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open Ident
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exception Unsupported of string

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module C = struct
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  type ty =
    | Tvoid
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    | Tsyntax of string * ty list
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    | Tptr of ty
    | Tarray of ty * expr
    | Tstruct of ident * (ident * ty) list
    | Tunion of ident * (ident * ty) list
    | Tnamed of ident (* alias from typedef *)
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    | Tnosyntax (* types that do not have a syntax, can't be printed *)
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    (* enum, const could be added *)

  (* int x=2, *y ... *)
  and names = ty * (ident * expr) list

  (* names with a single declaration *)
  and name = ty * ident * expr

  (* return type, parameter list. Variadic functions not handled. *)
  and proto = ty * (ty * ident) list

  and binop = Band | Bor | Beq | Bne | Bassign (* += and co. maybe to add *)

  and unop = Unot | Ustar | Uaddr (* (pre|post)(incr|decr) maybe to add *)

  and expr =
    | Enothing
    | Eunop of unop * expr
    | Ebinop of binop * expr * expr
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    | Equestion of expr * expr * expr (* c ? t : e *)
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    | Ecast of ty * expr
    | Ecall of expr * expr list
    | Econst of constant
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    | Evar of ident
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    | Esize_expr of expr
    | Esize_type of ty
    | Eindex of expr * expr (* Array access *)
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    | Edot of expr * ident (* Field access with dot *)
    | Earrow of expr * ident (* Pointer access with arrow *)
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    | Esyntax of string * ty * (ty array) * (expr*ty) list * bool
  (* template, type and type arguments of result, typed arguments,
     is/is not converter*)
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  and constant =
    | Cint of string
    | Cfloat of string
    | Cchar of string
    | Cstring of string

  type stmt =
    | Snop
    | Sexpr of expr
    | Sblock of body
    | Sseq of stmt * stmt
    | Sif of expr * stmt * stmt
    | Swhile of expr * stmt
    | Sfor of expr * expr * expr * stmt
    | Sbreak
    | Sreturn of expr

  and definition =
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    | Dfun of ident * proto * body
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    | Dinclude of ident
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    | Dproto of ident * proto
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    | Ddecl of names
    | Dtypedef of ty * ident

  and body = definition list * stmt

  type file = definition list

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  exception NotAValue

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  let rec is_nop = function
    | Snop -> true
    | Sblock ([], s) -> is_nop s
    | Sseq (s1,s2) -> is_nop s1 && is_nop s2
    | _ -> false

  let rec one_stmt = function
    | Snop -> true
    | Sexpr _ -> true
    | Sblock (d,s) -> d = [] && one_stmt s
    | _ -> false

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  (** [assignify v] transforms a statement that computes a value into
     a statement that assigns that value to v *)
  let rec assignify v = function
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    | Snop -> raise NotAValue
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    | Sexpr e -> Sexpr (Ebinop (Bassign, v, e))
    | Sblock (ds, s) -> Sblock (ds, assignify v s)
    | Sseq (s1, s2) when not (is_nop s2) -> Sseq (s1, assignify v s2)
    | Sseq (s1,_) -> assignify v s1
    | Sif (c,t,e) -> Sif (c, assignify v t, assignify v e)
    | Swhile (c,s) -> Swhile (c, assignify v s) (* can this be a value ?*)
    | Sfor (e0,e1,e2,s) -> Sfor (e0,e1,e2, assignify v s)
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    | Sbreak -> raise NotAValue
    | Sreturn _ -> raise NotAValue

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  (** [get_last_expr] extracts the expression computed by the given statement.
     This is needed when loop conditions are more complex than a simple expression. *)
  let rec get_last_expr = function
    | Snop -> raise NotAValue
    | Sexpr e -> Snop, e
    | Sblock (ds,s) ->
      let s',e = get_last_expr s in
      Sblock(ds,s'), e
    | Sseq (s1,s2) when not (is_nop s2) ->
      let s', e = get_last_expr s2 in
      Sseq(s1,s'), e
    | Sseq (s1,_) -> get_last_expr s1
    | Sif (c,Sexpr t,Sexpr e) -> Snop, Equestion(c,t,e)
    | Sif _ -> raise (Unsupported "while (complex if)")
    | Swhile (_c,_s) -> raise (Unsupported "while (while) {}")
    | Sfor _ -> raise (Unsupported "while (for)")
    | Sbreak -> raise NotAValue
    | Sreturn _ -> raise NotAValue

