phpman > perldoc > Sub::Util

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 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 AT leonerd.uk>.

    The XS implementation of "set_subname" was copied from Sub::Name by Matthijs van Duin
    <xmath AT cpan.org>