/
linearCheck.ml
642 lines (563 loc) · 16.3 KB
/
linearCheck.ml
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(*
Copyright (c) 2011, Julien Verlaguet
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. 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.
3. Neither the name of Julien Verlaguet nor the names of
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
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
OWNER 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.
*)
open Utils
open Stast
module Type = struct
type t =
| Safe
| Fresh
| Var of Pos.t * Ident.t
| Used of Pos.t
| As of Ident.t * status
| As_root of Ident.t
| As_child of Ident.t
| Obs of ISet.t
and kind = Child | Root
and status = Pos.t option * Pos.t IMap.t * int
let print = function
| Safe -> o "Safe"
| Fresh -> o "Fresh"
| Var(_, x) -> o "Var " ; o (Ident.debug x)
| Used _ -> o "Used"
| As _ -> o "As"
| As_root _ -> o "As_root"
| As_child _ -> o "As_child"
| Obs s -> o "Obs " ; ISet.iter (fun x -> o (Ident.to_string x) ; o " ") s
let rec fresh_ty (p, ty) = fresh_ty_ p ty
and fresh_ty_ p = function
| Tprim _ -> Safe
| Tapply ((_, x), _) when x = Naming.tobs -> Safe
| _ -> Fresh
and fresh tyl = List.map fresh_ty tyl
let rec unify ty1 ty2 = List.map2 unify_ ty1 ty2
and unify_ ty1 ty2 =
match ty1, ty2 with
| Obs x1, Obs x2 -> Obs (ISet.union x1 x2)
| ty, _ -> ty
let unify_list l =
let hd, tl = hdtl l in
List.fold_left unify hd tl
let pany_table = Hashtbl.create 23
let make_pany p =
try Hashtbl.find pany_table p
with Not_found ->
let id = (p, Ident.tmp()) in
Hashtbl.add pany_table p id ;
id
end
module PatVars = struct
type t = Pos.t IMap.t
let rec pat (_, p) acc =
List.fold_right pat_tuple p acc
and pat_tuple (_, pel) acc =
List.fold_right pat_el pel acc
and pat_el (ty, p) acc = pat_ (fst ty) p acc
and pat_ pos p acc =
match p with
| Pany -> pat_ pos (Pid (Type.make_pany pos)) acc
| Pid (p, x) -> IMap.add x p acc
| Pvalue _ -> acc
| Pvariant (_, p) -> pat p acc
| Precord pfl -> List.fold_right (pat_field pos) pfl acc
| Pas ((p, x), _) -> IMap.add x p acc
and pat_field pos (_, pf) acc = pat_field_ pos pf acc
and pat_field_ pos pf acc =
match pf with
| PFany -> pat_field_ pos (PFid (Type.make_pany pos)) acc
| PFid (p, x) -> IMap.add x p acc
| PField (_, p) -> pat p acc
end
module Env: sig
type t
val empty: t
val print: t -> unit
val get: Ident.t -> t -> Type.t
val bind: id -> Type.t -> t -> t
val use: id -> t -> t * Type.t list
val obs: id -> Type.t -> t -> t * Type.t list
val partial: t -> Type.t list -> t * Type.t list
val closure: t -> ISet.t -> t * Type.t list
val push: t -> t
val merge: t -> (Pos.t * t) list -> t
val pop: t -> unit
end = struct
open Type
type t = Type.t IMap.t list
let print t =
IMap.iter (
fun x ty ->
Ident.print x; Type.print ty ; o "\n" ;
) (List.hd t)
let empty = [IMap.empty]
let add x ty = function
| env :: rl ->
IMap.add x ty env :: rl
| _ -> assert false
let rec get x = function
| [] -> Safe
| env :: rl ->
(try IMap.find x env with Not_found -> get x rl)
let rec mem x = function
| [] -> false
| env :: rl ->
IMap.mem x env || mem x rl
let bind (p, x) ty t =
match ty with
| Fresh
| Used _ -> add x (Var (p, x)) t
| ty -> add x ty t
let rec obs (p, x) ty t =
match ty with
| Used p' -> Error.already_used p p'
| Var (p, y) ->
t, [Obs (ISet.singleton y)]
| Obs y ->
t, [Obs (ISet.add x y)]
| As (ptr, (left, right, _)) ->
(match left with
| None -> ()
| Some p' -> Error.already_used p p') ;
