[19442] in Perl-Users-Digest
Perl-Users Digest, Issue: 1637 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Tue Aug 28 09:10:31 2001
Date: Tue, 28 Aug 2001 06:10:12 -0700 (PDT)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Message-Id: <999004212-v10-i1637@ruby.oce.orst.edu>
Content-Type: text
Perl-Users Digest Tue, 28 Aug 2001 Volume: 10 Number: 1637
Today's topics:
Re: one character at a time (Yves Orton)
Re: Perl number conversion Utilities (Randal L. Schwartz)
Re: Perl number conversion Utilities (Peter J. Acklam)
Re: Perl number conversion Utilities (Randal L. Schwartz)
Re: Strange behavior of perl5 on HP-UX 11.0 <wiu09524@rrzc2.rz.uni-regensburg.de>
Re: Strange behavior of perl5 on HP-UX 11.0 <Martin.Jost@icn.siemens.de>
use() versus import() changing semantics? (Tassilo v. Parseval)
Re: use() versus import() changing semantics? <tinamue@zedat.fu-berlin.de>
Re: use() versus import() changing semantics? <kristian.fischer@koehlershohn.de>
Re: use() versus import() changing semantics? (Tassilo v. Parseval)
Re: use() versus import() changing semantics? <Tassilo.Parseval@post.rwth-aachen.de>
Re: use() versus import() changing semantics? <kristian.fischer@koehlershohn.de>
Re: use() versus import() changing semantics? <tinamue@zedat.fu-berlin.de>
Re: warnings with cgi will crash Win32 perl core <matthew.garrish@sympatico.ca>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: 28 Aug 2001 03:05:38 -0700
From: demerphq@hotmail.com (Yves Orton)
Subject: Re: one character at a time
Message-Id: <74f348f7.0108280205.798c833f@posting.google.com>
Benjamin Goldberg <goldbb2@earthlink.net> wrote in message news:<3B89C2D9.9D65A526@earthlink.net>...
> Yves Orton wrote:
> Not that it matters much, but I prefer to ask Benchmark to repeat each one for some number of seconds rather than some number of times...
>
> That is, Time(-10); instead of Time(100_000);
Done.
> You should have two substr versions, the second being:
> push @output, substr( $string, $i, 1 )
> for( 0 .. length( $string )-1 );
Done
> You should have two versions of regexp, the second one being:
> @output = $string =~ /(.)/gs
See below....
>
> Also, if . in the regex were replaced with [\x00-\xFF] it might go a bit faster, though I'm not sure.
Done, but that means 4 different types. Oh and the class is marginally
slower.
> You should have a second unpack version, with
> @output = unpack("C*", $string);
>
> Also, you didn't do the split solution:
> @output = split //, $string;
Yeah I didnt do any @list= variants. I kinda thought the idea was to
process each letter in turn not to turn the string into an array of
chars. So now i am testing them, but seperately, its interesting the
differences.
Incidentally I have rewritten the test and ran it against string
10,20..100 200,300,400,500 char long strings. The results are
slightly suprising. For short (<20) strings the substr4 method does
quite well... Heres my code and results:
#!perl
use strict;
use warnings;
use Benchmark qw(cmpthese timethese);
use Data::Dumper;
my $types={
Scalar_only=>{
'substr4' => 'substr ($s, 0, 1, "") while length($s)',
'substr3' => 'substr( $s, $_, 1 ) foreach (0..length($s)-1)',
},
Regexp=>{
'rex_dot' => '$s =~ /(.)/gs',
'rex_class' => '$s =~ /([\x00-\xFF])/gs',
},
List_only=>{
'unpack' => 'unpack("C*", $s)',
'split' => 'split(//,$s)',
},
};
sub build_test {
my $TestString=shift || "TEST";
my $Print=shift;
my $h='{my ($s,$r,@l)=("TEST","");'."\n";
$h=~s/(TEST)/$TestString/e;
my $f="}\n";
$f=";\n".'print "s=$s | r=$r | l=@l\n"'.$f if ($Print);
my $hash={};
foreach my $key (keys %{$types->{Scalar_only}}) {
