On 2017-07-21 12:30 PM, Darren Duncan wrote:
On 2017-07-21 5:07 AM, Timo Paulssen wrote:
You want (|) to get the union of two sets as a set.
https://docs.perl6.org/language/setbagmix#Set%2FBag_Operators
hth
- Timo
Right. Every set operation except 1 (multiset sum) should result in a set, and
is just a special case of the same behavior as the bag operation. Optionally
the Set implementation of multiset sum could toss the duplicates and still
result in a Set, thus being an alias for union with Sets, rather than resulting
in a bag that it otherwise normally would. Depends on designer prefs I suppose.
Now, looking at that link, I can see at least 2 things that perhaps ought to be
changed.
Firstly, I believe ∆ (U+2206) is the standard symbol for symmetric difference,
and not circled minus as the above url currently gives.
Secondly, I see there's an operator for multiplying 2 bags (which I hadn't heard
of before, but okay), but there should also be an operator for multiplying 1 bag
by a natural number, that is a scalar multiply of a bag. Unless it is assumed
the standard hyper-operator syntax is best for this.
Replying to myself. AFAIK, actually hyper-operators would NOT do the scalar
multiply I speak of. For a bag like {5,7}, a hyper by 2 would yield {10,14} but
the scalar I'm looking for is that {5,7} by 2 yields {5,5,7,7}.
-- Darren Duncan
