1 files changed, 5 insertions, 1 deletions
diff --git a/elab.sml b/elab.sml
index 52d0089..cc73c98 100644
--- a/elab.sml
+++ b/elab.sml
@@ -5,6 +5,10 @@ struct
   fun primop (s : string) : Syntax.primop =
     case s of
       "exit" => Syntax.PExit
+    | "add" => Syntax.PAdd
+    | "sub" => Syntax.PSub
+    | "mul" => Syntax.PMul
+    | "div" => Syntax.PDiv
     | _ => raise Fail ("invalid op: " ^ s)
 
   fun elab (env : int StringMap.map) (p : Syntax.expr) : Syntax.lexp =
@@ -41,7 +45,7 @@ struct
         end
     | Syntax.ECase (expr, []) => raise Fail "nonexhaustive match"
     | Syntax.ECase (expr, (pat, body) :: rest) =>
-        if rest <> [] then raise Fail "redundant match" else
+        if not (null rest) then raise Fail "redundant match" else
         let val v = Gensym.new () in
           case pat of
             Syntax.PWild => Syntax.LApp (Syntax.LFn (v, elab env body), elab env expr)