types.ml 20.5 KB
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open Recursive
open Printf
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type label = int
type atom  = int
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type const = Integer of Big_int.big_int | Atom of atom | Char of Chars.Unichar.t
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module I = struct
  type 'a t = {
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    ints  : Intervals.t;
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    atoms : atom Atoms.t;
    times : ('a * 'a) Boolean.t;
    arrow : ('a * 'a) Boolean.t;
    record: (label * bool * 'a) Boolean.t;
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    chars : Chars.t;
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  }
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  let empty = { 
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    times = Boolean.empty; 
    arrow = Boolean.empty; 
    record= Boolean.empty;
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    ints  = Intervals.empty;
    atoms = Atoms.empty;
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    chars = Chars.empty;
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  }
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  let any =  {
    times = Boolean.full; 
    arrow = Boolean.full; 
    record= Boolean.full; 
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    ints  = Intervals.any;
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    atoms = Atoms.full;
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    chars = Chars.full;
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  }
	       
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  let interval i j = { empty with ints = Intervals.atom i j }
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  let times x y = { empty with times = Boolean.atom (x,y) }
  let arrow x y = { empty with arrow = Boolean.atom (x,y) }
  let record label opt t = { empty with record = Boolean.atom (label,opt,t) }
  let atom a = { empty with atoms = Atoms.atom a }
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  let char c = { empty with chars = Chars.atom c }
  let char_class c1 c2 = { empty with chars = Chars.char_class c1 c2 }
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  let constant = function
    | Integer i -> interval i i
    | Atom a -> atom a
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    | Char c -> char c
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  let any_record = { empty with record = any.record }

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  let cup x y = 
    if x = y then x else { 
      times = Boolean.cup x.times y.times;
      arrow = Boolean.cup x.arrow y.arrow;
      record= Boolean.cup x.record y.record;
      ints  = Intervals.cup x.ints  y.ints;
      atoms = Atoms.cup x.atoms y.atoms;
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      chars = Chars.cup x.chars y.chars;
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    }
      
  let cap x y = 
    if x = y then x else {
      times = Boolean.cap x.times y.times;
      record= Boolean.cap x.record y.record;
      arrow = Boolean.cap x.arrow y.arrow;
      ints  = Intervals.cap x.ints  y.ints;
      atoms = Atoms.cap x.atoms y.atoms;
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      chars = Chars.cap x.chars y.chars;
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    }
      
  let diff x y = 
    if x = y then empty else { 
      times = Boolean.diff x.times y.times;
      arrow = Boolean.diff x.arrow y.arrow;
      record= Boolean.diff x.record y.record;
      ints  = Intervals.diff x.ints  y.ints;
      atoms = Atoms.diff x.atoms y.atoms;
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      chars = Chars.diff x.chars y.chars;
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    }

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  let neg x = diff any x
		   
  let equal e a b =
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    if not (Intervals.equal a.ints b.ints) then raise NotEqual;
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    if a.atoms <> b.atoms then raise NotEqual;
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    if a.chars <> b.chars then raise NotEqual;
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    Boolean.equal (fun (x1,x2) (y1,y2) -> e x1 y1; e x2 y2) a.times b.times;
    Boolean.equal (fun (x1,x2) (y1,y2) -> e x1 y1; e x2 y2) a.arrow b.arrow;
    Boolean.equal (fun (l1,o1,x1) (l2,o2,x2) -> 
		     if (l1 <> l2) || (o1 <> o2) then raise NotEqual;
		     e x1 x2) a.record b.record
      
