gourmet Hot Cocoa Mix ---- http://bestfriendscocoa.com ---------
------------------------------
Date: Fri, 18 Dec 2009 00:01:19 -0800 (PST)
From: Nathan <nathanabu@gmail.com>
Subject: WWW::Mechanize
Message-Id: <079e5631-4fe0-4ff3-81cc-2d2de287e039@m16g2000yqc.googlegroups.com>
Hi,
is anyone familiar with this module?
I have a form with a radio button, any idea how do I click on it???
to be more precise,I have an HTML page, with a radio button, and a
submit button, how do I click / set the radio button??? (I managed to
click the submit button...)
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>
Administrivia:
To submit articles to comp.lang.perl.announce, send your article to
clpa@perl.com.
Back issues are available via anonymous ftp from
ftp://cil-www.oce.orst.edu/pub/perl/old-digests.
#For other requests pertaining to the digest, send mail to
#perl-users-request@ruby.oce.orst.edu. Do not waste your time or mine
#sending perl questions to the -request address, I don't have time to
#answer them even if I did know the answer.
------------------------------
End of Perl-Users Digest V11 Issue 2729
***************************************
