[31536] in Perl-Users-Digest
Perl-Users Digest, Issue: 2795 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Fri Jan 29 06:09:28 2010
Date: Fri, 29 Jan 2010 03:09:11 -0800 (PST)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Fri, 29 Jan 2010 Volume: 11 Number: 2795
Today's topics:
[OT] Re: Inconsistent results from (dos)glob <m@rtij.nl.invlalid>
Re: [OT] Re: Inconsistent results from (dos)glob <ben@morrow.me.uk>
Re: [OT] Re: Inconsistent results from (dos)glob <sreservoir@gmail.com>
Re: [OT] Re: Inconsistent results from (dos)glob <hjp-usenet2@hjp.at>
complicated mapping <user@example.net>
Re: complicated mapping <ben@morrow.me.uk>
Re: complicated mapping <derykus@gmail.com>
Re: discarding stdout when using 'system(@args)' <tadmc@seesig.invalid>
Re: FAQ 4.44 How do I test whether two arrays or hashes <pgp@doc.ic.ac.uk>
Re: How to make a cgi program "die" without a software <bart.lateur@telenet.be>
How to make a cgi program "die" without a software erro <hsggwk@gmail.com>
Re: Inconsistent results from (dos)glob <john@castleamber.com>
Re: Inconsistent results from (dos)glob <jurgenex@hotmail.com>
Re: Modules for PDFs especially tables. <whynot@pozharski.name>
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@seesig.invalid
Re: should C<++$_ for -1..1> croak? <smallpond@juno.com>
Re: should C<++$_ for -1..1> croak? <john@castleamber.com>
Re: should C<++$_ for -1..1> croak? <nospam-abuse@ilyaz.org>
Re: should C<++$_ for -1..1> croak? <sreservoir@gmail.com>
Re: should C<++$_ for -1..1> croak? <tadmc@seesig.invalid>
Re: should C<++$_ for -1..1> croak? <nospam-abuse@ilyaz.org>
Re: What are the minimum and maximum float numbers and <c7eqjyg02@sneakemail.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Thu, 28 Jan 2010 20:40:01 +0100
From: Martijn Lievaart <m@rtij.nl.invlalid>
Subject: [OT] Re: Inconsistent results from (dos)glob
Message-Id: <hp5937-hps.ln1@news.rtij.nl>
On Thu, 28 Jan 2010 00:34:37 -0800, Theo van den Heuvel wrote:
> (Spaces in names IMO is one of the most unfortunate design mistakes in
> Windows).
Spaces are fine. Newlines in filenames on Unix, now there is trouble!
M4
------------------------------
Date: Fri, 29 Jan 2010 00:31:24 +0000
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: [OT] Re: Inconsistent results from (dos)glob
Message-Id: <srm937-fj81.ln1@osiris.mauzo.dyndns.org>
Quoth Martijn Lievaart <m@rtij.nl.invlalid>:
> On Thu, 28 Jan 2010 00:34:37 -0800, Theo van den Heuvel wrote:
>
> > (Spaces in names IMO is one of the most unfortunate design mistakes in
> > Windows).
>
> Spaces are fine. Newlines in filenames on Unix, now there is trouble!
Spaces are not always fine. You cannot, for instance, install Perl
anywhere under a directory with spaces in its name. (I can't remember
exactly what breaks, but something does.)
Ben
------------------------------
Date: Thu, 28 Jan 2010 19:53:51 -0500
From: sreservoir <sreservoir@gmail.com>
Subject: Re: [OT] Re: Inconsistent results from (dos)glob
Message-Id: <hjtbjf$pud$2@speranza.aioe.org>
On 1/28/2010 2:40 PM, Martijn Lievaart wrote:
> On Thu, 28 Jan 2010 00:34:37 -0800, Theo van den Heuvel wrote:
>
>> (Spaces in names IMO is one of the most unfortunate design mistakes in
>> Windows).
