Automatic typing

[Jonathan M Davis]

On Friday, June 28, 2013 02:34:53 JS wrote:
> Would it be possible for a language(specifically d) to have the
> ability to automatically type a variable by looking at its use
> cases without adding too much complexity? It seems to me that
> most compilers already can infer type mismatchs which would allow
> them to handle stuff like:
> 
> main()
> {
>     auto x;
>     auto y;
>     x = 3;   // x is an int, same as auto x = 3;
>     y = f(); // y is the same type as what f() returns
>     x = 3.9; // x is really a float, no mismatch with previous
> type(int)
> }
> 
> in this case x and y's type is inferred from future use. The
> compiler essentially just lazily infers the variable type.
> Obviously ambiguity will generate an error.

Regardless of whether such a feature would be of value (and honestly, I'm 
inclined to believe that it would do more harm than good), Walter would never 
go for it, because it would require code flow analysis, and he pretty much 
refuses to have that in the compiler or to have any feature which would 
require it in the language. So, while it may be technically feasible, it'll 
never happen.

- Jonathan M Davis