mirror of
https://github.com/c-cube/ocaml-containers.git
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139 lines
2.7 KiB
OCaml
139 lines
2.7 KiB
OCaml
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(* This file is free software, part of containers. See file "license" for more details. *)
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(** {1 Comparisons} *)
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type 'a t = 'a -> 'a -> int
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(** Comparison (total ordering) between two elements, that returns an int *)
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let compare = Pervasives.compare
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let opp f x y = - (f x y)
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let equiv i j =
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if i<0 then j<0
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else if i>0 then j>0
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else j=0
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(*$T
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equiv 1 2
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equiv ~-1 ~-10
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equiv 0 0
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equiv ~-1 ~-1
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not (equiv 0 1)
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not (equiv 1 ~-1)
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not (equiv 1 0)
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*)
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(*$Q
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Q.(pair int int) (fun (x,y) -> \
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(equiv x y) = (equiv y x))
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Q.(triple int int int) (fun (x,y,z) -> \
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if (equiv x y && equiv y z) then (equiv x z) else true)
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*)
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let int (x:int) y = Pervasives.compare x y
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let string (x:string) y = Pervasives.compare x y
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let bool (x:bool) y = Pervasives.compare x y
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let float (x:float) y = Pervasives.compare x y
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(*$T
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bool true false > 0
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bool false true < 0
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bool true true = 0
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bool false false = 0
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*)
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(** {2 Lexicographic Combination} *)
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let (<?>) c (ord,x,y) =
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if c = 0
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then ord x y
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else c
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let option c o1 o2 = match o1, o2 with
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| None, None -> 0
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| None, Some _ -> -1
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| Some _, None -> 1
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| Some x1, Some x2 -> c x1 x2
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(*$Q
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Q.(option int) (fun o -> option int None o <= 0)
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*)
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let pair o_x o_y (x1,y1) (x2,y2) =
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let c = o_x x1 x2 in
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if c = 0
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then o_y y1 y2
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else c
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(*$T
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pair int string (1, "b") (2, "a") < 0
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pair int string (1, "b") (0, "a") > 0
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pair int string (1, "b") (1, "b") = 0
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*)
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let triple o_x o_y o_z (x1,y1,z1) (x2,y2,z2) =
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let c = o_x x1 x2 in
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if c = 0
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then
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let c' = o_y y1 y2 in
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if c' = 0
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then o_z z1 z2
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else c'
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else c
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let rec list ord l1 l2 = match l1, l2 with
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| [], [] -> 0
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| [], _ -> -1
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| _, [] -> 1
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| x1::l1', x2::l2' ->
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let c = ord x1 x2 in
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if c = 0
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then list ord l1' l2'
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else c
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(*$T
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list int [1;2;3] [1;2;3;4] < 0
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list int [1;2;3;4] [1;2;3] > 0
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list int [1;2;3;4] [1;3;4] < 0
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*)
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(*$Q
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Q.(pair (list int)(list int)) CCOrd.(fun (l1,l2) -> \
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equiv (list int l1 l2) (Pervasives.compare l1 l2))
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*)
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let array ord a1 a2 =
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let rec aux i =
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if i = Array.length a1
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then if Array.length a1 = Array.length a2 then 0
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else -1
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else if i = Array.length a2
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then 1
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else
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let c = ord a1.(i) a2.(i) in
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if c = 0
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then aux (i+1) else c
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in
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aux 0
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(*$T
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array int [|1;2;3|] [|1;2;3;4|] < 0
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array int [|1;2;3;4|] [|1;2;3|] > 0
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array int [|1;2;3;4|] [|1;3;4|] < 0
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*)
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(*$Q & ~small:(fun (a1, a2) -> Array.length a1+Array.length a2)
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Q.(pair (array int)(array int)) CCOrd.(fun (a1,a2) -> \
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equiv (array int a1 a2) (list int (Array.to_list a1) (Array.to_list a2)))
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*)
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let map f ord a b = ord (f a) (f b)
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let (>|=) x f = map f x
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module Infix = struct
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let (>|=) = (>|=)
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let (<?>) = (<?>)
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end
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