[Bro-Dev] set and vector operators
jsiwek at corelight.com
Thu Apr 26 13:10:34 PDT 2018
On 4/26/18 11:29 AM, Vern Paxson wrote:
>> Just one more thing still: I'm actually feeling pretty strongly
>> against having multiple different operators for the same operation
>> (set union, set addition/removal).
I'm maybe convincing myself that it's at least not that useful or
there's alternative ways forward that don't introduce redundancies.
> I'm fine with removing "add" and "delete" for sets! (But seems we gotta
> keep them for a good while for backward compatibility. Plus, what would
> be the remove operator for tables? "t -= index" seems pretty weird to me.)
A nice thing about "add" and "delete" for sets is that you can infer the
data type that you're operating on just looking at the local code/line.
E.g. say you come back to some code after a few months and see "foo +=
1". Not obvious what 'foo' is anymore. Could be vector, set, or count,
> But I don't think we should forego '+' and '-' for sets. It would be too
> weird that "v += e" works but "s += e" does not (and "add v[e]" blows, so
> let's not consider going down that path :-P).
Yeah, I agree with that sentiment (on the condition that we did add +/-
I do also notice that you had "s + e" in the proposal and not "v + e".
Isn't that weird by the same logic or is it just an accidental omission?
> Once we have s += e, we
> certainly should have s -= e. And once we have "s + e", "s1 + s2" seems
> very natural to me too; I don't relish having to explain "oh *that* doesn't
> work, you have to use s1 | s2" :-P.
That also makes sense, though it's worth seeing what a minimal proposal
looks like without the contentious '+' operations:
s1 - s2, s1 -= s2 Set difference
s1 | s2, s1 |= s2 Set union
s1 & s2, s1 &= s2 Set intersection
s1 ^ s2, s1 ^= s2 Set symmetric difference
c1 | c2, c1 |= c2 Bitwise-or 'count' values
c1 & c2, c1 &= c2 Bitwise-and 'count' values
c1 ^ c2, c1 ^= c2 Bitwise-xor 'count' values
The only one now missing that I'd probably find myself using is:
v += e Append element to vector
And for that, a BiF or generic script-layer function call (if that were
possible) would even make me happy:
That also could go back to what I was saying before about readability:
it would then be more obvious than "v += e" regarding what data types
Same idea would apply to "s += v" and "s -= v" (if we were inclined):
Could that all be an alternative way forward? Or is it missing other
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