>
> Spaces are fine. Newlines in filenames on Unix, now there is trouble!
not really. you can have newlines without trouble. however, if you use
one of those filesystems that let you have nulls in filenames, some of
the standard utilities might segfault or overflow.
funny how segfault is in my dictionary and not filename.
--
"Six by nine. Forty two."
"That's it. That's all there is."
"I always thought something was fundamentally wrong with the universe"
------------------------------
Date: Fri, 29 Jan 2010 09:49:36 +0100
From: "Peter J. Holzer" <hjp-usenet2@hjp.at>
Subject: Re: [OT] Re: Inconsistent results from (dos)glob
Message-Id: <slrnhm5891.bpa.hjp-usenet2@hrunkner.hjp.at>
On 2010-01-29 00:53, sreservoir <sreservoir@gmail.com> wrote:
> On 1/28/2010 2:40 PM, Martijn Lievaart wrote:
>> On Thu, 28 Jan 2010 00:34:37 -0800, Theo van den Heuvel wrote:
>>
>>> (Spaces in names IMO is one of the most unfortunate design mistakes in
>>> Windows).
>>
>> Spaces are fine. Newlines in filenames on Unix, now there is trouble!
>
> not really. you can have newlines without trouble.
Right, the kernel API doesn't care about spaces or newlines. The only
characters (bytes) in filenames with special meaning are "/" and "\0".
But many standard utilities treat whitespace as delimiters. I can't
think of any which is explicitely intended for processing filenames
where newline is more special than other whitespace, but this is
certainly true for the general-purpose text processing tools (sort,
grep, ...).
Many GNU tools have an option to use "\0" instead of "\n"
as the record delimiter, so you can do someting like
find -print0 | grep -z | sort -z | xargs -0
but this isn't portable.
Writing shell scripts which correctly handle all filenames is possible
(at least on Linux) but you really have to know about and remember all
the corner cases. It is usually simpler to write a Perl script (although
Perl has its share of annoying DWIMmery, too).
> however, if you use one of those filesystems that let you have nulls
> in filenames, some of the standard utilities might segfault or
> overflow.
That's impossible. All the syscalls dealing with filenames treat "\0" as
a terminator. There is no way to create or access a file with a null in
its name[1]. If a filesystem allows such names and there is a possibility
that they actually exist (e.g., the filesystem is on an external disk
previously mounted under another OS) then the filesystem code must
provide a translation.
hp
[1] Yes, I do remember the MacOS/SunOS/NFS desaster. But in this case
the SunOS NFS server code (residing in the kernel) in effect created
a second API for accessing files.
------------------------------
Date: Thu, 28 Jan 2010 21:10:24 -0500
From: monkeys paw <user@example.net>
Subject: complicated mapping
Message-Id: <VJCdnfV6POQC3v_WnZ2dnUVZ_s-dnZ2d@insightbb.com>
Why does the output not contain the
"private_files" element from the code
below:
my $obj;
$idoc_out = [qw(IDOCRECORD1 IDOCRECORD2 IDOCRECORD3 IDOCRECORD4)];
push(@{$obj}, # Shouldn't private_files be pushed onto $obj here???
map {$_->{private_files} = [
{reg_tags => [{heading => 'Insurance Documents', tag => 'All'}]}]; $_ }
@{$idoc_out
}
);
use Data::Dumper;die 'DDDEBUG' . Dumper($obj);
OUTPUT:
DDDEBUG$VAR1 = [
'IDOCRECORD1',
'IDOCRECORD2',
'IDOCRECORD3',
'IDOCRECORD4'
];
------------------------------
Date: Fri, 29 Jan 2010 03:01:41 +0000
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: complicated mapping
Message-Id: <llv937-5e91.ln1@osiris.mauzo.dyndns.org>
Quoth monkeys paw <user@example.net>:
> Why does the output not contain the
> "private_files" element from the code
> below:
>
> my $obj;
>
> $idoc_out = [qw(IDOCRECORD1 IDOCRECORD2 IDOCRECORD3 IDOCRECORD4)];
>
> push(@{$obj}, # Shouldn't private_files be pushed onto $obj here???