IMap.iter (fun _ p' -> Error.already_used p p') right ;
obs (p, x) (get ptr t) t
| As_root ptr -> obs (p, x) (get ptr t) t
| As_child ptr -> obs (p, x) (get ptr t) t
| x -> t, [x]
let rec use (p, x) t =
let ty = get x t in
match ty with
| Safe
| Fresh -> t, [ty]
| Var (_, x) ->
let t = add x (Used p) t in
t, [Used p]
| Used p' -> Error.already_used p p'
| As_root ptr -> use_root p x ptr t
| As_child ptr -> use_child p x ptr t
| As _ -> assert false
| Obs vset ->
ISet.iter (fun x -> use_obs p x t (get x t)) vset ;
t, [ty]
and use_root p x ptr t =
match get ptr t with
| As (up, (left, right, size)) ->
IMap.iter (fun x p' -> Error.already_used p p') right ;
(match left with
| None -> ()
| Some p' -> Error.already_used p p') ;
let left = Some p in
let t = add ptr (As (up, (left, right, size))) t in
use (p, up) t
| _ -> assert false
and use_child p x ptr t =
match get ptr t with
| As (up, (left, right, size)) ->
(match left with
| None -> ()
| Some p' -> Error.already_used p p') ;
(try
let p' = IMap.find x right in
Error.already_used p p'
with Not_found ->
let right = IMap.add x p right in
let size = size - 1 in
let ty = As (up, (left, right, size)) in
let t = add ptr ty t in
if size = 0
then use (p, up) t
else t, [ty]
)
| Used p' -> Error.already_used p p'
| _ -> use (p, x) t
and use_obs p x t v =
match v with
| Used p' -> Error.already_used p p'
| As (root, (left, right, _)) ->
(match left with
| None -> ()
| Some p' -> Error.already_used p p') ;
IMap.iter (fun _ p' -> Error.already_used p p') right ;
()
| As_root ptr
| As_child ptr -> use_obs p x t (get ptr t)
| _ -> ()
let push t = IMap.empty :: t
let check_left (_, sub1) (bp, sub2) =
IMap.iter (
fun x p ->
if IMap.mem x sub2
then ()
else (Error.forgot_branch p bp)
) sub1
let check sub1 sub2 =
check_left sub1 sub2 ;
check_left sub2 sub1 ;
sub1
let just_used t (bp, sub) =
bp, IMap.fold (
fun x ty acc ->
match ty with
| Used xp when mem x t ->
IMap.add x xp acc
| _ -> acc
) sub IMap.empty
let check_unused (_, env) =
IMap.iter (
fun x ty ->
match ty with
| Var (p, _) -> Error.unused_variable p
| _ -> ()
) env
let merge t subl =
let subl = List.map (fun (p, t) -> p, List.hd t) subl in
List.iter check_unused subl ;
let subl = List.map (just_used t) subl in
let hd, tl = hdtl subl in
let subl = List.fold_left check hd tl in
IMap.fold (fun x p -> add x (Used p)) (snd subl) t
let pop t =
check_unused (Pos.none, List.hd t)
let closure t vset =
let env, t = hdtl t in
t, [Obs vset]
let partial t vl =
t, [Obs (
List.fold_left (
fun acc v ->
match v with
| Obs s -> ISet.union acc s
| _ -> acc
) ISet.empty vl
)]
end
module FreeObsVars = struct
let rec id obs env t (p, x) =
match Env.get x env with
| Type.As_root x -> id obs env t (p, x)
| Type.As_child x -> id obs env t (p, x)
| Type.As (x, _) -> id obs env t (p, x)
| Type.Var _ when obs -> Error.esc_scope p
| Type.Obs s -> ISet.add x (ISet.union s t)
| _ -> t
let rec obs_id obs env t (p, x) =
match Env.get x env with
| Type.As_root x -> obs_id obs env t (p, x)
| Type.As_child x -> obs_id obs env t (p, x)
| Type.As (x, _) -> obs_id obs env t (p, x)
| Type.Obs s when not obs -> Error.esc_scope p
| _ -> ISet.add x t
let rec pat obs t (_, ptl) =
List.fold_left (pat_tuple obs) t ptl
and pat_tuple obs t (_, pel) =
List.fold_left (pat_el obs) t pel
and pat_el obs t (_, p) = pat_ obs t p
and pat_ obs t = function
| Pany -> t
| Pid (_, x) -> ISet.remove x t
| Pvalue _ -> t
