NAME

       Return::MultiLevel - return across multiple call levels

SYNOPSIS

         use Return::MultiLevel qw(with_return);

         sub inner {
           my ($f) = @_;
           $f->(42);  # implicitly return from 'with_return' below
           print "You don't see this\n";
         }

         sub outer {
           my ($f) = @_;
           inner($f);
           print "You don't see this either\n";
         }

         my $result = with_return {
           my ($return) = @_;
           outer($return);
           die "Not reached";
         };
         print $result, "\n";  # 42

DESCRIPTION

       This module provides a way to return immediately from a deeply nested call stack. This is
       similar to exceptions, but exceptions don't stop automatically at a target frame (and they
       can be caught by intermediate stack frames). In other words, this is more like
       setjmp(3)/longjmp(3) than "die".

       Another way to think about it is that the "multi-level return" coderef represents a
       single-use/upward-only continuation.

   Functions
       The following functions are available (and can be imported on demand).

       with_return BLOCK
           Executes BLOCK, passing it a code reference (called $return in this description) as a
           single argument. Returns whatever BLOCK returns.

           If $return is called, it causes an immediate return from "with_return". Any arguments
           passed to $return become "with_return"'s return value (if "with_return" is in scalar
           context, it will return the last argument passed to $return).

           It is an error to invoke $return after its surrounding BLOCK has finished executing.
           In particular, it is an error to call $return twice.

   Implementation notes
       This module uses "unwind" from "Scope::Upper" to do its work.

       If "Scope::Upper" is not available, it substitutes its own pure Perl implementation, which
       is based on a combination of "eval" and "goto".

AUTHOR

       Lukas Mai, "<l.mai at web.de>"

COPYRIGHT & LICENSE

       Copyright 2013 Lukas Mai.

       This program is free software; you can redistribute it and/or modify it under the terms of
       either: the GNU General Public License as published by the Free Software Foundation; or
       the Artistic License.

       See http://dev.perl.org/licenses/ for more information.