Add external functions called during reduction

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

diff --git a/src/env.sml b/src/env.sml
index 167adce..f87278f 100644 (file)
--- a/src/env.sml
+++ b/src/env.sml
@@ -41,6 +41,11 @@ fun registerContainer (name, befor, after) =
     containers := SM.insert (!containers, name, (befor, after))
 fun container name = SM.find (!containers, name)
 
+val functions : (exp list -> exp option) SM.map ref = ref SM.empty
+fun registerFunction (name, f) =
+    functions := SM.insert (!functions, name, f)
+fun function name = SM.find (!functions, name)
+
 local
     val pr = ref (fn () => ())
 in
@@ -69,6 +74,20 @@ 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 +105,10 @@ 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
@@ -117,6 +140,14 @@ fun two func (name1, arg1, name2, arg2) f (_, [e1, e2]) =
                                SM.empty))
   | two func _ _ (_, es) = badArgs (func, es)
 
+fun three func (name1, arg1, name2, arg2, name3, arg3) f (_, [e1, e2, e3]) =
+    (case (arg1 e1, arg2 e2, arg3 e3) of
+        (NONE, _, _) => badArg (func, name1, e1)
+       | (_, NONE, _) => badArg (func, name2, e2)
+       | (_, _, NONE) => badArg (func, name3, e3)
+       | (SOME v1, SOME v2, SOME v3) => (f (v1, v2, v3);
+                                        SM.empty))
+  | three func _ _ (_, es) = badArgs (func, es)
 
 fun oneV func (name, arg) f (evs, [e]) =
     (case arg e of
@@ -151,6 +182,7 @@ fun type_one func arg f =
 fun action_none name f = registerAction (name, none name f)
 fun action_one name args f = registerAction (name, one name args f)
 fun action_two name args f = registerAction (name, two name args f)
+fun action_three name args f = registerAction (name, three name args f)
 
 fun actionV_none name f = registerAction (name, fn (env, _) => (f env; env))
 fun actionV_one name args f = registerAction (name, oneV name args f)