NAME

namespace::alias - Lexical aliasing of namespaces

SYNOPSIS

  use namespace::alias 'My::Company::Namespace::Customer';

  # plain aliasing of a namespace
  my $cust = Customer->new;  # My::Company::Namespace::Customer->new

  # namespaces relative to the alias
  my $pref = Customer::Preferred->new;  # My::Company::Namespace::Customer::Preferred->new

  # getting the expansion of an alias
  my $customer_class = Customer;

  # also works for packages relative to the alias
  my $preferred_class = Customer::Preferred;

  # calling a function in an aliased namespace
  Customer::some_func()

DESCRIPTION

This module allows you to load packages and use them with a shorter name within a lexical scope.

This is how you load a module and install an alias for it:

  use namespace::alias 'Some::Class';

This will load Some::Class and install the alias Class for it. You may also specify the name of the alias explicitly:

  use namespace::alias 'Some::Class', 'MyAlias';

This will load Some::Class and install the alias MyAlias for it.

After installing the alias, every method or function call using it will be expanded to the full namespace. Addressing namespaces relative to the aliased namespace is also possible:

  MyAlias::Bar->new; # this expands to Some::Class::Bar->new

Aliases may also used as barewords. They will expand to a string with the full namespace: To load a module and install an alias for it, do

  my $foo = MyAlias;       # 'Some::Class'
  my $bar = MyAlias::Bar;  # 'Some::Class::Bar'

This also means that function calls to aliased namespaces need to be followed with parens. If they aren't, they're expanded to strings instead.

  MyAlias::some_func();
  MyAlias::Bar::some_func();

Also note that the created aliases are lexical and available at compile-time only. They may also shadow existing packages for the scope they are installed in:

  {
      package Foo::Bar;
      sub baz { 0xaffe }

      package Baz;
      sub baz { 42 }
  }

  Baz::baz(); # 42

  {
      use namespace::alias 'Foo::Bar', 'Baz';
      Baz::baz(); # 0xaffe
  }

  Baz::baz(); # 42

BUGS

Subroutine calls without parentheses around the argument list (e.g., Baz::baz rather than Baz::baz()), on names that work through aliases, generally don't work on Perls prior to 5.11.2. From Perl 5.11.2 onwards, aliases match the behaviour of ordinary package names much better.

SEE ALSO

aliased

AUTHOR

Florian Ragwitz <rafl@debian.org>

With contributions from:

Robert 'phaylon' Sedlacek <rs@474.at>

Steffen Schwigon <ss5@renormalist.net>

COPYRIGHT AND LICENSE

Copyright (c) 2009 Florian Ragwitz

Licensed under the same terms as perl itself.