public function testChain()
{
$addTwo = function ($x) {
return Either::of($x + 2);
};
$id = function ($x) {
return $x;
};
$a = Either::of(5);
$b = new Left(4);
$this->assertEquals($a->chain($addTwo)->either($id, $id), 7, 'Chains a Right.');
$this->assertEquals($b->chain($addTwo)->either($id, $id), 4, 'Chains a Left.');
}
public function testAp()
{
$addTwo = Either::of(function ($x) {
return $x + 2;
});
$id = function ($x) {
return $x;
};
$a = Either::of(5);
$b = new Left(4);
$this->assertEquals($addTwo->ap($a)->either($id, $id), 7, 'Applies to a Right.');
$this->assertEquals($addTwo->ap($b)->either($id, $id), 4, 'Applies to a Left.');
}
public function testTryCatch()
{
$f = function ($bad) {
return function () use($bad) {
if ($bad) {
throw new \Exception();
}
return 'No exception';
};
};
$id = function ($x) {
return $x;
};
$this->assertEquals(Either::tryCatch($f(false))->either($id, $id), 'No exception', 'TryCatches a Right.');
$this->assertInstanceOf('Exception', Either::tryCatch($f(true))->either($id, $id), 'TryCatches a Left.');
}
/**
* Apply a wrapped paramater to this wrapped function.
* @param Either $that The parameter to apply.
* @return Either The wrapped result.
*/
public function ap(Either $that) : Either
{
return $this->chain(function ($f) use($that) {
return $that->map($f);
});
}
