anyone know of a good (or any) syntax for an empty aa

impetus:

auto aa = reduce!(g)(emptyaa, lst);

Ellery Newcomer:

> anyone know of a good (or any) syntax for an empty aa

Unfortunately "null" suffices where the function that receives knows the type of the AA it will receive. But I don't like this, a more typed style can be less bug prone.

So you can give a type to null:
cast(int[string])null

I have created a bit shorter template:
AA!(string, int)

But it doesn't gain much.

Something similar can be used for dynamic arrays:
cast(int[])null
With dynamic arrays you can also use (that I don't like) "null" and even the special []

Bye,
bearophile

On Sat, Mar 13, 2010 at 20:17, Ellery Newcomer <ellery-newcomer@utulsa.edu>wrote:

> anyone know of a good (or any) syntax for an empty aa
>
> impetus:
>
> auto aa = reduce!(g)(emptyaa, lst);
>

To associate a list of key/value pairs into one AA?

I use .init, but AA in general have become buggy for the past few releases.

auto aa = reduce!g((V[K]).init, lst); // this used to work, I think

But, as I said, it has become quite buggy recently:

auto aa = (int[string]).init; // empty AA?
aa["abc"] = 3; // error, no operator [] overload for
AssociativeArray!(string, int). I mean, come on.


Philippe

Ellery Newcomer:
> anyone know of a good (or any) syntax for an empty aa
> impetus:
> auto aa = reduce!(g)(emptyaa, lst);

Sorry, I have probably not understood your question.

Bye,
bearophile

On 03/13/2010 07:20 PM, bearophile wrote:
> Ellery Newcomer:
>> anyone know of a good (or any) syntax for an empty aa
>> impetus:
>> auto aa = reduce!(g)(emptyaa, lst);
>
> Sorry, I have probably not understood your question.
>
> Bye,
> bearophile

No, you hit it on the head. Here's the kind of thing I was after:

auto g = reduce!("a[b]=1,a")(cast(int[int]) null, [1,2,3,4]);

Works fine. The one-liner probably isn't worth it, but I think it's pretty funny. What does this do to Walter's arguments concerning nonnull?

Ellery Newcomer:
>What does this do to Walter's arguments concerning nonnull?<

I don't understand the question, sorry.

Bye,
bearophile