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[p5sagit/Devel-BeginLift.git] / README

NAME
    Devel::BeginLift - make selected sub calls evaluate at compile time

SYNOPSIS
      use Devel::BeginLift qw(foo baz);
      
  use vars qw($i);
      
  BEGIN { $i = 0 }
      
  sub foo { "foo: $_[0]\n"; }
      
  sub bar { "bar: $_[0]\n"; }
      
  for (1 .. 3) {
        print foo($i++);
        print bar($i++);
      }
      
  no Devel::BeginLift;
      
  print foo($i++);

    outputs -

    foo: 0 bar: 1 foo: 0 bar: 2 foo: 0 bar: 3 foo: 4

DESCRIPTION
    Devel::BeginLift 'lifts' arbitrary sub calls to running at compile time
    - sort of a souped up version of "use constant". It does this via some
    slightly insane perlguts magic.

  import
      use Devel::BeginLift qw(list of subs);

    Calls Devel::BeginLift->setup_for(__PACKAGE__ => \@list_of_subs);

  unimport
      no Devel::BeginLift;

    Calls Devel::BeginLift->teardown_for(__PACKAGE__);

  setup_for
      Devel::BeginLift->setup_for($package => \@subnames);

    Installs begin lifting magic (unless already installed) and registers
    "${package}::$name" for each member of @subnames to be executed when
    parsed and replaced with its output rather than left for runtime.

  teardown_for
      Devel::BeginLift->teardown_for($package);

    Deregisters all subs currently registered for $package and uninstalls
    begin lifting magic is number of teardown_for calls matches number of
    setup_for calls.

  setup_for_cv
      $id = Devel::BeginLift->setup_for_cv(\&code);

    Same as "setup_for", but only registers begin lifting magic for one code
    reference. Returns an id to be used in "teardown_for_cv".

  teardown_for_cv
      Devel::BeginLift->teardown_for_cv($id);

    Deregisters begin lifting magic referred to by $id.

AUTHOR
    Matt S Trout - <mst@shadowcatsystems.co.uk>

    Company: http://www.shadowcatsystems.co.uk/ Blog:
    http://chainsawblues.vox.com/

LICENSE
    This library is free software under the same terms as perl itself