Motive behind !empty() with front() instead of Optional front()
Piotr Mitana
piotr.mitana at gmail.com
Fri Mar 26 08:49:30 UTC 2021
On Wednesday, 24 March 2021 at 19:23:21 UTC, Per Nordlöw wrote:
> What's the motive behinds D's range design choice of needing
>
> if (!empty)
> {
> // use front or back
> }
>
> instead of having front returning an optional/maybe type with
> enforced pattern matching?
>
> Lack of builtin Optional type?
>
> Choosing the Optional path would have avoided the need for
> putting error diagnostics such as
>
> https://github.com/dlang/phobos/commit/9bd2f2ba8ff1124a044560c4e6912a13cb5ac694
>
> in the standard library of such an alternative solution.
Actually changing front() to return optionals would probably
break many things. However, it could be handy to add a method
called nullableFront or frontOrNull (and nullableBack or
backOrNull for bidirectional ranges) to std.range.
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