[Sml-implementers] flexible records

[Stephen W. <sw...@in...>]

Inspired by Andreas' tests, I was trying to understand type inference with
flexible records.  I created a few more flexrecord examples (below), and tried
them out on the SML compilers that I have around.  The results are in the table
below.  I would be interested to hear if and an explanation of why the
Definition requires any of these examples to succeed.

		SML/NJ	MosML	MLton	MLKit	Poly/ML	MLWorks	Alice
		110.0.7	2.00	011006	4.0.0	4.1.1	2.0	Oper2

flexrecord	+	+	+	+	+	-	+
flexrecord2	-	+	-	+	-
flexrecord3	-	+	-	+	-
flexrecord4	-	-	-	-	-

(* flexrecord2 *)
val _ =
   let
      val g = #foo
      val _ = g {foo = 13}
      val _ = g {foo = "yes"}
   in
      ()
   end
(* flexrecord2 *)

(* flexrecord3 *)
val _ =
   let
      val g = #foo
      val _ = g {foo = 13, goo = 1.0}
      val _ = g {foo = "yes", goo = 1.0}
   in
      ()
   end
(* flexrecord3 *)

(* flexrecord4 *)
val _ =
   let
      val g = #foo
      val _ = g {foo = 13, goo = 1.0}
      val _ = g {foo = "yes", goo = false}
   in
      ()
   end
(* flexrecord4 *)