| Pvariant (_, p) -> pat obs t p
| Precord pfl -> List.fold_left (pat_field obs) t pfl
| Pas ((_, x), p) -> ISet.remove x (pat obs t p)
and pat_field obs t (_, pf) = pat_field_ obs t pf
and pat_field_ obs t = function
| PFany -> t
| PFid (_, x) -> ISet.remove x t
| PField (_, p) -> pat obs t p
and tuple obs env t (_, tpl) =
List.fold_left (tuple_pos obs env) t tpl
and tuple_pos obs env t (_, e) = expr_ obs env t e
and expr obs env t (ty, e) = expr_ obs env t e
and expr_ obs env t = function
| Eid x -> id obs env t x
| Evalue _ -> t
| Evariant (_, e) -> tuple obs env t e
| Ebinop (_, e1, e2) ->
let t = expr obs env t e1 in
let t = expr obs env t e2 in
t
| Euop (_, e) -> expr obs env t e
| Erecord fdl -> List.fold_left (field obs env) t fdl
| Ewith (e, fdl) ->
let t = List.fold_left (field obs env) t fdl in
expr obs env t e
| Efield (e, _) -> expr obs env t e
| Ematch (e, al) ->
let t = List.fold_left (action obs env) t al in
tuple obs env t e
| Elet (p, e1, e2) ->
let t = tuple obs env t e1 in
let t = pat obs t p in
let t = tuple obs env t e2 in
t
| Eif (c, e1, e2) ->
let t = tuple obs env t e1 in
let t = tuple obs env t e2 in
expr obs env t c
| Eapply (_, _, x, e) ->
let t = id obs env t x in
let t = tuple obs env t e in
t
| Eseq (e1, e2) ->
let t = expr obs env t e1 in
let t = tuple obs env t e2 in
t
| Eobs x -> obs_id obs env t x
| Efree _ -> t
| Epartial (f, e) ->
let t = expr obs env t f in
let t = tuple obs env t e in
t
| Efun (_, _, pel, e) ->
let t = tuple obs env t e in
let t = List.fold_left (pat_el obs) t pel in
t
and field obs env t (_, e) = tuple obs env t e
and action obs env t (p, e) =
let t = tuple obs env t e in
let t = pat obs t p in
t
end
let rec program mdl =
List.iter module_ mdl
and module_ md =
List.iter def md.md_defs
and def (_, _, ((tyl, _) as p), e) =
let vl = Type.fresh (snd tyl) in
let t = pat Env.empty p vl in
let t, _ = tuple t e in
Env.pop t ;
Hashtbl.clear Type.pany_table
and pat t (_, pl) vl =
List.fold_left (pat_tuple vl) t pl
and pat_tuple vl t (_, pel) =
List.fold_left2 pat_el t pel vl
and pat_el t (ty, p) v =
pat_ t ty p v
and pat_ t ty p v =
match p with
| Pany ->
let v = match ty with
| _, Tfun _ (* turning closures off for now *)
| _, Tprim _ -> Type.Safe
| _ -> v in
Env.bind (Type.make_pany (fst ty)) v t
| Pid id ->
let v = match ty with
| _, Tfun _ (* turning closures off for now *)
| _, Tprim _ -> Type.Safe
| _ -> v in
Env.bind id v t
| Pvalue _ -> t
| Pvariant (_, p) -> pat t p (make_value v p)
| Precord pfl -> List.fold_left (pat_field (fst ty) v) t pfl
| Pas (x, p) ->
(match v with
| Type.Safe | Type.Obs _ ->
pat t p (make_value v p)
| _ ->
let up = Ident.fresh (snd x) in
let t = Env.bind (fst x, up) v t in
let vars = PatVars.pat p IMap.empty in
let size = IMap.fold (fun _ _ acc -> 1+acc) vars 0 in
let left = None in
let right = IMap.empty in
let ptr = Ident.tmp() in
let t = Env.bind (fst x, ptr) (Type.As (up, (left, right, size))) t in
let t = Env.bind x (Type.As_root ptr) t in
let v = Type.As_child ptr in
pat t p (make_value v p))
and pat_field pos v t (_, pf) = pat_field_ pos v t pf
and pat_field_ pos v t = function
| PFany _ -> Env.bind (Type.make_pany pos) v t
| PFid x -> Env.bind x v t
| PField (_, p) -> pat t p (make_value v p)
and make_value v ((_, tyl), pl) =
let v =
match v with
| Type.Safe
| Type.As_child _
| Type.Obs _ as v -> v
| _ -> Type.Fresh
in
List.map (fun _ -> v) tyl
and tuple t (_, tpl) =
(* Everything but identifiers *)
let t, pvl1 =
