in reply to Re: creating a class with encapsulation ?
in thread creating a class with encapsulation ?

so i have my code down fine, it compiles. how do i convert it to a class ? any suggestions ? on how to create an object and methods ? 
#!/usr/bin/perl
use strict;
use warnings;

my $in = ("/home/ki/Downloads/currenthumanccds.txt");
my $out = ("/home/ki/output.txt");

open (IN,"/home/ki/Downloads/CCDS.current.txt") or die "Cant open file
+: $!";
open (OUT,">/home/ki/output.txt") or die "Cant open file: $!";

while(<IN>){
    chomp;
    my@fields = (split/\t/);
    if ($fields[0] =~ m/16/ && $fields[6] eq"-" && $fields[5] =~ m/Pub
+lic/){;
        print OUT "$fields[0]    $fields[2]    $fields[6]    $fields[5
+]\n";
    }
}

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Re^3: creating a class with encapsulation ?
by Athanasius (Archbishop) on Apr 27, 2016 at 04:41 UTC

    Here is the standard approach:

    (1) In file X/CCD/Human.pm (where X is some directory listed in @INC):

    package CCD::Human;

use strict;
use warnings;

sub new
{
    my ($class, $in_filename, $out_filename) = @_;

    my %self =
    (
        in  => $in_filename,
        out => $out_filename,
    );

    return bless \%self, $class;
}

sub parse
{
    my ($self) = @_;

    open(my $in,  '<', $self->{in})
        or die "Cannot open file '$self->{in}' for reading: $!";

    open(my $out, '>', $self->{out})
        or die "Cannot open file '$self->{out}' for writing: $!";

    while (<$in>)
    {
        chomp;
        my @fields = split /\t/;
        print $out "$fields[0]    $fields[2]    $fields[6]    $fields[
+5]\n"
            if ($fields[0] =~ /16/ &&
                $fields[6] eq '-'  &&
                $fields[5] =~ /Public/);
    }

    close $in
        or die "Cannot close file '$self->{in}': $!";

    close $out
        or die "Cannot close file '$self->{out}': $!";
}

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    (2) Client code would use this class as follows:

    use CCD::Human;
...
my $human = CCD::Human->new
            (
                '/home/ki/Downloads/currenthumanccds.txt',
                '/home/ki/output.txt',
            );
...
$human->parse();

    [download]

    Disclaimers:

    1. The above compiles but is otherwise untested.
    2. This doesn’t look like a use-case for which a class is either required or appropriate. Simply putting your code into a subroutine within a module would likely be a better approach.

    Hope that helps,

    Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

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[select]
      im having trouble running it i tried your client code as a test file nothing happened. no output file was created. and yes i set the class as .pm
[reply]

        It works correctly for me. A few things to check:

        • Does your module file CCD/Human.pm begin and end like this?

          package CCD::Human;
...
1;    # return a true value

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        • Does your client code use CCD::Human;?

        • Are the data items on each line of .../home/ki/Downloads/currenthumanccds.txt separated by tab characters?

        • Is the file .../home/ki/output.txt created when you run the script? What does it contain?

        Hope that helps,

        Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

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[d/l]
[select]
        it isn't supposed to produce any output, also its incomplete, you have to finish it
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