On Monday, 18 June 2018 at 20:48:55 UTC, Per Nordlöw wrote:
T toDefaulted(T, S, U)(S value, /*lazy*/ U defaultValue)
if (is(typeof(() { T r = defaultValue; }))) // TODO use
std.traits.isAssignable!(T, U) ?
why not just make it
T toDefaulted(T, S)(S value, T defaultValue)
and forget U entirely?
The problem with this code is that throwing exceptions for the
default case is costly at least with dmd. Is there another way
to do this?
It depends on what the types are. If it is like string to int,
you can simply scan the string for the appropriate format.
For other conversions though, I don't think you can tell in
general. User-defined types might not even tell you except by
exception.