$hash->{'@= '.$key}=$h.'push
@l,'.$types->{Scalar_only}->{$key}.$f;
$hash->{'= '.$key}=$h.'$r='.$types->{Scalar_only}->{$key}.$f;
}
foreach my $key (keys %{$types->{Regexp}}) {
$hash->{'@= '.$key}=$h.'@l='.$types->{Regexp}->{$key}.$f;
$hash->{'= $_ '.$key}=$h.'$r= $_ foreach
('.$types->{Regexp}->{$key}.')'.$f;
$hash->{'= $1 '.$key}=$h.'$r= $1 while
'.$types->{Regexp}->{$key}.$f;
}
foreach my $key (keys %{$types->{List_only}}) {
$hash->{'@= '.$key}=$h.'@l='.$types->{List_only}->{$key}.$f;
$hash->{'= '.$key}=$h.'$r= $_ foreach
'.$types->{List_only}->{$key}.$f;
}
return $hash;
}
use Data::Dumper;
my $print =build_test("ABCDEF",1);
foreach my $name (sort keys %$print) {
print $name."\t";
eval $print->{$name};
die $@ if $@;
}
{
local $,="\n";
local $\="\n";
print '$hash={\n';
while (my ($k,$v)=each(%$print)) {
print "'$k'\t=>","'$v',";
}
print '};';
}
foreach my $mul (1..10,20,30,40,50) {
my $test=build_test("01234567890" x $mul);
my %list;
my %process;
map { (substr($_,0,1) eq "@")
? $list{$_}=$test->{$_}
: $process{$_}=$test->{$_}
} keys %$test;
print "-----------------------------------------------------
Testing against ".($mul*10)." char string....\n\n";
my $t=timethese (-60,\%list,"none");
my $p=timethese (-60,\%process,"none");
cmpthese($t);
print "\n";
cmpthese($p);
}
__END__
********************
* EDITED RESULTS *
********************
= $1 rex_class s=ABCDEF | r=F | l=
= $1 rex_dot s=ABCDEF | r=F | l=
= $_ rex_class s=ABCDEF | r=F | l=
= $_ rex_dot s=ABCDEF | r=F | l=
= split s=ABCDEF | r=F | l=
= substr3 s=ABCDEF | r=F | l=
= substr4 s= | r=F | l=
= unpack s=ABCDEF | r=70 | l=
@= rex_class s=ABCDEF | r= | l=A B C D E F
@= rex_dot s=ABCDEF | r= | l=A B C D E F
@= split s=ABCDEF | r= | l=A B C D E F
@= substr3 s=ABCDEF | r= | l=A B C D E F
@= substr4 s= | r= | l=A B C D E F
@= unpack s=ABCDEF | r= | l=65 66 67 68 69 70
$hash={\n
'= unpack' =>
'{my ($s,$r,@l)=("ABCDEF","");
$r= $_ foreach unpack("C*", $s);
print "s=$s | r=$r | l=@l\n"}
',
'@= unpack' =>
'{my ($s,$r,@l)=("ABCDEF","");
@l=unpack("C*", $s);
print "s=$s | r=$r | l=@l\n"}
',
'= split' =>
'{my ($s,$r,@l)=("ABCDEF","");
$r= $_ foreach split(//,$s);
print "s=$s | r=$r | l=@l\n"}
',
'= $_ rex_dot' =>
'{my ($s,$r,@l)=("ABCDEF","");
$r= $_ foreach ($s =~ /(.)/gs);
print "s=$s | r=$r | l=@l\n"}
',
'= $_ rex_class' =>
'{my ($s,$r,@l)=("ABCDEF","");
$r= $_ foreach ($s =~ /([\x00-\xFF])/gs);
print "s=$s | r=$r | l=@l\n"}
',
'= $1 rex_dot' =>
'{my ($s,$r,@l)=("ABCDEF","");
$r= $1 while $s =~ /(.)/gs;
print "s=$s | r=$r | l=@l\n"}
',
'@= rex_class' =>
'{my ($s,$r,@l)=("ABCDEF","");
@l=$s =~ /([\x00-\xFF])/gs;
print "s=$s | r=$r | l=@l\n"}
',
'@= split' =>
'{my ($s,$r,@l)=("ABCDEF","");
@l=split(//,$s);
print "s=$s | r=$r | l=@l\n"}
',
'= substr3' =>
'{my ($s,$r,@l)=("ABCDEF","");
$r=substr( $s, $_, 1 ) foreach (0..length($s)-1);
print "s=$s | r=$r | l=@l\n"}
',
'= substr4' =>
'{my ($s,$r,@l)=("ABCDEF","");
$r=substr ($s, 0, 1, "") while length($s);
print "s=$s | r=$r | l=@l\n"}
',
'@= substr3' =>
'{my ($s,$r,@l)=("ABCDEF","");
push @l,substr( $s, $_, 1 ) foreach (0..length($s)-1);
print "s=$s | r=$r | l=@l\n"}
',
'= $1 rex_class' =>
'{my ($s,$r,@l)=("ABCDEF","");
$r= $1 while $s =~ /([\x00-\xFF])/gs;
print "s=$s | r=$r | l=@l\n"}
',
'@= substr4' =>
'{my ($s,$r,@l)=("ABCDEF","");
push @l,substr ($s, 0, 1, "") while length($s);
print "s=$s | r=$r | l=@l\n"}
',
'@= rex_dot' =>
'{my ($s,$r,@l)=("ABCDEF","");
@l=$s =~ /(.)/gs;
print "s=$s | r=$r | l=@l\n"}
',
};
REMOVE PRINT STATEMENTS FOR THE BELOW TESTS
-----------------------------------------------------
Testing against 10 char string....
