fixes, optional type name added

tests/classes.lang

@@ -17,7 +17,7 @@ struct (Complex : #Value) =
 
 struct Task =
   & name : String
-  & duration : Float
+  & duration : Float!
 
 class Employee =
   & name : String

tests/test_code.lang

@@ -149,7 +149,7 @@ typeclass Show =
   & var show : -> String
 
 typeclass Read =
-  & var read : String -> Read
+  & read : String -> Read
 
 typeclass (Str : #Show #Read)
 
@@ -179,9 +179,11 @@ typeclass Enum =
 
 //
 
-decl print : String -> Unit
-decl scan : -> String
-decl random : -> Int // TODO
+namespace IO {
+  decl print : String -> Unit
+  decl scan : -> String
+  decl random : -> Int // TODO
+}
 
 //
 
@@ -211,19 +213,46 @@ def ( -- ) : begin end = {
   })
 }
 
-decl func : String -> Int -> Int
-def func : s i = {
-  ; print: s
-  var x = s
-  ; print: (i.show:)
-  return 5
-}
+// decl func : String -> Int -> Int
+// def func : s i = {
+//   ; print: s
+//   var x = s
+//   ; print: (i.show:)
+//   return 5
+// }
+//
+// exec main {
+//   for i in 0--19 do func: "a" (i * 2 +. 3)
+//   ; print: ({
+//     if true then bring scan: else { ; print: "aaa" }
+//     bring "nothing"
+//     ; print: "aaa"
+//   })
+// }
+
+decl scan_int : -> Int
+def scan_int = Int.read: (IO.scan:)
+
+decl print_int : Int -> Unit
+def print_int : x = IO.print: (x.show:)
+
+decl scan_anything ('A : #Read) : -> 'A
+def scan_anything = 'A.read: (IO.scan:)
+
+decl print_anything ('A : #Show) : 'A -> Unit
+def print_anything : x = IO.print: (x.show:)
+
+/*
+struct Array 'A = & data : 'A_0
+
+namespace Array {
+  decl construct : 'A_0 -> Array
+  def construct: x = $(Array 'A) & data = x
+} // TODO: construct decl + default def -> segfault
+*/
 
 exec main {
-  for i in 0--19 do func: "a" (i * 2 +. 3)
-  ; print: ({
-    if true then bring scan: else { ; print: "aaa" }
-    bring "nothing"
-    ; print: "aaa"
-  })
+  var n = scan_anything Int:
+  var a = for _ in 0--n do scan_int:
+  ; print_anything Int: n
 }