Code:
/for {
  set %var1 $gettok($1-,1,59)
  set %var2 $gettok($1-,2,59)
  set %var3 $gettok($1-,3,59)
  set %var4 $gettok($1-,4,59)
  echo -a %var1 %var2 %var3 %var4
  while (%var1 %var2 %var3) {
    msg # test %var1 %var2 %var3 %var4
    %var4 %var1
  }
  unset %var*
}

output:

/for 1;<=;5;inc
1 <= 5 inc
<MikeChat> test 1 <= 5 inc
<MikeChat> test 2 <= 5 inc
<MikeChat> test 3 <= 5 inc
<MikeChat> test 4 <= 5 inc
<MikeChat> test 5 <= 5 inc

/for 5;>=;1;dec
5 >= 1 dec
<MikeChat> test 5 >= 1 dec
<MikeChat> test 4 >= 1 dec
<MikeChat> test 3 >= 1 dec
<MikeChat> test 2 >= 1 dec
<MikeChat> test 1 >= 1 dec