* combi.c (comb_hash_while_fun, comb_hash_gen_fun, comb_hash): New

static functions.
(comb): Support hash tables.

* hash.c (print_key_val): When values are nil, print in a more condensed
way by omitting the second element. This notation is accepted as
input already by the parser.
(hash_insert_pair): New function.

* txr.1: Description of comb updated to indicate that it works over
hashes.

1 files changed, 8 insertions, 6 deletions

diff --git a/txr.1 b/txr.1
index f7b65d7d..2d7f5274 100644
--- a/txr.1
+++ b/txr.1
@@ -7957,18 +7957,20 @@ length <len> non-repeating combinations formed by taking items taken from
 element of <seq> more than once. If <seq> contains no duplicates, then
 the combinations contain no duplicates.
 
-Argument <len> must be a nonnegative integer, and <seq> must be a sequence.
+Argument <len> must be a nonnegative integer, and <seq> must be a sequence
+or a hash table.
 
-The combinations in the returned list are sequences of the same kind as <seq>.
+The combinations in the returned list are objects of the same kind as <seq>.
 
 If <len> is zero, then a list containing one combination is returned, and that
 permutations is of zero length.
 
-If <len> exceeds the length of <seq>, then an empty list is returned,
-since it is impossible to make a single non-repeating combination that
-requires more items than are available.
+If <len> exceeds the number of elements in <seq>, then an empty list is
+returned, since it is impossible to make a single non-repeating combination
+that requires more items than are available.
 
-The combinations are lexicographically ordered.
+If <seq> is a sequence, the returned combinations are lexicographically ordered.
+This requirement is not applicable when <seq> is a hash table.
 
 .SS Function rcomb