NAME

autorequire - Generate module code on demand

SYNOPSIS

use autorequire sub {
  my ($this, $f) = @_ ;
  if ($f eq 'Useless.pm'){
    return "package Useless ;\n1 ;"
  }
  return undef ;
} ;

DESCRIPTION

autorequire allows you to automatically generate code for modules that are missing from your installation. It does so by placing a handler at the end of the @INC array and forwarding requests for missing modules to the subroutine provided.

The subroutine argument can be either a coderef or scalar value, in which case it will be used as a symbolic reference. Note: no error will be generated if the symbolic reference does not resolve. This allows a handler to "kick in" at later time when the subroutine in question is actually defined.

The subroutine must return the code for the module in the form of a filehandle, a scalar reference or a scalar value. A return value of undef will pass control to the next handler (either a previous autorequire handler or Perl's default require mechanism).

CONSTRUCTOR

new ( HANDLER )

Creates a new autorequire object that will call HANDLER when invoked. For it to be of any use you must place the object in the proper array (in this case the @INC array) using the insert method.

METHODS

$ar->insert( POS )

Convenience method that places the autorequire object at position POS in the @INC array.

$ar->insert(-1)   is equivalent to   push @INC, $ar 
$ar->insert(0)    is equivalent to   unshift @INC, $ar

Note that it is possible to insert the same autorequire object multiple times in the @INC array by calling $ar->insert() repeatedly.

$ar->delete ()

Convenience method that removes every occurence of $ar from the @INC array.

$ar->disable ()

Disables $ar, effectively causing it to be skipped over when the INC array is processed.

$ar->enabled ()

Enabled $ar, effectively causing it to be considered when the INC array is processed.

autorequire->is_loaded( FILENAME )

Convenience method that returns the absolute path of FILENAME if the module FILENAME is found in the %INC hash. Returns undef is the module is not loaded.

autorequire->is_loaded($filename)   is equivalent to   $INC{$filename}

autorequire->is_installed( FILENAME )

Convenience method that returns the absolute path of FILENAME if the module FILENAME is installed on the system. It does this by concatenating every entry in @INC with FILENAME and checking if the resulting path exists. Returns undef if the module is not installed.

SEE ALSO

"require" in perlfunc.

AUTHOR

Patrick LeBoutillier, <patl@cpan.org>

COPYRIGHT AND LICENSE

Copyright (C) 2005 by Patrick LeBoutillier

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.5 or, at your option, any later version of Perl 5 you may have available.