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 theCORE::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 isundef. Returns the$code reference itself.

Caution: This function takes arguments in a different order to the previous copy of the code fromScalar::Util. This is to match the order ofset_subname, and other potential additions in this file. This order has been chosen as it allows a neat and simple chaining of otherSub::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. usingdelete_package fromSymbol),__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 bysub_fullname fromSub::Identify. The remaining functions thatSub::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 isnot the same asSub::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; theset_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 ofcaller, 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 fromSub::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 fromSub::Name by Matthijs van Duin <xmath@cpan.org>