basic combinators for ordering (including lexico combination)

_oasis

@@ -41,7 +41,7 @@ Library "containers"
   Modules:          CCVector, CCDeque, CCGen, CCSequence, CCFQueue, CCMultiMap,
                     CCMultiSet, CCBV, CCPrint, CCPersistentHashtbl,
                     CCLeftistheap, CCList, CCOpt, CCPair, CCFun, CCHash,
-                    CCKList, CCInt, CCBool, CCArray, CCBatch, CCLinq
+                    CCKList, CCInt, CCBool, CCArray, CCBatch, CCOrd, CCLinq
   FindlibName:      containers
 
 Library "containers_string"

core/CCOrd.ml

@@ -0,0 +1,55 @@
+
+(*
+copyright (c) 2013-2014, simon cruanes
+all rights reserved.
+
+redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+redistributions of source code must retain the above copyright notice, this
+list of conditions and the following disclaimer.  redistributions in binary
+form must reproduce the above copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other materials provided with
+the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*)
+
+(** {1 Comparisons} *)
+
+type 'a t = 'a -> 'a -> int
+(** Comparison (total ordering) between two elements, that returns an int *)
+
+let compare = Pervasives.compare
+
+let int_ (x:int) y = Pervasives.compare x y
+let string_ (x:string) y = Pervasives.compare x y
+let bool_ (x:bool) y = Pervasives.compare x y
+let float_ (x:float) y = Pervasives.compare x y
+
+(** {2 Lexicographic Combination} *)
+
+let (<?>) c (ord,x,y) =
+  if c = 0
+    then ord x y
+    else c
+
+let rec list_ ord l1 l2 = match l1, l2 with
+  | [], [] -> 0
+  | [], _ -> -1
+  | _, [] -> 1
+  | x1::l1', x2::l2' ->
+      let c = ord x1 x2 in
+      if c = 0
+        then list_ ord l1' l2'
+        else c
+

core/CCOrd.mli

@@ -0,0 +1,54 @@
+
+(*
+copyright (c) 2013-2014, simon cruanes
+all rights reserved.
+
+redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+redistributions of source code must retain the above copyright notice, this
+list of conditions and the following disclaimer.  redistributions in binary
+form must reproduce the above copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other materials provided with
+the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*)
+
+(** {1 Comparisons} *)
+
+type 'a t = 'a -> 'a -> int
+(** Comparison (total ordering) between two elements, that returns an int *)
+
+val compare : 'a t
+(** Polymorphic "magic" comparison *)
+
+val int_ : int t
+val string_ : string t
+val bool_ : bool t
+val float_ : float t
+
+(** {2 Lexicographic Combination} *)
+
+val (<?>) : int -> ('a t * 'a * 'a) -> int
+(** [c1 @@? (ord, x, y)] returns the same as [c1] if [c1] is not [0];
+    otherwise it uses [ord] to compare the two values [x] and [y],
+    of type ['a].
+
+    Example:
+    {[CCInt.compare 1 3
+      <?> (String.compare, "a", "b")
+      <?> (CCBool.compare, true, false)]}
+*)
+
+val list_ : 'a t -> 'a list t
+(** Lexicographic combination on lists *)