Distinguish between a null array and an empty array

[WebFreak001]

On Sunday, 24 May 2020 at 12:37:20 UTC, ag0aep6g wrote:
> On 24.05.20 14:29, bauss wrote:
>> Dang, that sucks there is no proper way and I would say that's 
>> a big flaw of D.
>> 
>> Because what I need it for is for some data serialization but 
>> if the value is an empty array then it should be present and 
>> if it's null then it should not be present.
>> 
>> Since null is used to say "ignore this" in the data 
>> serialization.
>
> You can use std.typecons.Nullable (or a similar wrapper) to add 
> an extra "ignore this" value to a type.

and just in case you use vibe.d serialization (JSON, BSON or 
other custom ones), there is a new @embedNullable UDA which 
treats Nullable!T inside a map as a T or completely omits it if 
it's null ;)