1 files changed, 44 insertions, 0 deletions
diff --git a/appl/lib/watchvars.b b/appl/lib/watchvars.b
new file mode 100644
index 00000000..ad6c6947
--- /dev/null
+++ b/appl/lib/watchvars.b
@@ -0,0 +1,44 @@
+implement Watchvars;
+include "watchvars.m";
+
+Watchvar[T].new(v: T): Watchvar
+{
+	e := Watchvar[T](chan[1] of (T, chan of T));
+	e.c <-= (v, chan[1] of T);
+	return e;
+}
+
+Watchvar[T].get(e: self Watchvar): T
+{
+	(v, ic) := <-e.c;
+	e.c <-= (v, ic);
+	return v;
+}
+
+Watchvar[T].set(e: self Watchvar, v: T)
+{
+	(ov, ic) := <-e.c;
+	ic <-= v;
+	e.c <-= (v, chan[1] of T);
+}
+
+Watchvar[T].wait(e: self Watchvar): T
+{
+	(v, ic) := <-e.c;
+	e.c <-= (v, ic);
+	v = <-ic;
+	ic <-= v;
+	return v;
+}
+
+Watchvar[T].waitc(e: self Watchvar): (T, chan of T)
+{
+	vic := <-e.c;
+	e.c <-= vic;
+	return vic;
+}
+
+Watchvar[T].waited(nil: self Watchvar, ic: chan of T, v: T)
+{
+	ic <-= v;
+}