Bug fix for tensor::replace_contr_index().

[ginac.git] / ginac / ex.h

diff --git a/ginac/ex.h b/ginac/ex.h
index 60ffa12934047f2054e3549be071d77849c6ea1a..3070b7ada020d68c917907b77434315b8992c12e 100644 (file)
--- a/ginac/ex.h
+++ b/ginac/ex.h
@@ -65,10 +65,11 @@ class const_preorder_iterator;
 class const_postorder_iterator;
 
 
-/** Lightweight wrapper for GiNaC's symbolic objects.  Basically all it does is
- *  to hold a pointer to the other objects, manage the reference counting and
- *  provide methods for manipulation of these objects.  (Some people call such
- *  a thing a proxy class.) */
+/** Lightweight wrapper for GiNaC's symbolic objects.  It holds a pointer to
+ *  the other object in order to do garbage collection by the method of
+ *  reference counting.  I.e., it is a smart pointer.  Also, the constructor
+ *  ex::ex(const basic & other) calls the methods that do automatic
+ *  evaluation.  E.g., x-x turns automatically into 0. */
 class ex {
        friend class archive_node;
        friend inline bool are_ex_trivially_equal(const ex &, const ex &);
@@ -686,6 +687,7 @@ struct ex_swap : public std::binary_function<ex, ex, void> {
 
 // Make it possible to print exvectors and exmaps
 std::ostream & operator<<(std::ostream & os, const exvector & e);
+std::ostream & operator<<(std::ostream & os, const exset & e);
 std::ostream & operator<<(std::ostream & os, const exmap & e);
 
 // wrapper functions around member functions