[31333] in Perl-Users-Digest
Perl-Users Digest, Issue: 2578 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Tue Sep 1 19:01:55 2009
Date: Tue, 1 Sep 2009 16:01:47 -0700 (PDT)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Tue, 1 Sep 2009 Volume: 11 Number: 2578
Today's topics:
How to get current directory path <moonhkt@gmail.com>
Re: How to get current directory path <glex_no-spam@qwest-spam-no.invalid>
Re: How to get current directory path <jurgenex@hotmail.com>
Re: How to get current directory path (Randal L. Schwartz)
Re: How to get current directory path <justin.0908@purestblue.com>
Re: How to get current directory path sln@netherlands.com
Re: module installation through VC++ <ben@morrow.me.uk>
Re: Perl 5.10.1 Smartmatch Num ~~ Numish <ben@morrow.me.uk>
Re: Perl 5.10.1 Smartmatch Num ~~ Numish <nospam-abuse@ilyaz.org>
Re: Perl 5.10.1 Smartmatch Num ~~ Numish <ben@morrow.me.uk>
Re: Perl 5.10.1 Smartmatch Num ~~ Numish <nospam-abuse@ilyaz.org>
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@seesig.invalid
Re: strategy for parsing text file sln@netherlands.com
Re: strategy for parsing text file <cartercc@gmail.com>
Re: Test::Simple etc ... do you leave them in the finis <ben@morrow.me.uk>
Re: trapping errors using $! <whynot@pozharski.name>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Tue, 1 Sep 2009 07:32:49 -0700 (PDT)
From: moonhkt <moonhkt@gmail.com>
Subject: How to get current directory path
Message-Id: <3dfe25c1-34ea-4f94-a871-fdc33388e042@m7g2000prd.googlegroups.com>
Hi All
How to get current directory path ?
e.g c:\temp
how to using perl get current directory path ? "c:\temp"
moonhkt
------------------------------
Date: Tue, 01 Sep 2009 09:47:28 -0500
From: "J. Gleixner" <glex_no-spam@qwest-spam-no.invalid>
Subject: Re: How to get current directory path
Message-Id: <4a9d3400$0$87067$815e3792@news.qwest.net>
moonhkt wrote:
> Hi All
>
> How to get current directory path ?
>
> e.g c:\temp
>
> how to using perl get current directory path ? "c:\temp"
perldoc Cwd
------------------------------
Date: Tue, 01 Sep 2009 08:05:22 -0700
From: Jürgen Exner <jurgenex@hotmail.com>
Subject: Re: How to get current directory path
Message-Id: <lvdq95du072js3f4te9cnhttvudap6g766@4ax.com>
moonhkt <moonhkt@gmail.com> wrote:
>How to get current directory path ?
>
>e.g c:\temp
perldoc Cwd
I think it's a standard module, but I may be wrong.
jue
------------------------------
Date: Tue, 01 Sep 2009 08:32:19 -0700
From: merlyn@stonehenge.com (Randal L. Schwartz)
Subject: Re: How to get current directory path
Message-Id: <86praasmt8.fsf@blue.stonehenge.com>
>>>>> "Jürgen" == Jürgen Exner <jurgenex@hotmail.com> writes:
Jürgen> perldoc Cwd
Jürgen> I think it's a standard module, but I may be wrong.
Yes, been standard for a long time. A *long* time. Perl 5.0, I think.
--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<merlyn@stonehenge.com> <URL:http://www.stonehenge.com/merlyn/>
Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc.
See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion
------------------------------
Date: Tue, 01 Sep 2009 15:44:11 -0000
From: Justin C <justin.0908@purestblue.com>
Subject: Re: How to get current directory path
Message-Id: <7121.4a9d414b.b7bbc@zem>
On 2009-09-01, moonhkt <moonhkt@gmail.com> wrote:
> Hi All
>
> How to get current directory path ?
