update of README

README.md

@@ -2,7 +2,24 @@ ocaml-containers
 ================
 
 A bunch of containers,written in different occasions. Probably not very high
-quality, since not all containers are tested. 
+quality, since not all containers are tested (yet). 
+
+The design is centerred around polymorphism rather than functors. Such
+structures comprise:
+
+- `PHashtbl`, a polymorphic hashtable (with open addressing)
+- `SplayTree`, a polymorphic splay heap implementation
+- `Heap`, an imperative heap based on `SplayTree`
+- `Graph`, a polymorphic imperative directed graph (on top of `PHashtbl`)
+- `Hashset`, a polymorphic imperative set on top of `PHashtbl`
+
+Other structures (not touched for months, may not work properly) are:
+
+- `Cache`, a low level memoization cache for pairs of keys
+- `Vector`, a growable array (pure OCaml, no C)
+- `Deque`, an imperative double ended FIFO (double-linked list)
+- `FlatHashtbl`, a deprecated open addressing hashtable with
+    a functorial interface (replaced by PHashtbl)
 
 ## Use
 
@@ -11,6 +28,8 @@ files to your own project. The last solution has the benefits that you
 don't have additional dependencies nor build complications (and it may enable
 more inlining). I therefore recommand it for its simplicity.
 
+If you have comments, requests, or bugfixes, please share them! :-)
+
 ## Build
 
 You need the library `sequence`. With opam, type `opam install sequence`.
@@ -21,11 +40,16 @@ Then:
 
 To build and run tests (requires `oUnit`):
 
+    $ opam install oUnit
     $ make tests
     $ ./tests.native
 
+To build the small benchmarking suite (requires `Bench`):
+
+    $ opam install bench
+    $ make bench
+    $ ./benchs.native
+
 ## License
 
-This code is free, under the BSD license. The module `leftistheap` is due
+This code is free, under the BSD license.
-to [Jean-Christophe Filliâtre](https://www.lri.fr/~filliatr/), under
-the GPL license.