[24068] in Perl-Users-Digest
Perl-Users Digest, Issue: 6263 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Tue Mar 16 06:05:37 2004
Date: Tue, 16 Mar 2004 03:05:06 -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 Tue, 16 Mar 2004 Volume: 10 Number: 6263
Today's topics:
Re: All capital permutations of a string? (Anno Siegel)
Re: All capital permutations of a string? <roel-perl@st2x.net>
Re: All capital permutations of a string? (Anno Siegel)
Re: block of code doesn't get executed <dave@dave.org.uk>
Re: browser tries to download perl code <dave@dave.org.uk>
Re: browser tries to download perl code <me@privacy.net>
Re: Hash slices and array references (Anno Siegel)
Re: Hash slices and array references <tassilo.parseval@rwth-aachen.de>
Re: Hash slices and array references <tassilo.parseval@rwth-aachen.de>
Re: How to remove lines containing "continuation" opera <roel-perl@st2x.net>
incrementing a string by a certain value <gned@telsmonopolytradotcom.remove.monopoly)>
Re: incrementing a string by a certain value <josef.moellers@fujitsu-siemens.com>
Re: incrementing a string by a certain value <roel-perl@st2x.net>
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@augustmail.com
Re:ligious, Emacs v. vi <bjr601553@cia.gov>
Re: variable initialization question (Anno Siegel)
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: 16 Mar 2004 09:04:08 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: All capital permutations of a string?
Message-Id: <c36fu8$gc8$1@mamenchi.zrz.TU-Berlin.DE>
Joe <joeblow341@hotmail.com> wrote in comp.lang.perl.misc:
>
> Does anyone have an elegant way of, given a string, generate all possible
> capitalization permutations of that string? ie:
>
> 000 abc
> 001 abC
> 010 aBc
> 011 aBC
> 100 Abc
> 101 AbC
> etc.
Before the days of bitwise character manipulation are irretrievably
gone, here is a ASCII-based solution (not recommended for production :)
use bytes;
my $str = 'abc';
my $n = length $str;
for ( map sprintf( "%0${n}b", $_), 0 .. 2 ** $n - 1 ) {
tr/01/\0\40/;
print $str ^ $_, "\n";
}
Anno
------------------------------
Date: 16 Mar 2004 09:22:18 GMT
From: Roel van der Steen <roel-perl@st2x.net>
Subject: Re: All capital permutations of a string?
Message-Id: <slrnc5dhr7.rts.roel-perl@localhost.localdomain>
Joe <joeblow341@hotmail.com> wrote in comp.lang.perl.misc:
>
> Does anyone have an elegant way of, given a string, generate all possible
> capitalization permutations of that string? ie:
>
> 000 abc
> 001 abC
> 010 aBc
> 011 aBC
> 100 Abc
> 101 AbC
> etc.
Well, this really appeals on people's creativity! Here is a recursive
solution:
#/usr/bin/perl
use strict;
use warnings;
sub lc_uc_permut {
my ($arr_ref, $index) = @_[0, 1];
$index ||= 0;
return if $index == length $$arr_ref[0]; # return if end of string
unless ($index) { $_ = lc $_ foreach @$arr_ref } # make lowercase on 1st call
my @new_permut = @$arr_ref;
substr($_, $index, 1) = uc substr($_, $index, 1) foreach @new_permut;
push @$arr_ref, @new_permut;
lc_uc_permut($arr_ref, ++$index);
}
my @permutations = ('abcde');
lc_uc_permut \@permutations;
{
local $, = "\n";
print @permutations;
}
__END__
------------------------------
Date: 16 Mar 2004 10:44:43 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: All capital permutations of a string?
Message-Id: <c36lqr$kdf$1@mamenchi.zrz.TU-Berlin.DE>
Roel van der Steen <roel-perl@st2x.net> wrote in comp.lang.perl.misc:
> Joe <joeblow341@hotmail.com> wrote in comp.lang.perl.misc:
> >
> > Does anyone have an elegant way of, given a string, generate all possible
> > capitalization permutations of that string? ie:
> >
> > 000 abc
> > 001 abC
> > 010 aBc
> > 011 aBC
> > 100 Abc
> > 101 AbC
> > etc.
