count(regex, string) computes length(findall(regex, string)) better

[StefanKarpinski]

Sometimes you just want to count how many times something occurs. I basically just copied the findall method above and counted instead of pushing. It could be refactored to share logic, but that seemed like overkill.

[StefanKarpinski]

FreeBSD failure is unrelated (FileWatching).

[StefanKarpinski]

Windows failures also unrelated (frippery.org can't be reached).

[StefanKarpinski]

I guess an API concern about this is that count(p, itr) counts items in itr that match p whereas this method counts subsequences of itr which match a regex. Does that matter?

[JeffBezanson]

Well, we also have methods of findall where the first argument is either a Function or a Regex, so that ship has sailed.

[StefanKarpinski]

Ok, in that case, there's no real reason not to do this.

[rfourquet]

Sorry, didn't have time to review before merge! (On holidays 😎, but will have a look later)

[tkf]

seemed like overkill.

Alas, if Base had transducers...

using Transducers
using Transducers: @next, complete

matches(t, s, overlap=false) = AdHocFoldable() do rf, acc, _
    i, e = firstindex(s), lastindex(s)
    while true
        r = findnext(t, s, i)
        isnothing(r) && return complete(rf, acc)
        acc = @next(rf, acc, r)
        j = overlap || isempty(r) ? first(r) : last(r)
        j > e && return complete(rf, acc)
        @inbounds i = nextind(s, j)
    end
end

count′(args...) = foldl(right, Count(), matches(args...); init=0)
findall′(args...) = foldl(push!, Map(identity), matches(args...); init=UnitRange{Int}[])
find3(args...) = foldl(push!, Take(3), matches(args...); init=UnitRange{Int}[])

(sorry, cannot help it)