/**
* @dataProvider provideData
*/
public function test_demonstrate_state_monad($expectedProducts)
{
$initialState = new InMemoryCache([]);
list($result1, $outputState1) = S\runState(searchRelated('asia'), $initialState);
$this->assertEquals($expectedProducts, $result1);
list($result2, $outputState2) = S\runState(searchRelated('asia'), $outputState1);
$this->assertEquals($expectedProducts, $result2);
// After second computation, state shouldn't be modified
// Because we have item already in cache
$this->assertSame($outputState1, $outputState2);
}
/**
* doo :: State IO m => [m a] -> m a
*
* Haskell like "do notation" simple implementation.
* Since "do" is reserved keyword in PHP then I use "doo".
*
* @param array|M\IO[] $monads
*
* @return M\IO
*/
function doo(array $monads)
{
return M\IO::of(function () use($monads) {
$result = null;
$data = [];
// TODO do it by foldWithKeys
foreach ($monads as $key => $monad) {
// TODO do it better - maybe?
if ($monad instanceof M\IO) {
$monad = ioState($monad);
}
$state = [$key, $data];
list($result, list(, $data)) = M\State\runState($monad, $state);
}
return $result;
});
}
