Re: Final variables

Hi David 2017-06-28 18:10 GMT+02:00 David Rodrigues <david.proweb@gmail.com>: > Hello internals, > > Java supports the "final" keyword before a variable to determines that this > variables never change it reference. If I declare a variable as "final", I > can only initialize that once, then I could not change it after (but I can > manipulate the instance, without issues). > > There some special reason to PHP doesn't supports things like that? It seems like what you are looking for here is actually a constant[1]. However constants do not support non scalar types, such as array or objects, what would really solve it on the objects side of things would be the introduction of a "readonly" keyword or similar, like that of C#[2] > final $number = 123; > $number = 456; // Error: you change change final variables. > > final $object = new stdClass; > $object->allowed = true; // No error. > > This feature make sense because it tells to dev that the variable value > could not be updated directly (new reference). Which make easy to identify > when a variable is modifiable or not. > > It is valid for a RFC? > > - It can uses the "final" keyword; > - It doesn't a BC; Anything is usually valid for an RFC, however I think (personally) that this should rather be an RFC for a readonly keyword if anything > I too think that a final variable can be useful to make some internal > improvements on language (but it could be a BC for PHP internals). I mean, > as the variable could not be modified, then it don't need be a "flexible" > type internally (I guess that it is a zval, right?). > > Reference: > https://github.com/kalessil/phpinspectionsea/issues/363 > > -- > David Rodrigues [1] http://php.net/constants [2] https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/readonly -- regards, Kalle Sommer Nielsen kalle@php.net