  (** [propagate_in_expr id v] and the associated functions replace
      all instances of [id] by [v] in an
      expression/statement/definition/block. It is used for constant
      propagation to reduce the number of variables. *)
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  let rec propagate_in_expr id (v:expr) = function
    | Evar i when Ident.id_equal i id -> v
    | Evar i -> Evar i
    | Eunop (u,e) -> Eunop (u, propagate_in_expr id v e)
    | Ebinop (b,e1,e2) -> Ebinop (b,
                                  propagate_in_expr id v e1,
                                  propagate_in_expr id v e2)
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    | Equestion (c,t,e) -> Equestion(propagate_in_expr id v c,
                                     propagate_in_expr id v t,
                                     propagate_in_expr id v e)
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    | Ecast (ty,e) -> Ecast (ty, propagate_in_expr id v e)
    | Ecall (e, l) -> Ecall (propagate_in_expr id v e,
                             List.map (propagate_in_expr id v) l)
    | Esize_expr e -> Esize_expr (propagate_in_expr id v e)
    | Eindex (e1,e2) -> Eindex (propagate_in_expr id v e1,
                                propagate_in_expr id v e2)
    | Edot (e,i) -> Edot (propagate_in_expr id v e, i)
    | Earrow (e,i) -> Earrow (propagate_in_expr id v e, i)
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    | Esyntax (s,t,ta,l,b) ->
      Esyntax (s,t,ta,List.map (fun (e,t) -> (propagate_in_expr id v e),t) l,b)
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    | Enothing -> Enothing
    | Econst c -> Econst c
    | Esize_type ty -> Esize_type ty

  let rec propagate_in_stmt id v = function
    | Sexpr e -> Sexpr (propagate_in_expr id v e)
    | Sblock b -> Sblock(propagate_in_block id v b)
    | Sseq (s1,s2) -> Sseq (propagate_in_stmt id v s1,
                            propagate_in_stmt id v s2)
    | Sif (e,s1,s2) -> Sif (propagate_in_expr id v e,
                            propagate_in_stmt id v s1,
                            propagate_in_stmt id v s2)
    | Swhile (e, s) -> Swhile (propagate_in_expr id v e,
                               propagate_in_stmt id v s)
    | Sfor (e1,e2,e3,s) -> Sfor (propagate_in_expr id v e1,
                                 propagate_in_expr id v e2,
                                 propagate_in_expr id v e3,
                                 propagate_in_stmt id v s)
    | Sreturn e -> Sreturn (propagate_in_expr id v e)
    | Snop -> Snop
    | Sbreak -> Sbreak

  and propagate_in_def id v d =
    let rec aux = function
      | [] -> [], true
      | (i,e)::t ->
        if Ident.id_equal i id then (i,e)::t, false
        else let t,b = aux t in ((i,propagate_in_expr id v e)::t), b
    in
    match d with
    | Ddecl (ty,l) ->
      let l,b = aux l in
      Ddecl (ty, l), b
    | Dinclude i -> Dinclude i, true
    | Dfun _ -> raise (Unsupported "nested function")
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    | Dtypedef _ -> raise (Unsupported "typedef inside function")
    | Dproto _ -> raise (Unsupported "prototype inside function")
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  and propagate_in_block id v (dl, s) =
    let dl, b = List.fold_left
      (fun (dl, acc) d ->
        if acc
        then
          let d, b = propagate_in_def id v d in
          (d::dl, b)
        else (d::dl, false))
      ([],true) dl in
    (List.rev dl, if b then propagate_in_stmt id v s else s)

