CORE(3pm) Perl Programmers Reference Guide CORE(3pm)
NAME
CORE - Pseudo-namespace for Perl's core routines
SYNOPSIS
BEGIN {
*CORE::GLOBAL::hex = sub { 1; };
}
print hex("0x50"),"
"; # prints 1
print CORE::hex("0x50"),"
"; # prints 80
DESCRIPTION
The "CORE" namespace gives access to the original built-in functions of Perl. There is no "CORE" package, and therefore you do not need to
use or require an hypothetical "CORE" module prior to accessing routines in this namespace.
A list of the built-in functions in Perl can be found in perlfunc.
OVERRIDING CORE FUNCTIONS
To override a Perl built-in routine with your own version, you need to import it at compile-time. This can be conveniently achieved with
the "subs" pragma. This will affect only the package in which you've imported the said subroutine:
use subs 'chdir';
sub chdir { ... }
chdir $somewhere;
To override a built-in globally (that is, in all namespaces), you need to import your function into the "CORE::GLOBAL" pseudo-namespace at
compile time:
BEGIN {
*CORE::GLOBAL::hex = sub {
# ... your code here
};
}
The new routine will be called whenever a built-in function is called without a qualifying package:
print hex("0x50"),"
"; # prints 1
In both cases, if you want access to the original, unaltered routine, use the "CORE::" prefix:
print CORE::hex("0x50"),"
"; # prints 80
AUTHOR
This documentation provided by Tels <nospam-abuse@bloodgate.com> 2007.
SEE ALSO
perlsub, perlfunc.
perl v5.12.1 2010-04-26 CORE(3pm)
