From 342e672574c4e67d510e46ab6acd0e21a7d0cf54 Mon Sep 17 00:00:00 2001 From: Karl Berry Date: Sun, 26 Apr 2015 22:16:26 +0000 Subject: (tl)perl 5.20.2 for windows, from siep git-svn-id: svn://tug.org/texlive/trunk@37064 c570f23f-e606-0410-a88d-b1316a301751 --- Master/tlpkg/tlperl/lib/CORE.pod | 96 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) create mode 100644 Master/tlpkg/tlperl/lib/CORE.pod (limited to 'Master/tlpkg/tlperl/lib/CORE.pod') diff --git a/Master/tlpkg/tlperl/lib/CORE.pod b/Master/tlpkg/tlperl/lib/CORE.pod new file mode 100644 index 00000000000..ce5feb5908a --- /dev/null +++ b/Master/tlpkg/tlperl/lib/CORE.pod @@ -0,0 +1,96 @@ +=head1 NAME + +CORE - 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 + CORE::say "yes"; # prints yes + + BEGIN { *shove = \&CORE::push; } + shove @array, 1,2,3; # pushes on to @array + +=head1 DESCRIPTION + +The C namespace gives access to the original built-in functions of +Perl. The C package is built into +Perl, and therefore you do not need to use or +require a hypothetical "CORE" module prior to accessing routines in this +namespace. + +A list of the built-in functions in Perl can be found in L. + +For all Perl keywords, a C prefix will force the built-in function +to be used, even if it has been overridden or would normally require the +L pragma. Despite appearances, this has nothing to do with the +CORE package, but is part of Perl's syntax. + +For many Perl functions, the CORE package contains real subroutines. This +feature is new in Perl 5.16. You can take references to these and make +aliases. However, some can only be called as barewords; i.e., you cannot +use ampersand syntax (C<&foo>) or call them through references. See the +C example above. These subroutines exist for all keywords except the following: + +C<__DATA__>, C<__END__>, C, C, C, C, C, +C, C, C, C, C, C, C, C, +C, C, C, C, C, C, C, C, C, +C, C, C, C, C, C, C, C, C, +C, C, C, C, C, C, C, C, C, +C, C, C, C, C, C, C, C, +C, C, C, C, C, C, C + +Calling with +ampersand syntax and through references does not work for the following +functions, as they have special syntax that cannot always be translated +into a simple list (e.g., C vs C): + +C, C, C, C, C, C, +C, C, C, C, C, C, C, +C, C, C, C, C, C, +C, C, C + +=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 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 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 prefix: + + print CORE::hex("0x50"),"\n"; # prints 80 + +=head1 AUTHOR + +This documentation provided by Tels 2007. + +=head1 SEE ALSO + +L, L. + +=cut -- cgit v1.2.3