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  let is_empty_block s = s = Sblock([], Snop)
  let block_of_expr e = [], Sexpr e
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(** [flatten_defs d s] appends all definitions in the statement [s] to d. *)
  (* TODO check ident unicity ? *)
  let rec flatten_defs d = function
    | Sseq (s1,s2) ->
      let d, s1' = flatten_defs d s1 in
      let d, s2' = flatten_defs d s2 in
      d, Sseq(s1',s2')
    | Sblock (d',s) ->
      let d',s' = flatten_defs d' s in
      d@d', s'
    | Sif (c,t,e) ->
      let d, t' = flatten_defs d t in
      let d, e' = flatten_defs d e in
      d,Sif(c,t',e')
    | Swhile (c,s) ->
      let d, s' = flatten_defs d s in
      d, Swhile (c, s')
    | Sfor (e1,e2,e3,s) ->
      let d, s' = flatten_defs d s in
      d, Sfor(e1,e2,e3,s')
    | s -> d,s

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  let rec group_defs_by_type l =
    (* heuristic to reduce the number of lines of defs*)
    let rec group_types t1 t2 =
      match t1, t2 with
      | Tsyntax (s1, l1), Tsyntax (s2, l2) ->
        List.length l1 = List.length l2
        && List.for_all2 group_types l1 l2
        && (s1 = s2)
        && (not (String.contains s1 '*'))
      | Tsyntax _, _ | _, Tsyntax _ -> false
      | t1, t2 -> t1 = t2
    in
    match l with
    | [] | [_] -> l
    | Ddecl (ty1, el1) :: Ddecl (ty2, el2) :: l'
        when group_types ty1 ty2
          -> group_defs_by_type (Ddecl(ty1, el1@el2)::l')
    | Ddecl (ty1, el1) :: Ddecl (ty2, el2) :: Ddecl (ty3, el3) :: l'
        when group_types ty1 ty3
          -> group_defs_by_type (Ddecl (ty1, el1@el3) :: Ddecl (ty2, el2) :: l')
    | Ddecl (ty1, el1) :: Ddecl (ty2, el2) :: Ddecl (ty3, el3) :: l'
        when group_types ty2 ty3
          -> group_defs_by_type (Ddecl (ty1, el1) :: Ddecl (ty2, el2@el3) :: l')
    | Ddecl (ty1, el1) :: l' ->
      Ddecl (ty1, el1) :: group_defs_by_type l'
    | _ -> l

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  let rec elim_empty_blocks = function
    | Sblock ([], s) -> elim_empty_blocks s
    | Sblock (d,s) -> Sblock (d, elim_empty_blocks s)
    | Sseq (s1,s2) -> Sseq (elim_empty_blocks s1, elim_empty_blocks s2)
    | Sif (c,t,e) -> Sif(c, elim_empty_blocks t, elim_empty_blocks e)
    | Swhile (c,s) -> Swhile(c, elim_empty_blocks s)
    | Sfor(e1,e2,e3,s) -> Sfor(e1,e2,e3,elim_empty_blocks s)
    | s -> s

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  let rec elim_nop = function
    | Sseq (s1,s2) ->
      let s1 = elim_nop s1 in
      let s2 = elim_nop s2 in
      begin match s1,s2 with
      | Snop, Snop -> Snop
      | Snop, s | s, Snop -> s
      | _ -> Sseq(s1,s2)
      end
    | Sblock (d,s) ->
      let s = elim_nop s in
      begin match d, s with
      | [], Snop -> Snop
      | _ -> Sblock(d,s)
      end
    | Sif (c,t,e) -> Sif(c, elim_nop t, elim_nop e)
    | Swhile (c,s) -> Swhile (c, elim_nop s)
    | Sfor(e1,e2,e3,s) -> Sfor(e1,e2,e3,elim_nop s)
    | s -> s

