1=head1 NAME 2 3CORE - Pseudo-namespace for Perl's core routines 4 5=head1 SYNOPSIS 6 7 BEGIN { 8 *CORE::GLOBAL::hex = sub { 1; }; 9 } 10 11 print hex("0x50"),"\n"; # prints 1 12 print CORE::hex("0x50"),"\n"; # prints 80 13 14=head1 DESCRIPTION 15 16The C<CORE> namespace gives access to the original built-in functions of 17Perl. There is no C<CORE> package, and therefore you do not need to use or 18require an hypothetical "CORE" module prior to accessing routines in this 19namespace. 20 21A list of the built-in functions in Perl can be found in L<perlfunc>. 22 23=head1 OVERRIDING CORE FUNCTIONS 24 25To override a Perl built-in routine with your own version, you need to 26import it at compile-time. This can be conveniently achieved with the 27C<subs> pragma. This will affect only the package in which you've imported 28the said subroutine: 29 30 use subs 'chdir'; 31 sub chdir { ... } 32 chdir $somewhere; 33 34To override a built-in globally (that is, in all namespaces), you need to 35import your function into the C<CORE::GLOBAL> pseudo-namespace at compile 36time: 37 38 BEGIN { 39 *CORE::GLOBAL::hex = sub { 40 # ... your code here 41 }; 42 } 43 44The new routine will be called whenever a built-in function is called 45without a qualifying package: 46 47 print hex("0x50"),"\n"; # prints 1 48 49In both cases, if you want access to the original, unaltered routine, use 50the C<CORE::> prefix: 51 52 print CORE::hex("0x50"),"\n"; # prints 80 53 54=head1 AUTHOR 55 56This documentation provided by Tels <nospam-abuse@bloodgate.com> 2007. 57 58=head1 SEE ALSO 59 60L<perlsub>, L<perlfunc>. 61 62=cut 63