> map {$_->{private_files} = [
> {reg_tags => [{heading => 'Insurance Documents', tag => 'All'}]}]; $_ }
> @{$idoc_out
> }
> );
>
> use Data::Dumper;die 'DDDEBUG' . Dumper($obj);
You should indent your code properly. It makes it much easier to read.
push(
@{$obj},
map {
$_->{private_files} = [ {
reg_tags => [ {
heading => 'Insurance Documents',
tag => 'All',
} ]
} ];
$_;
}
@{$idoc_out}
);
Now: @$idoc_out contains strings. This means the
$_->{private_files}
expression in the map block treats $_ as a symref and sets the value of
$IDOCRECORD1{private_files}
If you had been using 'strict', this would have been a fatal error and
you would have found the problem easily.
What are you actually trying to do here?
Ben
------------------------------
Date: Thu, 28 Jan 2010 20:50:49 -0800 (PST)
From: "C.DeRykus" <derykus@gmail.com>
Subject: Re: complicated mapping
Message-Id: <c2584bd6-0370-4209-a9fd-4d3f6eec9a6c@g8g2000pri.googlegroups.com>
On Jan 28, 6:10=A0pm, monkeys paw <u...@example.net> wrote:
> Why does the output not contain the
> "private_files" element from the code
> below:
>
> my $obj;
>
> $idoc_out =3D [qw(IDOCRECORD1 IDOCRECORD2 IDOCRECORD3 IDOCRECORD4)];
>
> push(@{$obj}, # Shouldn't private_files be pushed onto $obj here???
> map {$_->{private_files} =3D [
> {reg_tags =3D> [{heading =3D> 'Insurance Documents', tag =3D> 'All'}]}]; =
$_ }
> @{$idoc_out}
>
> );
>
> use Data::Dumper;die 'DDDEBUG' . =A0Dumper($obj);
>
> OUTPUT:
> DDDEBUG$VAR1 =3D [
> =A0 =A0 =A0 =A0 =A0 =A0'IDOCRECORD1',
> =A0 =A0 =A0 =A0 =A0 =A0'IDOCRECORD2',
> =A0 =A0 =A0 =A0 =A0 =A0'IDOCRECORD3',
> =A0 =A0 =A0 =A0 =A0 =A0'IDOCRECORD4'
> =A0 =A0 =A0 =A0 =A0];
And I thought an earlier thread involving 'map' was getting
complicated ...
I rarely trust my ESP but perhaps you were thinking of a
struct something like:
push( @{$obj}, # Shouldn't private_files be pushed onto $obj here???
map { { $_ =3D>
{ private_files =3D>
[ { reg_tags =3D> [ { heading =3D> 'Insurance
Documents',
tag =3D> 'All'
}
]
}
]
}
}
}
@{$idoc_out}
);
which dumps out:
$VAR1 =3D [
{ 'IDOCRECORD1' =3D> {
'private_files' =3D> [
{
'reg_tags' =3D> [
{
'heading' =3D> 'Insurance Documents',
'tag' =3D> 'All'
}
]
}
]
}
},
{ 'IDOCRECORD2' =3D> {
...
--
Charles DeRykus
------------------------------
Date: Thu, 28 Jan 2010 15:15:43 -0600
From: Tad McClellan <tadmc@seesig.invalid>
Subject: Re: discarding stdout when using 'system(@args)'
Message-Id: <slrnhm3vdd.95e.tadmc@tadbox.sbcglobal.net>
Justin C <justin.0911@purestblue.com> wrote:
> On 2010-01-28, Tad McClellan <tadmc@seesig.invalid> wrote:
>> Justin C <justin.0911@purestblue.com> wrote:
>>> I have:
>>>
>>> my @args = ("pdflatex", $fnames->{tex});
>>> system(@args) == 0 or warn "Problem running pdflatex : $?\n";
>>> This dumps a lot to stdout (the user's browser). I've tried the above
>>> with:
>>>
>>> my @args = ("pdflatex", $fnames->{tex}, "1>/dev/null 2>&1");
>>>
>>> But I still get unwanted output to the browser.
system has "more than one argument in LIST" so it executes pdflatex
*directly*, so there is no shell.
