[31740] in Perl-Users-Digest
Perl-Users Digest, Issue: 3003 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Fri Jun 25 06:09:45 2010
Date: Fri, 25 Jun 2010 03:09:07 -0700 (PDT)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Fri, 25 Jun 2010 Volume: 11 Number: 3003
Today's topics:
Re: Creating a makefile for installing a Perl applicati <apeiron@isuckatdomains.net.invalid>
How to use MIME::Lite to include the original message i <r.ted.byers@gmail.com>
OT: being helpful (was Re: UNIX datagram sockets) <RedGrittyBrick@spamweary.invalid>
Re: OT: being helpful (was Re: UNIX datagram sockets) <jak@isp2dial.com>
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@seesig.invalid
Re: Proposing a new module: Parallel::Loops <apeiron@isuckatdomains.net.invalid>
Re: Proposing a new module: Parallel::Loops <4ux6as402@sneakemail.com>
Re: Proposing a new module: Parallel::Loops <ben@morrow.me.uk>
Re: Proposing a new module: Parallel::Loops <4ux6as402@sneakemail.com>
Re: UNIX datagram sockets <hjp-usenet2@hjp.at>
Re: UNIX datagram sockets <jak@isp2dial.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Thu, 24 Jun 2010 16:22:07 +0000 (UTC)
From: Chris Nehren <apeiron@isuckatdomains.net.invalid>
Subject: Re: Creating a makefile for installing a Perl application (not a module)
Message-Id: <i000ne$atr$2@news.eternal-september.org>
On 2010-06-22, Henry Law scribbled these curious markings:
> All these components need to be placed in the right libraries on
> installation and I'm doing all that using "make", so that the user can
> type "configure", "make" and then "make install". There are also "make
> update" (to replace just the code) and "make uninstall".
Why are you not using the standard tools for this? ExtUtils::MakeMaker,
Module::Build, Module::Install, Dist::Zilla.
> Currently I have an entirely specific "configure" program (written in
> Perl) which understands the details of the programs and modules and
> where to put them, and which also understands the various system files
> and how to install those too (entries in /etc/init.d for example). It
> allows the user to change the default locations if required, and it also
> makes a number of checks (libraries already exist, users are defined,
> and the like).
Ibid.
> I'd like to think, though, that there's a more general-purpose utility
> somewhere, to which I could specify "this library's contents go there
> unless the user says otherwise", and "the following users must be
> defined on the system", and so on, which would then create the Makefile.
> I've searched but I can't find anything at all on installing a Perl
> _application_ (as distinct from installing Perl _modules_).
Trying to specify where things go on the user's system will only end in
tears--yours--after your user's sysadmins come screaming at you.
--
Thanks and best regards,
Chris Nehren
Unless noted, all content I post is CC-BY-SA.
------------------------------
Date: Thu, 24 Jun 2010 13:04:09 -0700 (PDT)
From: Ted Byers <r.ted.byers@gmail.com>
Subject: How to use MIME::Lite to include the original message in the reply when replying to a message?
Message-Id: <3d174d5c-8af8-49d1-a533-03b7834cdd79@q12g2000yqj.googlegroups.com>
I am using Activestate perl 5.10.0 on WXP.
I now have a script that uses Net::IMAP::Simple to get incoming
messages, and Email::Simple to parse the headers easily. Once I have
the information I need from the headers, I use MIME::Lite to send a
multipart/related message using our MS Exchange server. Once I
figured it out, the result seems easy and reliable.
The problem is that I have now been asked to include in the automated
replies the bodies of the messages the script is replying to, and
these too are multipart/related. Is there a relatively painless way
to add the body of the old message as yet another part to the message
I am sending? My first thought was to get the body from the object
returned by Email::Simple->new, from which I had already parsed the
headers, and add those lines of data to the new one using MIME::Lite-
>build on the old body to make another part to the message I am
sending, but that produced something incomprehensible (i.e. the result
was the intended new body with a nameless attachment with only a
single line of text - none of the data from the original message). It
is certain that this approach is wrong, but the question is, what
should I have done?
If I can get MIME::Parser to extract the html part and the images in
the incoming messages, so I can write those to files, I can then
create a new part from those files, but I have yet to get MIME::Parser
to parse multipart/related or multipart/alternative messages in a way
that I can get at either the html part or the images. I suspect I
haven't really understood, yet, how to use MIME::Parser properly with
multipart messages, but that is a different matter.
