63 lines
1.5 KiB
Text
63 lines
1.5 KiB
Text
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=head1 NAME
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CORE - Pseudo-namespace for Perl's core routines
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=head1 SYNOPSIS
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BEGIN {
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*CORE::GLOBAL::hex = sub { 1; };
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}
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print hex("0x50"),"\n"; # prints 1
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print CORE::hex("0x50"),"\n"; # prints 80
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=head1 DESCRIPTION
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The C<CORE> namespace gives access to the original built-in functions of
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Perl. There is no C<CORE> package, and therefore you do not need to use or
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require an hypothetical "CORE" module prior to accessing routines in this
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namespace.
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A list of the built-in functions in Perl can be found in L<perlfunc>.
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=head1 OVERRIDING CORE FUNCTIONS
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To override a Perl built-in routine with your own version, you need to
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import it at compile-time. This can be conveniently achieved with the
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C<subs> pragma. This will affect only the package in which you've imported
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the said subroutine:
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use subs 'chdir';
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sub chdir { ... }
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chdir $somewhere;
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To override a built-in globally (that is, in all namespaces), you need to
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import your function into the C<CORE::GLOBAL> pseudo-namespace at compile
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time:
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BEGIN {
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*CORE::GLOBAL::hex = sub {
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# ... your code here
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};
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}
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The new routine will be called whenever a built-in function is called
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without a qualifying package:
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print hex("0x50"),"\n"; # prints 1
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In both cases, if you want access to the original, unaltered routine, use
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the C<CORE::> prefix:
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print CORE::hex("0x50"),"\n"; # prints 80
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=head1 AUTHOR
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This documentation provided by Tels <nospam-abuse@bloodgate.com> 2007.
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=head1 SEE ALSO
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L<perlsub>, L<perlfunc>.
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=cut
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