On 4/15/18 6:52 PM, Giles Bathgate wrote:
I find this later code clunky and it requires two hashes/lookups. The proposed implementation adds support directly to rt/aaA.d to avoid this. I should also point out that the allocation of a new Person in the example is trivial, but it might often be the case that the person instance is created by fetching a record from a db, or an Image loaded from disk, or a movie downloaded from the internet.
I think this is a great addition. I've always disliked the double-lookup requirement for ensuring a key was initialized. I'll note that C++ gets around this by always initializing on any access.
The name "getOrAdd" is a bit mechanical sounding. The real reason you want this is to ensure that key's value is initialized. ensureInitialized is long. get is already taken (if get weren't already taken, I'd suggest that name). Others have suggested using flags, but I'll note to them, `Flag` and `Yes` are part of std.typecons, and not accessible here.
getWithDefault sounds reasonable but probably would be confusing with the current `get` overload. Maybe getInitialized? I don't know that either of these are giant leaps ahead of getOrAdd.
Another possibility is getPtr. get currently gets a value, or returns a default value if it doesn't exist. But getPtr would return a pointer to the value, ensuring it's initialized.
In any case, thumbs up to the concept, and I'm ambivalent on the name. -Steve
