Le 02/01/2014 01:44, bearophile a écrit :
Raphaël Jakse:
auto E = new Set!int([1,2,3,4]); // it is possible to declare
an empty set
You can add a factory helper:
auto e = set([1, 2, 3, 4]);
Or even:
auto e = set(1, 2, 3, 4);
I'm going to add this.
Two questions:
- By default, should set be typed or untyped?
I would go for typed set, but what about people's expectations?
- What is preferable: first version or second version of the proposed
set factory function? (imho both cannot co-exist because of sets of
arrays handling)
* The first version allows creation of a set from a array. That is
already possible with the constructor, but then you have to pass the
type template, this is not beautiful.
* The second version is more pretty. But then, we'll need a
setFromArray function which makes a set from a list.
I prefer the second option, but then, set([1, 2, 3, 4]) would make a
set containing on element: an array of four ints. Could this be misleading?
writeln("union: ", E.Union(F));
writeln("inter: ", E.Inter(F));
writeln("symmetric difference: ", E.SymDiff(F));
writeln("minus: ", E.Minus(F));
writeln("Powerset: ", E.Powerset);
In idiomatic D all the member functions start with a lowercase letter.
I prefer lowercase for first letters too, but there is the "union"
member, which is a keyword, so I put them all in uppercase.
Any idea?
And a little operator overloading helps, look at the Python set() for a
nice API.
// beware, because S is an untyped set (Set!() or
Set!Object),
Probably in idiomatic D you use templates, so Set!Object is a very
uncommon usage, unlike Java.
What do you mean?
about Set!Object:
I needed a means to specify the type of elements in the Set. So I went
with Set!the_type. Then, I needed a special type to make sets able to
hold any value. I went for Object. void might have been nice, though it
would probably have complicated things.
I tried to make `auto S = new Set;` create a untyped set, but I didn't
succeed.
So again, what do you suggest?
Should Phobos have something similar built in?
A set is a good thing to have in Phobos, but the API and design should
be a little different from yours.
I'm eager to make my library close to "idiomatic D", so feel free to
make any remark, suggestion for this or for anything else.
Bye,
bearophile
