Re: Inheritance without defining the object on inherited module

[Corion]

...
our @ISA = qw(Person);    # inherits from Person

my $firstName = $object->getFirstName();
print "This is the first name: " . $firstName . "\n";

Can you explain in English what this code is supposed to do and when it is supposed to be executed?

The code is not in a subroutine so it will run at use time.

[thanos1983]

Hello Corion,

This is actually the key point of my question. I want to find a way to pass/ inherit the value to my $firstName when the module will be called.

My intention is to use warnings on my script instead of die functions and store the error on a directory.

Sample of pseudo code Employee.pm:

So my question is how to pass the $fileDirectory into %WARNS so I can use it to print the error on correct location. I can pass it as a parameter through main.pl.

Sample of new main.pl:

#!/usr/bin/perl
use Person;
use strict;
use warnings;
use Employee;

my $dirToBePassed = "/path/Dir";

my $object = new Person( "Thanos", "Test", 123456);
my $firstName = $object->getFirstName();
print "This is the first name: $firstName\n";

my $secondObject = new Employee( "refToBeUsed" );
my $solution = $secondObject->somethingCalledFromMain();
print "This is the solution : $solution\n";

Sample of new Employee.pm

#!/usr/bin/perl
use strict;
use warnings;

package Employee;

sub new
{
    my $class = shift;
    my $self = {
        refFromMain => shift,
    };
    bless $self, $class;
    return $self;
}

sub somethingCalledFromMain
{
    my( $self ) = @_;
=comment
    do something here;
    warn "I was not able to complete the process!\n";
=cut
    return $self->{refFromMain};
}

my %WARNS;
local $SIG{__WARN__} = sub {
    my $message = shift;
    return if $WARNS{$message}++;
    logger('warning', $message);
};

sub logger {
    my ($level, $msg) = @_;
    if (open my $out, '>>', 'log.txt') {
        chomp $msg;
        print $out "$level - $msg\n";
    close $out;
    }
}

1;

Sample of working output:

This is the first name: Thanos
This is the solution : refToBeUsed

It is really easy to pass the my $dirToBePassed = "/path/Dir"; to Employee.pm as somethingCalledFromMain($dirToBePassed); with minor code modifications. The problem is how to pass this parameter to %WARNS. So I can print the warnings on the correct directory.

Thank you for your time and effort reading and replying to my question.

[Corion]

Your problem does not show anything related to inheritance - the code shows no relation between Person and Employee.

If you want to do a global capturing of all warnings raised by code in the Employee class, you will need to store the "current" Employee instance in a global variable and then reuse that variable in your %SIG handler for warnings. The easiest approach is to set the "current" employee in the main program:

local $Employee::current= $secondObject;
$secondObject->doSomethingThatRaisesWarnings();

Note that your statement of

local $SIG{__WARN__} = sub {
...
}

loses its effect as soon as Employee.pm has been compiled. This may or may not be what you want.

Personally, I would recommend to avoid capturing warnings in such a global way. I think it's better to have your Employee (or Person) class implement a ->logMessage() or ->warn() method that will store the warning with the employee.

[thanos1983]

Hello again Corion,

That is true the sample code that I have provided it does not explain exactly so I will try to explain in English.

I want to use a subroutine from Person to Employees. More precisely I want to invoke a subroutine input main.pl</p> that calls a method from <code>Person and replies back with a hash. I want to invoke the same subroutine from Employees without the need to use the object.

My goal the whole time was to get a hash with the directories where all my %WARNS will be stored in different folders in case of an error.

I hope now that I explained everything in English that it makes a bit more sense why I wanted to use both Perl Modules.

Again thank you for your time and effort.

[Anonymous Monk]

Its simple :P use Log::Log4perl / Log::Log4perl::FAQ

Does this make sense ?

Employee::logger_outfile( "/path/Dir" );
...
##Employee.pm
my $outfile ; sub Employee::logger_outfile {
    my $path = shift;
    croak "This is not a method" if ref $path or int@_;
    $outfile = $path;
}
sub Employee::logger {
   open ... $outfile ...
}

[thanos1983]

Hello Anonymous Monk,

That is probably what exactly I need.

Thanks for your time and effort.