NAME

Data::Monad::Base::MonadZero - The base class of monads which have the zero.

SYNOPSIS

  package YourMonadClass;
  use base qw/Data::Monad::Base::MonadZero/;

  sub unit {
      my ($class, @v) = @_;
      ...
  }

  sub flat_map {
      my ($self, $f) = @_;
      ...
  }

  sub zero {
      my $class = shift;
      ...
  }

DESCRIPTION

Data::Monad::Base::MonadZero has the zero element which will not be changed by any monadic operations.

You must implement zero() according to some of monadplus laws.

METHODS

$m = YourMonad->zero;

Represents the zero value.

$m2 = $m1->filter(sub { ... });

Filters values by predicates. If the predicate returns false, filter will use the zero value.

AUTHOR

hiratara <hiratara {at} cpan.org>

SEE ALSO

Data::Monad::Base::Monad

LICENSE

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