@= substr3 33489/s
@= rex_class 34165/s
@= rex_dot 35212/s
@= substr4 36117/s
@= split 41859/s
@= unpack 84778/s
= $1 rex_class 28994/s
= $1 rex_dot 29886/s
= $_ rex_class 32732/s
= $_ rex_dot 33915/s
= split 34041/s
= substr3 51807/s
= unpack 57781/s
= substr4 57959/s
-----------------------------------------------------
Testing against 20 char string....
@= rex_class 18616/s
@= rex_dot 19178/s
@= substr3 19327/s
@= substr4 19739/s
@= split 22983/s
@= unpack 49074/s
= $1 rex_class 15850/s
= $1 rex_dot 16360/s
= $_ rex_class 18827/s
= split 19421/s
= $_ rex_dot 19668/s
= substr3 31502/s
= substr4 31870/s
= unpack 35170/s
-----------------------------------------------------
Testing against 30 char string....
@= rex_class 12732/s
@= substr4 13177/s
@= rex_dot 13307/s
@= substr3 13465/s
@= split 15849/s
@= unpack 34655/s
= $1 rex_class 10983/s
= $1 rex_dot 11345/s
= $_ rex_class 13335/s
= split 13683/s
= $_ rex_dot 13741/s
= substr4 22059/s
= substr3 22778/s
= unpack 25335/s
-----------------------------------------------------
Testing against 40 char string....
@= rex_class 9634/s
@= rex_dot 10126/s
@= substr4 10279/s
@= substr3 10373/s
@= split 12212/s
@= unpack 26740/s
= $1 rex_class 8192/s
= $1 rex_dot 8730/s
= $_ rex_class 10214/s
= split 10362/s
= $_ rex_dot 10687/s
= substr4 17088/s
= substr3 17783/s
= unpack 19785/s
-----------------------------------------------------
Testing against 50 char string....
@= rex_class 7856/s
@= rex_dot 8175/s
@= substr4 8295/s
@= substr3 8435/s
@= split 9817/s
@= unpack 21827/s
= $1 rex_class 6849/s
= $1 rex_dot 7158/s
= $_ rex_class 8317/s
= split 8544/s
= $_ rex_dot 8714/s
= substr4 13716/s
= substr3 14564/s
= unpack 16227/s
-----------------------------------------------------
Testing against 60 char string....
@= rex_class 6576/s
@= rex_dot 6869/s
@= substr4 6952/s
@= substr3 7136/s
@= split 8125/s
@= unpack 18344/s
= $1 rex_class 5729/s
= $1 rex_dot 5876/s
= $_ rex_class 7022/s
= split 7208/s
= $_ rex_dot 7337/s
= substr4 11399/s
= substr3 12353/s
= unpack 13727/s
-----------------------------------------------------
Testing against 70 char string....
@= rex_class 5658/s
@= rex_dot 5875/s
@= substr4 5977/s
@= substr3 6113/s
@= split 7120/s
@= unpack 15943/s
= $1 rex_class 5002/s
= $1 rex_dot 5189/s
= $_ rex_class 6053/s
= split 6244/s
= $_ rex_dot 6347/s
= substr4 9951/s
= substr3 10726/s
= unpack 11922/s
-----------------------------------------------------
Testing against 80 char string....
@= rex_class 4982/s
@= rex_dot 5183/s
@= substr4 5254/s
@= substr3 5374/s
@= split 6229/s
@= unpack 14023/s
= $1 rex_class 4352/s
= $1 rex_dot 4519/s
= $_ rex_class 5322/s
= split 5482/s
= $_ rex_dot 5598/s
= substr4 8757/s
= substr3 9461/s
= unpack 10535/s
----------------------------------------------------
Testing against 90 char string....