  let rec add_to_last_call params = function
    | Sblock (d,s) -> Sblock (d, add_to_last_call params s)
    | Sseq (s1,s2) when not (is_nop s2) ->
      Sseq (s1, add_to_last_call params s2)
    | Sseq (s1,_) -> add_to_last_call params s1
    | Sexpr (Ecall(fname, args)) ->
      Sexpr (Ecall(fname, params@args)) (*change name to ensure no renaming ?*)
    | Sreturn (Ecall (fname, args)) ->
      Sreturn (Ecall(fname, params@args))
    | _ -> raise (Unsupported "tuple pattern matching with too complex def")
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  let rec stmt_of_list (l: stmt list) : stmt =
    match l with
    | [] -> Snop
    | [s] -> s
    | h::t -> Sseq (h, stmt_of_list t)

  let simplify_expr (d,s) : expr =
    match (d,s) with
    | [], Sexpr e -> e
 (*   | [], Sreturn e -> assert false
    | [], Snop -> assert false
    | [], Sblock _ -> assert false *)
    | _ -> assert false
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end
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type info = Pdriver.printer_args = private {
  env         : Env.env;
  prelude     : Printer.prelude;
  thprelude   : Printer.prelude_map;
  blacklist   : Printer.blacklist;
  syntax      : Printer.syntax_map;
  converter   : Printer.syntax_map;
}

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let debug = false

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module Print = struct

  open C
  open Format
  open Printer
  open Pp

  exception Unprinted of string

  let c_keywords = ["auto"; "break"; "case"; "char"; "const"; "continue"; "default"; "do"; "double"; "else"; "enum"; "extern"; "float"; "for"; "goto"; "if"; "int"; "long"; "register"; "return"; "short"; "signed"; "sizeof"; "static"; "struct"; "switch"; "typedef"; "union"; "unsigned"; "void"; "volatile"; "while" ]

  let () = assert (List.length c_keywords = 32)

  let sanitizer = sanitizer char_to_lalpha char_to_alnumus
  let printer = create_ident_printer c_keywords ~sanitizer

  let print_ident fmt id = fprintf fmt "%s" (id_unique printer id)

  let protect_on x s = if x then "(" ^^ s ^^ ")" else s

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  let extract_stars ty =
    let rec aux acc = function
      | Tptr t -> aux (acc+1) t
      | t -> (acc, t)
    in
  aux 0 ty

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  let rec print_ty ?(paren=false) fmt = function
    | Tvoid -> fprintf fmt "void"
    | Tsyntax (s, tl) ->
      syntax_arguments
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	s
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        (print_ty ~paren:false) fmt tl
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    | Tptr ty -> fprintf fmt "%a *" (print_ty ~paren:true) ty
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    (* should be handled in extract_stars *)
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    | Tarray (ty, expr) ->
      fprintf fmt (protect_on paren "%a[%a]")
        (print_ty ~paren:true) ty (print_expr ~paren:false) expr
    | Tstruct _ -> raise (Unprinted "structs")
    | Tunion _ -> raise (Unprinted "unions")
    | Tnamed id -> print_ident fmt id
    | Tnosyntax -> raise (Unprinted "type without syntax")

  and print_unop fmt = function
    | Unot -> fprintf fmt "!"
    | Ustar -> fprintf fmt "*"
    | Uaddr -> fprintf fmt "&"

  and print_binop fmt = function
    | Band -> fprintf fmt "&&"
    | Bor -> fprintf fmt "||"
    | Beq -> fprintf fmt "=="
    | Bne -> fprintf fmt "!="
    | Bassign -> fprintf fmt "="