">" is a _shell_ redirection metacharacter, but here there
is no shell to see it...
> Note that argument processing varies
> depending on the number of arguments. If there is more than
> one argument in LIST, or if LIST is an array with more than one
> value, starts the program given by the first element of the
> list with arguments given by the rest of the list. If there is
> only one scalar argument, the argument is checked for shell
> metacharacters, and if there are any, the entire argument is
> passed to the system's command shell for parsing
> The bottom line is, I do not understand what it is with "system(@args)"
> that means I'm getting STDOUT even though STDOUT is being re-directed.
You only *think* it is being redirected, it is not being redirected
because the thingie that understand redirection (shell) is not involved.
>> If you want to use shell redirection, then you must use the
>> form of system that calls a shell:
>>
>> system "pdflatex $fnames->{tex} 1>/dev/null 2>&1";
>
> Reading the documentation for system, again, I don't understand how this
> differs from what I have.
You have
if LIST is an array with more than one value
My suggestion, that did include shell metacharacters (redirection), has
If there is only one scalar argument, the argument is checked for
shell metacharacters,
You are not invoking a shell.
My suggestion invokes a shell.
If you want to use shell redirection, then you must use the
form of system that calls a shell.
--
Tad McClellan
email: perl -le "print scalar reverse qq/moc.liamg\100cm.j.dat/"
------------------------------
Date: Fri, 29 Jan 2010 09:24:22 +0000
From: Philip Potter <pgp@doc.ic.ac.uk>
Subject: Re: FAQ 4.44 How do I test whether two arrays or hashes are equal?
Message-Id: <hju9g5$tug$1@speranza.aioe.org>
On 28/01/2010 23:00, PerlFAQ Server wrote:
> The following code works for single-level arrays. It uses a stringwise
> comparison, and does not distinguish defined versus undefined empty
> strings. Modify if you have other needs.
>
> $are_equal = compare_arrays(\@frogs, \@toads);
>
> sub compare_arrays {
> my ($first, $second) = @_;
> no warnings; # silence spurious -w undef complaints
> return 0 unless @$first == @$second;
> for (my $i = 0; $i < @$first; $i++) {
> return 0 if $first->[$i] ne $second->[$i];
> }
> return 1;
> }
Wouldn't a more Perlish for loop be written like this?
for my $i (0..$#$first) {
return 0 if $first->[$i] ne $second->[$i];
}
Given how often newbies are told to program in Perl style rather than C
style, shouldn't the FAQ set an example?
Phil
------------------------------
Date: Fri, 29 Jan 2010 09:58:56 +0100
From: Bart Lateur <bart.lateur@telenet.be>
Subject: Re: How to make a cgi program "die" without a software error message being printed to page
Message-Id: <3k85m55li1ljjnmmtq9p9ji8pb6kvqmum7@4ax.com>
gsa wrote:
> I have this cgi code that sometimes forks depending on the
>size of input. If there is an error, a subroutine called print_error
>is called and this subroutine prints an error message and dies. If the
>cgi forks and there is a child, then this error message is captured by
>an eval statement and is printed to the log file. However, if the cgi
>does not fork, there is an ugly software error message on the page. Is
>there a way to die so that when the cgi forks, eval captures the error
>message but at the same time there is no nasty software error when the
>cgi doesn't fork?
fork returns a child process id if it forks, so you can know if you're
in the parent or in the child. Store it in a variable. Simply let the
error handler behave differently depending on what's in that variable.
You may want to use a dummy value in that variable in case you skip
forking, and thus, you actually are in the parent.
--
Bart.
