T.init for static arrays?

[Philippe Sigaud]

On Sat, Mar 13, 2010 at 21:13, Walter Bright <newshound1 at digitalmars.com>wrote:

> Currently, given an array:
>
>   alias T[3] A;
>   A a;
>
> the default initializer for A, A.init, is T.init. It is done this way for
> memory efficiency, as:
>
>   a = A.init;
>
> doesn't need to create an array for the rvalue. But it does cause generic
> programming problems, especially with the advent of static arrays now being
> passed by value rather than by ref.
>
> So, I propose changing A.init from being T.init to being [T.init, T.init,
> T.init].
>
> What do you think?
>

That's bug 3826

http://d.puremagic.com/issues/show_bug.cgi?id=3826

I'm all for A.init being [T.init (n times)], as it indeed broke some of my
code, so thank you for the suggestion Walter.
I was very surprised to see that A.init was T.init.

Andrei:
>My understanding is that you propose to transform A.init into a literal
with as many elements
>as the length of the array. That has a an issue.
>Currently array literals default to T[], not T[N].

Ah, yes.

>So this would do the unexpected:

>alias int[3] A;
>A a;
>auto b =  A.init;
>assert(is(typeof(b) == int[]); // pass

Currently, this does something as unexpected (at least for me):

assert( !is (typeof(b) == typeof(a))); // b is an int, a is a int[3]

In parallel to what grauzone said, I think this assert should never fail:

T x;
assert(is(typeof(x) == typeof(T.init));


But then I only use small-size static arrays, as parameters in templates. By
small, I mean less than a dozen elements. Other using bigger arrays may
shout at this change...


 Philippe
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