  let map f a =
    { times = Boolean.map (fun (x1,x2) -> (f x1, f x2)) a.times;
      arrow = Boolean.map (fun (x1,x2) -> (f x1, f x2)) a.arrow;
      record= Boolean.map (fun (l,o,x) -> (l,o, f x)) a.record;
      ints  = a.ints;
      atoms = a.atoms;
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      chars = a.chars;
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    }
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  let hash h a =
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    (Hashtbl.hash { map h a with ints = Intervals.empty })
    + (Intervals.hash a.ints)
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  let iter f a =
    ignore (map f a)
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  let deep = 4
end
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module Algebra = Recursive.Make(I)
include I
include Algebra
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let check d =
  Boolean.check d.times;
  Boolean.check d.arrow;
  Boolean.check d.record;
  ()
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(*
let define n d = check d; define n d
*)
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let cons d =
  let n = make () in
  define n d;
  internalize n
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module Positive =
struct
  type rhs = [ `Type of descr | `Cup of v list | `Times of v * v ]
  and v = { mutable def : rhs; mutable node : node option }
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  let rec make_descr seen v =
    if List.memq v seen then empty
    else
      let seen = v :: seen in
      match v.def with
	| `Type d -> d
	| `Cup vl -> 
	    List.fold_left (fun acc v -> cup acc (make_descr seen v)) empty vl
	| `Times (v1,v2) -> times (make_node v1) (make_node v2)
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  and make_node v =
    match v.node with
      | Some n -> n
      | None ->
	  let n = make () in
	  v.node <- Some n;
	  let d = make_descr [] v in
	  define n d;
	  n
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  let forward () = { def = `Cup []; node = None }
  let def v d = v.def <- d
  let cons d = let v = forward () in def v d; v
  let ty d = cons (`Type d)
  let cup vl = cons (`Cup vl)
  let times d1 d2 = cons (`Times (d1,d2))
  let define v1 v2 = def v1 (`Cup [v2]) 
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  let solve v = internalize (make_node v)
end
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let get_record r =
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  let add = SortedMap.add (fun (o1,t1) (o2,t2) -> (o1&&o2, cap t1 t2)) in
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  let line (p,n) =
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    let accu = List.fold_left 
		 (fun accu (l,o,t) -> add l (o,descr t) accu) [] p in
    List.fold_left 
      (fun accu (l,o,t) -> add l (not o,neg (descr t)) accu) accu n in
  List.map line r
    

let counter_label = ref 0
let label_table = Hashtbl.create 63
let label_names = Hashtbl.create 63
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let label s =
  try Hashtbl.find label_table s
  with Not_found ->
    incr counter_label;
    Hashtbl.add label_table s !counter_label;
    Hashtbl.add label_names !counter_label s;
    !counter_label
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let label_name l =
  Hashtbl.find label_names l
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let mk_atom = label

let atom_name = label_name
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(* Subtyping algorithm *)

let diff_t d t = diff d (descr t)
let cap_t d t = cap d (descr t)
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let cap_product l = 
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  List.fold_left 
    (fun (d1,d2) (t1,t2) -> (cap_t d1 t1, cap_t d2 t2))
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    (any,any)
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    l
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module Assumptions = Set.Make(struct type t = descr let compare = compare end)
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let memo = ref Assumptions.empty
let cache_false = ref Assumptions.empty
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exception NotEmpty
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let rec empty_rec d =
  if Assumptions.mem d !cache_false then false 
  else if Assumptions.mem d !memo then true
  else if not (Intervals.is_empty d.ints) then false
  else if not (Atoms.is_empty d.atoms) then false
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  else if not (Chars.is_empty d.chars) then false
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  else (
    let backup = !memo in
    memo := Assumptions.add d backup;
    if 
      (empty_rec_times d.times) &&
      (empty_rec_arrow d.arrow) &&
      (empty_rec_record d.record) 
    then true
    else (
      memo := backup;
      cache_false := Assumptions.add d !cache_false;
      false
    )
  )

and empty_rec_times c =
  List.for_all empty_rec_times_aux c

and empty_rec_times_aux (left,right) =
  let rec aux accu1 accu2 = function
    | (t1,t2)::right ->
        let accu1' = diff_t accu1 t1 in
        if not (empty_rec accu1') then aux accu1' accu2 right;
        let accu2' = diff_t accu2 t2 in
        if not (empty_rec accu2') then aux accu1 accu2' right
    | [] -> raise NotEmpty
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  in
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  let (accu1,accu2) = cap_product left in
  (empty_rec accu1) || (empty_rec accu2) ||
  (try aux accu1 accu2 right; true with NotEmpty -> false)

