graph: imported graph as a subtree

graph/internal/set/same_appengine.go

@@ -0,0 +1,18 @@
+// Copyright ©2014 The gonum Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//+build appengine
+
+package set
+
+import "reflect"
+
+// same determines whether two sets are backed by the same store. In the
+// current implementation using hash maps it makes use of the fact that
+// hash maps are passed as a pointer to a runtime Hmap struct. A map is
+// not seen by the runtime as a pointer though, so we use reflect to get
+// the maps' pointer values to compare.
+func same(a, b Nodes) bool {
+	return reflect.ValueOf(a).Pointer() == reflect.ValueOf(b).Pointer()
+}