Value closures (no GC allocation)

[Stanislav Blinov via Digitalmars-d]

On Thursday, 25 May 2017 at 03:10:04 UTC, Adam D. Ruppe wrote:

>
> "Currently FunctionLiterals that capture their outer context 
> (i.e. closures/delegates) require an allocation and the garbage 
> collector. "
>
>
> Not necessarily true, make sure you actually mention `scope 
> delegate` and `alias` params that do not return it. Those 
> capture but do not allocate.

It's an infant document, wording is out there somewhere...

> "We will be proposing a syntax redundant w.r.t. current 
> behavior (i.e. capture by reference), so maybe we should 
> consider proposing deprecation?"
>
> Don't do that.

Why not? I, personally, have a simple, but solid, justification:

Captures, if any, should be explicit. That is all :)

That is solely my opinion, hence the cautious "maybe"...

> "Capture by reference"
>
> I'm against that, no need adding it and it complicates the 
> whole thing. For example, "ref int _i;" as a struct member; 
> there's no such thing in D. (the compiler could do it but 
> still). And you'd have to explain the lifetime. Just no point 
> doing this, the current behavior is completely fine for this.

By inference, adding capture syntax at all will also complicate 
the whole thing. IMHO, we either should have one, or the other, 
but not both. P.S. have you seen the TODO at the bottom of that 
section?