and empty_rec_arrow c =
  List.for_all empty_rec_arrow_aux c
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and empty_rec_arrow_aux (left,right) =
  let single_right (s1,s2) =
    let rec aux accu1 accu2 = function
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      | (t1,t2)::left ->
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          let accu1' = diff_t accu1 t1 in
          if not (empty_rec accu1') then aux accu1 accu2 left;
          let accu2' = cap_t accu2 t2 in
          if not (empty_rec accu2') then aux accu1 accu2 left
      | [] -> raise NotEmpty
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    in
    let accu1 = descr s1 in
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    (empty_rec accu1) ||
    (try aux accu1 (diff any (descr s2)) left; true with NotEmpty -> false)
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  in
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  List.exists single_right right
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and empty_rec_record c =
  let aux = List.exists (fun (_,(opt,t)) -> (not opt) && (empty_rec t)) in
  List.for_all aux (get_record c)
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let is_empty d =
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  let r = empty_rec d in
  memo := Assumptions.empty;
  cache_false := Assumptions.empty;
  r
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let non_empty d = 
  not (is_empty d)

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let subtype d1 d2 =
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  is_empty (diff d1 d2)
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(* Sample value *)
module Sample =
struct
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let rec find f = function
  | [] -> raise Not_found
  | x::r -> try f x with Not_found -> find f r

type t =
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  | Int of Big_int.big_int
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  | Atom of atom
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  | Char of Chars.Unichar.t
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  | Pair of t * t
  | Record of (label * t) list
  | Fun of (node * node) list

let rec gen_atom i l =
  if SortedList.mem l i then gen_atom (succ i) l  else i

let rec sample_rec memo d =
  if (Assumptions.mem d memo) || (is_empty d) then raise Not_found 
  else 
    try Int (Intervals.sample d.ints) with Not_found ->
    try Atom (Atoms.sample (gen_atom 0) d.atoms) with Not_found ->
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    try Char (Chars.sample d.chars) with Not_found ->
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    try sample_rec_arrow d.arrow with Not_found ->

    let memo = Assumptions.add d memo in
    try sample_rec_times memo d.times with Not_found ->
    try sample_rec_record memo d.record with Not_found -> 
    raise Not_found


and sample_rec_times memo c = 
  find (sample_rec_times_aux memo) c

and sample_rec_times_aux memo (left,right) =
  let rec aux accu1 accu2 = function
    | (t1,t2)::right ->
        let accu1' = diff_t accu1 t1 in
        if non_empty accu1' then aux accu1' accu2 right else
          let accu2' = diff_t accu2 t2 in
          if non_empty accu2' then aux accu1 accu2' right else
	    raise Not_found
    | [] -> Pair (sample_rec memo accu1, sample_rec memo accu2)
  in
  let (accu1,accu2) = cap_product left in
  if (is_empty accu1) || (is_empty accu2) then raise Not_found;
  aux accu1 accu2 right
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and sample_rec_arrow c =
  find sample_rec_arrow_aux c
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and check_empty_simple_arrow_line left (s1,s2) = 
  let rec aux accu1 accu2 = function
    | (t1,t2)::left ->
        let accu1' = diff_t accu1 t1 in
        if non_empty accu1' then aux accu1 accu2 left;
        let accu2' = cap_t accu2 t2 in
        if non_empty accu2' then aux accu1 accu2 left
    | [] -> raise NotEmpty
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  in
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  let accu1 = descr s1 in
  (is_empty accu1) ||
  (try aux accu1 (diff any (descr s2)) left; true with NotEmpty -> false)

and check_empty_arrow_line left right = 
  List.exists (check_empty_simple_arrow_line left) right

and sample_rec_arrow_aux (left,right) =
  if (check_empty_arrow_line left right) then raise Not_found
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  else Fun left


and sample_rec_record memo c =
  Record (find (sample_rec_record_aux memo) (get_record c))
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and sample_rec_record_aux memo fields =
  let aux acc (l,(o,t)) = if o then acc else (l, sample_rec memo t) :: acc in
  List.fold_left aux [] fields

let get x = sample_rec Assumptions.empty x
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end

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module Product =
struct
  type t = (descr * descr) list

