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