On Monday, 16 September 2013 at 21:01:48 UTC, Aleksey wrote:
On Monday, 16 September 2013 at 20:53:18 UTC, Namespace wrote:
On Monday, 16 September 2013 at 20:43:01 UTC, Aleksey wrote:
I get strange type errors in the following code, and I don't
understand why =( Could anybody help?
struct I {
int i;
I opBinary(string op)(ref I that)
if (op == "+") {
return I(i + that.i);
}
}
void main() {
auto a = I(1);
auto d = a + (a + a);
}
Error: incompatible types for ((a) + (a.opBinary(a))): 'I'
and 'I'
If I remove ref or parens around (a+a) the code compiles just
fine.
opBinary returns a rvalue. But your code accepts only lvalues.
(a + a) produce an rvalue so a + (a + a) is the same as lvalue
+ rvalue and rvalues aren't accepted. You could use auto ref
for that purpose.
Thank you! auto ref is exactly what I was looking for!
You should know, that auto ref is only useable for template
functions/methods. Maybe this will change, but not in the next
years.