To be clear, it is trivial for me to append an original message to an
automated reply when the original is plain text (regardless of the
MIME type of the automated reply), but I am presently at a loss as to
how to do so when both the automated reply (without the original) and
the original messages are multipart/related MIME messages (using html
for the body and various different media either embedded or attached.
I clearly need a little guidance on which MIME packages I should
examine, and how to use them to achieve what is required.
Thanks
Ted
------------------------------
Date: Thu, 24 Jun 2010 14:49:40 +0100
From: RedGrittyBrick <RedGrittyBrick@spamweary.invalid>
Subject: OT: being helpful (was Re: UNIX datagram sockets)
Message-Id: <4c236275$0$28009$db0fefd9@news.zen.co.uk>
On 24/06/2010 14:00, John Kelly wrote:
> On Thu, 24 Jun 2010 04:01:07 +0000, John Kelly<jak@isp2dial.com> wrote:
>
[Much]
...
Just my ¤0.02 worth:
If I wanted to write an essay about some aspect of Perl usage, I would
open an account somewhere like blogger.com.
If I wanted to fill a gap in the Perl docs or FAQ, I would draft a
revised FAQ entry or revised doc section and submit it to the relevant
maintainers. I'd expect to have to rewrite it once or twice if asked. I
would set my expectations minimally.
If I wanted to make some sort of helpful announcement in CLPM I'd say so
in the subject, or at least at the top of the posting. (Obviously there
is a certain amount of hindsight here, but I like to think I would
probably have done this anyway).
I would try to remember that gifts should not be conditional on the
recipients' gratitude or even appreciation.
If I was tempted to engage in, or continue, an acrimonious argument, I'd
go for a walk in the park, until the temptation faded away†.
As may be evident, in my case the above are somewhat aspirational.
As I said, just my ¤0.02 worth. Your Mileage May Vary.
--
RGB
†It doesn't always work :-(
------------------------------
Date: Thu, 24 Jun 2010 14:09:53 +0000
From: John Kelly <jak@isp2dial.com>
Subject: Re: OT: being helpful (was Re: UNIX datagram sockets)
Message-Id: <2gp6261qjnt4fqbforemp3q2ie104bir8p@4ax.com>
On Thu, 24 Jun 2010 14:49:40 +0100, RedGrittyBrick
<RedGrittyBrick@spamweary.invalid> wrote:
>If I wanted to write an essay about some aspect of Perl usage, I would
>open an account somewhere like blogger.com.
>
>If I wanted to fill a gap in the Perl docs or FAQ, I would draft a
>revised FAQ entry or revised doc section and submit it to the relevant
>maintainers. I'd expect to have to rewrite it once or twice if asked. I
>would set my expectations minimally.
>
>If I wanted to make some sort of helpful announcement in CLPM I'd say so
>in the subject, or at least at the top of the posting. (Obviously there
>is a certain amount of hindsight here, but I like to think I would
>probably have done this anyway).
>
>I would try to remember that gifts should not be conditional on the
>recipients' gratitude or even appreciation.
>
>If I was tempted to engage in, or continue, an acrimonious argument, I'd
>go for a walk in the park, until the temptation faded away†.
>
>As may be evident, in my case the above are somewhat aspirational.
Oh I agree that's good advice. But I don't always have time to think
that far ahead. So I just throw it out there and let it fall where it
may.
If anyone wants to take my posts and make an FAQ or whatever, go for it.
I don't do this for personal accolades or status. I just enjoy talking
up good ideas.
--
Web mail, POP3, and SMTP
http://www.beewyz.com/freeaccounts.php
------------------------------
Date: Fri, 25 Jun 2010 02:14:48 -0500
From: tadmc@seesig.invalid
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
Message-Id: <SZWdnVcBE5r1yrnRnZ2dnUVZ_jCdnZ2d@giganews.com>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
- Do not provide too much information
- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
- Asking a question easily answered by a cursory doc search
- Asking for emailed answers
- Beware of saying "doesn't work"
- Sending a "stealth" Cc copy
Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($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/"
The above message is a Usenet post.
I don't recall having given anyone permission to use it on a Web site.