>
> e.g c:\temp
>
> how to using perl get current directory path ? "c:\temp"
The Current Working Directory?...
perldoc Cwd
------------------------------
Date: Tue, 01 Sep 2009 12:32:51 -0700
From: sln@netherlands.com
Subject: Re: How to get current directory path
Message-Id: <sktq9556cacbnmd415mi3agbc7rhgtlk3i@4ax.com>
On Tue, 1 Sep 2009 07:32:49 -0700 (PDT), moonhkt <moonhkt@gmail.com> wrote:
>Hi All
>
>How to get current directory path ?
>
>e.g c:\temp
>
>how to using perl get current directory path ? "c:\temp"
>
>
>moonhkt
use strict;
use warnings;
use Cwd;
use File::Spec::Functions ':ALL';
my $path = lc rel2abs('c:\\temp\\');
print "Are we in this direcoty?\n\t$path\n";
if (chdir($path) and lc rel2abs(cwd()) eq $path) {
print "Yes indeed, the current directory is:\n\t$path\n";
} else {
print "Nope, doesen't appear so..\n";
}
-sln
------------------------------
Date: Mon, 31 Aug 2009 11:54:11 +0100
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: module installation through VC++
Message-Id: <jnmsm6-e5h1.ln1@osiris.mauzo.dyndns.org>
Quoth zeeshan <zeeshan2ahmed@gmail.com>:
> Hi All,
> Im trying to install perl html::strip module using visual C++ express
> edition.
You need to build modules with the same compiler that your perl was
built with. There are combinations of compilers that will work together,
but this is unsupported; in particular, mixing versions of MSVC is a
very bad idea since they usually link to different versions of the CRT.
(Why MS don't understand that the CRT is part of the OS, not the
application, is beyond me, but there we go.)
If you are using the 32-bit version of ActivePerl, it's built with VC6,
which is now (I believe) unavailable. It is apparently possible to
install gcc and use that instead, but I've never tried it: IIRC you
start by installing the 'MinGW' ppm. If you are using the 64-bit
version, then I'm not sure which compiler it uses, but it's not VC6
(since that didn't do 64-bit). Poking through the output of perl -V (or
possibly perldoc -m Config_heavy.pl) should tell you.
If possible, I would strongly recommed installing Strawberry Perl, which
comes with the compiler used to build it.
> I was able to do it comfortably on my laptop without any
> problems but now im stuck on the server.
> Im able to nmake it...but whn i type "nmake test" it gives me error
> Cant load `blib\arch/auto/HTML/Strip/Strip.dll' for module
> HTML::Strip: load_file: The specified module could not be found at
> D:/.../Dynaloader.pm line 230. at test.pl line 10
Did you get any other error before this, or a popup box? I would have
expected the dynamic linker to throw some sort of error if the dlopen
failed.
Ben
------------------------------
Date: Mon, 31 Aug 2009 12:13:02 +0100
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: Perl 5.10.1 Smartmatch Num ~~ Numish
Message-Id: <uqnsm6-e5h1.ln1@osiris.mauzo.dyndns.org>
Quoth tuser <tuser1@gmail.com>:
>
> Why is 2 ~~ '2.0' false in Perl 6 (case #A2), whereas the identical
> expression in Perl 5.10.1 (case #B2) is true ?
>
> Or in other words:
> Why is there a rule in Perl 5.10.1 ("Num numish numeric equality"),
> where there is no equivalent in Perl 6 ?
For a proper answer you would have to ask p5p, but I would guess it's so
that something like
my $x = 3;
print $x;
"3.0" ~~ $x;
does what is expected. The 'print' statement has converted $x into a
dualvar, and there is no way to tell which part (string or number) came
'first', so perl will treat it as a string. It's different from Perl 6
because Perl 5's dynamic type system is quite different from Perl 6's.
