Problem Statement

Write a program to find the mode value of a collection. The case where the collection is empty may be ignored. Care must be taken to handle the case where the mode is non-unique. If it is not appropriate or possible to support a general collection, use a vector (array), if possible. If it is not appropriate or possible to support an unspecified value type, use integers.

Let's start with the solution:

procedure main(args)
    every write(!mode(args))
end

procedure mode(A)
    hist := table(0)
    every hist[!A] +:= 1
    hist := sort(hist, 2)
    modeCnt := hist[*hist][2]
    every modeP := hist[*hist to 1 by -1] do {
        if modeCnt = modeP[2] then suspend modeP[1]
        else fail
        }
end