Possible Duplicate:
How do I include functions from another file in my Perl script?
I have a perl file suppose a.pl and I want to use a function from perl file b.pl. How do i do it
views:
109answers:
4
+2
A:
The best/conventional way is to keep all your functions in a Perl module file (.pm): See perlmod. This would require you to convert b.pl to a package. You would then access your module file (MyFuncs.pm) from a.pl with:
use MyFuncs;
toolic
2010-02-02 22:03:28
You can also turn your module as modulinos, a perl module that can be called as a script - See this link for more infohttp://www252.pair.com/comdog/mastering_perl/Chapters/18.modulinos.html
ccheneson
2010-02-02 22:13:56
@ccheneson See also http://stackoverflow.com/questions/1131304/in-perl-how-can-i-find-out-if-my-file-is-being-used-as-a-module-or-run-as-a-scri
Sinan Ünür
2010-02-02 22:32:43
A:
Use the 'use' keyword to use functions from another module.
Example:
File a.pl:
use b;
f_in_b();
File b.pm:
sub f_in_b()
{
print "f_in_b\n";
}
1;
Important:
File b.pm must have the final 1;
Curd
2010-02-02 22:06:39
It isn't nearly so simple. Firstly, **never** use lowercase module names unless you're writing a pragma to change the behavoir of perl, secondly, B.pm in this example would have to have a configured `sub import {}`, this can be set up with `Exporter`, or `Sub::Install` or something, but the magic doesn't happen without that. You can still get to `f_in_b()` without it, but you have to use package-qualification, `use b; B::f_in_b();`
Evan Carroll
2010-02-02 22:15:15
@Evan Carroll: I guess you are wrong: This example actually works. You don't need package qualification `B::` here.
Curd
2010-02-02 22:31:11
This is something I forgot, reason being no sane person would want this. Technically what is happening is you're polluting `package main;` which is a bad thing. If you had `f_in_b()`, in the `a.pl`, the one in `b.pm` would be overwritten.
Evan Carroll
2010-02-02 23:04:29
If you make a file called *.pm, it should conform to the standards of a module, unless your intent is to sabotage the code maintenance efforts of your employer or client. Your code sets up a false expectation that b.pm will respect the `main` namespace. You managed to trip up a skilled Perl programmer with an insane and ill-considered move. Please read perldoc perlmod -- http://perldoc.perl.org/perlmod.html.
daotoad
2010-02-03 16:18:34
Yes, I know, that this example is not the official way to define a perl module. Neither did I claim that this is the case nor was it the question of manugupt1. His question was how to use a function from another perl file; nothing more. And this is probably the most minimalistic answer. I don't understand this excitement about it.
Curd
2010-02-03 23:02:07
+3
A:
Turn b.pl into a module
- Call it something descriptive like
MyBModule(Bis reserved by core). - rename the file to the something
.pmlikeMyBModule.pm. - Add a package at the top, like
package MyBModule; - Set a true return code on the package by making the last line
1;
You don't have to do anything else if you want to use your package name when calling the sub.
use MyBModule;
use strict;
use warnings;
MyBModule::sub1();
If you don't want to qualify it with the package name, read on...
Use Exporter.pm
Now configure Exporter.
- Add the
use Exporter;statement at the top of your module. - add a line
our @EXPORT_OK = qw(sub1 sub2);
After you're done your module should look something like this
package MyBModule;
use strict;
use warnings;
use Exporter;
our @EXPORT_OK = qw(sub1 sub2);
sub sub1 { ... }
sub sub2 { ... }
Edit the caller
- Make sure the library is in
@INC, or the module in the current directory. If not append the directory toPERL5LIB. - Add a line like
use MyBModule qw(sub1 sub2);
Read perldoc Exporter for more information
Your script should look like this afterward:
use strict;
use warnings;
use MyModuleB qw( sub1 sub2 );
It really isn't that hard, it takes about 15 seconds after you get used to doing it.
Evan Carroll
2010-02-02 22:21:00