Sub::Util(3) User Contributed Perl Documentation Sub::Util(3)
NAME
Sub::Util - A selection of utility subroutines for subs and CODE
references
SYNOPSIS
use Sub::Util qw( prototype set_prototype subname set_subname );
DESCRIPTION
"Sub::Util" contains a selection of utility subroutines that are useful
for operating on subs and CODE references.
The rationale for inclusion in this module is that the function
performs some work for which an XS implementation is essential because
it cannot be implemented in Pure Perl, and which is sufficiently-widely
used across CPAN that its popularity warrants inclusion in a core
module, which this is.
FUNCTIONS
prototype
my $proto = prototype( $code )
Since version 1.40.
Returns the prototype of the given $code reference, if it has one, as a
string. This is the same as the "CORE::prototype" operator; it is
included here simply for symmetry and completeness with the other
functions.
set_prototype
my $code = set_prototype $prototype, $code;
Since version 1.40.
Sets the prototype of the function given by the $code reference, or
deletes it if $prototype is "undef". Returns the $code reference
itself.
Caution: This function takes arguments in a different order to the
previous copy of the code from "Scalar::Util". This is to match the
order of "set_subname", and other potential additions in this file.
This order has been chosen as it allows a neat and simple chaining of
other "Sub::Util::set_*" functions as might become available, such as:
my $code =
set_subname name_here =>
set_prototype '&@' =>
set_attribute ':lvalue' =>
sub { ...... };
subname
my $name = subname( $code )
Since version 1.40.
Returns the name of the given $code reference, if it has one. Normal
named subs will give a fully-qualified name consisting of the package
and the localname separated by "::". Anonymous code references will
give "__ANON__" as the localname. If the package the code was compiled
in has been deleted (e.g. using "delete_package" from Symbol),
"__ANON__" will be returned as the package name. If a name has been set
using "set_subname", this name will be returned instead.
This function was inspired by "sub_fullname" from Sub::Identify. The
remaining functions that "Sub::Identify" implements can easily be
emulated using regexp operations, such as
sub get_code_info { return (subname $_[0]) =~ m/^(.+)::(.*?)$/ }
sub sub_name { return (get_code_info $_[0])[0] }
sub stash_name { return (get_code_info $_[0])[1] }
Users of Sub::Name beware: This function is not the same as
"Sub::Name::subname"; it returns the existing name of the sub rather
than changing it. To set or change a name, see instead "set_subname".
set_subname
my $code = set_subname $name, $code;
Since version 1.40.
Sets the name of the function given by the $code reference. Returns the
$code reference itself. If the $name is unqualified, the package of the
caller is used to qualify it.
This is useful for applying names to anonymous CODE references so that
stack traces and similar situations, to give a useful name rather than
having the default of "__ANON__". Note that this name is only used for
this situation; the "set_subname" will not install it into the symbol
table; you will have to do that yourself if required.
However, since the name is not used by perl except as the return value
of "caller", for stack traces or similar, there is no actual
requirement that the name be syntactically valid as a perl function
name. This could be used to attach extra information that could be
useful in debugging stack traces.
This function was copied from "Sub::Name::subname" and renamed to the
naming convention of this module.
AUTHOR
The general structure of this module was written by Paul Evans
<leonerd@leonerd.org.uk>.
The XS implementation of "set_subname" was copied from Sub::Name by
Matthijs van Duin <xmath@cpan.org>
perl v5.34.3 2024-09-20 Sub::Util(3)
scalar-list-utils 1.660.0 - Generated Thu Oct 3 09:01:05 CDT 2024