Setting array length to 0 discards reserved allocation?

[Jakob Ovrum via Digitalmars-d]

On Sunday, 27 July 2014 at 12:03:05 UTC, Jonathan M Davis wrote:
> Except that no concepts are being conflated. T[] is the dynamic 
> array. There's a block of memory managed by the GC underneath, 
> but it's completely hidden from the programmer. It is _not_ the 
> dynamic array. It's just a block of memory managed by the GC 
> which is used to manage the memory for dynamic arrays, and it 
> has a completely different type from T[]. It's not even an 
> array in the D sense. The block of memory is referred to by a 
> pointer, not a D array.
>
> It's talk of "which array" owns the memory and the like which 
> causes confusion, and talking about the GC-managed block of 
> memory as being the dynamic array and the T[] that the 
> programmer sees as being the slice is just plain wrong. The T[] 
> is both a slice and a dynamic array (because they're the same 
> thing), whereas the block of memory is neither. I think that 
> the fact that the article tried to call the underlying block of 
> memory a dynamic array has caused a lot of unnecessary 
> confusion.
>
> - Jonathan M Davis

This very thread is a testament to the fact that no, it's not 
completely hidden, and it is the conflation that causes 
confusion, and clarity only comes when the two concepts are 
explained separately.

This matches my experience when I teach about D's arrays on IRC 
too - people generally feel enlightened after reading the array 
article.

It's debatable whether hamfisting dynamic array capabilities onto 
a simple slice type was a good idea or not (T[new], anyone?), but 
we should be as clear with the current situation as possible. 
Pretending there isn't a problem is ignoring the cries of D 
newbies everywhere. Please stop.