On Thursday, 9 May 2013 at 04:00:55 UTC, Manu wrote:
Perhaps you're arguing that the problem is that the user
_isn't_ getting
compiler complaints when the code is changed? The call that
modifies it
will still work fine, but it will obviously apply the changes
to a temp
that is then lost? Surely this is to be expected?
The call will not still work fine in C++.
Here's the code again:
class Collection(T) {
ref T opIndex(size_t i) { ... }
...
}
void fix(ref double x) { if (isnan(x)) x = 0; }
void fixAll(Collection!double c) {
foreach (i; 0 .. c.length) {
fix(c[i]);
}
}
In (analogous) C++, if Collection's opIndex changes to return by
value then the call to fix is a compile time error (the rvalues
don't bind to unqualified ref). I believe Andrei is arguing that
D must _at least_ do this to make progress, i.e. not be "worse"
(than C++).