  and print_expr ~paren fmt = function
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    | Enothing -> if debug then Format.printf "enothing"; ()
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    | Eunop(u,e) -> fprintf fmt (protect_on paren "%a %a")
      print_unop u (print_expr ~paren:true) e
    | Ebinop(b,e1,e2) ->
      fprintf fmt (protect_on paren "%a %a %a")
        (print_expr ~paren:true) e1 print_binop b (print_expr ~paren:true) e2
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    | Equestion(c,t,e) ->
      fprintf fmt (protect_on paren "%a ? %a : %a")
        (print_expr ~paren:true) c
        (print_expr ~paren:true) t
        (print_expr ~paren:true) e
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    | Ecast(ty, e) ->
      fprintf fmt (protect_on paren "(%a)%a")
        (print_ty ~paren:false) ty (print_expr ~paren:true) e
    | Ecall (e,l) -> fprintf fmt (protect_on paren "%a(%a)")
      (print_expr ~paren:true) e (print_list comma (print_expr ~paren:false)) l
    | Econst c -> print_const fmt c
    | Evar id -> print_ident fmt id
    | Esize_expr e ->
      fprintf fmt (protect_on paren "sizeof(%a)") (print_expr ~paren:false) e
    | Esize_type ty ->
      fprintf fmt (protect_on paren "sizeof(%a)") (print_ty ~paren:false) ty
    | Eindex _ | Edot _ | Earrow _ -> raise (Unprinted "struct/array access")
    | Esyntax (s, t, args, lte,_) ->
      gen_syntax_arguments_typed snd (fun _ -> args)
        (if paren then ("("^s^")") else s)
        (fun fmt (e,_t) -> print_expr ~paren:false fmt e)
        (print_ty ~paren:false) (C.Enothing,t) fmt lte

  and print_const  fmt = function
    | Cint s | Cfloat s | Cchar s | Cstring s -> fprintf fmt "%s" s

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  let print_id_init ~stars fmt ie =
    (if stars > 0
    then fprintf fmt "%s " (String.make stars '*')
    else ());
    match ie with
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    | id, Enothing -> print_ident fmt id
    | id,e -> fprintf fmt "%a = %a" print_ident id (print_expr ~paren:false) e

  let rec print_stmt ~braces fmt = function
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    | Snop -> if debug then Format.printf "snop"; ()
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    | Sexpr e -> fprintf fmt "%a;" (print_expr ~paren:false) e;
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    | Sblock ([] ,s) when (not braces || (one_stmt s && not (is_nop s))) ->
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      (print_stmt ~braces:false) fmt s
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    | Sblock b -> fprintf fmt "@[<hov>{@\n  @[<hov>%a@]@\n}@]" print_body b
    | Sseq (s1,s2) -> fprintf fmt "%a@\n%a"
      (print_stmt ~braces:false) s1
      (print_stmt ~braces:false) s2
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    | Sif(c,t,e) when is_nop e ->
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       fprintf fmt "if(%a)@\n%a" (print_expr ~paren:false) c
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         (print_stmt ~braces:true) (Sblock([],t))
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    | Sif (c,t,e) -> fprintf fmt "if(%a)@\n%a@\nelse@\n%a"
      (print_expr ~paren:false) c
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      (print_stmt ~braces:true) (Sblock([],t))
      (print_stmt ~braces:true) (Sblock([],e))
    | Swhile (e,b) -> fprintf fmt "while (%a)@;<1 2>%a"
      (print_expr ~paren:false) e (print_stmt ~braces:true) (Sblock([],b))
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    | Sfor _ -> raise (Unprinted "for loops")
    | Sbreak -> fprintf fmt "break;"
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    | Sreturn Enothing -> fprintf fmt "return;"
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    | Sreturn e -> fprintf fmt "return %a;" (print_expr ~paren:true) e

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  and print_def fmt def =
    try match def with
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    | Dfun (id,(rt,args),body) ->
       fprintf fmt "%a %a(@[%a@])@ @[<hov>{@;<1 2>@[<hov>%a@]@\n}@\n@]"
               (print_ty ~paren:false) rt
               print_ident id
               (print_list comma
			   (print_pair_delim nothing space nothing
					     (print_ty ~paren:false) print_ident))
	       args
               print_body body
    | Dproto (id, (rt, args)) ->
      fprintf fmt "%a %a(@[%a@]);@;"
        (print_ty ~paren:false) rt
        print_ident id
        (print_list comma
           (print_pair_delim nothing space nothing
			     (print_ty ~paren:false) print_ident))
	args
    | Ddecl (ty, lie) ->
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      let nb, ty = extract_stars ty in
      assert (nb=0);
      fprintf fmt "%a @[<hov>%a@];"
	(print_ty ~paren:false) ty
	(print_list comma (print_id_init ~stars:nb)) lie
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    | Dinclude id ->
       fprintf fmt "#include<%a.h>@;" print_ident id
    | Dtypedef (ty,id) ->
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       fprintf fmt "@[<hov>typedef@ %a@;%a;@]"
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	       (print_ty ~paren:false) ty print_ident id
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    with Unprinted s -> Format.printf "Missed a def because : %s@." s
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  and print_body fmt (def, s) =
    if def = []
    then print_stmt ~braces:true fmt s
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    else
      print_pair_delim nothing newline nothing
        (print_list newline print_def)
        (print_stmt ~braces:true)
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        fmt (def,s)
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  let print_file fmt info ast =
    Mid.iter (fun _ sl -> List.iter (fprintf fmt "%s\n") sl) info.thprelude;
    newline fmt ();
    fprintf fmt "@[<v>%a@]@." (print_list newline print_def) ast

