X-Git-Url: https://git.hcoop.net/hcoop/domtool2.git/blobdiff_plain/8c57a89d75cc1d4fd050bd3767f9c881b1766c4a..e1b99e23f8d30efc7842ee006e0ff3ef0347b7df:/src/ast.sml

diff --git a/src/ast.sml b/src/ast.sml
index ba00f78..0e8688d 100644
--- a/src/ast.sml
+++ b/src/ast.sml
@@ -105,4 +105,17 @@ type file = string option * decl list * exp option
 fun multiApp (f, loc, args) =
     foldl (fn (arg, e) => (EApp (e, arg), loc)) f args
 
+datatype unification_error =
+	 UnifyPred of pred * pred
+       | UnifyTyp of typ * typ
+       | UnifyOccurs of string * typ
+
+exception Unify of unification_error
+
+datatype type_error =
+	 WrongType of string * exp * typ * typ * unification_error option
+       | WrongForm of string * string * exp * typ * unification_error option
+       | UnboundVariable of string
+       | WrongPred of string * pred * pred
+
 end