foreach - premature optimization vs cultivating good habits

[Laeeth Isharc via Digitalmars-d-learn]

On Friday, 30 January 2015 at 12:55:20 UTC, Adam D. Ruppe wrote:
> On Friday, 30 January 2015 at 11:55:16 UTC, Laeeth Isharc wrote:
>> As I understand it, foreach allocates when a simple C-style 
>> for using an array index would not.
>
> foreach is just syntax sugar over a for loop. If there's any 
> allocations, it is because your code had some, it isn't inherit 
> to the loop. The doc definition even lists the translation of 
> foreach to for in the case of ranges explicitly:
>
> http://dlang.org/statement.html#ForeachStatement
>
>
> The most likely allocation would be to a user-defined opApply 
> delegate, and you can prevent that by making it opApply(scope 
> your_delegate) - the scope word prevents any closure allocation.

Thanks, Adam.  That's what I had thought (your first paragraph), 
but something Ola on a different thread confused me and made me 
think I didn't understand it, and I wanted to pin it down.

The second paragraph is very helpful - appreciate it.


Laeeth.