------------------------------
Date: Thu, 28 Jan 2010 14:58:41 -0800 (PST)
From: gsa <hsggwk@gmail.com>
Subject: How to make a cgi program "die" without a software error message being printed to page
Message-Id: <3c479c4f-887a-40a1-aba5-eaa37d78f661@p13g2000pre.googlegroups.com>
Hi all,
I have this cgi code that sometimes forks depending on the
size of input. If there is an error, a subroutine called print_error
is called and this subroutine prints an error message and dies. If the
cgi forks and there is a child, then this error message is captured by
an eval statement and is printed to the log file. However, if the cgi
does not fork, there is an ugly software error message on the page. Is
there a way to die so that when the cgi forks, eval captures the error
message but at the same time there is no nasty software error when the
cgi doesn't fork? I guess the easiest way is to turn CGI::Carp off but
is there another way to exit/die?
Thanks a lot!
Gayathri
------------------------------
Date: Thu, 28 Jan 2010 20:30:05 -0600
From: John Bokma <john@castleamber.com>
Subject: Re: Inconsistent results from (dos)glob
Message-Id: <87636lmymq.fsf@castleamber.com>
Theo van den Heuvel <tcmvandenheuvel@gmail.com> writes:
> the path on the spaces. (Spaces in names IMO is one of the most
> unfortunate design mistakes in Windows).
Heh, I would say it the other way around: not supporting spaces in
filenames/directory names is a design mistake. (One that is even to some
extent visible on the www...)
--
John Bokma j3b
Hacking & Hiking in Mexico - http://johnbokma.com/
http://castleamber.com/ - Perl & Python Development
------------------------------
Date: Thu, 28 Jan 2010 19:21:22 -0800
From: Jürgen Exner <jurgenex@hotmail.com>
Subject: Re: Inconsistent results from (dos)glob
Message-Id: <cuk4m59k0u4v6ldo8hncp5fq3hr399ts6n@4ax.com>
John Bokma <john@castleamber.com> wrote:
>Theo van den Heuvel <tcmvandenheuvel@gmail.com> writes:
>
>> the path on the spaces. (Spaces in names IMO is one of the most
>> unfortunate design mistakes in Windows).
>
>Heh, I would say it the other way around: not supporting spaces in
>filenames/directory names is a design mistake.
Are there any widely used file systems that don't support spaces in file
names?
jue
------------------------------
Date: Fri, 29 Jan 2010 09:57:15 +0200
From: Eric Pozharski <whynot@pozharski.name>
Subject: Re: Modules for PDFs especially tables.
Message-Id: <slrnhm556r.8fq.whynot@orphan.zombinet>
with <10b5.4b616df5.f513@zem> Justin C wrote:
*SKIP*
> Thanks again for your suggestions, I didn't realise there were so many
> different solutions to the problem.
And you've omitted (or missed) interfaces on (so called) wordprocessors
Sincerly yours, TeX freak
--
Torvalds' goal for Linux is very simple: World Domination
Stallman's goal for GNU is even simpler: Freedom
------------------------------
Date: Fri, 29 Jan 2010 02:13:31 -0600
From: tadmc@seesig.invalid
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
Message-Id: <zNadnQYvUrs2Bf_WnZ2dnUVZ_rednZ2d@giganews.com>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
- Do not provide too much information
- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
- Asking a question easily answered by a cursory doc search
- Asking for emailed answers
- Beware of saying "doesn't work"
- Sending a "stealth" Cc copy
Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
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Do not spend them indicating "experience level" (guru, newbie...).
Do not spend them pleading (please read, urgent, help!...).
Do not spend them on non-Subjects (Perl question, one-word
Subject...)
For more information on choosing a Subject see "Choosing Good
Subject Lines":
http://www.cpan.org/authors/id/D/DM/DMR/subjects.post
Part of the beauty of newsgroup dynamics, is that you can contribute
to the community with your very first post! If your choice of
Subject leads a fellow Perler to find the thread you are starting,
then even asking a question helps us all.
Use an effective followup style
When composing a followup, quote only enough text to establish the
context for the comments that you will add. Always indicate who
wrote the quoted material. Never quote an entire article. Never
quote a .signature (unless that is what you are commenting on).
