[28042] in Perl-Users-Digest
Perl-Users Digest, Issue: 9406 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Thu Jun 29 14:06:14 2006
Date: Thu, 29 Jun 2006 11:05:06 -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 Thu, 29 Jun 2006 Volume: 10 Number: 9406
Today's topics:
Re: accessing object variables from callback function anno4000@zrz.tu-berlin.de
Re: accessing object variables from callback function <nobull67@gmail.com>
Re: Date formatting <bart@nijlen.com>
Re: Debugging Memory consumption for Perl Program <bart@nijlen.com>
deflate parts of a file <sridhara@yahoo.com>
Re: deflate parts of a file <Paul.Marquess@btinternet.com>
Re: deflate parts of a file <sridhara@yahoo.com>
Re: How to ignore 1st line in a file when reading <rvtol+news@isolution.nl>
Re: How to ignore 1st line in a file when reading anno4000@zrz.tu-berlin.de
Re: How to ignore 1st line in a file when reading <rvtol+news@isolution.nl>
Re: Is this a Hash and how can I test a value? <qbert@comcast.net>
Perl Object Creation problem... <howachen@gmail.com>
Re: Perl Object Creation problem... <aukjan@gmail.com>
Re: Perl Object Creation problem... <ced@blv-sam-01.ca.boeing.com>
Re: Perl Object Creation problem... <howachen@gmail.com>
Re: Perl Object Creation problem... <nobull67@gmail.com>
Re: Perl Object Creation problem... <howachen@gmail.com>
Re: Perl Object Creation problem... lawrence@hummer.not-here.net
Re: Perl Object Creation problem... <howachen@gmail.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: 29 Jun 2006 10:07:09 GMT
From: anno4000@zrz.tu-berlin.de
Subject: Re: accessing object variables from callback function
Message-Id: <4ghn2dF1lg9b9U1@news.dfncis.de>
kaisung@gmail.com <kaisung@gmail.com> wrote in comp.lang.perl.misc:
> Hi,
>
> I'm trying to write a Class which uses XML::Parser. XML::Parser uses
> callback functions. If I use an object method as the callback
> function, how can I access object variables from within that callback
> function if it doesn't get passed a reference to $self?
Then don't use the object method, but use a closure that calls the
object method. You're not saying of what class the object method
is supposed to belong and what $self is going to be. I'll assume
XML::Parser and $parser respectively. See below (code untested).
> Here's what I
> have so far:
>
> -----BEGIN PERL-----
> package Test;
>
> use XML::Parser;
>
> sub new {
> my $invocant = shift;
> my $class = ref($invocant) || $invocant;
> my $self = { @_ };
> bless($self, $class);
> return $self;
> }
>
> sub load {
> my $parser = new XML::Parser(ErrorContext => 2);
> $parser->setHandlers(Start => \&_start_handler);
Use a closure that encloses the object you want to call _start_handler()
with:
$parser->setHandlers(Start => sub { $parser->_start_handler });
> $parser->parsefile("file.xml");
> }
>
> sub _start_handler {
> # In this function, I want to set $self->{var}, however don't have
> # access to $self
> }
You do if it is called from the closure.
Anno
------------------------------
Date: 29 Jun 2006 07:36:11 -0700
From: "Brian McCauley" <nobull67@gmail.com>
Subject: Re: accessing object variables from callback function
Message-Id: <1151591771.666590.39950@m73g2000cwd.googlegroups.com>
anno4000@zrz.tu-berlin.de wrote:
> kaisung@gmail.com <kaisung@gmail.com> wrote in comp.lang.perl.misc:
> > I'm trying to write a Class which uses XML::Parser. XML::Parser uses
> > callback functions. If I use an object method as the callback
> > function, how can I access object variables from within that callback
> > function if it doesn't get passed a reference to $self?
>
> Then don't use the object method, but use a closure that calls the
> object method. You're not saying of what class the object method
> is supposed to belong and what $self is going to be. I'll assume
> XML::Parser and $parser respectively. See below (code untested).
Actually it's more likely that the OP intended Test::load to be a
method.
