Does D have too many features?

[H. S. Teoh]

On Mon, Apr 30, 2012 at 06:54:31PM +0200, bearophile wrote:
> H. S. Teoh:
> 
> >Which means your code is at the mercy of the external library.
> >Upstream updates a class, and suddenly a whole bunch of code is
> >unnecessarily broken
> 
> How? (I think you are wrong again).
[...]

	struct S {
		int x;
	}
	void main() {
		int y;
		S s;

		with(s) {
			x = 1;
			y = 2;
		}
	}

This works. Now suppose S is updated to:

	struct S {
		int x;
		int y;
	}

Now the program fails to compile because S.y conflicts with the local y.

This is bad because unrelated code is broken just by changing S: it
breaks encapsulation. This is just a small example; imagine if a lot of
code uses S. Many places may break when S changes just because they
happen to use the wrong local variable names.

Whereas if you had _not_ used with, this is a non-problem, since you'd
be referring to s.x, and the fact that S now has a new member does not
break any existing code regardless of how it was named.


T

-- 
People say I'm indecisive, but I'm not sure about that. -- YHL, CONLANG