Re: Implicit isset/isempty check on short-ternary operator

On 17/04/11 9:14 AM, Ángel González wrote:

Ben Schmidt wrote:

$var = $arr['key'] ?? : 'empty';

Also note this is possible with the recent proposal Hannes and I were discussing. It simply looks like $var = $arr?['key'] ?: 'empty'; The ?[ avoids notices and the ?: works as it always has. Ben.

If it was going to be ?[, I'd much prefer $arr['key'?]. It was proposed as $arr[?'key'] instead to avoid a backtracking (would that really be noticeable? I'd prefer readibility), but ?[ would have the same problem.

The backtracking issue was part of a different proposal where a ternary operator had an optional 'else' part. It is not an issue with notice-free array lookups as more recently proposed, and I see no reason we couldn't use ?[ or [? or ?] as the syntax. In all cases, either that combination of characters can be scanned as a single token, or the parsing can be done with just one token of lookahead and no backtracking. I don't know what kind of parser PHP uses, though, so I'm just guessing; but AFAICT any standard kind of parser shouldn't have much trouble here. The one argument I can find for favouring ?[ or [? is that this generalises more naturally. Perhaps [? is the best. It generalises nicely if required: $array[?'key'] $?variable $object->?property I personally only think we need the first one, but there are a few votes for the second, too. I personally also don't care very much about the syntax; I'd be equally happy with $array['key'?] or $array?['key']. I'm just keen to have the functionality (and separately, the !==null operator(s)). Ben.