transduce.t

transduce.t

use Test::Most;

use Yoda qw(append compose divide filter flip take transduce);

my $is_even  = sub { $_[0] % 2 == 0 };
my $dividend = 100;
my $divisors = [ -25, -20, -10, -5, -2, 0 ];

throws_ok(
    sub { Yoda::map(divide($dividend), $divisors) },
    qr/Illegal division by zero/,
    'dies when dividing 100 by 0',
);

my $transducer = compose(
    Yoda::map(divide($dividend)),
    filter($is_even),
    take(3),
);

# map(divide()) => [ -4 ] => [ -4, -5 ] => [ -4, -10 ] => [ -4, -10, -20 ]
# filter()      => [ -4 ] => [ -4 ]     => [ -4, -10 ] => [ -4, -10, -20 ]
# take(3)       => [ -4 ] => [ -4 ]     => [ -4, -10 ] => [ -4, -10, -20 ]

eq_or_diff(
    transduce($transducer, flip(append()), [], $divisors),
    [ -4, -10, -20 ],
    'transduced divisors left to right',
);

done_testing;