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

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

NNAAMMEE #

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

SSYYNNOOPPSSIISS #

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

DDEESSCCRRIIPPTTIIOONN #

 "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.

FFUUNNCCTTIIOONNSS #

pprroottoottyyppee my $proto = prototype( $code )

 _S_i_n_c_e _v_e_r_s_i_o_n _1_._4_0_.

 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.

sseett__pprroottoottyyppee my $code = set_prototype $prototype, $code;

 _S_i_n_c_e _v_e_r_s_i_o_n _1_._4_0_.

 Sets the prototype of the function given by the $code reference, or
 deletes it if $prototype is "undef". Returns the $code reference itself.

 _C_a_u_t_i_o_n: 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 { ...... };

ssuubbnnaammee my $name = subname( $code )

 _S_i_n_c_e _v_e_r_s_i_o_n _1_._4_0_.

 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] }

 _U_s_e_r_s _o_f _S_u_b_:_:_N_a_m_e _b_e_w_a_r_e: This function is nnoott 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".

sseett__ssuubbnnaammee my $code = set_subname $name, $code;

 _S_i_n_c_e _v_e_r_s_i_o_n _1_._4_0_.

 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.

AAUUTTHHOORR #

 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 v5.36.3 2023-02-15 Sub::Util(3p)