What exactly does this do that isn't implemented with substr already? Have I misread the docs? Seems it handles positive and negative offsets. Also, wouldn't s

What exactly does this do that isn't implemented with substr already? Have I misread the docs? Seems it handles positive and negative offsets. Also, wouldn't startsWith and endsWith also be already implemented as strpos and strrpos? Don't get me wrong, none of those functions are particularly elegant, but at least they are the "PHP way".