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  let get d =
    let line accu (left,right) =
      let rec aux accu d1 d2 = function
	| (t1,t2)::right ->
	    let accu = 
	      let d1 = diff_t d1 t1 in
              if is_empty d1 then accu else aux accu d1 d2 right in
	    let accu =
              let d2 = diff_t d2 t2 in
              if is_empty d2 then accu else aux accu d1 d2 right in
	    accu
	| [] ->  (d1,d2) :: accu
      in
      let (d1,d2) = cap_product left in
      if (is_empty d1) || (is_empty d2) then accu else aux accu d1 d2 right
    in
    List.fold_left line [] d.times
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  let pi1 = List.fold_left (fun acc (t1,_) -> cup acc t1) empty
  let pi2 = List.fold_left (fun acc (_,t2) -> cup acc t2) empty
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  let restrict_1 rects pi1 =
    let aux accu (t1,t2) = 
      let t1 = cap t1 pi1 in if is_empty t1 then accu else (t1,t2)::accu in
    List.fold_left aux [] rects
  
  type normal = t
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  let normal d =
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    let res = ref [] in

    let add (t1,t2) =
      let rec loop t1 t2 = function
	| [] -> res := (ref (t1,t2)) :: !res
	| ({contents = (d1,d2)} as r)::l ->
	    (*OPT*) 
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	    if d1 = t1 then r := (d1,cup d2 t2) else
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	      let i = cap t1 d1 in
	      if is_empty i then loop t1 t2 l
	      else (
		r := (i, cup t2 d2);
		let k = diff d1 t1 in 
		if non_empty k then res := (ref (k,d2)) :: !res;
		
		let j = diff t1 d1 in 
		if non_empty j then loop j t2 l
	      )
      in
      loop t1 t2 !res
    in
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    List.iter add (get d);
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    List.map (!) !res

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  let any = { empty with times = any.times }
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end
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module Record = 
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struct
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  type t = (label, (bool * descr)) SortedMap.t list
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  let get d =
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    let line r = List.for_all (fun (l,(o,d)) -> o || non_empty d) r in
    List.filter line (get_record d.record)


  let restrict_label_present t l =
    let aux = SortedMap.change l (fun (_,d) -> (false,d)) (false,any) in
    List.map aux t

  let restrict_label_absent t l =
    let restr = function (true, _) -> (true,empty) | _ -> raise Exit in
    let aux accu r =  
      try SortedMap.change l restr (true,empty) r :: accu
      with Exit -> accu in
    List.fold_left aux [] t

  let restrict_field t l d =
    let restr (_,d1) = 
      let d1 = cap d d1 in 
      if is_empty d1 then raise Exit else (false,d1) in
    let aux accu r = 
      try SortedMap.change l restr (false,d) r :: accu 
      with Exit -> accu in
    List.fold_left aux [] t

  let project_field t l =
    let aux accu x =
      match List.assoc l x with
	| (false,t) -> cup accu t
	| _ -> raise Not_found
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    in
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    List.fold_left aux empty t

  type normal = 
      [ `Success
      | `Fail
      | `Label of label * (descr * normal) list * normal ]

  let rec merge_record n r =
    match (n, r) with
      | (`Success, _) | (_, []) -> `Success
      | (`Fail, r) ->
	  let aux (l,(o,t)) n = `Label (l, [t,n], if o then n else `Fail) in
	  List.fold_right aux r `Success
      | (`Label (l1,present,absent), (l2,(o,t2))::r') ->
	  if (l1 < l2) then
	    let pr =  List.map (fun (t,x) -> (t, merge_record x r)) present in
	    `Label (l1,pr,merge_record absent r)
	  else if (l2 < l1) then
	    let n' = merge_record n r' in
	    `Label (l2, [t2, n'], if o then n' else n)
	  else
	    let res = ref [] in
	    let aux a (t,x) = 
	      (let t = diff t t2 in 
	       if non_empty t then res := (t,x) :: !res);
	      (let t = cap t t2 in
	       if non_empty t then res := (t, merge_record x r') :: !res);
	      diff a t 
	    in
	    let t2 = List.fold_left aux t2 present in
	    let () = 
	      if non_empty t2 then 
	      res := (t2, merge_record `Fail r') :: !res in
	    let abs = if o then merge_record absent r' else absent in
	    `Label (l1, !res, abs)


  let normal d =
    List.fold_left merge_record `Fail (get d)
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  let project d l =
    let aux accu x =
      match List.assoc l x with
	| (false,t) -> cup accu t
	| _ -> raise Not_found
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    in
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    List.fold_left aux empty (get_record d.record)
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  let any = { empty with record = any.record }
  let is_empty d = d = []
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end

