pure or not pure?

[Janice Caron]

On 10/04/2008, Steven Schveighoffer <schveiguy at yahoo.com> wrote:
>  Then I should be able to do
>
>  h(x)
>  {
>     statement1;
>     statement2;
>  }
>
>  f(x)
>  {
>    h(x);
>  }
>
>  g(x)
>  {
>    h(x);
>  }

What you're asking for is what someone else called "amoral" (slightly
pure). You're suggesting that h be pure-/ish/. It doesn't have to be
completely pure per se, but it must be pure /enough/ such that when
embedded within f or g, f and g remain pure.

I have no idea whether or not D will be able to accomodate this
concept. Strictly functional programming doesn't have it. D might or
might not. If we do, I suspect it will require another keyword.



>  char[] c = new char[5];
>
> is invalid inside a pure function because the compiler cannot verify
>  uniqueness of mutable heap data, right?

No. As I said, new is special. It's integral to the language.