@= rex_class 4427/s
@= substr4 4531/s
@= rex_dot 4604/s
@= substr3 4815/s
@= split 5564/s
@= unpack 12532/s
= $1 rex_class 3874/s
= $1 rex_dot 4029/s
= $_ rex_class 4771/s
= split 4900/s
= $_ rex_dot 4987/s
= substr4 7771/s
= substr3 8478/s
= unpack 9424/s
-----------------------------------------------------
Testing against 100 char string....
@= rex_class 3992/s
@= rex_dot 4164/s
@= substr4 4221/s
@= substr3 4392/s
@= split 5019/s
@= unpack 11327/s
= $1 rex_class 3491/s
= $1 rex_dot 3664/s
= $_ rex_class 4311/s
= split 4408/s
= $_ rex_dot 4499/s
= substr4 7006/s
= substr3 7676/s
= unpack 8492/s
-----------------------------------------------------
Testing against 200 char string....
@= rex_class 2015/s
@= rex_dot 2100/s
@= substr4 2128/s
@= substr3 2203/s
@= split 2535/s
@= unpack 5760/s
= $1 rex_class 1729/s
= $1 rex_dot 1829/s
= $_ rex_class 2190/s
= split 2246/s
= $_ rex_dot 2291/s
= substr4 3569/s
= substr3 3941/s
= unpack 4365/s
-----------------------------------------------------
Testing against 300 char string....
@= rex_class 1345/s
@= rex_dot 1402/s
@= substr4 1408/s
@= substr3 1496/s
@= split 1658/s
@= unpack 3853/s
= $1 rex_class 1179/s
= $1 rex_dot 1237/s
= $_ rex_class 1463/s
= split 1500/s
= $_ rex_dot 1505/s
= substr4 2396/s
= substr3 2653/s
= unpack 2935/s
-----------------------------------------------------
Testing against 400 char string....
@= rex_class 1004/s
@= rex_dot 1036/s
@= substr4 1064/s
@= substr3 1111/s
@= split 1270/s
@= unpack 2890/s
= $1 rex_class 900/s
= $1 rex_dot 918/s
= $_ rex_class 1101/s
= split 1127/s
= $_ rex_dot 1154/s
= substr4 1724/s
= substr3 1999/s
= unpack 2212/s
----------------------------------------------------
Testing against 500 char string....
@= rex_class 799/s
@= rex_dot 833/s
@= substr4 847/s
@= substr3 877/s
@= split 1015/s
@= unpack 2236/s
= $1 rex_class 697/s
= $1 rex_dot 741/s
= $_ rex_class 864/s
= split 898/s
= $_ rex_dot 917/s
= substr4 1405/s
= substr3 1603/s
= unpack 1771/s
------------------------------
Date: 28 Aug 2001 03:48:11 -0700
From: merlyn@stonehenge.com (Randal L. Schwartz)
Subject: Re: Perl number conversion Utilities
Message-Id: <m166b8o3ys.fsf@halfdome.holdit.com>
>>>>> "Joseph" == Joseph Hasting <hasting@agere.com> writes:
Joseph> Hi, I spent some time putting these number conversion subroutines
Joseph> together. It was very difficult to find the non-printf ways to convert
Joseph> number formats, so I thought I would share them:
Joseph> sub dec2hex {return sprintf("%lx ", shift);}
Joseph> sub hex2dec {return hex(shift);}
Joseph> sub bin2dec {return unpack("N", pack("B32", substr("0" x 32 . shift,
Joseph> -32)));}
Joseph> sub dec2bin {my $str = unpack("B32", pack("N", shift)); $str =~
Joseph> s/^0+(?=\d)//; return $str;}
Joseph> sub bin2hex {return dec2hex(bin2dec(shift));}
Joseph> sub hex2bin {return dec2bin(hex2dec(shift));}
But those aren't "dec2hex", "hex2dec" and so on. Those are "num2hex"
and "hex2num", and so on. They don't convert to decimal digits. They
convert to internal numbers. It's Perl's I/O routines that are
converting between internal numbers and external decimal digits.
Let's get the terminology right. I keep seeing this meme go around,
and I intend on killing it!
print "Just another Perl hacker,"
--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<merlyn@stonehenge.com> <URL:http://www.stonehenge.com/merlyn/>
Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!
------------------------------
Date: 28 Aug 2001 13:13:39 +0200
From: jacklam@math.uio.no (Peter J. Acklam)
Subject: Re: Perl number conversion Utilities
Message-Id: <cxczo8kh1y4.fsf@tiamat.uio.no>
merlyn@stonehenge.com (Randal L. Schwartz) wrote:
> But those aren't "dec2hex", "hex2dec" and so on. Those are
> "num2hex" and "hex2num", and so on.
