[OT] Some neat ideas from the Kotlin language

[Nick Sabalausky via Digitalmars-d]

On 02/19/2016 07:16 AM, Jacob Carlborg wrote:
> On 2016-02-19 00:33, Yuxuan Shui wrote:
>> Just come across Kotlin today, and found some interesting ideas skimming
>> through its tutorial:
>>
>> 1) Null check
>>
>> Kotlin has Optional types, suffixed with a '?'. Like 'Int?', same as in
>> Swift. But instead of explicitly unwrapping them (e.g. var! in Swift, or
>> var.unwrap() in Rust), Kotlin let you do this:
>>
>>
>>      var: Int?
>>      if (var != null)
>>          //You can use var here
>>

Me want.

>
>> 2) Smart cast
>>
>> This is a similar to previous one, instead of:
>>
>>      var1: Object;
>>      var2 = cast(String)var1;
>>
>> You do this:
>>
>>      if (var1 is String)
>>          //You can use var1 as a String here
>
> It's similar how it works in D, for Objects:
>
> class Foo {}
> Object foo = new Foo;
>
> if (auto o = cast(Foo) foo)
>      // use o as Foo here
>
> When casting to a subclass it will return null reference if the cast fails.
>

It'd be nice if it didn't require a new variable name though. When I do 
that, I usually find I wind up needing to resort to some 
hungarian-notation-inspired "start including the type in the variable's 
name" verbosity. It's a fantastic feature of D, but that Kotlin version 
seems much nicer.