>
> Well, this really appeals on people's creativity! Here is a recursive
> solution:
Oh, recursion!
But your solution does too much. You don't need an explicit index to
keep track of the position, recursion does that for you.
Here's an alternative:
sub lc_uc_permut {
for ( shift ) {
return ( '') unless length;
my ( $first, $rest) = /(.)(.*)/;
return map { $first . $_, uc( $first) . $_ } uc_lc( $rest);
}
}
Anno
For reference:
> #/usr/bin/perl
> use strict;
> use warnings;
>
> sub lc_uc_permut {
> my ($arr_ref, $index) = @_[0, 1];
> $index ||= 0;
> return if $index == length $$arr_ref[0]; # return if end of string
> unless ($index) { $_ = lc $_ foreach @$arr_ref } # make lowercase on 1st call
> my @new_permut = @$arr_ref;
> substr($_, $index, 1) = uc substr($_, $index, 1) foreach @new_permut;
> push @$arr_ref, @new_permut;
> lc_uc_permut($arr_ref, ++$index);
> }
>
> my @permutations = ('abcde');
> lc_uc_permut \@permutations;
> {
> local $, = "\n";
> print @permutations;
> }
>
> __END__
------------------------------
Date: Tue, 16 Mar 2004 08:26:06 +0000
From: Dave Cross <dave@dave.org.uk>
Subject: Re: block of code doesn't get executed
Message-Id: <pan.2004.03.16.08.26.06.94132@dave.org.uk>
On Tue, 16 Mar 2004 02:09:44 +0000, Jürgen Exner wrote:
> David K. Wall wrote:
>> stalwart <hammer@thatbox.net> wrote:
> [...]
>>> s/^_RC//;
>>> s/_RC^/"\n"/;
>>
>> A carat (^) in a regex means the beginning of a string. How can
>> '_RC' be *before* the beginning of the string?
>
> Almost right. A carat matches the beginning of the string iff it is at the
> beginning of the RE. Otherwise it is just an ordinary character.
Or if the /m option is used.
Dave...
------------------------------
Date: Tue, 16 Mar 2004 08:29:58 +0000
From: Dave Cross <dave@dave.org.uk>
Subject: Re: browser tries to download perl code
Message-Id: <pan.2004.03.16.08.29.58.599096@dave.org.uk>
On Mon, 15 Mar 2004 21:28:15 +0100, Tore Aursand wrote:
>> #!/usr/local/bin/perl
>
> use strict;
> use warnings;
> use CGI qw(:cgi);
>
>> print "Content-type: text/html/n/n";
>
> my $CGI = CGI->new();
> print $CGI->header(-type => 'text/html');
If you're importing functions into your namespace ("use CGI qw(:cgi)")
then why bother creating a CGI object? The :cgi export group includes the
"header" function. Also text/html is the default type used by "header".
#!/usr/local/bin/perl
use strict;
use warnings;
use CGI qw(:cgi);
print header;
hth,
Dave...
------------------------------
Date: Tue, 16 Mar 2004 21:29:12 +1300
From: "Tintin" <me@privacy.net>
Subject: Re: browser tries to download perl code
Message-Id: <c36dvo$24fn7v$1@ID-172104.news.uni-berlin.de>
"Ki" <docskky@yahoo.com> wrote in message
news:935d4411.0403150905.7f412932@posting.google.com...
> Hello.
> I am currently using apache server and trying to write perl programs.
> It is working for some other perl programs, but my browser tries to
> download not actual output but perl source code.
Try replacing the Perl code, with a shell script, python script, VB script,
C binary etc. Then you will clearly see you don't have a Perl problem
(apart from a severe lack of Perl knowledge)
> This is the code I am trying to write.
[snip of the God most awful code I've seen in some time]
------------------------------
Date: 16 Mar 2004 08:27:23 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: Hash slices and array references
Message-Id: <c36dpb$etu$1@mamenchi.zrz.TU-Berlin.DE>
David <davidol@hushmail.com> wrote in comp.lang.perl.misc:
> Dear all,
>
> I pass an array of hashes by reference into a function and dereference
> it like so:
>
> my $ret_val = func ( \@table );
>
> sub func {
> my @table = @{ $_[0] };
That creates a copy of the anonymous array. While this has no serious
consequences in this case, it is unnecessary. Keep the array ref as
such and de-reference from case to case.
sub func {
my $table = shift;
# ...
> ...