Since they are all limited to dealing with integers, I prefer
"int2hex", "hex2int", etc.
Peter
--
#!/local/bin/perl5 -wp -*- mode: cperl; coding: iso-8859-1; -*-
# matlab comment stripper (strips comments from Matlab m-files)
s/^((?:(?:[])}\w.]'+|[^'%])+|'[^'\n]*(?:''[^'\n]*)*')*).*/$1/x;
------------------------------
Date: 28 Aug 2001 05:47:40 -0700
From: merlyn@stonehenge.com (Randal L. Schwartz)
Subject: Re: Perl number conversion Utilities
Message-Id: <m1g0acmjv7.fsf@halfdome.holdit.com>
>>>>> "Peter" == Peter J Acklam <jacklam@math.uio.no> writes:
Peter> merlyn@stonehenge.com (Randal L. Schwartz) wrote:
>> But those aren't "dec2hex", "hex2dec" and so on. Those are
>> "num2hex" and "hex2num", and so on.
Peter> Since they are all limited to dealing with integers, I prefer
Peter> "int2hex", "hex2int", etc.
Ooh yes. Thank you. I'll add that to the Stamp Out dec2hex Crusade FAQ. :)
--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<merlyn@stonehenge.com> <URL:http://www.stonehenge.com/merlyn/>
Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!
------------------------------
Date: 28 Aug 2001 12:45:58 +0200
From: Ulrich Windl <wiu09524@rrzc2.rz.uni-regensburg.de>
Subject: Re: Strange behavior of perl5 on HP-UX 11.0
Message-Id: <snfofp04g49.fsf@rrzc2.rz.uni-regensburg.de>
I just checked it with our Perl 5.6.0 (also binary install), it works!
tanya.ruttenberg@ssa.gov (Tanya Ruttenberg) writes:
> I'm not sure if this is an HP OS problem or a Perl problem. That's why
> I'm posting it to both newsgroups.
>
> The sys admin installed perl5.00503 yesterday (downloaded the binary
> distribution from the HP developer resource website) but it is
> unusable due to an inability to execute it:
>
> s12da21: /usr/local/bin/perl -e 'print "Hello\n";'
> sh: /usr/local/bin/perl: Execute permission denied.
>
> But it appears to be executable:
>
> s12da21: ls -l /usr/local/bin/perl
> -rwxr-xr-x 2 bin bin 384637 Jun 12 15:34 /usr/local/bin/perl
>
> He (the sys admin) got the same error when trying to run it as root!?
>
> I asked him to trace the process to see exactly which file was claiming
> insufficient permissions, but he either didn't hear me, didn't know
> how, or didn't want to for some other reason. He said he'd "look into it"
> but I am skeptical he'll get back to me anytime soon.
>
> Has anyone seen this problem before and do you know how to fix it?
------------------------------
Date: Tue, 28 Aug 2001 14:27:02 +0200
From: Martin Jost <Martin.Jost@icn.siemens.de>
Subject: Re: Strange behavior of perl5 on HP-UX 11.0
Message-Id: <3B8B8E16.71BC9795@icn.siemens.de>
Ulrich Windl wrote:
>
> I just checked it with our Perl 5.6.0 (also binary install), it works!
So does mine ;-)
See below for some suggestions
> tanya.ruttenberg@ssa.gov (Tanya Ruttenberg) writes:
>
> > The sys admin installed perl5.00503 yesterday (downloaded the binary
> > distribution from the HP developer resource website) but it is
> > unusable due to an inability to execute it:
> >
> > s12da21: /usr/local/bin/perl -e 'print "Hello\n";'
> > sh: /usr/local/bin/perl: Execute permission denied.
> >
> > But it appears to be executable:
> >
> > s12da21: ls -l /usr/local/bin/perl
> > -rwxr-xr-x 2 bin bin 384637 Jun 12 15:34 /usr/local/bin/perl
> >
Ok, just wild guessing...
What does the following commands "say":
which perl
perl -v
perl -V
(One of my guesses are 'old' perl-parts laying around or something
like this)
Is your perl installed under /usr/local or /opt or .... ???
HTH
Martin
------------------------------
Date: 28 Aug 2001 10:30:53 GMT
From: Tassilo.Parseval@post.rwth-aachen.de (Tassilo v. Parseval)
Subject: use() versus import() changing semantics?
