PERL CGI Beginners - Running a Perl module

Author

Running a Perl module

Octavian Rasnita

2004-05-22, 11:31 am

Hi all

I want to run a certain perl module by getting the name of the perl module
from a scalar variable like:

$module ="Test";
require $module;

I have read in the POD documentation that I need to use:

eval {require $module};
or
eval "require $module";

But the problem is that I cannot get a value returned by that module.

The Test module returns a value named $value.

If I use:

require Test;
print $value;

The var $value is printed without problems, but if I call require for the
$module, the var $value is not exported and I cannot use it.

Is Perl able to run a certain module if getting the name of the module from
a variable, and able to access a value returned by that module?

Thank you very much.

Teddy

Bob Showalter

2004-05-22, 11:31 am

Octavian Rasnita wrote:
> Hi all
>
> I want to run a certain perl module by getting the name of the perl
> module from a scalar variable like:
>
> $module ="Test";
> require $module;
>
> I have read in the POD documentation that I need to use:
>
> eval {require $module};
> or
> eval "require $module";

You need to use the latter. The former won't do what you want. And you need
to check for errors.

>
> But the problem is that I cannot get a value returned by that module.
>
> The Test module returns a value named $value.
>
> If I use:
>
> require Test;
> print $value;
>
> The var $value is printed without problems, but if I call require for
> the $module, the var $value is not exported and I cannot use it.

require() does not do exporting, so I'm not sure what you're saying here.

The following are equivalent:

require MyModule;

$mod = "MyModule";
eval "require $mod";

>
> Is Perl able to run a certain module if getting the name of the
> module from a variable, and able to access a value returned by that
> module?

Not sure what you mean by "returned by that module". Modules are required to
return a true value to indicate that they were successfully initialized. If
you want that specific value, just assign the results of the require() or
eval.

Octavian Rasnita

2004-05-22, 11:31 am

Hi,

Ok, I see. Please tell me if there is a way to do what I want.

I want to get a certain string value from a text file, use that text string
as the name for a module, execute that module, and get the result of a
certain variable which is created in that module for using it in the program
which calls the module.

It is not absolutely necessary to use a .pm module, but I want to choose
what perl file I want to execute and get its result in the program that
calls it.
I would like not to be forced to use the shell, and i hope it is possible.

Thank you.

Teddy

----- Original Message -----
From: "Bob Showalter" <Bob_Showalter@taylorwhite.com>
To: "'Octavian Rasnita'" <orasnita@fcc.ro>; <beginners-cgi@perl.org>
Sent: Monday, April 05, 2004 3:29 PM
Subject: RE: Running a Perl module

[color=darkred]
> Octavian Rasnita wrote:

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