Associative array literal is non-constant?

[H. S. Teoh]

On Mon, Feb 06, 2012 at 11:46:00AM -0800, H. S. Teoh wrote:
[...]
> As for what type the literal should be by default:
> 
> 	auto X = ["a":1, "b":2, ...];
> 
> I think typeof(X) should be const int[string].

Hmm, I just checked TDPL again, and it seems that precedence has already
been set for typeof(X) to be non-const.

Which is OK, I guess, since with the current implementation we have:

	auto A = [1,2,3];	// int[]
	const B = [1,2,3];	// const(const(int)[]) -- why does
				// writeln(typeid(B)) give this funny
				// expression?

	auto X = ["a":1, "b":2];	// int[immutable(char)[]]
	const Y = ["a":1, "b":2];	// const(const(int)[immutable(char)[]])

(Of course, Y is currently still constructed on the heap.)

Alternatively, if we don't want to risk breaking backward compatibility,
maybe the new AA type should be "static T[U]" instead? I.e., introduce a
new type called "static AA" which has a different implementation that is
be computed at compile-time, and which is not compatible with the
current AA's except via a .dup method that creates a heap-based AA.

(Or should it be "immutable AA"?)


T

-- 
The best compiler is between your ears. -- Michael Abrash