Message-Id: <9mfrst$nji$1@nets3.rz.RWTH-Aachen.DE>
I just hit a - for me - quite inexplicable behaviour related to
including modules with either use() or import. The below is part of a
subroutine and should illustrate it:
[...]
eval { require URI::Find; };
if ($@) {
carp <<EOW;
You need the URI::Find module in order to use
extract_urls.
EOW
return;
}
else { use URI::Find; return find_uris($text, $coderef); }
The above works fine, with the only exception that 'make test' will fail
complaining about the missing URI::Find module on machines where it is
not installed. So I changed the else part to something like:
else { return URI::Find::find_uris($text, $coderef); }
Now, the test-scripts wont break at compile-time but instead at runtime,
complaining that :
t/5mbox.............ok 2/4Can't use string ("* Tassilo von Parseval
(tassilo.") as a SCALAR ref while "strict refs" in use at
/usr/local/share/perl/5.6.1/URI/Find.pm line 49.
I can make this work by passing \$text instead of $test to find_uris.
And now, I don't know why this is so. I can pass a simple scalar-vaiable
containing a string to find_uris when including it with use() but I have
to pass a reference otherwise.
Does anyone have an explanation for that?
Tassilo
--
$a=[(74,116)];$b=[($a->[1]-1,$a->[1]++,0x20)];$c=[(97,110)];$d=[($c->
[1]+1,$b->[1],"her")];for(@{[$a,$b,$c,$d]}){for(@{$_}){$_=~/\d+/?print
(chr($_)):print;}}$c=sub{$l=shift;[(0x20+$l-1,0x50,0x65,0x73-0x01,108
),(0x20,0x68,0x61,)]};print(map{chr($_)}@{($c->(1))});$h={a=>33*3,b=>
10**2+7,c=>"1"."0"."1",d=>0162};@h=sort(keys(%$h));for(@h){print(chr(
ord(chr($h->{$_}))))};
------------------------------
Date: 28 Aug 2001 11:40:29 GMT
From: Tina Mueller <tinamue@zedat.fu-berlin.de>
Subject: Re: use() versus import() changing semantics?
Message-Id: <9mfvvd$21ogl$2@fu-berlin.de>
Tassilo v. Parseval <Tassilo.Parseval@post.rwth-aachen.de> wrote:
> I just hit a - for me - quite inexplicable behaviour related to
> including modules with either use() or import. The below is part of a
> subroutine and should illustrate it:
> [...]
> eval { require URI::Find; };
> if ($@) {
> carp <<EOW;
> You need the URI::Find module in order to use
> extract_urls.
> EOW
> return;
> }
> else { use URI::Find; return find_uris($text, $coderef); }
> The above works fine, with the only exception that 'make test' will fail
> complaining about the missing URI::Find module on machines where it is
> not installed. So I changed the else part to something like:
> else { return URI::Find::find_uris($text, $coderef); }
> Now, the test-scripts wont break at compile-time but instead at runtime,
> complaining that :
> t/5mbox.............ok 2/4Can't use string ("* Tassilo von Parseval
> (tassilo.") as a SCALAR ref while "strict refs" in use at
> /usr/local/share/perl/5.6.1/URI/Find.pm line 49.
> I can make this work by passing \$text instead of $test to find_uris.
> And now, I don't know why this is so. I can pass a simple scalar-vaiable
> containing a string to find_uris when including it with use() but I have
> to pass a reference otherwise.
> Does anyone have an explanation for that?
phew, i searched the perldocs, but i didn't find a clear
explanation. i think it might have something to do with
prototypes. the method find_uris() has (\$&) as a
prototype, that means it'll take the first argument
as a reference. it takes it and calls another method, find(),
and find expects a reference.
"normally" you'd say
use URI::Find;
find_uri($text, $code);
perl will pass $text as a reference, and everything's fine.
if you say:
require URI::Find;
i guess that you can't check prototypes. the only possibility is to
put that at the BEGIN()ning.
so the following does not work:
require URI::Find;
print URI::Find::find_uris($test,$code);
(errormessage:
Can't use string ("test") as a SCALAR ref while "strict refs"
in use at /usr/lib/perl5/site_perl/5.6.0/URI/Find.pm line 124.
