# The 'source' file ("constants.plx")
use constant {
    FOO => 1,
    BAR => 2,
    QUX => 3
};

##</code><code>##

#!/usr/bin/perl -wl

BEGIN { do "constants.plx"; }

print "Foo: ". FOO. "\nBar: ". BAR. "\nQux: ". QUX;

##</code><code>##

Foo: 1
Bar: 2
Qux: 3