Intersperse your comments *following* each section of quoted text to
which they relate. Unappreciated followup styles are referred to as
"top-posting", "Jeopardy" (because the answer comes before the
question), or "TOFU" (Text Over, Fullquote Under).
Reversing the chronology of the dialog makes it much harder to
understand (some folks won't even read it if written in that style).
For more information on quoting style, see:
http://web.presby.edu/~nnqadmin/nnq/nquote.html
Speak Perl rather than English, when possible
Perl is much more precise than natural language. Saying it in Perl
instead will avoid misunderstanding your question or problem.
Do not say: I have variable with "foo\tbar" in it.
Instead say: I have $var = "foo\tbar", or I have $var = 'foo\tbar',
or I have $var = <DATA> (and show the data line).
Ask perl to help you
You can ask perl itself to help you find common programming mistakes
by doing two things: enable warnings (perldoc warnings) and enable
"strict"ures (perldoc strict).
You should not bother the hundreds/thousands of readers of the
newsgroup without first seeing if a machine can help you find your
problem. It is demeaning to be asked to do the work of a machine. It
will annoy the readers of your article.
You can look up any of the messages that perl might issue to find
out what the message means and how to resolve the potential mistake
(perldoc perldiag). If you would like perl to look them up for you,
you can put "use diagnostics;" near the top of your program.
Do not re-type Perl code
Use copy/paste or your editor's "import" function rather than
attempting to type in your code. If you make a typo you will get
followups about your typos instead of about the question you are
trying to get answered.
Provide enough information
If you do the things in this item, you will have an Extremely Good
chance of getting people to try and help you with your problem!
These features are a really big bonus toward your question winning
out over all of the other posts that you are competing with.
First make a short (less than 20-30 lines) and *complete* program
that illustrates the problem you are having. People should be able
to run your program by copy/pasting the code from your article. (You
will find that doing this step very often reveals your problem
directly. Leading to an answer much more quickly and reliably than
posting to Usenet.)
Describe *precisely* the input to your program. Also provide example
input data for your program. If you need to show file input, use the
__DATA__ token (perldata.pod) to provide the file contents inside of
your Perl program.
Show the output (including the verbatim text of any messages) of
your program.
Describe how you want the output to be different from what you are
getting.
If you have no idea at all of how to code up your situation, be sure
to at least describe the 2 things that you *do* know: input and
desired output.
Do not provide too much information
Do not just post your entire program for debugging. Most especially
do not post someone *else's* entire program.
Do not post binaries, HTML, or MIME
clpmisc is a text only newsgroup. If you have images or binaries
that explain your question, put them in a publically accessible
place (like a Web server) and provide a pointer to that location. If
you include code, cut and paste it directly in the message body.
Don't attach anything to the message. Don't post vcards or HTML.
Many people (and even some Usenet servers) will automatically filter
out such messages. Many people will not be able to easily read your
post. Plain text is something everyone can read.
Social faux pas to avoid
The first two below are symptoms of lots of FAQ asking here in clpmisc.
It happens so often that folks will assume that it is happening yet
again. If you have looked but not found, or found but didn't understand
the docs, say so in your article.
Asking a Frequently Asked Question
It should be understood that you may have missed the applicable FAQ
when you checked, which is not a big deal. But if the Frequently
Asked Question is worded similar to your question, folks will assume
that you did not look at all. Don't become indignant at pointers to
the FAQ, particularly if it solves your problem.
Asking a question easily answered by a cursory doc search
If folks think you have not even tried the obvious step of reading
the docs applicable to your problem, they are likely to become
annoyed.
If you are flamed for not checking when you *did* check, then just
shrug it off (and take the answer that you got).
Asking for emailed answers
Emailed answers benefit one person. Posted answers benefit the
entire community. If folks can take the time to answer your
question, then you can take the time to go get the answer in the
same place where you asked the question.
It is OK to ask for a *copy* of the answer to be emailed, but many
will ignore such requests anyway. If you munge your address, you
should never expect (or ask) to get email in response to a Usenet
post.