List.fold_right (
fun (tyl, e) (t, acc) ->
match e with
| Eid _ -> t, (fst tyl, []) :: acc
| _ ->
let t, vl = expr_ t (snd tyl) e in
t, (fst tyl, vl) :: acc
) tpl (t, []) in
(* Identifiers *)
let t, pvl2 =
List.fold_right (
fun (tyl, e) (t, acc) ->
match e with
| Eid _ ->
let t, vl = expr_ t (snd tyl) e in
t, (fst tyl, vl) :: acc
| _ -> t, (fst tyl, []) :: acc
) tpl (t, []) in
let pvl =
List.fold_right2 (
fun x y acc ->
match x, y with
| (_, []), v
| v, _ -> v :: acc
) pvl1 pvl2 [] in
List.iter (
fun (p, vl) ->
List.iter (
function
| Type.Obs v ->
ISet.iter (
fun x ->
ignore (Env.obs (p, x) (Env.get x t) t)
) v
| _ -> ()
) vl
) pvl ;
let vl = List.flatten (List.map snd pvl) in
t, vl
and expr t (ty, e) = expr_ t [ty] e
and expr_ t ty = function
| Eid x ->
(match ty with
(* turning closures off for now *)
| [_, Tfun _]
| [_, Tprim _] ->
Env.bind x Type.Safe t, [Type.Safe]
| _ -> Env.use x t)
| Evalue _ ->
t, [Type.Safe]
| Evariant (x, e) ->
let t, _ = tuple t e in
t, Type.fresh ty
| Ebinop (_, e1, e2) ->
let t, _ = expr t e1 in
let t, _ = expr t e2 in
t, [Type.Safe]
| Euop (_, e) ->
let t, _ = expr t e in
t, [Type.Safe]
| Erecord fdl ->
let t = List.fold_left field t fdl in
t, Type.fresh ty
| Ewith (e, fdl) ->
let t = List.fold_left field t fdl in
let t, _ = expr t e in
t, Type.fresh ty
| Efield (e, _) ->
(match ty with
(* turning closures off for now *)
| [_, Tfun _]
| [_, Tprim _] -> t, [Type.Safe]
| [_, Tapply (x, (_, [_, Tfun _]))] when snd x = Naming.tobs ->
t, [Type.Safe]
| [_, Tapply (x, (_, [_, Tprim _]))] when snd x = Naming.tobs ->
t, [Type.Safe]
| _ -> proj t e)
| Ematch (e, al) ->
let t, vl = tuple t e in
let t' = Env.push t in
let tall = List.map (action t' vl) al in
let tl, all = List.split tall in
let t = Env.merge t tl in
t, Type.unify_list all
| Elet (p, e1, e2) ->
let t, v = tuple t e1 in
let t = pat t p v in
let t, v = tuple t e2 in
t, v
| Eif (c, e1, e2) ->
let t, _ = expr t c in
let t' = Env.push t in
let t1, vl1 = tuple t' e1 in
let t2, vl2 = tuple t' e2 in
let pos1 = fst (fst e1) in
let pos2 = fst (fst e2) in
let t = Env.merge t [pos1, t1; pos2, t2] in
t, Type.unify vl1 vl2
| Eapply (_, _, x, e) ->
(* let t, _ = Env.use x t in *)
(* turning this off for now *)
let t, vl = tuple t e in
apply ty t e vl
| Eseq (e1, e2) ->
let t, _ = expr t e1 in
tuple t e2
| Eobs x ->
Env.obs x (Env.get (snd x) t) t
| Efree (_, x) ->
Env.use x t
| Epartial (f, e) ->
let t, _ = expr t f in
let t, vl = tuple t e in
let t, vl = Env.partial t vl in
t, vl
| Efun (_, obs, p, e) as e_ ->
let vset = FreeObsVars.expr_ obs t ISet.empty e_ in
let t = Env.push t in
let tyl = List.map fst p in
let tyl = List.fold_right (fun x acc -> x :: acc) tyl [] in
let t = List.fold_left2 pat_el t p (Type.fresh tyl) in
let t, _ = tuple t e in
if obs
then Env.closure t vset
else t, [Type.Fresh]
and field t (_, e) =
let t, _ = tuple t e in
t
and action t vl (p, a) =
let t = pat t p vl in
let pos = fst (fst a) in
let t, vl = tuple t a in
(pos, t), vl
and proj t (ty, e) =
match e with
| Eid x -> Env.obs x (Env.get (snd x) t) t
| Efield (e, _) -> proj t e
| _ -> assert false
and apply tyl t x vl =
let obs_set = List.fold_left (
fun acc v ->
match v with
| Type.Obs s -> ISet.union acc s
| _ -> acc
) ISet.empty vl in
if ISet.is_empty obs_set
then t, Type.fresh tyl
else
t, List.map (
function
| _, Tprim _ -> Type.Safe
| _, Tapply ((_, x), _) when x = Naming.tobs -> Type.Obs obs_set
| _ -> Type.Fresh
) tyl