/**
* Test the Functions::combine method.
*/
public function testCombine()
{
$a = function ($value) {
return $value + 2;
};
$b = function ($value) {
return $value * 3;
};
$result = Functions::combine($a, $b);
$this->assertTrue(is_callable($result), 'Combined function should be callable.');
$this->assertEquals($result(3), 15);
}
/**
* Flatten the underlying stream.
*
* This method takes each element and unpacks it into a sequence of elements.
* All individual sequences are concatenated in the resulting stream.
*
* @param callable $unpacker [optional] An unpacker function that can unpack
* elements into something iterable. Default is to use the identity function.
* @return Stream
*/
public function flatMap(callable $unpacker = null)
{
if ($unpacker == null) {
$unpacker = Functions::identity();
}
return new FlatMapOperation($this, $unpacker);
}