------------------------------
Date: Thu, 24 Jun 2010 16:20:06 +0000 (UTC)
From: Chris Nehren <apeiron@isuckatdomains.net.invalid>
Subject: Re: Proposing a new module: Parallel::Loops
Message-Id: <i000jl$atr$1@news.eternal-september.org>
On 2010-06-22, Peter Valdemar Mørch scribbled these curious markings:
> perldoc perlmodlib suggests posting here before posting on CPAN, so
> here goes:
I find it quaint that some people still follow that guideline. Most
folks just upload.
> I have a new module that I'd like to upload: Parallel::Loops, and
> following is the bulk of the synopsis. Is the Parallel::Loops name
> appropriate and does anybody have any comments on it before I post it
> on CPAN?
How does this differ from e.g. Coro or other similar modules?
> my $pl = new Parallel::Loops($maxProcs);
Indirect object syntax considered harmful:
http://www.shadowcat.co.uk/blog/matt-s-trout/indirect-but-still-fatal/
>
> my @input = ( 0 .. 9 );
>
> my %output;
> $pl->tieOutput( \%output );
Why are you using tie here?
--
Thanks and best regards,
Chris Nehren
Unless noted, all content I post is CC-BY-SA.
------------------------------
Date: Thu, 24 Jun 2010 14:56:19 -0700 (PDT)
From: =?ISO-8859-1?Q?Peter_Valdemar_M=F8rch?= <4ux6as402@sneakemail.com>
Subject: Re: Proposing a new module: Parallel::Loops
Message-Id: <cc4e4141-f47a-4338-aeb6-4490aaa46d2d@w12g2000yqj.googlegroups.com>
On Jun 24, 6:20=A0pm, Chris Nehren <apei...@isuckatdomains.net.invalid>
wrote:
> How does this differ from e.g. Coro or other similar modules?
It differs from Coro especially because there are several processes
involved in Parallel::Loops. Each of the iterations in the loop run in
each their own process - in parallel. Whereas Coro::Intro has:
> only one thread ever has the CPU, and if another thread wants
> the CPU, the running thread has to give it up
, the idea behind Parallel::Loops is exactly to make it easy to use
several CPUs in what resembles code for one CPU.
> > my %output;
> > $pl->tieOutput( \%output );
>
> Why are you using tie here?
Hmm... I thought the idea would be more obvious than it apparently
is...
Outside the $pl->foreach() loop, we're running in the parent process.
Inside the $pl->foreach() loop, we're running in a child process. $pl-
>tieOutput is actually the raison d'etre of Parallel::Loops. When the
child process has a result, it stores it in %output (which is tied
with Tie::Hash behind the scenes in the child process).
Behind the scenes, when the child process exits, it sends the results
(the keys written to %output) back to the parent process's version/
copy of %output, so that the user of Parallel::Loops doesn't have to
do any inter-process communication.
Perhaps the Synopsis needs to be a bit more clear on these points.
> > my $pl =3D new Parallel::Loops($maxProcs);
>
> Indirect object syntax considered harmful:http://www.shadowcat.co.uk/blog=
/matt-s-trout/indirect-but-still-fatal/
OK, thanks, I'll fix that
------------------------------
Date: Fri, 25 Jun 2010 02:16:47 +0100
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: Proposing a new module: Parallel::Loops
Message-Id: <vkcdf7-64i2.ln1@osiris.mauzo.dyndns.org>
Quoth =?ISO-8859-1?Q?Peter_Valdemar_M=F8rch?= <4ux6as402@sneakemail.com>:
> On Jun 24, 6:20 pm, Chris Nehren <apei...@isuckatdomains.net.invalid>
> wrote:
> > How does this differ from e.g. Coro or other similar modules?
>
> It differs from Coro especially because there are several processes
> involved in Parallel::Loops. Each of the iterations in the loop run in
> each their own process - in parallel. Whereas Coro::Intro has:
>
> > only one thread ever has the CPU, and if another thread wants
> > the CPU, the running thread has to give it up
>
> , the idea behind Parallel::Loops is exactly to make it easy to use
> several CPUs in what resembles code for one CPU.
OK; how is this different from forks and forks::shared?