> ...
> }
>
> I can then modify hash elements directly using a loop like this:
>
> my $num = 0;
> for (my $i = 0; $i < $#table; $i++) {
> $table[$i]{seq_no} = ++$num;
> ...
> ...
> }
Side note: In your loop you have $i and $num, which are always
1 apart, so only one of them is really needed.
> Instead of using $table[$i]{seq_no} which seems a bit clumsy, I'd like
> to extract the ith element from the array with %rec = %{ $table[$i] }
Again, that makes a copy of the anonymous hash. This time it *has*
consequences, as you have noted.
> and then access (and modify) hash elements with a $rec{seq_no} =
> ++$num.
> The problem is, when I try and assign something to $rec{seq_no}, the
> array that I've passed in (by reference) doesn't actually change.
Right, you're working on a copy.
> Can I modify %rec = %{ $table[$i] } so that the assignment
> $rec{seq_no} = ++$num directly modifies the array?
You can keep a reference to the hash instead of the hash itself:
my $rec = $table[ $i];
$rec->{seq_no} = ++$num;
# etc.
But it's even simpler than that. Use a Perl style for-loop to
iterate over the list of hashes. Putting it together (untested,
obviously):
sub func {
my $table = shift;
my $num = 0;
for my $rec ( @$table ) {
$rec->{seq_no} = ++$num;
# ...
}
}
Anno
------------------------------
Date: 16 Mar 2004 08:56:28 GMT
From: "Tassilo v. Parseval" <tassilo.parseval@rwth-aachen.de>
Subject: Re: Hash slices and array references
Message-Id: <c36ffs$15n$1@nets3.rz.RWTH-Aachen.DE>
Also sprach Anno Siegel:
> David <davidol@hushmail.com> wrote in comp.lang.perl.misc:
>> Dear all,
>>
>> I pass an array of hashes by reference into a function and dereference
>> it like so:
>>
>> my $ret_val = func ( \@table );
>>
>> sub func {
>> my @table = @{ $_[0] };
>
> That creates a copy of the anonymous array. While this has no serious
> consequences in this case, it is unnecessary. Keep the array ref as
> such and de-reference from case to case.
>
> sub func {
> my $table = shift;
> # ...
Which makes me wonder why Perl has no builtin aliasing feature for this
case. Something like this (abusing Perl6's aliasing operator):
sub t {
my @alias := @{$_[0]};
push @alias, 1;
}
t(\my @ary);
# @ary now (1)
This can be done from XS, but the interface is butt-ugly:
sub t {
deref(shift, \my @alias);
push @alias, 1;
}
This seems to come from the fact that there is no way to return a real
array or hash. Maybe an XSUB can do that, I have to re-investigate.
Tassilo
--
$_=q#",}])!JAPH!qq(tsuJ[{@"tnirp}3..0}_$;//::niam/s~=)]3[))_$-3(rellac(=_$({
pam{rekcahbus})(rekcah{lrePbus})(lreP{rehtonabus})!JAPH!qq(rehtona{tsuJbus#;
$_=reverse,s+(?<=sub).+q#q!'"qq.\t$&."'!#+sexisexiixesixeseg;y~\n~~dddd;eval
------------------------------
Date: 16 Mar 2004 09:04:39 GMT
From: "Tassilo v. Parseval" <tassilo.parseval@rwth-aachen.de>
Subject: Re: Hash slices and array references
Message-Id: <c36fv7$2pq$1@nets3.rz.RWTH-Aachen.DE>
Also sprach Tassilo v. Parseval:
> Also sprach Anno Siegel:
>> That creates a copy of the anonymous array. While this has no serious
>> consequences in this case, it is unnecessary. Keep the array ref as
>> such and de-reference from case to case.
>>
>> sub func {
>> my $table = shift;
>> # ...