Ask the question here, get the answer here (maybe).
Beware of saying "doesn't work"
This is a "red flag" phrase. If you find yourself writing that,
pause and see if you can't describe what is not working without
saying "doesn't work". That is, describe how it is not what you
want.
Sending a "stealth" Cc copy
A "stealth Cc" is when you both email and post a reply without
indicating *in the body* that you are doing so.
Be extra cautious when you get upset
Count to ten before composing a followup when you are upset
This is recommended in all Usenet newsgroups. Here in clpmisc, most
flaming sub-threads are not about any feature of Perl at all! They
are most often for what was seen as a breach of netiquette. If you
have lurked for a bit, then you will know what is expected and won't
make such posts in the first place.
But if you get upset, wait a while before writing your followup. I
recommend waiting at least 30 minutes.
Count to ten after composing and before posting when you are upset
After you have written your followup, wait *another* 30 minutes
before committing yourself by posting it. You cannot take it back
once it has been said.
AUTHOR
Tad McClellan and many others on the comp.lang.perl.misc newsgroup.
--
Tad McClellan
email: perl -le "print scalar reverse qq/moc.liamg\100cm.j.dat/"
------------------------------
Date: Thu, 28 Jan 2010 15:12:02 -0500
From: Steve C <smallpond@juno.com>
Subject: Re: should C<++$_ for -1..1> croak?
Message-Id: <hjsr32$umn$1@news.eternal-september.org>
Steve C wrote:
> Dr.Ruud wrote:
>> Should C<++$_ for -1..1> croak?
>>
>> Or is it better to leave it as it is?
>>
>>
>>
>> $ perl -wle'++$_ for 1..1'
>>
>>
>> $ perl -wle'++$_ for 1'
>> Modification of a read-only value attempted at -e line 1.
>>
>>
>
> for implicitly aliases $_ to the constant 1, which cannot be incremented.
perl -wle 'sub mod{++$_[0]} mod(1)'
Modification of a read-only value attempted at -e line 1.
The for example seems to be consistent behavior, if that's what you're asking.
I guess I would be upset if after calling mod the constant 1 became 2.
That used to happen to me with FORTRAN programs on IBM when I passed a
constant to a sub which modified its parameters.
------------------------------
Date: Thu, 28 Jan 2010 15:41:22 -0600
From: John Bokma <john@castleamber.com>
Subject: Re: should C<++$_ for -1..1> croak?
Message-Id: <87tyu552m5.fsf@castleamber.com>
Steve C <smallpond@juno.com> writes:
> Dr.Ruud wrote:
>> Should C<++$_ for -1..1> croak?
>>
>> Or is it better to leave it as it is?
>>
>>
>>
>> $ perl -wle'++$_ for 1..1'
>>
>>
>> $ perl -wle'++$_ for 1'
>> Modification of a read-only value attempted at -e line 1.
>
> for implicitly aliases $_ to the constant 1, which cannot be
> incremented.
Note that there are two examples and only the last one complains about a
modification of ro value.
--
John Bokma j3b
Hacking & Hiking in Mexico - http://johnbokma.com/
http://castleamber.com/ - Perl & Python Development
------------------------------
Date: Fri, 29 Jan 2010 00:40:57 +0000 (UTC)
From: Ilya Zakharevich <nospam-abuse@ilyaz.org>
Subject: Re: should C<++$_ for -1..1> croak?
Message-Id: <slrnhm4bko.ajd.nospam-abuse@powdermilk.math.berkeley.edu>
On 2010-01-28, Dr.Ruud <rvtol+usenet@xs4all.nl> wrote:
> Should C<++$_ for -1..1> croak?
> Or is it better to leave it as it is?
Tough call. I reported it many years ago. *Then* it was like this
> perl5.00455 -wle "sub f{ for(1..3) {print $_++ }} f; print q(==); f"
1
2
3
==
2
3
4
This was fixed; nowadays it is "not that bad"...
