Morning, > Given that public is implied for all properties above there > is a value in having the same rule for type.
public $bar, int $foo; What does this mean? If it's not an error, what does this mean ? public $bar, int $foo, $qux; If it's an error, why is it an error ? Both of these examples are just as ambiguous as public int $foo, $bar, $qux; Access modifiers are assumed to apply to all declarations in a group, because that's what grouping is actually for. We don't need to make grouping about types, we need to make type declarations unambiguous. > Anyway, in Hack following syntax passes: https://3v4l.org/3tUu9 Hack does not consider types implicitly nullable. <?hh class Foo { public int $int = null; public stdClass $std = null; } things.php:3:10,12: Wrong type hint (Typing[4110]) things.php:3:10,12: This is an int things.php:3:21,24: It is incompatible with a nullable type things.php:4:10,17: Wrong type hint (Typing[4110]) things.php:4:10,17: This is an object of type stdClass things.php:4:26,29: It is incompatible with a nullable type <?hh function foo(int $int = null, stdClass $std = null) {} things.php:2:18,21: Wrong type hint (Typing[4110]) things.php:2:14,16: This is an int things.php:2:25,28: It is incompatible with a nullable type things.php:2:40,43: Wrong type hint (Typing[4110]) things.php:2:31,38: This is an object of type stdClass things.php:2:47,50: It is incompatible with a nullable type HHVM doesn't care about types ... we don't compare our type system to that ... Cheers Joe On Wed, Mar 30, 2016 at 11:10 PM, Björn Larsson <bjorn.x.lars...@telia.com> wrote: > Den 2016-03-30 kl. 05:16, skrev Joe Watkins: > >> Morning Dmitry, >> >> 1) static typed properties are prohibited. why? >>> >> Feels like that's a separate feature, static properties are as good as >> makes no difference, global variables. >> >> Instance properties, the engine has good control over their manipulation, >> for static properties it doesn't, it's not impossible, but feels separate. >> > Good that it's clarified in the RFC since one could easily > believe that it's possible to set type for a static property. > >> >> 2) The handling of multiple properties in the same declaration statement >>> >> is inconsistent. >> >> This feels consistent to me .. in other languages where the type is >> required, it makes sense to assume the type is implied. >> >> In a language where the type is optional, public int $foo, $bar; feels >> ambiguous to me. >> > Given that public is implied for all properties above there > is a value in having the same rule for type. > >> >> 3) We already have nullable arguments without any special syntax. We >>> >> should reuse the similar approach for properties. >> >> Making properties implicitly nullable defeats the object of trying to >> provide type safety. >> >> Null is never a valid value for a typed property, if it were, you would >> never be sure of the type of variable you are getting, and would have to >> litter your code with is_null checks. >> > Maybe good to clarify difference towards default parameters? > Anyway, in Hack following syntax passes: https://3v4l.org/3tUu9 > >> >> I think it might be better to implicitly initialize them according to >>> >> type (if default value is not provided): bool by false, int by 0, double >> by >> 0.0, string by "" (interned), array by [] (immutable), objects by NULL >> (always nullable). >> >> Definitely not, lying about the default value isn't a good idea. >> >> There are times when 0 is as valid as 1, or any other value for an int. >> >> If you have declared that you know the type of the property, and you write >> code that accesses that property before there is any possible chance you >> have set the property, that's a programming error. >> >> We should not hide that error with a default value, or by allowing the >> engine to return null. >> > Don't have a strong opinion on this one, can see both views. > Maybe a bit affected by programming in Java recently, having > a slightly more positive attitude towards default values ;-) > > Regards //Björn Larsson > >
