Hello! This is my first post on discuss. (And excuse me that first post is about “Complaints”…)
Well, as the title says, when I first used
<a-Z>, I was a little bit confused because I thought there’s no difference between “a: append lists” and “u: union.”
the union of a collection of sets is the set of all elements in the collection.
Yes, this definition is correct. And selection seems a kind of set contains characters as its elements. So I expected both
<a-z>u to “add” registered selections to current ones. However, you know, this exactly is what
<a-z>a is doing, not
What “u: union” is doing is… for my poor English, I can’t find proper words… a sort of “connect each selections.” Hmm… in my intuition, “union” never add elements that are outside sets…
After that, I found these conventions came from vis’ pairwise combining operator. So now I don’t think we should rename these operators, but do think adding some more explanations to infobox helps newcomers.
How do you think?