record point(x,y)

procedure main()
    minDist := 0
    minPair := &null
    every (points := [],p1 := readPoint()) do {
        if *points == 1 then minDist := dSquared(p1,points[1])
        every minDist >=:= dSquared(p1,p2 := !points) do minPair := [p1,p2]
        push(points, p1)
        }

    if \minPair then {
        write("(",minPair[1].x,",",minPair[1].y,") -> ",
              "(",minPair[2].x,",",minPair[2].y,")")
        }
    else write("One or fewer points!")
end

procedure readPoint()  # Skips lines that don't have two numbers on them
    suspend !&input ? point(numeric(tab(upto(', '))), numeric((move(1),tab(0))))
end

procedure dSquared(p1,p2)    # Compute the square of the distance
    return (p2.x-p1.x)^2 + (p2.y-p1.y)^2  # (sufficient for closeness)
end