stated relations between vector, string, list, general sequence procedures

s48/sequences/README

@@ -108,9 +108,32 @@ the maker of the actual type of the (first) sequence argument.
 Sequence arguments of vector and absequence procedures must be vectors
 resp. absequences, notwithstanding the generic parameter name S used below.
 Sequence arguments of general sequence procedures may have different
-actual sequence types, e.g. (SEQUENCE-EVERY CHAR=? "abc" '#(#\a)) is
+actual sequence types, e.g. (SEQUENCES-EVERY CHAR=? "abc" '#(#\a)) is
 ok since both String and Vector <= Sequence.
 
+Equivalences
+  as far as the specs go, that is: the equivalences don't extend to
+unspecified behaviour but I didn't bother to spell this out in detail.
+The stated equivalences may have to suffer from exceptions as the
+library grows, but please report deviations anyway.
+
+* (sequences-foo x ...) = (sequence-foo x ...) and
+  (vectors-foo x ...) = (vector-foo x ...)
+  if the arg.list is admissible for both procedures.
+  [ SEQUENCES-procedures don't support optional [start:end)
+  parameters;  SEQUENCE-procedures don't support an arbitrary number
+  of sequence arguments.  Same for vectors. ]
+
+* if all sequence arguments to a general sequence procedure are
+  vectors the result is that of the corresponding vector procedure.
+  E.g. ``sequence-map = vector-map'' on vectors.
+
+* if all sequence arguments to a general sequence procedure are lists
+  (strings) and there is a corresponding list (string) procedure in
+  the respective srfi, the result complies with the srfi spec.
+  E.g. ``sequences-fold = fold'' on lists,
+       ``sequence-fold = string-fold'' on strings.
+
 
 * Predicates