[lib] Split auxiliary libraries into Coq-specific and general.

Up to this point the `lib` directory contained two different library
archives, `clib.cma` and `lib.cma`, which a rough splitting between
Coq-specific libraries and general-purpose ones.

We know split the directory in two, as to make the distinction clear:

- `clib`: contains libraries that are not Coq specific and implement
  common data structures and programming patterns. These libraries
  could be eventually replace with external dependencies and the rest
  of the code base wouldn't notice much.

- `lib`: contains Coq-specific common libraries in widespread use
  along the codebase, but that are not considered part of other
  components. Examples are printing, error handling, or flags.

In some cases we have coupling due to utility files depending on Coq
specific flags, however this commit doesn't modify any files, but only
moves them around, further cleanup is welcome, as indeed a few files
in `lib` should likely be placed in `clib`.

Also note that `Deque` is not used ATM.

1 files changed, 81 insertions, 0 deletions

diff --git a/clib/iStream.mli b/clib/iStream.mli
new file mode 100644
index 000000000..cd7940e8d
--- /dev/null
+++ b/clib/iStream.mli
@@ -0,0 +1,81 @@
+(************************************************************************)
+(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
+(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2017     *)
+(*   \VV/  **************************************************************)
+(*    //   *      This file is distributed under the terms of the       *)
+(*         *       GNU Lesser General Public License Version 2.1        *)
+(************************************************************************)
+
+(** {5 Purely functional streams}
+
+  Contrarily to OCaml module [Stream], these are meant to be used purely
+  functionally. This implies in particular that accessing an element does not
+  discard it. *)
+
+type +'a t
+(** Type of pure streams. *)
+
+type ('a,'r) u =
+| Nil
+| Cons of 'a * 'r
+(** View type to decompose and build streams. *)
+
+(** {6 Constructors} *)
+
+val empty : 'a t
+(** The empty stream. *)
+
+val cons : 'a -> 'a t -> 'a t
+(** Append an element in front of a stream. *)
+
+val thunk : (unit -> ('a,'a t) u) -> 'a t
+(** Internalize the lazyness of a stream. *)
+
+val make : ('a -> ('b, 'a) u) -> 'a -> 'b t
+(** Coiteration constructor. *)
+
+(** {6 Destructors} *)
+
+val is_empty : 'a t -> bool
+(** Whethere a stream is empty. *)
+
+val peek : 'a t -> ('a , 'a t) u
+(** Return the head and the tail of a stream, if any. *)
+
+(** {6 Standard operations}
+
+    All stream-returning functions are lazy. The other ones are eager. *)
+
+val app : 'a t -> 'a t -> 'a t
+(** Append two streams. Not tail-rec. *)
+
+val map : ('a -> 'b) -> 'a t -> 'b t
+(** Mapping of streams. Not tail-rec. *)
+
+val iter : ('a -> unit) -> 'a t -> unit
+(** Iteration over streams. *)
+
+val fold : ('a -> 'b -> 'a) -> 'a -> 'b t -> 'a
+(** Fold over streams. *)
+
+val concat : 'a t t -> 'a t
+(** Appends recursively a stream of streams. *)
+
+val map_filter : ('a -> 'b option) -> 'a t -> 'b t
+(** Mixing [map] and [filter]. Not tail-rec. *)
+
+val concat_map : ('a -> 'b t) -> 'a t -> 'b t
+(** [concat_map f l] is the same as [concat (map f l)]. *)
+
+(** {6 Conversions} *)
+
+val of_list : 'a list -> 'a t
+(** Convert a list into a stream. *)
+
+val to_list : 'a t -> 'a list
+(** Convert a stream into a list. *)
+
+(** {6 Other}*)
+
+val force : 'a t -> 'a t
+(** Forces the whole stream. *)