On 03/06/2016 11:16, Thomas Bley wrote:
why not try all types weakly from left to right in weak mode?
Rule: if type check would give a fatal error for a type, try next type.
This is what I suggested, but Bob is insistent that weak mode should
always select the same type as strict mode where there is a valid strict
match, which I guess makes sense.
A strict left-to-right check violates that:
function i(string | int $x) { echo gettype($x); }
i(10); // string in weak mode, int in strict mode
function j(int | string $x) { echo gettype($x); }
j('10'); // int in weak mode, string in strict mode
The main complication that I haven't quite got my head round yet is the
fact that an int->float coercion is allowed in strict mode. So to be
consistent, weak mode needs to privilege that cast:
function k(string | float $x) { echo gettype($x); }
k(10); // float
But in other cases it doesn't seem sensible to privilege float over string:
function l(string | float $x) { echo gettype($x); }
l("1.5a"); // I would expect string, but float would succeed if attempted
Regards,
--
Rowan Collins
[IMSoP]
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