loading a method

Aryan

Greetings!

I was wondering whether loading of a program and a method is possible in Perl just like what happens in Java Reflections.

For example I have a props file

 
operation1 = perl_method1
operation2 = perl_method2

I want to read this file to get the name of the method to be executed. Now what i have with me is the string "perl_method1" which is the name of the perl function. In Java I can use refections to call this method. Can I do the same in perl? In short I want to load a method and all I have is the name of the method in a string.

Adam Stoller

Greetings! I was wondering whether loading of a program and a method is possible in Perl just like what happens in Java Reflections. For example I have a props file operation1 = perl_method1 operation2 = perl_method2 I want to read this file to get the name of the method to be executed. Now what i have with me is the string "perl_method1" which is the name of the perl function. In Java I can use refections to call this method. Can I do the same in perl? In short I want to load a method and all I have is the name of the method in a string.

I'm not sure I completely understand what you're asking - but I'll take a stab at answering it anyway....

Assuming the module to which the method belongs is already loaded via a

use

statement, it is possible to either

eval

or reference the method in an abstract manner - e.g.:

sub foo {
    print "Hello World\n";
}
my $x = q(foo);
&{$x}; # calls the foo subroutine

Although as a "good" programmer, I would enable strictures and warnings, and would then have to explicitly disable the strictures around that dereference like so:

use strict;
use warnings;
sub foo {
    print "Hello World\n";
}
my $x = q(foo);
no strict qw(refs);# disable strict ref checking
&{$x};
use strict qw(refs);# re-enable strict ref checking

The above is obviously a simplistic case, but hopefully gives you some idea about this.
There are probably several other ways to approach the same thing - like:

use strict;
use warnings;
sub foo {
    print "Hello World\n";
}
my $x = q(foo);
eval ($x . "();");# the parens are needed to have it eval'd as a function call
eval ('&' . $x);# the '&' is an alternative way of declaring it as a function call - but the parens are probably better

perldoc perlrefs might provide some additional ideas.

Hope that helps.