Subroutine My::Tool::method redefined at /usr/local/share/perl/5.10.0/MooseX/Method/Signatures.pm line 38.
Argument cannot be 'type' at /usr/local/share/perl/5.10.0/MooseX/Types/TypeDecorator.pm line 81
	MooseX::Types::TypeDecorator::new('MooseX::Types::TypeDecorator=HASH(0xa3f6fe8)', 'type', 'mass', 'from', 'kg', 'to', 'g') called at /home/surikov/lib/My/Tool.pm line 12
	My::Tool::__ANON__('My::Tool=HASH(0x93cf9e0)', 'HASH(0x93cf760)') called at t.pl line 56

##</code><code>##

package My::Types;

use strict;
use warnings;

use MooseX::Types -declare => [qw(Measure MeasureType MeasureUnit some other types)];
use MooseX::Types::Moose qw(Num Int Str);
use MooseX::Types::Structured qw(Dict);

use List::MoreUtils qw(any);

my @measure_types = qw(some data here);
my @measure_units = qw(and here);

subtype MeasureType,
    as Str,
    where   { my $measure_type = $_; any { $measure_type eq lc } @measure_types },
    message { 'Unknown measure type' };
subtype MeasureUnit,
    as Str,
    where   { my $measure_unit = $_; any { $measure_unit eq lc } @measure_units },
    message { 'Unknown measure unit' };
subtype Measure,
    as Dict[
        type   => MeasureType,
        from   => MeasureUnit,
        to     => MeasureUnit,
        amount => Num,
    ],
    message { 'Invalid Measure struct' };

# more subtypes goes here

##</code><code>##

class My::Tool {
# ...
    multi method convert(Measure $measure) {
        my $converter = My::Tool->new(
            type => $measure->{type},
            from => $measure->{from},
            to   => $measure->{to},
        );
        $converter->calculate($measure->{amount})
    }
# more 'convert' methods omitted
}