> > -----BEGIN PERL-----
> > package Test;
> > sub load {
> > my $parser = new XML::Parser(ErrorContext => 2);
> > $parser->setHandlers(Start => \&_start_handler);
>
> Use a closure that encloses the object you want to call _start_handler()
> with:
>
> $parser->setHandlers(Start => sub { $parser->_start_handler });
sub load {
my $self = shift;
my $parser = new XML::Parser(ErrorContext => 2);
$parser->setHandlers(Start => sub { $self->start_handler } );
}
------------------------------
Date: 29 Jun 2006 04:26:55 -0700
From: "Bart Van der Donck" <bart@nijlen.com>
Subject: Re: Date formatting
Message-Id: <1151580415.690711.119230@x69g2000cwx.googlegroups.com>
Ted wrote:
> I am trying to use Date::Manip, and have most of what I need working.
>
> The final peice, though, is eluding me. The following statement works
> fine:
>
> $market_date = DateCalc($file_time,ParseDateDelta("- 1 business
> days"));
>
> I does precisely what I need, WRT computation. However, I have yet to
> figure out how to tell it I want the date part only, and that the time
> part can be discarded.
>
> I may have just missed the relevant part of the documentation that
> tells me this, but I haven't found, in the Date::Manip documentation,
> how to get only the date part of the return value from DateCalc. How
> do I do this?
One way is to manually cut out the part you need. The first 8
characters from your output string should always hold the date in
YYYYMMDD-format:
#!perl
use strict;
use warnings;
use Date::Manip;
print substr(DateCalc('2006-05-29 08:00:00','+3 business days'),0,8);
Hope this helps,
--
Bart
------------------------------
Date: 29 Jun 2006 04:45:56 -0700
From: "Bart Van der Donck" <bart@nijlen.com>
Subject: Re: Debugging Memory consumption for Perl Program
Message-Id: <1151581556.553475.317430@i40g2000cwc.googlegroups.com>
janicehwang1325@yahoo.com wrote:
> I would like to know is there any way to debug the memory consumption
> of a perl program running? For example, I have a program running and i
> would like to keep tract of the memory consumption of this program so
> that I can retart the program if the memory consumption is going to
> high. Thank you very much.
Yes, there are a number of techniques for that. See:
http://perldoc.perl.org/perldebguts.html#Debugging-Perl-memory-usage
--
Bart
------------------------------
Date: 29 Jun 2006 09:03:19 -0700
From: "sid" <sridhara@yahoo.com>
Subject: deflate parts of a file
Message-Id: <1151596999.818114.126060@y41g2000cwy.googlegroups.com>
I need to compress parts of a file, say some sections of an xml file
while leaving others as ASCII on the ouput stream. I took the deflate
example from cpan and started gathering all lines of a section in a
string and then doing one deflate, ouput, flush and output the
compressed section. But this doesn't seem to be working. I am seeing
"use of uninitialized values" warnings and the final output file
doesn't look right. I would see some compressed data then a whole bunch
of xml without any compressed data in between and so forth. The
compress method has a horrible performance. It actually made the file
much bigger. Hence I only want to use the deflate method. It works fine
on the whole file. But I want to use it on sections of a file. Are
there examples that someone can point me to?
thanks
SS
------------------------------
Date: Thu, 29 Jun 2006 17:39:15 +0100
From: "Paul Marquess" <Paul.Marquess@btinternet.com>
Subject: Re: deflate parts of a file
Message-Id: <44a40251$0$11539$4d4eb98e@read.news.uk.uu.net>
"sid" <sridhara@yahoo.com> wrote in message
news:1151596999.818114.126060@y41g2000cwy.googlegroups.com...
>I need to compress parts of a file, say some sections of an xml file
> while leaving others as ASCII on the ouput stream. I took the deflate
> example from cpan
Which deflate example are you referring to?
>and started gathering all lines of a section in a
> string and then doing one deflate, ouput, flush and output the
> compressed section. But this doesn't seem to be working. I am seeing
> "use of uninitialized values" warnings and the final output file
> doesn't look right.
> I would see some compressed data then a whole bunch
> of xml without any compressed data in between and so forth.
Can you post some code please?
> The
> compress method has a horrible performance. It actually made the file
> much bigger.
> Hence I only want to use the deflate method. It works fine
> on the whole file.
Compression isn't worth the effort on small strings. Ending up with
something bigger is one of the main reasons for not doing it.
> But I want to use it on sections of a file. Are
> there examples that someone can point me to?
