- subs() can be used to substitute functions, tensors and indexed objects

- op(0) of an idx object returns the index value; a nice side-effect of
  this is that idx'es no longer all have the same hash value

diff --git a/NEWS b/NEWS
index 2283ab9082e9eda5101a401610a7e00878205ec2..a2ef2d1fac86302e9da0584923c1b8cb7f9f86de 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -12,6 +12,8 @@ This file records noteworthy changes.
      gamma~0 in p.mu*gamma~mu should be p.0 but is returned as 0
    - using coeff(), tcoeff(), lcoeff() or collect() on elements of
      noncommutative products might return wrong or surprising results
+* Likewise, subs() can be used to substitute functions, tensors and indexed
+  expressions.
 * Added preliminary (re)implementations of color and clifford classes.
 * simplify_indexed(): contraction of symmetric and antisymmetric tensors
   is zero.