On 07/13/2014 11:28 AM, Zeev Suraski wrote:
Again, option #1 as I see it (and is mostly described in the 2010 RFC
https://wiki.php.net/rfc/typecheckingstrictandweak) - it's identical in
terms of rules to those of PHP's casting, but with warnings emitted for lost
data and 'bogus' conversions. If we introduce this feature in a major
version, we could also consider change the casting code to emit these same
warnings so that we get full consistency - but that I think is in fact a
separate decision.
Zeev
I want to call out this point because I think it's key. Remember that
when an E_* is emitted, if it's not trapped then code execution
continues. That means we can, and should, think about what the
resulting value is independently of what if any E_* message is emitted.
That is:
function give_int(int $foo) { }
give_int('123abc');
The value of $foo should be 123 (int), because that's what casting rules
say. However, because that's lossy an E_* should get emitted to warn
the developer "hey, not what I meant!" If the error handler doesn't
terminate the process, though, then give_array() will continue to
execute and in that case the value that results from the cast MUST be
the same as if it were done explicitly.
We can discuss when the E_* should be emitted separately from what the
cast result is.
The one caveat to that is arrays, as someone else noted:
Current PHP:
function give_array(array $foo) { var_dump($foo); }
give_array('abc');
// Catchable fatal error.
Whereas if it follows the hint rules, apparently:
array(1) { [0]=> string(3) "abc" }
Which as a developer I wouldn't want, since that's likely to break my
code's assumptions. Array is weird in that we'd be changing from a type
specifier to a type caster. (ie, less like objects, more like
primitives.) As long as it's an error of some kind it may be OK, but
perhaps we want to leave array as is (strict behavior) rather than
changing it to the primitive logic (cast behavior)?
--Larry Garfield
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