NAME
CORE - Pseudo-namespace for Perl's core routines
SYNOPSIS
BEGIN { *CORE::GLOBAL::hex = sub { 1; }; }
print hex("0x50"),"\n"; # prints 1 print CORE::hex("0x50"),"\n"; # 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"),"\n"; # prints 1
In both cases, if you want access to the original, unaltered routine, use
the CORE::
prefix:
print CORE::hex("0x50"),"\n"; # prints 80
AUTHOR
This documentation provided by Tels <nospam-abuse@bloodgate.com> 2007.
