NAME

Sub::Exporter::Lexical - to export lexically-available subs with Sub::Exporter

VERSION

version 0.092292

SYNOPSIS

Achtung! I don't know why I wrote this. I don't use it and never have. Originally, it was not lexical, but dynamic, despite the name. What was I thinking? Clearly this was a bad brain day. I have rewritten the code now to use Lexical::Sub, which should make the behavior actually lexical, but I have not expanded the test suite. To continue...

In an exporting library:

  package Some::Toolkit;

  use Sub::Exporter -setup => {
    exports   => [ qw(foo bar baz) ],
  };

  sub foo { ... }
  sub bar { ... }
  sub baz { ... }

In an importing library:

  package Vehicle::Autobot;

  use Sub::Exporter::Lexical lexical_installer => { -as => 'lex' };

  ...;

  {
    use Some:::Toolkit { installer => lex }, qw(foo bar);

    foo(1,2,3);
    my $x = bar;

    ...
  };

  # ... and here, foo and bar are no longer available ...

DESCRIPTION

Sub::Exporter::Lexical provides an alternate installer for Sub::Exporter. Installers are documented in Sub::Exporter's documentation; all you need to know is that by using Sub::Exporter::Lexical's installer, you can import routines into a lexical scope that will be cleaned up when that scope ends.

There are two places it makes sense to use the lexical installer: when configuring Sub::Exporter in your exporting package or when importing from a package that uses Sub::Exporter. For the first case, do something like this:

  package Some::Toolkit;
  use Sub::Exporter::Lexical ();
  use Sub::Exporter -setup => {
    exports   => [ ... ],
    installer => Sub::Exporter::Lexical::lexical_installer,
  };

For the second:

  package My::Library;

  use Sub::Exporter::Lexical ();
  use Some::Toolkit
    { installer => Sub::Exporter::Lexical::lexical_installer },
    qw(foo bar baz);

EXPORTS

Sub::Exporter::Lexical offers only one routine for export, and it may also be called by its full package name:

lexical_installer

This routine returns an installer suitable for use as the installer argument to Sub::Exporter. It installs all requested routines as usual, but marks them to be removed from the target package as soon as the block in which it was called is complete.

It does not affect the behavior of routines exported into scalar references.

More importantly, it does not affect scopes in which it is invoked at runtime, rather than compile time. This is important! It means that this works:

  {
    use Some::Toolkit { installer => lexical_installer }, qw(foo);
    foo(1,2,3);
  }

  foo(); # this dies

...but this does not...

  {
    require Some::Toolkit;
    Some::Toolkit->import({ installer => lexical_installer }, qw(foo));
    foo(1,2,3);
  }

  foo(); # this does not die, even though you might expect it to

Finally, you can't supply a -as => \$var install destination yet.

AUTHOR

Ricardo Signes <rjbs@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2013 by Ricardo Signes.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

cpanm Sub::Exporter::Lexical

perl -MCPAN -e shell
install Sub::Exporter::Lexical