Ben
------------------------------
Date: Fri, 25 Jun 2010 01:14:11 -0700 (PDT)
From: =?ISO-8859-1?Q?Peter_Valdemar_M=F8rch?= <4ux6as402@sneakemail.com>
Subject: Re: Proposing a new module: Parallel::Loops
Message-Id: <a9880c05-f088-4f2d-8d6d-ee20ac873428@c33g2000yqm.googlegroups.com>
On Jun 25, 3:16=A0am, Ben Morrow <b...@morrow.me.uk> wrote:
> OK; how is this different from forks and forks::shared?
It is _much_ more similar to forks and forks::shared than to Coro.
While the forks and forks::shared API emulate the API of threads and
threads::shared (perfectly?), Parallel::Loops tries to emulate the
standard foreach and while loops as close as possible as in:
$pl->foreach(\@input, sub {
$output{$_} =3D do_some_hefty_calculation($_);
});
All the forking, waiting for subprocesses to finish etc. is done
behind the scenes. I find that so often, I have large calculations
that need to operate on all the elements of an array or hash, that
really could be parallelized, and with this close-to-foreach syntax,
it is so easy to write and understand/read later on.
I guess Parallel::Loops could have been written with forks and
forks::shared, and only provided syntactic sugar. (In fact it uses
Parallel::ForkManager and Tie::Hash/Tie::Array instead.)
Perhaps $pl->share(\%output) is a better name than $pl->tieOutput(\
%output), tough. I guess now is the time to change it! ;-)
I'm impressed that you guys take the time to read and comment. Thanks!
------------------------------
Date: Thu, 24 Jun 2010 16:17:10 +0200
From: "Peter J. Holzer" <hjp-usenet2@hjp.at>
Subject: Re: UNIX datagram sockets
Message-Id: <slrni26q77.mai.hjp-usenet2@hrunkner.hjp.at>
On 2010-06-23 04:39, John Kelly <jak@isp2dial.com> wrote:
>
> Stein has an example of UNIX datagram sockets in his Networking book,
> but it includes other ideas that, to me, made it hard to see the forest
> for the trees. So I distilled it down to the bare essential elements
> related to socket setup.
I thought there should be lots of examples floating around on the web,
but they seem hard to find (maybe my Google-Fu is weak, or maybe nobody
uses Unix datagram sockets (I know I don't)). So I think your example is
useful.
> Please ignore bad practices in this code, it's only intended to show how
> to set up the datagram sockets, which to me, seemed mysterious without a
> simple example.
>
>
> --- CLIENT ---
>
> #!/usr/bin/perl
>
> use strict;
> use warnings;
> use IO::Socket::UNIX;
>
> my $peer = '/tmp/server.sock';
> my $node = '/tmp/client1.sock';
> unlink $node;
>
> my $sock = IO::Socket::UNIX->new (
> Local => $node,
> Peer => $peer,
> Type => SOCK_DGRAM
> ) or die "$!";
The usage of Local here does seem a bit mysterious. But since
the DGRAM service is connectionless it's clear that a different socket
is needed to receive the replies. If you had added a few comments
explaining stuff like that it would have been even more useful.
hp
------------------------------
Date: Thu, 24 Jun 2010 14:32:25 +0000
From: John Kelly <jak@isp2dial.com>
Subject: Re: UNIX datagram sockets
Message-Id: <ipq6265ec8sj9f2rk41h1irbnj0ea7bgm2@4ax.com>
On Thu, 24 Jun 2010 16:17:10 +0200, "Peter J. Holzer"
<hjp-usenet2@hjp.at> wrote:
>> my $peer = '/tmp/server.sock';
>> my $node = '/tmp/client1.sock';
>> unlink $node;
>>
>> my $sock = IO::Socket::UNIX->new (
>> Local => $node,
>> Peer => $peer,
>> Type => SOCK_DGRAM
>> ) or die "$!";
>
>The usage of Local here does seem a bit mysterious. But since
>the DGRAM service is connectionless it's clear that a different socket
>is needed to receive the replies.
It's clear once you see the big picture. But when you're learning, and
swimming in details, it may not be so obvious.
>If you had added a few comments explaining stuff like that it would
>have been even more useful.
Agreed. I eventually got around to that, in subsequent posts. Maybe
that's not such a bad thing. The longer a post is, the fewer people who
will read it.
--
Web mail, POP3, and SMTP
http://www.beewyz.com/freeaccounts.php
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End of Perl-Users Digest V11 Issue 3003
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