NAME

SYNOPSIS

  use Symbol::Util ':all';

  my $caller = caller;
  *{ fetch_glob("${caller}::foo") } = sub { "this is foo" };
  my $coderef = fetch_glob("${caller}::bar", "CODE");
  sub baz { 42; }
  export_glob($caller, "baz");

  print join "\n", keys %{ stash("main") };

  delete_glob("${caller}::foo", "CODE");

  use constant PI => 3.14159265;
  delete_sub "PI";   # remove constant from public API

  require YAML;
  export_package(__PACKAGE__, "YAML", "Dump");   # import YAML::Dump
  unexport_package(__PACKAGE, "YAML");   # remove imported symbols

  no Symbol::Util;   # clean all symbols imported from Symbol::Util

DESCRIPTION

All Perl symbols from the same package are organized as a stash. Each symbol (glob) contains one or more of following slots: "SCALAR", "ARRAY", "HASH", "CODE", "IO", "FORMAT". These slots are also accessible as standard variables or bare words.

The Perl symbols table is directly accessible with typeglob prefix but it can be difficult to read and problematic if strict mode is used. Also the access to stash, glob and one of its slot have different syntax notation.

"stash" and "fetch_glob" functions gets stash or glob without need to use "no strict 'refs'".

"delete_glob" function allows to delete specific slot of symbol name without deleting others.

"delete_sub" removes the symbol from class API. This symbol won't be available as an object method.

"export_glob" function exports a glob to the target package.

"export_package" works like Exporter module and allows to export symbols from one package to other.

"unexport_package" allows to delete previously exported symbols.

USAGE

use Symbol::Util ':all';

Imports all available symbols.

no Symbol::Util;

Deletes all imported symbols from caller name space.

FUNCTIONS

stash( name : Str ) : HashRef

Returns a reference to the stash for the specified name. If the stash does not already exist then it will be created. The name of the stash does not include the "::" at the end. It is safe to use this function with "use strict 'refs'".

  print join "\n", keys %{ stash("main") };
    

fetch_glob( name : Str ) : GlobRef

fetch_glob( name : Str, slot : Str ) : Ref

Returns a reference to the glob for the specified symbol name. If the symbol does not already exist then it will be created. If the symbol name is unqualified then it will be looked up in the calling package. It is safe to use this function with "use strict 'refs'".

If the slot argument is defined and this slot contains defined value, reference to this value is returned. The slot argument can be one of the following strings: "SCALAR", "ARRAY", "HASH", "CODE", "IO", "FORMAT").

  my $caller = caller;
  *{ fetch_glob("${caller}::foo") } = sub { "this is foo" };
  my $coderef = fetch_glob("${caller}::foo", "CODE");
    

list_glob_slots( name ) : Maybe[Array]

Returns a list of slot names for glob with specified name which contain defined value. If the glob is undefined, the "undef" value is returned. If the glob is defined and has no defined slots, the empty list is returned.

The "SCALAR" slot is used only if it contains defined value.

  my $foo = 42;
  my @foo = (1, 2);
  sub foo { 1; };
  print join ",", list_glob_slots("foo");   # SCALAR,ARRAY,CODE
    

export_glob( target, name : Str ) : GlobRef

export_glob( target, name : Str, slots : Array ) : Ref

Exports a glob name to the target package. Optionally exports only specified slots of the glob.

  sub my_function { ... };
  sub import {
      my $caller = caller;
      export_glob($caller, "my_function");
  }
    

delete_glob( name : Str, slots : Array[Str] ) : Maybe[GlobRef]

Deletes the specified symbol name if slots are not specified, or deletes the specified slots in the symbol name (could be one or more of the following strings: "SCALAR", "ARRAY", "HASH", "CODE", "IO", "FORMAT").

Function returns the glob reference if there are any slots defined.

  our $FOO = 1;
  sub FOO { "bar" };

  delete_glob("FOO", "CODE");

  print $FOO;  # prints "1"
  FOO();       # error: sub not found
    

delete_sub( name : Str ) : Maybe[GlobRef]

Deletes (or hides) the specified subroutine name from class API. It means that this subroutine will be no longer available as a class method. The purpose of this function is the same as namespace::clean pragma has: it cleans a package's namespace from unwanted subroutines. Function doesn't delete other slots than "CODE" slot of the glob.

Function returns the glob reference if there are any other slots still defined than <CODE> slot.

  package My::Class;

  use constant PI => 3.14159265;

  use Symbol::Util 'delete_sub';
  delete_sub "PI";   # remove constant from public API
  no Symbol::Util;   # remove also Symbol::Util::* from public API

  sub area {
      my ($self, $r) = @_;
      return PI * $r ** 2;
  }

  print My::Class->area(2);   # prints 12.5663706
  print My::Class->PI;        # Can't locate object method
    

export_package( target : Str, package : Str, names : Array[Str] ) : Bool

export_package( target : Str, package : Str, spec : HashRef, names : Array[Str] ) : Bool

Exports symbols from package to target. If spec is defined as hash reference, it contains the specification for exporter. Otherwise the standard global variables of package are used (@EXPORT, @EXPORT_OK and %EXPORT_TAGS) to build the specification for exporter. The optional list of names defines an import list.

The spec is a reference to hash with following keys:

  package My::Package;
  sub myfunc { };
  sub import {
      my ($package, @names) = @_;
      my $caller = caller();
      return export_package($caller, $package, {
          OK => [ qw( myfunc ) ],
      }, @names);
  };

unexport_package( target : Str, package : Str ) : Bool

Deletes symbols previously exported from package to target with "export_package" function. If the symbol was "CODE" reference it is deleted with "delete_sub" function. Otherwise it is deleted with "delete_glob" function with proper slot as an argument.

Deleting with "delete_sub" function means that this symbol is not available via class API as an object method.

  require YAML;
  export_package(__PACKAGE__, "YAML", "Dump");
  unexport_package(__PACKAGE__, "YAML");
  print Dump @INC;     # OK
  __PACKAGE__->Dump;   # Can't locate object method
    

This function can be used as a helper in "unimport" method.

  package My::Package;
  sub unimport {
      my ($package, @names) = @_;
      my $caller = caller();
      return unexport_package($caller, $package);
  };

  package main;
  use My::Package qw(something);
  no My::Package;
  main->something;   # Can't locate object method
    

The function returns true value if there were no errors.

SEE ALSO

BUGS

"delete_glob" and "delete_sub" delete "SCALAR" slot if it exists and contains "undef" value.

"delete_glob" and "delete_sub" always delete "FORMAT" slot.

If you find the bug or want to implement new features, please report it at <http://rt.cpan.org/NoAuth/Bugs.html?Dist=Symbol-Util>

AUTHOR

LICENSE

This is free software; you can redistribute it and/or modify it under the same terms as perl itself.

See <http://dev.perl.org/licenses/artistic.html>