New function: hist-sort-by.

* eval.c (eval_init): Register hist-sort-by intrinsic.

* lib.c (hist_sort_by): New function.
(hist_sort): Wrapper for hist_sort_by now.

* lib.h (hist_sort_by): Declared.

* tests/012/sort.tl: Tests.

* txr.1: Documented.

1 files changed, 7 insertions, 2 deletions

diff --git a/lib.c b/lib.c
index c5722241..e1ca5e9e 100644
--- a/lib.c
+++ b/lib.c
@@ -11600,14 +11600,19 @@ static val hist_succ(val left, val right)
   return succ(left);
 }
 
-val hist_sort(val seq, varg hashv_args)
+val hist_sort_by(val fun, val seq, varg hashv_args)
 {
   val hash = group_reduce(hashv(hashv_args),
-                          identity_f, hist_succ_f,
+                          fun, hist_succ_f,
                           seq, zero, nil);
   return nsort(hash_alist(hash), gt_f, cdr_f);
 }
 
+val hist_sort(val seq, varg hashv_args)
+{
+  return hist_sort_by(identity_f, seq, hashv_args);
+}
+
 val nrot(val seq, val n_in)
 {
   val len = length(seq);