Improved the comments explaining what the class ex does.

[ginac.git] / ginac / ex.h

diff --git a/ginac/ex.h b/ginac/ex.h
index 228b44e5450474754253f38eae94041f5b66270e..574e6800774b4b0304f556ffe5ea03426951f890 100644 (file)
--- a/ginac/ex.h
+++ b/ginac/ex.h
@@ -52,6 +52,12 @@ private:
 /** For construction of flyweights, etc. */
 static library_init library_initializer;
 
+/** Rotate bits of unsigned value by one bit to the left.
+  * This can be necesary if the user wants to define its own hashes. */
+inline unsigned rotate_left(unsigned n)
+{
+       return (n & 0x80000000U) ? (n << 1 | 0x00000001U) : (n << 1);
+}
 
 class scalar_products;
 class const_iterator;
@@ -59,10 +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 &);