procedure spell(n)		#: spell out integer (short scale)
   local m, i
   static scale
   initial {
      scale := [ "thousand", "million", "billion", "trillion", "quadrillion", "quintillion", "sextillion","septillion"]
      every scale[i := 1 to *scale ] := [ integer(repl("999",i + 1)), -3 * i, " "||scale[i] ]
      push(scale,[999,2," hundred"])
     }

   n := integer(n) | stop(image(n)," is not an integer")
   if n < 0 then return "negative " || spell(-n)
   if n <= 12 then return {
      "0zero,1one,2two,3three,4four,5five,6six,7seven,8eight,_
         9nine,10ten,11eleven,12twelve," ? {
            tab(find(n))
            move(*n)
            tab(find(","))
            }
      }
   else if n <= 19 then return {
      spell(n[2] || "0") ?
         (if ="for" then "four" else tab(find("ty"))) || "teen"
      }
   else if n <= 99 then return {
      "2twen,3thir,4for,5fif,6six,7seven,8eigh,9nine," ? {
         tab(find(n[1]))
         move(1)
         tab(find(",")) || "ty" ||
            (if n[2] ~= 0 then "-" || spell(n[2]) else "")
         }
      }
   else if n <= scale[i := 1 to *scale,1] then return {     # generalize based on scale
      spell(n[1:scale[i,2]]) || scale[i,3] ||
         (if (m := n[scale[i,2]:0]) ~= 0 then " and " || spell(m) else "")
      }
   else fail                                                # really big
end