Ben
------------------------------
Date: Tue, 1 Sep 2009 01:40:11 +0000 (UTC)
From: Ilya Zakharevich <nospam-abuse@ilyaz.org>
Subject: Re: Perl 5.10.1 Smartmatch Num ~~ Numish
Message-Id: <slrnh9ourr.hf5.nospam-abuse@chorin.math.berkeley.edu>
On 2009-08-31, Ben Morrow <ben@morrow.me.uk> wrote:
>> Why is there a rule in Perl 5.10.1 ("Num numish numeric equality"),
>> where there is no equivalent in Perl 6 ?
>
> For a proper answer you would have to ask p5p, but I would guess it's so
> that something like
>
> my $x = 3;
> print $x;
> "3.0" ~~ $x;
>
> does what is expected. The 'print' statement has converted $x into a
> dualvar, and there is no way to tell which part (string or number) came
> 'first',
I hope there is. At least there was a way - after I "regularized"
Perl handling of numbers.
Obviously, there MUST be a way - otherwise one would not be able to
"correctly" translate a 2-headed value into a 3-headed one... (Ask if
one wants to know more details. ;-)
Hope this helps,
Ilya
------------------------------
Date: Tue, 1 Sep 2009 10:31:57 +0100
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: Perl 5.10.1 Smartmatch Num ~~ Numish
Message-Id: <d96vm6-jou1.ln1@osiris.mauzo.dyndns.org>
Quoth Ilya Zakharevich <nospam-abuse@ilyaz.org>:
> On 2009-08-31, Ben Morrow <ben@morrow.me.uk> wrote:
> >
> > For a proper answer you would have to ask p5p, but I would guess it's so
> > that something like
> >
> > my $x = 3;
> > print $x;
> > "3.0" ~~ $x;
> >
> > does what is expected. The 'print' statement has converted $x into a
(It sems I was mistaken about print performing a conversion. Sorry about
that.)
> > dualvar, and there is no way to tell which part (string or number) came
> > 'first',
>
> I hope there is. At least there was a way - after I "regularized"
> Perl handling of numbers.
I don't think there is:
~% perl -MDevel::Peek -e'$x = 3; $x.""; Dump $x'
SV = PVIV(0x810380c) at 0x8117060
REFCNT = 1
FLAGS = (IOK,POK,pIOK,pPOK)
IV = 3
PV = 0x8102020 "3"\0
CUR = 1
LEN = 4
~% perl -MDevel::Peek -e'$x = "3"; $x+0; Dump $x'
SV = PVIV(0x810380c) at 0x8117060
REFCNT = 1
FLAGS = (IOK,POK,pIOK,pPOK)
IV = 3
PV = 0x8102020 "3"\0
CUR = 1
LEN = 4
~%
Those two end up as identical dualvars.
> Obviously, there MUST be a way - otherwise one would not be able to
> "correctly" translate a 2-headed value into a 3-headed one... (Ask if
> one wants to know more details. ;-)
Yes, please... AFAIK, perl doesn't have any triplevars, if by that you
mean some sort of PVIVNV. Numeric conversion between IV, UV and NV don't
use the string value at all.
Ben
------------------------------
Date: Tue, 1 Sep 2009 22:02:19 +0000 (UTC)
From: Ilya Zakharevich <nospam-abuse@ilyaz.org>
Subject: Re: Perl 5.10.1 Smartmatch Num ~~ Numish
Message-Id: <slrnh9r6fb.r1e.nospam-abuse@chorin.math.berkeley.edu>
On 2009-09-01, Ben Morrow <ben@morrow.me.uk> wrote:
>> I hope there is. At least there was a way - after I "regularized"
>> Perl handling of numbers.
> (It sems I was mistaken about print performing a conversion. Sorry about
> that.)
print() not performing conversion is a bug (=unnecessary slowdown). I
did not realize that Perl has degenerated so much while I was not
looking...
>> Obviously, there MUST be a way - otherwise one would not be able to
>> "correctly" translate a 2-headed value into a 3-headed one... (Ask if
>> one wants to know more details. ;-)
> Yes, please... AFAIK, perl doesn't have any triplevars, if by that you
> mean some sort of PVIVNV.