)
while this works:
BEGIN{require URI::Find;}
print URI::Find::find_uris($test,$code);
so i think require() not in a BEGIN-block disables prototype
checking. but i didn't find the corresponding explanation
in the docs. anyone can help?
regards,
tina
--
http://www.tinita.de \ enter__| |__the___ _ _ ___
tina's moviedatabase \ / _` / _ \/ _ \ '_(_-< of
search & add comments \ \ _,_\ __/\ __/_| /__/ perception
--- Warning: content of homepage hopelessly out-dated ---
------------------------------
Date: Tue, 28 Aug 2001 13:50:02 +0200
From: Kristian Fischer <kristian.fischer@koehlershohn.de>
Subject: Re: use() versus import() changing semantics?
Message-Id: <3B8B856A.A93DC234@koehlershohn.de>
Hallo
"Tassilo v. Parseval" wrote:
>
> I just hit a - for me - quite inexplicable behaviour related to
> including modules with either use() or import. The below is part of a
> subroutine and should illustrate it:
>
> [...]
> eval { require URI::Find; };
> if ($@) {
> carp <<EOW;
> You need the URI::Find module in order to use
> extract_urls.
> EOW
> return;
> }
> else { use URI::Find; return find_uris($text, $coderef); }
>
> The above works fine, with the only exception that 'make test' will fail
> complaining about the missing URI::Find module on machines where it is
> not installed. So I changed the else part to something like:
>
> else { return URI::Find::find_uris($text, $coderef); }
>
> Now, the test-scripts wont break at compile-time but instead at runtime,
> complaining that :
>
> t/5mbox.............ok 2/4Can't use string ("* Tassilo von Parseval
> (tassilo.") as a SCALAR ref while "strict refs" in use at
> /usr/local/share/perl/5.6.1/URI/Find.pm line 49.
>
> I can make this work by passing \$text instead of $test to find_uris.
> And now, I don't know why this is so. I can pass a simple scalar-vaiable
> containing a string to find_uris when including it with use() but I have
> to pass a reference otherwise.
>
> Does anyone have an explanation for that?
Try this for an example:
perl -e '$var = 1; unless($var){ use URI::Find; } print $@ if($@);'
The use statement is *allways* executed at compile-time.
Gruß
Kristian
------------------------------
Date: 28 Aug 2001 11:50:39 GMT
From: Tassilo.Parseval@post.rwth-aachen.de (Tassilo v. Parseval)
Subject: Re: use() versus import() changing semantics?
Message-Id: <9mg0if$sqc$1@nets3.rz.RWTH-Aachen.DE>
On 28 Aug 2001 11:40:29 GMT, Tina Mueller <tinamue@zedat.fu-berlin.de> wrote:
> "normally" you'd say
> use URI::Find;
> find_uri($text, $code);
> perl will pass $text as a reference, and everything's fine.
> if you say:
> require URI::Find;
> i guess that you can't check prototypes. the only possibility is to
> put that at the BEGIN()ning.
> so the following does not work:
> require URI::Find;
> print URI::Find::find_uris($test,$code);
>
> (errormessage:
> Can't use string ("test") as a SCALAR ref while "strict refs"
> in use at /usr/lib/perl5/site_perl/5.6.0/URI/Find.pm line 124.
> )
> while this works:
> BEGIN{require URI::Find;}
> print URI::Find::find_uris($test,$code);
>
> so i think require() not in a BEGIN-block disables prototype
> checking. but i didn't find the corresponding explanation
> in the docs. anyone can help?
Hmmh, thanks for your inquiry into that...this is quite interesting
really. I guess I will have to do it with a BEGIN-block instead of
passing a reference. Who knows whether future Perl releases will have
the same behaviour and - since it is a module - I can't maintain
several releases for each different Perl.
Tassilo
--
$a=[(74,116)];$b=[($a->[1]-1,$a->[1]++,0x20)];$c=[(97,110)];$d=[($c->
[1]+1,$b->[1],"her")];for(@{[$a,$b,$c,$d]}){for(@{$_}){$_=~/\d+/?print
(chr($_)):print;}}$c=sub{$l=shift;[(0x20+$l-1,0x50,0x65,0x73-0x01,108
),(0x20,0x68,0x61,)]};print(map{chr($_)}@{($c->(1))});$h={a=>33*3,b=>
10**2+7,c=>"1"."0"."1",d=>0162};@h=sort(keys(%$h));for(@h){print(chr(
ord(chr($h->{$_}))))};
------------------------------
Date: Tue, 28 Aug 2001 14:10:16 +0200
From: Tassilo von Parseval <Tassilo.Parseval@post.rwth-aachen.de>
Subject: Re: use() versus import() changing semantics?
Message-Id: <3B8B8A28.1060106@post.rwth-aachen.de>
Kristian Fischer wrote:
> perl -e '$var = 1; unless($var){ use URI::Find; } print $@ if($@);'
>
> The use statement is *allways* executed at compile-time.