>
> Which makes me wonder why Perl has no builtin aliasing feature for this
> case. Something like this (abusing Perl6's aliasing operator):
>
> sub t {
> my @alias := @{$_[0]};
> push @alias, 1;
> }
> t(\my @ary);
> # @ary now (1)
>
> This can be done from XS, but the interface is butt-ugly:
>
> sub t {
> deref(shift, \my @alias);
> push @alias, 1;
> }
I forgot prototypes, which make it slightly bearable:
sub t {
deref($_[0] => my @alias);
push @alias, 1;
}
Still no beauty because the fat comma wont let me simply write 'shift'.
:-/
Tassilo
--
$_=q#",}])!JAPH!qq(tsuJ[{@"tnirp}3..0}_$;//::niam/s~=)]3[))_$-3(rellac(=_$({
pam{rekcahbus})(rekcah{lrePbus})(lreP{rehtonabus})!JAPH!qq(rehtona{tsuJbus#;
$_=reverse,s+(?<=sub).+q#q!'"qq.\t$&."'!#+sexisexiixesixeseg;y~\n~~dddd;eval
------------------------------
Date: 16 Mar 2004 09:59:11 GMT
From: Roel van der Steen <roel-perl@st2x.net>
Subject: Re: How to remove lines containing "continuation" operator
Message-Id: <slrnc5dk0c.rts.roel-perl@localhost.localdomain>
On Tue, 16 Mar 2004 at 03:28 GMT, werlax wrote:
> charley@pulsenet.com (Chris Charley) wrote in message news:<4f7ed6d.0403151500.64d48cb7@posting.google.com>...
>> [snip]
>>
>> perldoc perlrun
>>
>> Will explain it. Scroll down to the '-i' command switch.
>>
>>
> Your '[snip]' removed the portion where I said "From reading
> the manpage I thought it was supposed to automatically use the
> original filename as the default for print commands?" but I will read
> through it again to see if I missed something. I'm trying this for
> the first time and am missing something. Maybe RTFM again will help.
> Thanks.
Hint: the empty angle operator is only magical when it's used in a
"while" loop:
Compare:
#!/usr/bin/perl
use strict;
use warnings;
local ($^I, @ARGV) = ('.bak', glob('*.c'));
print <>;
__END__
with
#!/usr/bin/perl
use strict;
use warnings;
local ($^I, @ARGV) = ('.bak', glob('*.c'));
print $_ while <>;
__END__
------------------------------
Date: Tue, 16 Mar 2004 20:01:37 +1100
From: "C3" <gned@telsmonopolytradotcom.remove.monopoly)>
Subject: incrementing a string by a certain value
Message-Id: <4056c215$0$8356$afc38c87@news.optusnet.com.au>
Hi everyone,
How do I shift a string n letters up/down the alphabet?
e.g. if n = -1
"hello" becomes "gdkkn"
or if n = 2, "jgnnq"
Ideally, I would like a wrap-around of the letters, so for n=3 and the
string "you", the output should be "brx".
thanks,
C3
------------------------------
Date: Tue, 16 Mar 2004 11:49:52 +0100
From: =?ISO-8859-1?Q?Josef_M=F6llers?= <josef.moellers@fujitsu-siemens.com>
Subject: Re: incrementing a string by a certain value
Message-Id: <c36lsi$ht8$1@nntp.fujitsu-siemens.com>
C3 wrote:
> Hi everyone,
>=20
> How do I shift a string n letters up/down the alphabet?
>=20
> e.g. if n =3D -1
> "hello" becomes "gdkkn"
> or if n =3D 2, "jgnnq"
>=20
> Ideally, I would like a wrap-around of the letters, so for n=3D3 and th=
e
> string "you", the output should be "brx".
Standard answer: what have you tried so far, where did you fail, when is =
the homework due?
I'd probably use a hash and some form of the map operator.
--=20
Josef M=F6llers (Pinguinpfleger bei FSC)
If failure had no penalty success would not be a prize
-- T. Pratchett
------------------------------
Date: 16 Mar 2004 10:47:35 GMT
From: Roel van der Steen <roel-perl@st2x.net>
Subject: Re: incrementing a string by a certain value
Message-Id: <slrnc5dmr4.rts.roel-perl@localhost.localdomain>
On Tue, 16 Mar 2004 at 09:01 GMT, C3 wrote:
> Hi everyone,
>
> How do I shift a string n letters up/down the alphabet?
