Module StepByStep {
    Function CombinationsStep (a, nn) {
        c1=lambda (&f, &a) ->{
            =car(a) : a=cdr(a) : f=len(a)=0
        }
        m=len(a)
        c=c1
        n=m-nn+1
        p=2
        While m>n
            c1=lambda c2=c,n=p, z=(,) (&f, &m) ->{
                if len(z)=0 then z=cdr(m)
                =cons(car(m),c2(&f, &z))
                if f then z=(,) : m=cdr(m) : f=len(m)+len(z)<n
                }
            c=c1
            p++
            m--
        End While
        =lambda c, a (&f) -> {
             =c(&f, &a)
            }
    }
    enum out {screen="", file="out.txt"}
    m=each(out)
    while m
          open eval(m) for output as #f
          k=false
          StepA=CombinationsStep((1, 2, 3, 4,5), 3)
          While not k
                 Print #f,  StepA(&k)#str$()
          End While
          Print #f
          k=false
          StepA=CombinationsStep((0, 1, 2, 3, 4), 3)
          While not k
                  Print #f, StepA(&k)#str$()
          End While
          Print #f
          k=false
          StepA=CombinationsStep(("A", "B", "C", "D","E"), 3)
          While not k
                   Print #f,  StepA(&k)#str$("-")
          End While
          Print #f
          k=false
          StepA=CombinationsStep(("CAT", "DOG", "BAT"), 2)
          While not k
                    Print #f,  StepA(&k)#str$("-")
          End While
          close #f
      end while
      win "notepad", dir$+file
}
StepByStep