I'm not sure how an appeal to PHP as lowest-common-denominator of language sanity argues against understanding the return values of functions you call.
> understanding the return values of functions you call
Sure you should. But confusion between keys and values isn't useful, so there's no reason for a subexpression to be able to do that, and in PHP it can't.
I'm not sure how an appeal to PHP as lowest-common-denominator of language sanity argues against understanding the return values of functions you call.