lodash like utility/algorithms library for D

[Paul Backus]

On Saturday, 29 September 2018 at 12:40:14 UTC, aliak wrote:
> I.e. by allowing you to define the unexepcted you could for 
> instance:
>
> enum JSONError {
>   invalidKey, notString, notNumber
> }
>
> auto a = parse(jsonData);
>
> a.getAsString("key").match!(
>     (string value) => // yay
>     (JSONError error) => // small domain of what went wrong
> );

I agree that this is useful, but why not just return a naked 
`SumType!(string, JSONError)` in that case? Is there some 
additional value added by the `Expect` wrapper that I'm not 
seeing?