Extended Type Design.

[Bruno Medeiros]

Walter Bright wrote:
> Bruno has answered your specific questions, so I'll take a more general 
> tack.
> 
> A symbol is a name to which is 'bound' a value.
> 
> static int x = 3;
> 
> '3' is the value.
> 'int' is the type.
> 'x' is the symbol.
> 'static' is the storage class.
> 
> Here, we bind a new value to the symbol x:
>     x = 4;
> 
> A storage class originally meant where the symbol is stored, such as in 
> the data segment, on the stack, in a register, or in ROM. It's been 
> generalized a bit since then. The main way to tell a storage class apart 
> is that:
> 1) a storage class applies to the symbol
> 2) a type is independent of storage class, i.e. you cannot create a type 
> that is "pointer to static" or "array of extern". Storage classes do not 
> affect overloading, nor type deduction.
> 
> 'invariant' and 'const' are type modifiers (aka type constructors), 
> which mean when they are applied to a type, a new type is created that 
> is a combination.
> 
> 'invariant' is a guarantee that any data of that type will never change. 
> 'const' is a guarantee that any data of that type will never be modified 
> through a reference to that type (though other, non-const references to 
> that type can modify the data).

So 'final' will be a storage class and not a type modifier? That's one 
of the questions I still have with regards to your design, because I'm 
not seeing how 'final' can also not-be a type modifier. In particular, 
again, what is
   typeof(&foo)
where foo is:
   final Foo foo;
?

-- 
Bruno Medeiros - MSc in CS/E student
http://www.prowiki.org/wiki4d/wiki.cgi?BrunoMedeiros#D