I know this does not help,
Ilya
------------------------------
Date: Thu, 28 Jan 2010 19:51:46 -0500
From: sreservoir <sreservoir@gmail.com>
Subject: Re: should C<++$_ for -1..1> croak?
Message-Id: <hjtbfi$pud$1@speranza.aioe.org>
On 1/28/2010 7:40 PM, Ilya Zakharevich wrote:
> "sub f{ for(1..3) {print $_++ }} f; print q(==); f"
does your shell do no substitution?
--
"Six by nine. Forty two."
"That's it. That's all there is."
"I always thought something was fundamentally wrong with the universe"
------------------------------
Date: Thu, 28 Jan 2010 21:49:22 -0600
From: Tad McClellan <tadmc@seesig.invalid>
Subject: Re: should C<++$_ for -1..1> croak?
Message-Id: <slrnhm4mfh.9o4.tadmc@tadbox.sbcglobal.net>
sreservoir <sreservoir@gmail.com> wrote:
> On 1/28/2010 7:40 PM, Ilya Zakharevich wrote:
>> "sub f{ for(1..3) {print $_++ }} f; print q(==); f"
>
> does your shell do no substitution?
I've asked a similar question before.
Ilya runs OS/2.
http://groups.google.com/group/comp.lang.perl.misc/browse_thread/thread/c9783d98168f3361/ab75c9917820ed89?q=#ab75c9917820ed89
--
Tad McClellan
email: perl -le "print scalar reverse qq/moc.liamg\100cm.j.dat/"
------------------------------
Date: Fri, 29 Jan 2010 08:17:22 +0000 (UTC)
From: Ilya Zakharevich <nospam-abuse@ilyaz.org>
Subject: Re: should C<++$_ for -1..1> croak?
Message-Id: <slrnhm56ci.bhc.nospam-abuse@powdermilk.math.berkeley.edu>
On 2010-01-29, sreservoir <sreservoir@gmail.com> wrote:
> On 1/28/2010 7:40 PM, Ilya Zakharevich wrote:
>> "sub f{ for(1..3) {print $_++ }} f; print q(==); f"
>
> does your shell do no substitution?
There is no hope to give command line examples which would work with
all 3 major shell types... This is why I always use q() and qq() in
my posts: one needs to change only two delimiters to suit your shell...
Hope this helps,
Ilya
------------------------------
Date: Fri, 29 Jan 2010 01:13:14 -0800 (PST)
From: ilovelinux <c7eqjyg02@sneakemail.com>
Subject: Re: What are the minimum and maximum float numbers and integers?
Message-Id: <9be0eb82-c123-4afd-804b-5faf4daf6921@l11g2000yqb.googlegroups.com>
On 26 jan, 18:52, s...@netherlands.com wrote:
> Something like this should get you in the range.
[...]
> printf ("INT: =A0 =A0+/- %d\n", sprintf ("%u", -1) / 2);
This didn't work for me; it printed:
INT: +/- -9223372036854775808
(platform =3D CYGWIN_NT-5.1 1.7.1(0.218/5/3))
Replacing it with:
printf ("INT: +/- %d\n", sprintf ("%u", -1) / 2 - 1);
didn't help, surprisingly:
INT: +/- -9223372036854775808
But the following did the trick:
printf ("INT: +/- %d\n", sprintf("%u", -1)>>1);
INT: +/- 9223372036854775807
As an aside, the format specification with the embedded $places in the
format, in
> printf ("FLOAT: =A0+/- %.".$places."e\n", $mant * 10**$exp);
has a more official counterpart, which was derived from printf(3) and
also works in C:
printf ("FLOAT: +/- %.*e\n", $places, $mant * 10**$exp);
Instead of interpolating "$places", use a * in the format
specification and add $places as an extra argument to printf.
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>
Administrivia:
To submit articles to comp.lang.perl.announce, send your article to
clpa@perl.com.
Back issues are available via anonymous ftp from
ftp://cil-www.oce.orst.edu/pub/perl/old-digests.
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------------------------------
End of Perl-Users Digest V11 Issue 2795
***************************************
