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

       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 v5.40.0                                       2024-10-20                                     Sub::Util(3pm)

       "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.

prototype
           my $proto = prototype( $code )

       Sinceversion1.40.

       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;

       Sinceversion1.40.

       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 )

       Sinceversion1.40.

       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] }

       UsersofSub::Namebeware: 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;

       Sinceversion1.40.

       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.

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

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