iterators.tm

(33 lines)
   1 
   2 struct Pair(x:Text, y:Text)
   3 
   4 func pairwise(strs:[Text] -> func(->Pair?))
   5     i := 1
   6     return func(-> Pair?)
   7         i += 1
   8         return Pair(strs[i-1] or return none, strs[i] or return none)
   9 
  10 func range(first:Int, last:Int -> func(->Int?))
  11     i := first
  12     return func(->Int?)
  13         if i > last
  14             return none
  15         i += 1
  16         return (i-1)
  17 
  18 func main()
  19     values := ["A", "B", "C", "D"]
  20 
  21     assert (++: "($(foo.x)$(foo.y))" for foo in pairwise(values))! == "(AB)(BC)(CD)"
  22     assert ["$(foo.x)$(foo.y)" for foo in pairwise(values)] == ["AB", "BC", "CD"]
  23 
  24     do
  25         result : @[Text]
  26         for foo in pairwise(values)
  27             result.insert("$(foo.x)$(foo.y)")
  28         assert result[] == ["AB", "BC", "CD"]
  29 
  30     assert [i for i in range(5, 10)] == [5, 6, 7, 8, 9, 10]
  31 
  32     assert (+: range(5, 10))! == 45
  33