NAME

    Long::Jump - Mechanism for returning to a specific point from a deeply
    nested stack.

DESCRIPTION

    This module essentially provides a multi-level return. You can mark a
    spot with setjump() and then unwind the stack back to that point from
    any nested stack frame by name using longjump(). You can also provide a
    list of return values.

    This is not quite a match for C's long jump, but it is "close enough".
    It is safer than C's jump in that it only lets you escape frames by
    going up the stack, you cannot jump in other ways.

SYNOPSIS

        use Long::Jump qw/setjump longjump/;
    
        my $out = setjump foo => sub {
            bar();
            ...; # Will never get here
        };
        is($out, [qw/x y z/], "Got results of the long jump");
    
        $out = setjump foo => sub {
            print "Not calling longjump";
        };
        is($out, undef, "longjump was not called so we got an undef response");
    
        sub bar {
            baz();
            return 'bar'; # Will never get here
        }
    
        sub baz {
            bat();
            return 'baz'; # Will never get here
        }
    
        sub bat {
            my @out = qw/x y z/;
            longjump foo => @out;
    
            return 'bat'; # Will never get here
        }

EXPORTS

    $out = setjump($NAME, sub { ... })

    $out = setjump $NAME, sub { ... }

    $out = setjump($NAME => sub { ... })

    $out = setjump $NAME => sub { ... }

      Set a named point to which you will return when calling longjump().
      $out will be undef if longjump() was not called. $out will be an
      arrayref if longjump() was called. The $out arrayref will be empty,
      but present if longjump() is called without any return values.

      The return value will always be false if longjump was not called, and
      will always be true if it was called.

      You cannot nest multiple jump points with the same name, but you can
      nest multiple jump points if they have unqiue names. longjump() will
      always jump to the correct name.

    longjump($NAME)

    longjump $NAME

    longjump($NAME, @RETURN_LIST)

    longjump($NAME => @RETURN_LIST)

    longjump $NAME => @RETURN_LIST

      Jump to the named point, optionally with values to return. This will
      throw exceptions if you use an invalid $NAME, which includes the case
      of calling it without a set jump point.

    $bool = havejump($NAME)

    $bool = havejump $NAME

      Check if a jump point with the given $NAME is currently set somewhere
      on the call stack. Returns a true value (1) if the named jump point
      is active and would be reachable via longjump($NAME), otherwise
      returns false (0).

      This is useful for code that wants to conditionally call longjump()
      only when an enclosing setjump() is actually present, avoiding the
      exception that would be thrown for an unknown name.

SOURCE

    The source code repository for Long-Jump can be found at
    https://github.com/exodist/Long-Jump/.

MAINTAINERS

    Chad Granum <exodist@cpan.org>

AUTHORS

    Chad Granum <exodist@cpan.org>

COPYRIGHT

    Copyright 2018 Chad Granum <exodist7@gmail.com>.

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

    See http://dev.perl.org/licenses/

