filling an array of structures

[Steven Schveighoffer]

On Tue, 11 Jan 2011 00:39:55 -0500, Brad  
<brad.lanam.comp_nospam at nospam_gmail.com> wrote:

> Given an array of structures that you need to populate.
> Also assume the structure is quite large and has many
> elements to fill in.
>
> S s[];
> while (something) {
>   s.length += 1;
>   auto sp = &s[$-1];   // method 1
>   sp.a = 1;
>   ...
>   with (s[$-1]) {   // method 2
>     a = 1;
>   }
>   ...
>   foreach (ref sp; s[$-1..$]) {  // method 3
>     sp.a = 1;
>   }
> }
>
> I don't mind 'with' statements, but they have a readability and
> maintenance problem if their scope is large.  The reader would have
> to be aware of the context of the structure and the local variables,
> whereas 'sp.a' is self documenting.
>
> method 3 is fine, and provides me with a reference to s[$-1],
> but I'd really like to have:
>    auto sp = ref s[$-1];  // possible method 4
> where sp is a reference, but no pointer arithmetic can be done on it.
>
> Another alternative would be runtime aliases.
>    alias s[$-1] as sp;
> Or
>    sp = with (s[$-1]); // I don't much like this syntax...
>
> In the meantime, I'll go with method 1.


What about:

S sp;
sp.a = 1;
s ~= sp;

Or if you have a constructor for S, or a is the only member in it:

s ~= S(1);

-Steve