implemented generic converters

tests/compile/tsecondarrayproperty.nim

@@ -0,0 +1,28 @@
+
+type
+  TFoo = object
+    data: array[0..100, int]
+  TSecond = distinct TFoo
+
+proc `[]` (self: var TFoo, x: int): var int =
+  return self.data[x]
+
+proc `[]=` (self: var TFoo, x, y: int) =
+  # only `[]` returning a 'var T' seems to not work for now :-/
+  self.data[x] = y
+
+proc second(self: var TFoo): var TSecond =
+  return TSecond(self)
+
+proc `[]`(self: var TSecond, x: int): var int =  
+  return TFoo(self).data[2*x]
+
+var f: TFoo
+
+for i in 0..f.data.high: f[i] = 2 * i
+
+echo f.second[1]
+
+#echo `second[]`(f,1)
+# this is the only way I could use it, but not what I expected
+

tests/run/tgenericconverter.nim

@@ -0,0 +1,30 @@
+discard """
+  output: '''666
+666'''
+"""
+
+# test the new generic converters:
+
+type
+  TFoo2[T] = object
+    x: T
+
+  TFoo[T] = object
+    data: array[0..100, T]
+
+converter toFoo[T](a: TFoo2[T]): TFoo[T] =
+  result.data[0] = a.x
+
+proc p(a: TFoo[int]) =
+  echo a.data[0]
+
+proc q[T](a: TFoo[T]) =
+  echo a.data[0]
+
+
+var
+  aa: TFoo2[int]
+aa.x = 666
+
+p aa
+q aa