Paul
------------------------------
Date: 29 Jun 2006 10:16:44 -0700
From: "sid" <sridhara@yahoo.com>
Subject: Re: deflate parts of a file
Message-Id: <1151601404.346322.71780@m73g2000cwd.googlegroups.com>
use Compress::Zlib ;
binmode STDIN;
binmode STDOUT;
$x = deflateInit()
or die "Cannot create a deflation stream\n" ;
while (<>)
{
($output, $status) = $x->deflate($_) ;
$status == Z_OK
or die "deflation failed\n" ;
print $output ;
}
($output, $status) = $x->flush() ;
$status == Z_OK
or die "deflation failed\n" ;
print $output ;
--------------------------------------------------------------
My code is based on this:
while(<>){
if(begin_xmltag)then set flag
if(flag){$string.=$_}
else {print $_}
if(end_xmltag) {
set output to compressed string using deflate procedre
print $output
do a flush on the deflate stream
set string to null
}
}
Paul Marquess wrote:
> "sid" <sridhara@yahoo.com> wrote in message
> news:1151596999.818114.126060@y41g2000cwy.googlegroups.com...
> >I need to compress parts of a file, say some sections of an xml file
> > while leaving others as ASCII on the ouput stream. I took the deflate
> > example from cpan
>
> Which deflate example are you referring to?
>
> >and started gathering all lines of a section in a
> > string and then doing one deflate, ouput, flush and output the
> > compressed section. But this doesn't seem to be working. I am seeing
> > "use of uninitialized values" warnings and the final output file
> > doesn't look right.
> > I would see some compressed data then a whole bunch
> > of xml without any compressed data in between and so forth.
>
> Can you post some code please?
>
> > The
> > compress method has a horrible performance. It actually made the file
> > much bigger.
> > Hence I only want to use the deflate method. It works fine
> > on the whole file.
>
> Compression isn't worth the effort on small strings. Ending up with
> something bigger is one of the main reasons for not doing it.
>
> > But I want to use it on sections of a file. Are
> > there examples that someone can point me to?
>
> Paul
------------------------------
Date: Thu, 29 Jun 2006 13:38:26 +0200
From: "Dr.Ruud" <rvtol+news@isolution.nl>
Subject: Re: How to ignore 1st line in a file when reading
Message-Id: <e80lbt.1d4.1@news.isolution.nl>
Dr.Ruud schreef:
> @array = <$fh> ;
> shift @array ;
But don't do it that way if your first line can be multi-MB.
--
Affijn, Ruud
"Gewoon is een tijger."
------------------------------
Date: 29 Jun 2006 12:16:32 GMT
From: anno4000@zrz.tu-berlin.de
Subject: Re: How to ignore 1st line in a file when reading
Message-Id: <4ghul0F1nb2baU1@news.dfncis.de>
Dr.Ruud <rvtol+news@isolution.nl> wrote in comp.lang.perl.misc:
> Deepu schreef:
>
> > I would like to know when reading a file which has around 10 - 20
> > lines in it. How can it be done to ignore 1st line and start reading
> > from 2nd till last.
[...]
> @array = <$fh> ;
> shift @array ;
( undef, @array) = <$fh>;
Anno
------------------------------
Date: Thu, 29 Jun 2006 18:03:22 +0200
From: "Dr.Ruud" <rvtol+news@isolution.nl>
Subject: Re: How to ignore 1st line in a file when reading
Message-Id: <e814rg.16c.1@news.isolution.nl>
anno4000@zrz.tu-berlin.de schreef:
> Dr.Ruud:
>> Deepu:
>>> I would like to know when reading a file which has around
>>> 10 - 20 lines in it. How can it be done to ignore 1st line
>>> and start reading from 2nd till last.
>>
>> @array = <$fh> ;
>> shift @array ;
>
> ( undef, @array) = <$fh>;
Yes, good correction.
--
Affijn, Ruud
"Gewoon is een tijger."
------------------------------
Date: Thu, 29 Jun 2006 12:43:01 -0400
From: "Jockser" <qbert@comcast.net>
Subject: Re: Is this a Hash and how can I test a value?
Message-Id: <BP-dnf2iAeSRnjnZnZ2dnUVZ_oadnZ2d@comcast.com>
Thanks for the responses worked out good.
------------------------------
Date: 29 Jun 2006 03:31:29 -0700
From: "howa" <howachen@gmail.com>
Subject: Perl Object Creation problem...
