On 11/26/2014 04:25 PM, David Held wrote:
> class Foo
> {
> override
> size_t toHash() @trusted pure const nothrow
> {
> // error: no property 'toHash' for type 'int[]'
> return importantStuff.toHash();
> }
The getHash() member function of the particular TypeInfo can be used.
However, it is not currently pure, so you must comment that out from
your toHash:
override
size_t toHash() @trusted /* pure */ const nothrow
{
return typeid(importantStuff).getHash(&importantStuff);
}
If a function can safely be casted to pure, you can use the following
yet-missing-in-phobos function template:
import std.traits;
auto assumePure(T)(T t)
if (isFunctionPointer!T || isDelegate!T)
{
enum attrs = functionAttributes!T | FunctionAttribute.pure_;
return cast(SetFunctionAttributes!(T, functionLinkage!T, attrs)) t;
}
// ...
override
size_t toHash() @trusted pure const nothrow
{
auto func = assumePure(&(typeid(importantStuff).getHash));
return func(&importantStuff);
}
Note that now your toHash can be pure.
Ali
