54 lines
1.3 KiB
OCaml
54 lines
1.3 KiB
OCaml
type 'a termpc =
|
|
[`And of 'a * 'a
|
|
|`Or of 'a * 'a
|
|
|`Not of 'a
|
|
|`Atom of string
|
|
]
|
|
|
|
type 'a termk =
|
|
[`Dia of 'a
|
|
|`Box of 'a
|
|
|'a termpc
|
|
]
|
|
|
|
module type T = sig
|
|
type term
|
|
val map : (term -> term) -> term -> term
|
|
val nnf : term -> term
|
|
val nnf_not : term -> term
|
|
end
|
|
|
|
module Fpc(X : T with type term = private [> 'a termpc] as 'a) =
|
|
struct
|
|
type term = X.term termpc
|
|
let nnf = function
|
|
|`Not(`Atom _) as x -> x
|
|
|`Not x -> X.nnf_not x
|
|
| x -> X.map X.nnf x
|
|
let map f : term -> X.term = function
|
|
|`Not x -> `Not (f x)
|
|
|`And(x,y) -> `And (f x, f y)
|
|
|`Or (x,y) -> `Or (f x, f y)
|
|
|`Atom _ as x -> x
|
|
let nnf_not : term -> _ = function
|
|
|`Not x -> X.nnf x
|
|
|`And(x,y) -> `Or (X.nnf_not x, X.nnf_not y)
|
|
|`Or (x,y) -> `And (X.nnf_not x, X.nnf_not y)
|
|
|`Atom _ as x -> `Not x
|
|
end
|
|
|
|
module Fk(X : T with type term = private [> 'a termk] as 'a) =
|
|
struct
|
|
type term = X.term termk
|
|
module Pc = Fpc(X)
|
|
let map f : term -> _ = function
|
|
|`Dia x -> `Dia (f x)
|
|
|`Box x -> `Box (f x)
|
|
|#termpc as x -> Pc.map f x
|
|
let nnf = Pc.nnf
|
|
let nnf_not : term -> _ = function
|
|
|`Dia x -> `Box (X.nnf_not x)
|
|
|`Box x -> `Dia (X.nnf_not x)
|
|
|#termpc as x -> Pc.nnf_not x
|
|
end
|