[Bro-Dev] set and vector operators

[Azoff, Justin S]

> On Apr 25, 2018, at 1:40 PM, Vern Paxson <vern at icir.org> wrote:
> 
> I'm working on some scripts that use sets and vectors, sometimes together,
> and am finding it clunky that Bro doesn't offer much in the way of operators
> for this.  To that end, I'm thinking of implementing some along the following
> lines, where values starting with 's' are sets, 'v' are vectors, and 'e'
> are type-compatible elements:
> 
> 	s1 + s2		Set union (for sets of the same type, of course)
> 	s1 || s2	Set union
> 
> 	s1 && s2	Set intersection
> 	s1 - s2		Set difference
> 
> 	s += e		Add the element 'e' to set 's'
> 				(same as the current "add s[e]")
> 	s -= e		Remove the 'e' element from 's', if present
> 				(same as the current "delete s[e]")
> 
> 	s1 += s2	Same as "s1 = s1 + s2"
> 	s1 -= s2	Same as "s1 = s1 - s2"
> 
> 	v += e		Append the element 'e' to the vector 'v'
> 	v += s		Append the elements of 's' to the vector 'v',
> 				with the order not being defined
> 
> 	s += v		Add the elements of 'v' to 's'
> 	s -= v		Remove the elements of 'v' from 's', if present
> 
> These strike me as pretty straightforward, but please chime in if you
> have comments!

That's very similar to what python does, except they use & and | instead of && and ||.
I think they do that because 'set or' is closer to 'bitwise or' than 'logical or'

They also use ^ for symmetric difference.

>>> a=set([1,2,3])
>>> b=set([2,3,4])
>>> a & b
{2, 3}
>>> a | b
{1, 2, 3, 4}
>>> a - b
{1}
>>> b - a
{4}
>>> a ^ b
{1, 4}



— 
Justin Azoff