IIRC, any variable except PV, IV, NV, PVIV may be a triple-variable (if
all the corresponding flags are set).
> Numeric conversion between IV, UV and NV don't use the string value
> at all.
This is a bug. Consider $a = "1234568790123445678". After you use it in
an NV context, it might be converted to 1234568790123445504; this
value MUST be stored in the NV slot to avoid future slowdowns.
However, this value may be exactly representable as an integer value.
So the stored in NV slot value MUST be marked as "not trustworthy", so
that a future conversion to integer would go PV --> IV, not NV --> IV.
All this was working about 10 years ago...
Hope this helps,
Ilya
------------------------------
Date: Tue, 01 Sep 2009 02:20:38 -0500
From: tadmc@seesig.invalid
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
Message-Id: <47udna6u2vPbVgHXnZ2dnUVZ_tCdnZ2d@giganews.com>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
- Do not provide too much information
- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
- Asking a question easily answered by a cursory doc search
- Asking for emailed answers
- Beware of saying "doesn't work"
- Sending a "stealth" Cc copy
Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($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.noitatibaher\100cmdat/"
------------------------------
Date: Tue, 01 Sep 2009 11:05:12 -0700
From: sln@netherlands.com
Subject: Re: strategy for parsing text file
Message-Id: <8onq951nigu3a21iq43iofst1ehhbpm081@4ax.com>
On Sat, 29 Aug 2009 03:33:26 -0700 (PDT), ccc31807 <cartercc@gmail.com> wrote:
>On Aug 28, 10:53 pm, Tad J McClellan <ta...@seesig.invalid> wrote:
>> while ( <DATA> ) {
>> next unless /^9[12]\d\d\d$/; # 5 digits, starts with 91 or 92
>> my %record = (number => $_);
>> $record{bandname} = <DATA>;
>> $record{grade} = <DATA>;
>> $record{branch} = <DATA>;
>> chomp %record;
>> print Dumper \%record;}
>
>Yes. This is almost identical to what I had after I saw your first
>solution, except for a small variation in the hash variable. I chose a
>hash because I anticipated a need to sort by branch and possible by
>grade.
>
>This was a throwaway script, that I ran exactly once, so while I agree
>with checking the value of open() and using more meaningful names,
>this was just the first cut and was all I needed.
>
>Thanks for your help. I now know about using <> in inner loops.
>
>CC.
Another difference is that you are accumulating a hash of the
total of all the records, he is just making a temp hash on a record
by record basis.
Neither way cares about error checking, blank lines, headers,
field position or any validation whatsoever.
So, in all the responces here, there is no method or technique being better
or worse in this light, its just throwaway.
while (<DATA>) {
chomp;
(/^9[12]\d{3}$/ and
@{$bands{$_}}{'name','grade','branch'}
= split /\n/, <DATA>.<DATA>.<DATA>)
}
or same, but slurp file ..
$_ = join '',<DATA>;
while (/(^9[12]\d{3})\n((?:^(?!9[12]\d{3}\n).*\n){3})/mg) {
@{$bands{$1}}{'name','grade','branch'} = split /\n/, $2;
}
-sln
------------------------------
Date: Tue, 1 Sep 2009 12:00:13 -0700 (PDT)
From: ccc31807 <cartercc@gmail.com>
Subject: Re: strategy for parsing text file
Message-Id: <74888d3d-cbd8-4e38-baef-482c9d5b22f8@g6g2000vbr.googlegroups.com>
On Sep 1, 2:05=A0pm, s...@netherlands.com wrote:
> So, in all the responces here, there is no method or technique being bett=
er
> or worse in this light, its just throwaway.
>
> while (<DATA>) {
> =A0 =A0 chomp;
> =A0 =A0 (/^9[12]\d{3}$/ and
> =A0 =A0 @{$bands{$_}}{'name','grade','branch'}
> =A0 =A0 =A0 =3D split /\n/, <DATA>.<DATA>.<DATA>)
>
> }
Yes! I like this!
