manpagez: man pages & more
man Sub::Util(3)
Home | html | info | man
Sub::Util(3)          User Contributed Perl Documentation         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 v5.26.1                      2018-02-20                      Sub::Util(3)

scalar-list-utils 1.500.0 - Generated Tue Feb 27 18:15:09 CST 2018
© 2000-2018
Individual documents may contain additional copyright information.