# HG changeset patch
# User Chris Cannam
# Date 1562077726 -3600
# Node ID 826e0cb77d8e40db3271774c14ed2e717e279eef
# Parent  074b860a78281b72365a60b9fc81a27d70a046e9
Add isa

diff -r 074b860a7828 -r 826e0cb77d8e base/ById.h
--- a/base/ById.h	Tue Jul 02 14:08:25 2019 +0100
+++ b/base/ById.h	Tue Jul 02 15:28:46 2019 +0100
@@ -121,9 +121,15 @@
 public:
     static void add(int, std::shared_ptr<WithId>);
     static void release(int);
-    static std::shared_ptr<WithId> get(int);
+    static std::shared_ptr<WithId> get(int); 
 
     template <typename Derived>
+    static bool isa(int id) {
+        std::shared_ptr<WithId> p = get(id);
+        return bool(std::dynamic_pointer_cast<Derived>(p));
+    }
+   
+    template <typename Derived>
     static std::shared_ptr<Derived> getAs(int id) {
         std::shared_ptr<WithId> p = get(id);
         return std::dynamic_pointer_cast<Derived>(p);
@@ -154,6 +160,11 @@
     }
 
     template <typename Derived>
+    static bool isa(Id id) {
+        return AnyById::isa<Derived>(id.untyped);
+    }
+
+    template <typename Derived>
     static std::shared_ptr<Derived> getAs(Id id) {
         return AnyById::getAs<Derived>(id.untyped);
     }