Re: [RFC][DISCUSSION] Strong Typing Syntax

This proposal contains some interesting ideas, which I see as separate: 1. A syntax to declare the type of local variables. 2. A syntax to declare the type of object properties. 3. Preventing local variables, object properties and parameters to change their type after initialization/declaration. For me the point 3 is the most interesting one. I think the other points are already discussed elsewhere in some way, although they are clearly related to 3. Point 3 would be a BC break, if we would introduce it for parameters. Current behavior: https://3v4l.org/bjaLQ Local variables and object properties currently cannot be types, so point 3 would not be a BC break for them, if we introduce it together with 1 and 2. But then we would have an inconsistency between parameters and local vars / object properties. What we could do to avoid BC break is to introduce declare(fixed_parameter_types=1) in addition to declare(strict_types=1). For local variables and object properties, the type would always be fixed. But for parameters, it would only be fixed if the declare(fixed_parameter_types=1) is active. Maybe to make it less verbose, we could say declare(strict_types=2), which would mean the combination of both those things? Or some other type of shortcut. I think we will have to think about shortcuts like this if we introduce more "modes" in the future. > Currently the var keyword is used to formally declare a variable. Are you talking about local variables? In which PHP version? https://3v4l.org/o0PFg Afaik, currently var is only used for class/object properties from the time when people did not declare the visibility as public/protected/private. > If the type is omitted, scalar is assumed. If Fleshgrinder's scalar RFC is > accepted then it would make sense to allow programmers to explicitly > declare the variable as a scalar, but in any event when the type is omitted > scalar must be assumed for backwards compatibility. If no type is specified, then "mixed" should be assumed, not "scalar". Assuming "scalar" would be a BC break, and it would be confusing. On 3 January 2018 at 10:03, Michael Morris <tendoaki@gmail.com> wrote: > On Wed, Jan 3, 2018 at 3:50 AM, Niklas Keller <me@kelunik.com> wrote: > >> Hey Michael, >> >> I don't think the BC break is acceptable. You argue that scalar type >> declarations are relatively new, but in fact they're already years old now. >> They're used in most PHP 7+ packages. Even if changing types might be >> discouraged, it still happens a lot. >> > > Hmm. Well, that aspect of this can be dropped. What about the rest of it?