/* 

  Spelling numbers (English) in Picat.

  From my Euler #17 program:
  http://www.hakank.org/picat/euler17.pi


  This Picat model was created by Hakan Kjellerstrand, hakank@gmail.com
  See also my Picat page: http://www.hakank.org/picat/

*/


% import util.
% import cp.


main => go.


go =>
  foreach(N in 1..10) 
    println(english(N))
  end,  
  
  nl.

go2 =>

  foreach(I in 1..10) 
    N = 1+(random2() mod 10**I),
    println([N,english(N)])
  end,  
  
  nl.


english(N) = English =>
    Divs      =  [1000000000, 1000000,  1000,       100],
    Divnames  =  ["billion", "million", "thousand", "hundred"],
    Prefixes  =  ["0", "twen", "thir", "for", "fif", "six", "seven", "eigh", "nine"],
    _Ordinals  = ["first", "second", "third", "fourth", "fifth", "sixth", "seventh",
                  "eighth", "ninth", "tenth", "eleventh", "twelfth", "thirteenth", 
                  "fourteenth","fifteenth", "sixteenth", "seventeenth", 
                  "eighteenth", "nineteenth"],
    Cardinals =  ["one", "two", "three", "four", "five", "six", "seven",
                  "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen",
                  "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"],

    Sstr = "",
    Printed = 0,
    if N < 0 then
        Sstr := "minus" ++ Sstr,
        N := -N
    end,
    foreach(I in 1..Divs.length) 
        D = N div Divs[I],
        N := N mod Divs[I],
        if D != 0 then
	    Sstr := Sstr ++ english(D) ++ Divnames[I],
	    Printed := 1
        end
    end,
    if N > 0, Printed = 1 then
        Sstr := Sstr ++ " and "
    end,
    if N == 0 then      
        1 == 1 % dummy
    elseif N > 19 then
        D = N div 10,
        N := N mod 10,
        Sstr := Sstr ++ Prefixes[D] ++ "ty" ++ english(N)
    else 
        Sstr := Sstr ++ Cardinals[N]
    end,
    English = Sstr.