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Sub::Util(3)	       Perl Programmers	Reference Guide		  Sub::Util(3)

       Sub::Util - A selection of utility subroutines for subs and CODE

	   use Sub::Util qw( prototype set_prototype subname set_subname );

       "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.

	   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

	   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

       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 { ...... };

	   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 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".

	   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.

       The general structure of	this module was	written	by Paul	Evans

       The XS implementation of	"set_subname" was copied from Sub::Name	by
       Matthijs	van Duin <>

perl v5.28.3			  2020-05-14			  Sub::Util(3)


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