/**
* Get a function that expects two other functions and returns the composition
* the two.
*
* @return IValue
*/
public static function composition()
{
return V::composition();
}
/**
* Tests fourth applicative law: u <*> (v <*> w) = pure (.) <*> u <*> v <*> w
* @dataProvider formlets_and_values
*/
public function testApplicativeComposition($formlet, $fn1, $fn2, $value, $contains_applicable)
{
if (!$contains_applicable) {
$left = F::pure($fn1)->cmb(F::pure($fn2)->cmb($formlet));
$right = F::pure(V::composition())->cmb(F::pure($fn1))->cmb(F::pure($fn2))->cmb($formlet);
$this->assertFormletsEqual($left, $right, $value, false);
} else {
$left = F::pure($fn1)->cmb($formlet->cmb(F::pure($value)));
$right = F::pure(V::composition())->cmb(F::pure($fn1))->cmb($formlet)->cmb(F::pure($value));
$this->assertFormletsEqual($left, $right, $value, false);
}
}