Start of Apache

[hcoop/domtool2.git] / src / env.sml

diff --git a/src/env.sml b/src/env.sml
index 167adce..d9905dd 100644 (file)
--- a/src/env.sml
+++ b/src/env.sml
@@ -69,6 +69,20 @@ fun post () = !pst ()
 
 end
 
+local
+    val pr = ref (fn () => ())
+in
+
+fun registerPreTycheck f =
+    let
+       val old = !pr
+    in
+       pr := (fn () => (old (); f ()))
+    end
+fun preTycheck () = !pr ()
+
+end
+
 fun badArgs (name, args) =
     (print ("Invalid arguments to " ^ name ^ "\n");
      app (fn arg => Print.preface ("Argument: ", Print.p_exp arg)) args;
@@ -86,6 +100,10 @@ fun int (EInt n, _) = SOME n
 fun string (EString s, _) = SOME s
   | string _ = NONE
 
+fun bool (EVar "false", _) = SOME false
+  | bool (EVar "true", _) = SOME true
+  | bool _ = NONE
+
 fun mapFail f [] = SOME []
   | mapFail f (h :: t) =
     case f h of