On Wed, 16 Dec 2009 09:21:16 -0500, Michel Fortin
<michel.for...@michelf.com> wrote:
On 2009-12-16 08:54:03 -0500, "Denis Koroskin" <2kor...@gmail.com> said:
I just realized that 'inout' could have a real use even for functions
with no return value. Consider this:
void doSomething(inout(Object)[] a, inout(Object)[] b) {
a[0] = b[0]; // works only when objects in both arrays have the
same constness.
}
Doesn't work.
doSomething("hello", "world");
Well, of course it doesn't...
Here's what I meant:
void doSomething(inout(MyStruct)*[] a, inout(MyStruct)*[] b) {
a[0] = b[0]; // works only when structs in both arrays have the same
constness.
}
This is dangerous.
We should figure out a reason why this shouldn't compile. It's hard for
me to wrap my head around it. Either the implicit cast when calling the
function shouldn't work, or the assignment shouldn't work. My intuition
is that the implicit cast should fail.
Consider the following function with today's notation:
void doSomething(const(MyStruct)*[] a, const(MyStruct*)[] b) {
a[0] = b[0];
}
Now:
immutable(MyStruct)*[] im;
MyStruct*[] mut;
MyStruct *s = new MyStruct;
mut ~= s;
im.length = 1;
doSomething(im, mut);
Oops, without a cast, we have changed s into an immutable struct. Hidden
inside a function no less!
Does this code compile today? If so, we need to fix this. With this
fixed, the inout version naturally becomes invalid.
-Steve
