NAME
Sub::Util - A selection of utility subroutines for subs and CODE references
SYNOPSIS
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>