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module MapDescr = Map.Make(struct type t = descr let compare = compare end)
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let memo_normalize = ref MapDescr.empty
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let map_sort f l =
  SortedList.from_list (List.map f l)
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let rec rec_normalize d =
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  try MapDescr.find d !memo_normalize
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  with Not_found ->
    let n = make () in
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    memo_normalize := MapDescr.add d n !memo_normalize;
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    let times = 
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      map_sort
	(fun (d1,d2) -> [(rec_normalize d1, rec_normalize d2)],[])
	(Product.normal d)
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    in
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    let record = 
      map_sort
	(fun f -> map_sort (fun (l,(o,d)) -> (l,o,rec_normalize d)) f, [])
	(Record.get d)
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    in
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    define n { d with times = times; record = record };
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    n

let normalize n =
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  internalize (rec_normalize (descr n))
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module Print =
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struct
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  module DescrHash = 
    Hashtbl.Make(
      struct 
	type t = descr
	let hash = hash_descr
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	let equal = equal_descr
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      end
    )

  let named = DescrHash.create 10
  let register_global name d = DescrHash.add named d name

  let marks = DescrHash.create 63
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  let wh = ref []
  let count_name = ref 0
  let name () =
    incr count_name;
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    "X" ^ (string_of_int !count_name)
(* TODO: 
   check that these generated names does not conflict with declared types *)
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  let bool_iter f b =
    List.iter (fun (p,n) -> List.iter f p; List.iter f n) b
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  let trivial b = b = Boolean.empty || b = Boolean.full
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  let worth_abbrev d = 
    not (trivial d.times && trivial d.arrow && trivial d.record) 

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  let rec mark n = mark_descr (descr n)
  and mark_descr d =
    if not (DescrHash.mem named d) then
      try 
	let r = DescrHash.find marks d in
	if (!r = None) && (worth_abbrev d) then 
	  let na = name () in 
	  r := Some na;
	  wh := (na,d) :: !wh
      with Not_found -> 
	DescrHash.add marks d (ref None);
    	bool_iter (fun (n1,n2) -> mark n1; mark n2) d.times;
    	bool_iter (fun (n1,n2) -> mark n1; mark n2) d.arrow;
    	bool_iter (fun (l,o,n) -> mark n) d.record
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  let rec print_union ppf = function
    | [] -> Format.fprintf ppf "Empty"
    | [h] -> h ppf
    | h::t -> Format.fprintf ppf "@[%t |@ %a@]" h print_union t

  let print_atom ppf a = Format.fprintf ppf "`%s" (atom_name a)

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  let rec print ppf n = print_descr ppf (descr n)
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  and print_descr ppf d = 
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    try 
      let name = DescrHash.find named d in
      Format.fprintf ppf "%s" name
    with Not_found ->
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      try
      	match !(DescrHash.find marks d) with
      	  | Some n -> Format.fprintf ppf "%s" n
      	  | None -> real_print_descr ppf d
      with
	  Not_found -> Format.fprintf ppf "XXX"
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  and real_print_descr ppf d = 
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    if d = any then Format.fprintf ppf "Any" else
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      print_union ppf 
	(Intervals.print d.ints @
	 Chars.print d.chars @
	 Atoms.print "AnyAtom" print_atom d.atoms @
	 Boolean.print "(Any,Any)" print_times d.times @
	 Boolean.print "(Empty -> Any)" print_arrow d.arrow @
	 Boolean.print "{ }" print_record d.record
	)
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  and print_times ppf (t1,t2) =
    Format.fprintf ppf "@[(%a,%a)@]" print t1 print t2
  and print_arrow ppf (t1,t2) =
    Format.fprintf ppf "@[(%a -> %a)@]" print t1 print t2
  and print_record ppf (l,o,t) =
    Format.fprintf ppf "@[{ %s =%s %a }@]" 
      (label_name l) (if o then "?" else "") print t
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  let end_print ppf =
    (match List.rev !wh with
       | [] -> ()
       | (na,d)::t ->
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	   Format.fprintf ppf " where@ @[%s = %a" na real_print_descr d;
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	   List.iter 
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	     (fun (na,d) -> 
		Format.fprintf ppf " and@ %s = %a" na real_print_descr d)
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	     t;
	   Format.fprintf ppf "@]"
    );
    Format.fprintf ppf "@]";
    count_name := 0;
    wh := [];
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    DescrHash.clear marks
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  let print_descr ppf d =
    mark_descr d;
    Format.fprintf ppf "@[%a" print_descr d;
    end_print ppf
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   let print ppf n = print_descr ppf (descr n)

