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Diffstat (limited to 'Master/tlpkg/tlperl0/lib/CORE.pod')
-rwxr-xr-x | Master/tlpkg/tlperl0/lib/CORE.pod | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/Master/tlpkg/tlperl0/lib/CORE.pod b/Master/tlpkg/tlperl0/lib/CORE.pod new file mode 100755 index 00000000000..c917bba44a0 --- /dev/null +++ b/Master/tlpkg/tlperl0/lib/CORE.pod @@ -0,0 +1,62 @@ +=head1 NAME + +CORE - Pseudo-namespace for Perl's core routines + +=head1 SYNOPSIS + + BEGIN { + *CORE::GLOBAL::hex = sub { 1; }; + } + + print hex("0x50"),"\n"; # prints 1 + print CORE::hex("0x50"),"\n"; # prints 80 + +=head1 DESCRIPTION + +The C<CORE> namespace gives access to the original built-in functions of +Perl. There is no C<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 L<perlfunc>. + +=head1 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 +C<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 C<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 C<CORE::> prefix: + + print CORE::hex("0x50"),"\n"; # prints 80 + +=head1 AUTHOR + +This documentation provided by Tels <nospam-abuse@bloodgate.com> 2007. + +=head1 SEE ALSO + +L<perlsub>, L<perlfunc>. + +=cut |