I have developed a habit of using a hash slice when dealing with data
file that come with their own header, and use the hash to populate a
hash for each line to manage and mangle the output.
Sometimes I have a need to sort the data by some strange and alien
method, so I have also developed the habit of using a hash for the
data. Recently I have build several scripts that output PDFs of
multiple records categorized in various ways, and have found that
hashes are ideal for this purpose.
Anyway, the essential insight is that <> can be used to get the next
record regardless of the level of the braces.
CC
>
> or same, but slurp file ..
>
> $_ =3D join '',<DATA>;
> while (/(^9[12]\d{3})\n((?:^(?!9[12]\d{3}\n).*\n){3})/mg) {
> =A0 @{$bands{$1}}{'name','grade','branch'} =3D split /\n/, $2;
>
> }
>
> -sln
------------------------------
Date: Mon, 31 Aug 2009 12:05:16 +0100
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: Test::Simple etc ... do you leave them in the finished program?
Message-Id: <ccnsm6-e5h1.ln1@osiris.mauzo.dyndns.org>
Quoth Henry Law <news@lawshouse.org>:
> J. Gleixner wrote:
> > Henry Law wrote:
> >> The thing I can't find is the strategy
> >> for using them.
>
> > The tests would 'use YourModule', instantiate things, call methods, make
>
> Thank you (and also thanks to Steve C); I understand now. I had the
> wrong idea altogether, and was thinking of "ok" as a kind of "assert"
> statement which was included inline in the code.
>
> One last point of clarification. Am I right then in thinking that I can
> use Test::whatever for _modules_ that I write, but not for the mainline
> code which uses them? If so that looks like something of a limitation.
Generally the reverse :). Test::More is designed to be used in a test
script, that produces output looking like
1..2
ok 1 - foo is ok
ok 2 - bar is ok
so unless you're writing a testing module, you don't want to use
Test::More in your actual module. That would cause it to try to turn any
program using your module into a test script. Instead, you have a small
script that uses Your::Module and Test::More and runs the tests.
If you were actually asking 'can I test my mainline code', then the
answer is 'yes, of course, but you need to be a little careful'. In
general the easiest solution is to push as much code as possible into a
module (the App:: namespace on CPAN is used for modules that just
implement a specific program), so you can load that module in a test
script and test the functions in the normal way. The main program would
then look like
use App::MyScript;
App::MyScript::main(@ARGV);
or something equally trivial.
If your main program really needs to do something clever that you can't
push into a module, then you can invoke it with 'system' or 'open3' or
something and test that you get the output you expected. This is
non-trivial, particularly if you want to make it portable (many
platforms can't invoke a script directly, for example, so you need to
run "$^X script" instead).
Ben
------------------------------
Date: Mon, 31 Aug 2009 10:16:29 +0300
From: Eric Pozharski <whynot@pozharski.name>
Subject: Re: trapping errors using $!
Message-Id: <slrnh9mu6d.g1j.whynot@orphan.zombinet>
On 2009-08-30, Ben Morrow <ben@morrow.me.uk> wrote:
>
> Quoth "John" <john1949@yahoo.com>:
>>
>>
>> At the moment I'm using :
>>
>> eval {read (STDIN,$request,$length);};
>> if ($@ ne '') {$response=$error1}
>>
>> which appears to be working.
>
> Well, yes, it works as long as nothing goes wrong. 'read' doesn't throw
> an exception on error (unless you 'use Fatal' or 'use autodie', which I
> would probably recommend nowadays), so you are just completely ignoring
> any possible errors.
I would say: if you're going for B<read> then you know what you're
doing.
# ignoring eof and counts
defined read STDIN, $request, $length or
die $!;
--
Torvalds' goal for Linux is very simple: World Domination
Stallman's goal for GNU is even simpler: Freedom
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