Yes, and this was my problem since I looked for a way to include
URI::Find at runtime depending on whether the box has this module
installed. It seems to work the way Tina suggested: Putting require into
a BEGIN-block. In case of failure I now set a global-variable that is
later checked when the method is invoked.
I think URI::Find::find_uris should change its function parameter
profile from (\$&) to ($&) where there first parameter would have to be
an explicit scalar-ref.
Tassilo
--
$a=[(74,116)];$b=[($a->[1]-1,$a->[1]++,0x20)];$c=[(97,110)];$d=[($c->
[1]+1,$b->[1],"her")];for(@{[$a,$b,$c,$d]}){for(@{$_}){$_=~/\d+/?print
(chr($_)):print;}}$c=sub{$l=shift;[(0x20+$l-1,0x50,0x65,0x73-0x01,108
),(0x20,0x68,0x61,)]};print(map{chr($_)}@{($c->(1))});$h={a=>33*3,b=>
10**2+7,c=>"1"."0"."1",d=>0162};@h=sort(keys(%$h));for(@h){print(chr(
ord(chr($h->{$_}))))};
------------------------------
Date: Tue, 28 Aug 2001 14:37:48 +0200
From: Kristian Fischer <kristian.fischer@koehlershohn.de>
Subject: Re: use() versus import() changing semantics?
Message-Id: <3B8B909C.3F7230CC@koehlershohn.de>
Hallo
Tassilo von Parseval wrote:
>
> Kristian Fischer wrote:
>
> > perl -e '$var = 1; unless($var){ use URI::Find; } print $@ if($@);'
> >
> > The use statement is *allways* executed at compile-time.
>
> Yes, and this was my problem since I looked for a way to include
> URI::Find at runtime depending on whether the box has this module
> installed. It seems to work the way Tina suggested: Putting require into
> a BEGIN-block. In case of failure I now set a global-variable that is
> later checked when the method is invoked.
>
> I think URI::Find::find_uris should change its function parameter
> profile from (\$&) to ($&) where there first parameter would have to be
> an explicit scalar-ref.
AFAIK this is the right way:
eval { require URI::Find; import URI::Find; }
if($@){
# error
}else{
# do it
}
so you'll not run in problems later.
Kristian
------------------------------
Date: 28 Aug 2001 13:04:00 GMT
From: Tina Mueller <tinamue@zedat.fu-berlin.de>
Subject: Re: use() versus import() changing semantics?
Message-Id: <9mg4s0$22lto$1@fu-berlin.de>
Tassilo von Parseval <Tassilo.Parseval@post.rwth-aachen.de> wrote:
> Kristian Fischer wrote:
>> perl -e '$var = 1; unless($var){ use URI::Find; } print $@ if($@);'
>>
>> The use statement is *allways* executed at compile-time.
> Yes, and this was my problem since I looked for a way to include
> URI::Find at runtime depending on whether the box has this module
> installed. It seems to work the way Tina suggested: Putting require into
> a BEGIN-block. In case of failure I now set a global-variable that is
> later checked when the method is invoked.
> I think URI::Find::find_uris should change its function parameter
> profile from (\$&) to ($&) where there first parameter would have to be
> an explicit scalar-ref.
well, the author says, that find_uris() is deprecated, so you
shouldn't use it at all. maybe you can do the same using
find() and other methods, but i haven't looked into the
docs too much...
regards,
tina
--
http://www.tinita.de \ enter__| |__the___ _ _ ___
tina's moviedatabase \ / _` / _ \/ _ \ '_(_-< of
search & add comments \ \ _,_\ __/\ __/_| /__/ perception
--- Warning: content of homepage hopelessly out-dated ---
------------------------------
Date: Tue, 28 Aug 2001 08:40:46 -0400
From: "Matt Garrish" <matthew.garrish@sympatico.ca>
Subject: Re: warnings with cgi will crash Win32 perl core
Message-Id: <AgMi7.26190$Hr2.1683001@news20.bellglobal.com>
"Godzilla!" <godzilla@stomp.stomp.tokyo> wrote in message
news:3B8B21A7.B3E4258B@stomp.stomp.tokyo...
<all that crap sent to digital heaven>
I guess your pain comes from being so consistently wrong all the time. Maybe
you should start posting exclusively to alt.perl; you'd fit in well with all
the dimwits who post questions without checking the perldocs.
Matt
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
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Subject: Digest Administrivia (Last modified: 6 Apr 01)
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