>
> e.g. if n = -1
> "hello" becomes "gdkkn"
> or if n = 2, "jgnnq"
>
> Ideally, I would like a wrap-around of the letters, so for n=3 and the
> string "you", the output should be "brx".
>
>
> thanks,
>
> C3
>
>
Use the tr/// operator, as follows:
#!/usr/bin/perl
use strict;
use warnings;
my ($str, $n) = @ARGV[0..1];
my $repl = join '', 'a'..'z';
$repl = substr substr($repl, $n) . $repl, 0, length $repl;
eval "\$str =~ tr/a-z/$repl/";
print "$str\n";
__END__
then:
% ./shifter.pl hello -1
gdkkn
% ./shifter.pl hello 2
jgnnq
% ./shifter.pl you 3
brx
(assuming that you named your script "shifter.pl".)
------------------------------
Date: Tue, 16 Mar 2004 02:22:15 -0600
From: tadmc@augustmail.com
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.5 $)
Message-Id: <4KadnRnS6uGqJMvd4p2dnA@august.net>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
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- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
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Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($Revision: 1.5 $)
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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 <tadmc@augustmail.com> and many others on the
comp.lang.perl.misc newsgroup.
------------------------------
Date: Tue, 16 Mar 2004 09:43:41 GMT
From: Tweetie Pooh <bjr601553@cia.gov>
Subject: Re:ligious, Emacs v. vi
Message-Id: <5d04bfe7be0810a35a7a273b4bdbf1fe@news.teranews.com>
"Bernard El-Hagin" <bernard.el-haginDODGE_THIS@lido-tech.net> honoured
comp.lang.perl.misc on Tue 16 Mar 2004 07:50:33a with
news:Xns94AE59442E84Delhber1lidotechnet@62.89.127.66:
> Ben Morrow <usenet@morrow.me.uk> wrote:
>
> [...]
>
>
>> Things I miss from emacs are its intelligent indent mode, which is
>> rather cleverer than vim's (though the flip side of this is that
>> vim mucks up your indenting by mistake much less often); and the
>> fact that emacs won't let you delete something without copying it
>> to the kill ring. It is of course possible that both of these are
>> due to my unfamiliarity with vim... :)
>
>
> They most certainly are. :-)
>
>
Oh bring back the joy of using WordStar. Runs from a floppy, no
file size limits can also be used to write the documentation.
------------------------------
Date: 16 Mar 2004 08:05:20 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: variable initialization question
Message-Id: <c36cg0$ds7$1@mamenchi.zrz.TU-Berlin.DE>
James Willmore <jwillmore@adelphia.net> wrote in comp.lang.perl.misc:
> On Mon, 15 Mar 2004 17:49:46 +0000, Anno Siegel wrote:
> > Tore Aursand <tore@aursand.no> wrote in comp.lang.perl.misc:
> >> On Mon, 15 Mar 2004 11:06:28 +0000, Anno Siegel wrote:
> >> >>> There's generally no reason to initialize a variable to 0.
[...]
> >> Why not, actually? I really _like_ the idea of having each variable in a
> >> program initialized before use. What are the arguments against doing
> >> this?
>
> > Unlike other languages, Perl variables *are* initialized. Despite its
> > name, undef is a well defined value with a well defined function, and
> > every scalar comes initialized to it. Nothing more dangerous than a
> > friendly warning happens if you use the value inappropriately. By
> > overwriting it you tell the reader, "Undef isn't good enough, I need
> > something else." Don't tell them that if it isn't true.
>
> Maybe I mis-understood what the point of your posts were... and if so,
> sorry for the grief. I agree that "declaring" variables up front is good,
> "initializing" them to some value can be good, but undesired in *all*
> cases. Did I get it?
Yes. Declaring all variables is a good thing, and you hardly have
a choice under strictures. Initialization is only needed in some
cases and should only be done when needed.
Anno
------------------------------
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:
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------------------------------
End of Perl-Users Digest V10 Issue 6263
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