const, final, scope function parameters

[Walter Bright]

Frank Benoit wrote:
> Perhaps we look at it from the wrong side.
> 
> If we want to change the D language to make it more const, the keywords
> 'const', 'invariant'... are probably the wrong choice.
> 
> How about restricting keywords and add their opposites: 'mutable',
> 'once' (write once) and then make every variable declaration const by
> default? Each variable/parameter needs to be made modifyable with
> modifiers if needed.

I think having to write:

	mutable int x;

instead of:

	int x;

just isn't going to please people.