Message-Id: <1151577089.344510.63220@d56g2000cwd.googlegroups.com>
Hi,
I encountered a problem when using perl's OOP feature"
Directory Layout:
----------------------
c:\temp\perl\test.pl
c:\temp\perl\class\user.pm
user.pm
----------------------
package class::user;
sub new {
my ($class) = @_;
my $objref = {};
bless $objref, $class;
}
sub print_me {
my ($self) = @_;
print "is me!";
}
1;
----------------------
test.pl
----------------------
use lib "C:\\temp\\perl";
use class::user;
$u = new user();
----------------------
and it returns :
Can't locate object method "new" via package "user" (perhaps you forgot
to load
"user"?) at test.pl line 5.
what's wrong with the codes?
thanks...
------------------------------
Date: Thu, 29 Jun 2006 13:31:10 +0200
From: Aukjan van Belkum <aukjan@gmail.com>
Subject: Re: Perl Object Creation problem...
Message-Id: <206bf$44a3b9b9$c2abfc64$27572@news2.tudelft.nl>
howa wrote:
> use lib "C:\\temp\\perl";
>
> use class::user;
>
> $u = new user();
> ----------------------
>
This should be:
$u = new class::user; (or pref.: my $u = new class::user;)
or
$u = class::user->new(); (or pref.: my $u = class::user->new();)
Aukjan.
------------------------------
Date: Thu, 29 Jun 2006 13:02:44 GMT
From: Charles DeRykus <ced@blv-sam-01.ca.boeing.com>
Subject: Re: Perl Object Creation problem...
Message-Id: <J1MHKL.K3w@news.boeing.com>
howa wrote:
> Hi,
>
> I encountered a problem when using perl's OOP feature"
>
>
> Directory Layout:
> ----------------------
> c:\temp\perl\test.pl
> c:\temp\perl\class\user.pm
>
>
> user.pm
> ----------------------
> package class::user;
>
> sub new {
> my ($class) = @_;
> my $objref = {};
>
> bless $objref, $class;
> }
>
> sub print_me {
> my ($self) = @_;
>
> print "is me!";
> }
>
> 1;
>
>
>
> ----------------------
> test.pl
> ----------------------
> use lib "C:\\temp\\perl";
>
> use class::user;
>
> $u = new user();
> ----------------------
>
>
> and it returns :
>
> Can't locate object method "new" via package "user" (perhaps you forgot
> to load
> "user"?) at test.pl line 5.
>
> what's wrong with the codes?
I'm not sure what you intended with the parens but `$u = new user()`
gets parsed as 'user->new'. However, your class is 'class::user' not
'user' so you'll need: $u = new class::user which is better expressed
as user::class->new. Customarily, package names start with an upper
case letter too, eg, Class::User. 'Class' is usually not an appropriate
choice for the name either.
You might want to review the OO documentation for more info:
perlboot Perl OO tutorial for beginners
perltoot Perl OO tutorial, part 1
perltootc Perl OO tutorial, part 2
perlobj Perl objects
perlbot Perl OO tricks and examples
hth,
--
Charles DeRykus
------------------------------
Date: 29 Jun 2006 07:19:14 -0700
From: "howa" <howachen@gmail.com>
Subject: Re: Perl Object Creation problem...
Message-Id: <1151590754.424368.10660@x69g2000cwx.googlegroups.com>
Aukjan van Belkum =E5=AF=AB=E9=81=93=EF=BC=9A
> howa wrote:
>
> > use lib "C:\\temp\\perl";
> >
> > use class::user;
> >
> > $u =3D new user();
> > ----------------------
> >
>
> This should be:
> $u =3D new class::user; (or pref.: my $u =3D new class::user;)
> or
> $u =3D class::user->new(); (or pref.: my $u =3D class::user->new();)
>
>
> Aukjan.
thx first....
but is it possible to use
$u =3D new user;
just like in c++, i.e. using namespace std;
sorry as i am really new to perl...
------------------------------
Date: 29 Jun 2006 07:44:25 -0700
From: "Brian McCauley" <nobull67@gmail.com>
Subject: Re: Perl Object Creation problem...
