[Assorted-commits] SF.net SVN: assorted:[1262] sandbox/trunk/src/cc/fwd.cc

[<yan...@us...>]

Revision: 1262
          http://assorted.svn.sourceforge.net/assorted/?rev=1262&view=rev
Author:   yangzhang
Date:     2009-03-06 20:54:16 +0000 (Fri, 06 Mar 2009)

Log Message:
-----------
added demo of using templates to circumvent forward declarations

Added Paths:
-----------
    sandbox/trunk/src/cc/fwd.cc

Added: sandbox/trunk/src/cc/fwd.cc
===================================================================
--- sandbox/trunk/src/cc/fwd.cc	                        (rev 0)
+++ sandbox/trunk/src/cc/fwd.cc	2009-03-06 20:54:16 UTC (rev 1262)
@@ -0,0 +1,57 @@
+// This doesn't work: invalid use of incomplete type.
+#if 0
+struct container;
+struct iter {
+  container &c;
+  int *p;
+  iter(container &c) : c(c), p(&c.value()) {}
+};
+struct container {
+  int x;
+  int &value() { return x; }
+  iter begin() { return iter(*this); }
+};
+int main() {
+  container c;
+  c.begin();
+  return 0;
+}
+#endif
+
+// This *does* work.
+template<typename T> struct container;
+template<typename T> struct iter {
+  container<T> &c;
+  T *p;
+  iter(container<T> &c) : c(c), p(&c.value()) {}
+};
+template<typename T> struct container {
+  T x;
+  T &value() { return x; }
+  iter<T> begin() { return iter<T>(*this); }
+};
+int main() {
+  container<int> c;
+  c.begin();
+  return 0;
+};
+
+// This doesn't work either.
+#if 0
+template<typename T> struct container;
+template<typename T> struct iter {
+  container<int> &c;
+  int *p;
+  iter(container<int> &c) : c(c), p(&c.value()) {}
+};
+template<typename T> struct container {
+  int x;
+  int &value() { return x; }
+  iter<int> begin() { return iter<int>(*this); }
+};
+int main() {
+  container<int> c;
+  c.begin();
+  return 0;
+}
+#endif


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