From 0a58a380d8a92b5f29d24a8c6f99826fc3bdf61a Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Tue, 2 Apr 2013 23:48:51 +0200
Subject: [PATCH] added Gen.compare and Gen.eq functions

---
 gen.ml  | 27 +++++++++++++++++++++------
 gen.mli |  6 ++++++
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/gen.ml b/gen.ml
index c95afe14..281cbe27 100644
--- a/gen.ml
+++ b/gen.ml
@@ -398,7 +398,20 @@ let max ?(lt=fun x y -> x < y) enum =
   let first = try gen () with EOG -> raise Not_found in
   Gen.fold (fun max x -> if lt max x then x else max) first gen
 
-let lexico ?(cmp=compare) e1 e2 =
+let eq ?(eq=(=)) e1 e2 =
+  let gen1 = e1 ()
+  and gen2 = e2 () in
+  let rec check () =
+    let x1 = try Some (gen1 ()) with EOG -> None in
+    let x2 = try Some (gen2 ()) with EOG -> None in
+    match x1, x2 with
+    | None, None -> true
+    | Some x1, Some x2 when eq x1 x2 -> check ()
+    | _ -> false
+  in
+  check ()
+
+let lexico ?(cmp=Pervasives.compare) e1 e2 =
   let gen1 = e1() in
   let gen2 = e2() in
   let rec lexico () =
@@ -413,6 +426,8 @@ let lexico ?(cmp=compare) e1 e2 =
     | None, Some _ -> -1
   in lexico ()
 
+let compare ?cmp e1 e2 = lexico ?cmp e1 e2
+
 (** {2 Complex combinators} *)
 
 (** Pick elements fairly in each sub-enum *)
@@ -511,7 +526,7 @@ end
 
 (** Intersection of two sorted sequences. Only elements that occur in both
     inputs appear in the output *)
-let intersection ?(cmp=compare) e1 e2 =
+let intersection ?(cmp=Pervasives.compare) e1 e2 =
   fun () ->
     let gen1, gen2 = e1 (), e2 () in
     let next1 () = try Some (gen1 ()) with EOG -> None in
@@ -534,7 +549,7 @@ let intersection ?(cmp=compare) e1 e2 =
     in next
 
 (** Binary sorted merge of two sorted sequences *)
-let sorted_merge ?(cmp=compare) e1 e2 =
+let sorted_merge ?(cmp=Pervasives.compare) e1 e2 =
   fun () ->
     let gen1, gen2 = e1 (), e2 () in
     let next1 () = try Some (gen1 ()) with EOG -> None in
@@ -557,7 +572,7 @@ let sorted_merge ?(cmp=compare) e1 e2 =
 
 (** Assuming subsequences are sorted in increasing order, merge them
     into an increasing sequence *)
-let sorted_merge_n ?(cmp=compare) enum =
+let sorted_merge_n ?(cmp=Pervasives.compare) enum =
   fun () ->
     (* make a heap of (value, generator) *)
     let cmp (v1,_) (v2,_) = cmp v1 v2 in
@@ -791,7 +806,7 @@ let uniq ?(eq=(=)) enum =
       else (prev := x; x)
     in next
 
-let sort ?(cmp=compare) enum =
+let sort ?(cmp=Pervasives.compare) enum =
   fun () ->
     (* build heap *)
     let h = Heap.empty ~cmp in
@@ -801,7 +816,7 @@ let sort ?(cmp=compare) enum =
         then raise EOG
         else Heap.pop h
 
-let sort_uniq ?(cmp=compare) enum =
+let sort_uniq ?(cmp=Pervasives.compare) enum =
   uniq ~eq:(fun x y -> cmp x y = 0) (sort ~cmp enum)
 
 (*
diff --git a/gen.mli b/gen.mli
index 2a1f7550..5fbdf593 100644
--- a/gen.mli
+++ b/gen.mli
@@ -193,9 +193,15 @@ val min : ?lt:('a -> 'a -> bool) -> 'a t -> 'a
 val max : ?lt:('a -> 'a -> bool) -> 'a t -> 'a
   (** Maximum element *)
 
+val eq : ?eq:('a -> 'a -> bool) -> 'a t -> 'a t -> bool
+  (** Equality of generators. *)
+
 val lexico : ?cmp:('a -> 'a -> int) -> 'a t -> 'a t -> int
   (** Lexicographic comparison of generators *)
 
+val compare : ?cmp:('a -> 'a -> int) -> 'a t -> 'a t -> int
+  (** Synonym for {! lexico} *)
+
 (** {2 Complex combinators} *)
 
 val merge : 'a t t -> 'a t