Message-Id: <1151592265.708375.12870@d56g2000cwd.googlegroups.com>
howa wrote:
> Aukjan van Belkum =E5=AF=AB=E9=81=93=EF=BC=9A
>
> > howa wrote:
> >
> > > use lib "C:\\temp\\perl";
> > >
> > > use class::user;
> > >
> > > $u =3D new user();
> > > ----------------------
> > >
> >
> > This should be:
> > $u =3D new class::user; (or pref.: my $u =3D new class::user;)
> > or
> > $u =3D class::user->new(); (or pref.: my $u =3D class::user->new();)
> but is it possible to use
>
> $u =3D new user;
>
> just like in c++, i.e. using namespace std;
No, there is no such mechanism builtin[1] to Perl5. All class names
must be specified absolutely.
[1] I say builtin because it's just the sort of thing you might expect
to see in an Acme::* modules. Note Acme::* modules are only intended as
jokes.
------------------------------
Date: 29 Jun 2006 08:40:18 -0700
From: "howa" <howachen@gmail.com>
Subject: Re: Perl Object Creation problem...
Message-Id: <1151595618.294715.113300@m73g2000cwd.googlegroups.com>
Brian McCauley =E5=AF=AB=E9=81=93=EF=BC=9A
> howa wrote:
> > Aukjan van Belkum =E5=AF=AB=E9=81=93=EF=BC=9A
> >
> > > howa wrote:
> > >
> > > > use lib "C:\\temp\\perl";
> > > >
> > > > use class::user;
> > > >
> > > > $u =3D new user();
> > > > ----------------------
> > > >
> > >
> > > This should be:
> > > $u =3D new class::user; (or pref.: my $u =3D new class::user;)
> > > or
> > > $u =3D class::user->new(); (or pref.: my $u =3D class::user->new();)
> > but is it possible to use
> >
> > $u =3D new user;
> >
> > just like in c++, i.e. using namespace std;
>
> No, there is no such mechanism builtin[1] to Perl5. All class names
> must be specified absolutely.
>
> [1] I say builtin because it's just the sort of thing you might expect
> to see in an Acme::* modules. Note Acme::* modules are only intended as
> jokes.
it seems a little stupid if the class name must be the package full
name...
anyway, thanks!
------------------------------
Date: 29 Jun 2006 09:54:48 -0700
From: lawrence@hummer.not-here.net
Subject: Re: Perl Object Creation problem...
Message-Id: <87slln6gx3.fsf@hummer.i-did-not-set--mail-host-address--so-shoot-me>
"howa" <howachen@gmail.com> writes:
>
> it seems a little stupid if the class name must be the package full
> name...
>
Perhaps this will offer enlightenement:
Suppose I have two classes Road::Apple and Fruit::Apple
#/usr/local/bin/howas-private-perl-like-language
use Road::Apple;
use Fruit::Apple;
my $thing = new Apple;
What kind of apple whould $thing be? One is delicious, the other not
so much.
-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
Lawrence Statton - lawrenabae@abaluon.abaom s/aba/c/g
Computer software consists of only two components: ones and
zeros, in roughly equal proportions. All that is required is to
sort them into the correct order.
------------------------------
Date: 29 Jun 2006 10:14:59 -0700
From: "howa" <howachen@gmail.com>
Subject: Re: Perl Object Creation problem...
Message-Id: <1151601299.426528.285910@p79g2000cwp.googlegroups.com>
lawre...@hummer.not-here.net =E5=AF=AB=E9=81=93=EF=BC=9A
> "howa" <howachen@gmail.com> writes:
> >
> > it seems a little stupid if the class name must be the package full
> > name...
> >
>
> Perhaps this will offer enlightenement:
>
> Suppose I have two classes Road::Apple and Fruit::Apple
>
> #/usr/local/bin/howas-private-perl-like-language
> use Road::Apple;
> use Fruit::Apple;
>
> my $thing =3D new Apple;
>
> What kind of apple whould $thing be? One is delicious, the other not
> so much.
>
> -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
> Lawrence Statton - lawrenabae@abaluon.abaom s/aba/c/g
> Computer software consists of only two components: ones and
> zeros, in roughly equal proportions. All that is required is to
> sort them into the correct order.
in other language, you also have this problem, java or c.
in fact, this is not a problem at all, if you want to specifiy, you can
still use the full path if needed.
the namespace and the class name are not the same thing.
------------------------------
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 9406
***************************************
