Re: Final variables

​ Walter Parker <walterp@gmail.com> ​ wrote:​ > ​ Constant may not have been the right word (or idea), but I agree with Kalle. We should use readonly as the keyword here and not final as the keyword. We can keep the same scoping rules so the following would work: >​ ​> function randomNumber() { ​>​ *readonly *$number = mt_rand(); ​ ​I agree that "readonly" is a better keyword, but we have to points here: 1. "final" is used on some language (Java, C++ I guess); 2. "final" keyword does exists on PHP with a "similar" behaviour; If we can implements "readonly" is good too, because turn it more implicit. 2017-06-28 15:46 GMT-03:00 David Rodrigues <david.proweb@gmail.com>: > 2017-06-28 13:59 GMT-03:00 Kalle Sommer Nielsen <kalle@php.net>: > >> Hi David >> >> 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] >> > ​​ > > ​Not on reality.​ :( > > The "final" keyworks make a "local scope" variable value "blocked to > rewrite" after instantiate it. > Okay, it sounds like a "const", and it is, but "not as we known it". > > While constants are class member (or globals), a final variable is just a > variable blocked to rewrite, and it could be initialized with a new data > content every time that the context is called (eg. a function). > > For instance (note that the parameter is "final", then I can't modify the > parameter variable, but it can receives a new value each time that I call > this function): > > function write(final $message) { echo $message; } > write("Hello"); > write("World"); > // Write "Hello World" on ouput. > > Or then: > > function randomNumber() { > final $number = mt_rand(); > echo $number; > > // $number = mt_rand_again(); // <-- will not be allowed! > } > randomNumber(); > ​ // Write "0.123" > randomNumber(); > ​ // Write "0.456" > ​ > > > >> >> [1] http://php.net/constants >> [2] >> https://docs.microsoft.com/en-us/dotnet/csharp/language-refe >> rence/keywords/readonly >> > > -- > David Rodrigues > -- David Rodrigues