On Fri, Apr 01, 2016 at 07:26:46PM +1100, Daniel Murphy via Digitalmars-d wrote:
> On 1/04/2016 6:24 AM, deadalnix wrote:
> >Pretty much as per title. I has that in the back of my mind for a
> >while. Would that work ?
>
> Don't forget that builtin AAs have been an epic disaster, and this
> would require an appalling amount of effort to implement in the
> compiler types, ctfe, druntime, new traits etc.
>
> Phobos seems like a better place - and while not quite as concise, the
> syntax should still be pretty intuitive.
Yeah, having yet another language builtin is a bad idea, it complicates
the compiler and ties you to a specific implementation of sets. Why not
just Set!T instead, implemented in Phobos?
Sets behave pretty much like bit arrays, so for operations you can have:
Set!T s1, s2, s3
T e;
s1.add(e);
s2.remove(e);
auto s3 = s1 | s2; // union
auto s4 = s1 & s2; // intersection
auto s5 = s1 * s2; // cartesian product
auto s6 = s1 - s2; // set difference
auto s7 = s1 ^ s2; // symmetric difference
which gives us nice enough syntax for standard set operations, perfectly
implementable via operator overloading in a library. (Note: above
operators are only suggestions.)
I don't think AA syntax is very well-suited for sets. (What on earth
is `set[x] = true` supposed to mean?! You want to add an element to the
set, not to set an element to true in the set. It doesn't make sense
mnemonically.)
T
--
What did the alien say to Schubert? "Take me to your lieder."