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  let rec print_sep f sep ppf = function
    | [] -> ()
    | [x] -> f ppf x
    | x::rem -> f ppf x; Format.fprintf ppf "%s" sep; print_sep f sep ppf rem


  let rec print_sample ppf = function
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    | Sample.Int i -> Format.fprintf ppf "%s" (Big_int.string_of_big_int i)
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    | Sample.Atom a -> Format.fprintf ppf "`%s" (atom_name a)
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    | Sample.Char c -> Chars.Unichar.print ppf c
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    | Sample.Pair (x1,x2) -> 
	Format.fprintf ppf "(%a,%a)" 
        print_sample x1
        print_sample x2
    | Sample.Record r ->
	Format.fprintf ppf "{ %a }"
	  (print_sep 
	     (fun ppf (l,x) -> 
		Format.fprintf ppf "%s = %a"
		(label_name l)
		print_sample x
	     )
	     " ; "
	  ) r
    | Sample.Fun iface ->
	Format.fprintf ppf "(fun ( %a ) x -> ...)"
	  (print_sep
	     (fun ppf (t1,t2) ->
		Format.fprintf ppf "%a -> %a; "
		print t1 print t2
	     )
	     " ; "
	  ) iface
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end

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module Arrow =
struct
  type t = descr * (descr * descr) list list

  let get t =
    List.fold_left
      (fun ((dom,arr) as accu) (left,right) ->
	 if Sample.check_empty_arrow_line left right 
	 then accu
	 else (
	   let left =
	     List.map 
	       (fun (t,s) -> (descr t, descr s)) left in
	   let d = List.fold_left (fun d (t,_) -> cup d t) empty left in
	   (cap dom d, left :: arr)
	 )
      )
      (any, [])
      t.arrow

  let domain (dom,_) = dom

  let apply_simple t result left = 
    let rec aux result accu1 accu2 = function
      | (t1,s1)::left ->
          let result = 
	    let accu1 = diff accu1 t1 in
            if non_empty accu1 then aux result accu1 accu2 left
            else result in
          let result =
	    let accu2 = cap accu2 s1 in
            aux result accu1 accu2 left in
	  result
      | [] -> 
          if subtype accu2 result 
	  then result
	  else cup result accu2
    in
    aux result t any left
      
  let apply (_,arr) t =
    List.fold_left (apply_simple t) empty arr

  let any = { empty with arrow = any.arrow }
end
  

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module Int = struct
  let get d = d.ints
  let put i = { empty with ints = i }
  let is_int d = is_empty { d with ints = Intervals.empty }
  let any = { empty with ints = Intervals.any }
end
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(*
let rec print_normal_record ppf = function
  | Success -> Format.fprintf ppf "Yes"
  | Fail -> Format.fprintf ppf "No"
  | FirstLabel (l,present,absent) ->
      Format.fprintf ppf "%s?@[<v>@\n" (label_name l);
      List.iter
        (fun (t,n) ->
	   Format.fprintf ppf "(%a)=>@[%a@]@\n" 
	     Print.print_descr t
	     print_normal_record n
	) present;
      if absent <> Fail then
	Format.fprintf ppf "(absent)=>@[%a@]@\n" print_normal_record absent;
      Format.fprintf ppf "@]" 
*)
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(* 
let pr s = Types.Print.print Format.std_formatter (Syntax.make_type (Syntax.parse s));;
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let pr' s = Types.Print.print Format.std_formatter 
   (Types.normalize (Syntax.make_type (Syntax.parse s)));;
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BUG:
pr "'a | 'b where 'a = ('a , 'a) and 'b= ('b , 'b)";;
*)
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(*
  let nr s =
    let t = Types.descr (Syntax.make_type (Syntax.parse s)) in
    let n = Types.normal_record' t.Types.record in
    Types.print_normal_record Format.std_formatter n;;
*)