Brother frankus,

Perl does not force you to OO. You have to decide one day to cross the threshold and find out what's in it for you.

So, let me stick my neck out. I'm not crazy about objects, in Perl or otherwise. I just use them.

In my experience, Perl objects are good for structuring any program, from the lowly quick hack to a large application involving tens of modules, other people's and your own.

IMO, all those classical OO benefits show up more often than not in the programmer's daily work - the bread that our sandwiches are made of, so to speak

• bundling the code and data together
• encapsulating the data
• managing object instances, each with it's state properly initialized and maintained
• abstraction
• separating interface from implementation
• reusable modules
• easy testing of modules

Let me give you an example - a quick hack I did last night.

I wanted to have a simple probe for the quantity of memory that my perl program is hogging at different phases of execution. I looked around for a Win32 module that could help me, and I found two - IProcess and Win32::PerfLib. I installed the former, tried the test scripts that came with it, and then simplified one of scripts and packed it into a module.

Here is my test script - just to exercise my module

#! perl -w
# TestPerlprocdata.pl 

use Perlprocdata;

my $pp = new Perlprocdata;

my @x;
for (0..5) {
    $pp->printProcessMemInfoShort; # probe
    # gobble some memory
    push @x, 1 for (0...100000);
    sleep 1;
}

# free the memory (to perl, not to the OS)
@x = ();


for (0..10) {
    $pp->printProcessMemInfoShort;  # probe
    # gobble some more memory
    push @x, 1 for (0...100000);
    sleep 1;
}

# free the memory (to perl, not to the OS)
@x = ();


__END__

           [Name] [PageFaults/s]    [PeakWS]        [WS]

         perl.exe            841     3436544     3436544
         perl.exe           1366     5586944     5586944
         perl.exe           1894     7753728     7753728
         perl.exe           2694    11034624    11034624
         perl.exe           2945    12062720    12062720
         perl.exe           3344    13697024    13697024
         perl.exe           4545    18620416    18620416
         perl.exe           4545    18620416    18620416
         perl.exe           4545    18620416    18620416
         perl.exe           4545    18620416    18620416
         perl.exe           4545    18620416    18620416
         perl.exe           4545    18620416    18620416
         perl.exe           4545    18620416    18620416
         perl.exe           4647    19038208    19038208
         perl.exe           5046    20676608    20676608
         perl.exe           5444    22306816    22306816
         perl.exe           5844    23949312    23949312
[download]

And here is my quick and dirty module:

#! perl -w
# Perlprocdata.pm by Rudif@bluemail.ch

use strict;

package Perlprocdata;


# uses Win32::IProcess by Amine Moulay Ramdane                
# from website: http://www.generation.net/~aminer/Perl/ 


use Win32::IProcess qw(
    PROCESS_QUERY_INFORMATION PROCESS_VM_READ INHERITED INHERITED DIGI
+TAL NOPATH
);  


#----------------------------------------------------------
sub new {
    my ($class, %args) = @_;
    my $self = {};
    bless $self, $class;

    my $obj = $self->{obj} = new Win32::IProcess || die "Can not creat
+e an IProcess object..\n";

    my @EnumInfo;
    $obj->EnumProcesses(\@EnumInfo);

    my $size=scalar(@EnumInfo);

    for(my $j=0;$j<$size;$j++) {
        if ($EnumInfo[$j]->{ProcessName} =~ /perl/i) {
            $self->{EnumInfo} = $EnumInfo[$j];
            my $Info;
            $obj->GetProcessMemInfo($EnumInfo[$j]->{ProcessId},\$Info)
+;
            $self->{Info} = $Info;
            my @data = (
                $EnumInfo[$j]->{ProcessName},
                $Info->{PageFaultCount},
                $Info->{PeakWorkingSetSize},
                $Info->{WorkingSetSize},
                $Info->{QuotaPagedPoolUsage},
                $Info->{QuotaNonPagedPoolUsage},
                $Info->{PagefileUsage});
        }
    }

    return $self;
}

#----------------------------------------------------------
sub getProcessMemInfo {
    my $self = shift;
    $self->{obj}->GetProcessMemInfo($self->{EnumInfo}{ProcessId},\$sel
+f->{Info});
}

#----------------------------------------------------------
sub printProcessMemInfoShort {
    my $self = shift;
    $self->getProcessMemInfo;
    printf("\n\n%17.15s%15.14s%12.11s%12.11s\n\n",
            "[Name]","[PageFaults/s]", "[PeakWS]","[WS]")
            unless $self->{printed}++;
    printf("%17.15s%15.14s%12.11s%12.11s\n",
        $self->{EnumInfo}{ProcessName},
        $self->{Info}{PageFaultCount},
        $self->{Info}{PeakWorkingSetSize},
        $self->{Info}{WorkingSetSize});
}

1;

__END__
[download]

In this little exercice I can see just about every OO benefit that I listed above.
Convinced?

HTH
Rudif

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.