On Sunday, 21 May 2017 at 10:03:58 UTC, Nicholas Wilson wrote:
As in the function signature of the function you call `ok` or
`error` in.
Result!(int, SomeEnum) myfunc(bool foo)
{
if(!foo)
return ok(42);
else
return error(SomeEnum.fooHappened);
}
should work.
This is what I've got right now.
--- [module 1]
struct Result(OkType, ErrType)
{
this(OkType ok) pure nothrow
{
isOk = true;
okPayload = ok;
}
this(ErrType error) pure nothrow
{
isOk = false;
errorPayload = error;
}
bool isOk;
union
{
OkType okPayload;
ErrType errorPayload;
}
}
auto ok(T, E)(T payload) { return Result!(T, E)(payload); }
auto error(T, E)(T payload) { return Result!(T, E)(payload); }
--- [module 2]
Result!(string, int) fn(bool shouldErr) {
if (!shouldErr)
return ok("No problem");
return error(0);
}
---
But it can't infer the second parameter.
"template result.ok cannot deduce function from argument types
!()(string)"
