1 files changed, 9 insertions, 0 deletions
diff --git a/src/mono_opt.sml b/src/mono_opt.sml
index dfa0420c..205ae3fb 100644
--- a/src/mono_opt.sml
+++ b/src/mono_opt.sml
@@ -30,6 +30,8 @@ structure MonoOpt :> MONO_OPT = struct
 open Mono
 structure U = MonoUtil
 
+val bless = ref (fn _ : string => true)
+
 fun typ t = t
 fun decl d = d
 
@@ -371,6 +373,13 @@ fun exp e =
 
       | EJavaScript (_, _, SOME (e, _)) => e
 
+      | EFfiApp ("Basis", "bless", [(se as EPrim (Prim.String s), loc)]) =>
+        (if !bless s then
+             ()
+         else
+             ErrorMsg.errorAt loc "Invalid URL passed to 'bless'";
+         se)
+
       | EFfiApp ("Basis", "checkString", [(EPrim (Prim.String s), loc)]) => 
         let
             fun uwify (cs, acc) =