end
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(*TODO simplifications : propagate constants, collapse blocks with only a statement and no def*)
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module MLToC = struct

  open Ity
  open Ty
  open Expr
  open Term
  open Printer
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  open Mltree
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  open C

  let rec ty_of_mlty info = function
    | Tvar tv ->
      begin match query_syntax info.syntax tv.tv_name
        with
        | Some s -> C.Tsyntax (s, [])
        | None -> C.Tnamed (tv.tv_name)
      end
    | Tapp (id, tl) ->
       begin match query_syntax info.syntax id
        with
        | Some s -> C.Tsyntax (s, List.map (ty_of_mlty info) tl)
        | None -> C.Tnosyntax
       end
    | Ttuple _ -> raise (Unsupported "type tuple")

  let rec ty_of_ty info ty = (*FIXME try to use only ML tys*)
    match ty.ty_node with
    | Tyvar v ->
      begin match query_syntax info.syntax v.tv_name
        with
        | Some s -> C.Tsyntax (s, [])
        | None -> C.Tnamed (v.tv_name)
      end
    | Tyapp (ts, tl) ->
       begin match query_syntax info.syntax ts.ts_name
        with
        | Some s -> C.Tsyntax (s, List.map (ty_of_ty info) tl)
        | None -> C.Tnosyntax
       end

  let ity_of_expr e = match e.e_ity with
    | I i -> i
    | _ -> assert false

  let pv_name pv = pv.pv_vs.vs_name

  type syntax_env = { in_unguarded_loop : bool;
                      computes_return_value : bool;
		      returns_tuple: bool * ident list;
                      breaks : Sid.t;
                      returns : Sid.t; }


  let is_true e = match e.e_node with
    | Eapp (s, []) -> rs_equal s rs_true
    | _ -> false

  let is_false e = match e.e_node with
    | Eapp (s, []) -> rs_equal s rs_false
    | _ -> false

  let is_unit = function
    | I i -> ity_equal i Ity.ity_unit
    | C _ -> false

  let return_or_expr env (e:C.expr) =
    if env.computes_return_value
    then Sreturn e
    else Sexpr e

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  let rec expr info env (e:Mltree.expr) : C.body =
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    assert (not e.e_effect.eff_ghost);
    match e.e_node with
    | Eblock [] ->
       if env.computes_return_value
       then C.([], Sreturn(Enothing))
       else C.([], Snop)
    | Eblock [_] -> assert false
    | Eblock l ->
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       let env_f = { env with computes_return_value = false } in
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       let rec aux = function
         | [] ->
            if env.computes_return_value
            then C.([], Sreturn(Enothing))
            else C.([], Snop)
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         | [s] -> ([], C.Sblock (expr info env s))
         | h::t -> ([], C.Sseq (C.Sblock (expr info env_f h),
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                                C.Sblock (aux t)))
       in
       aux l
    | Eapp (rs, []) when rs_equal rs rs_true ->
       ([],return_or_expr env (C.Econst (Cint "1")))
    | Eapp (rs, []) when rs_equal rs rs_false ->
       ([],return_or_expr env (C.Econst (Cint "0")))
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    | Mltree.Evar pv ->
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       let e = C.Evar (pv_name pv) in
       ([], return_or_expr env e)
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    | Mltree.Econst ic ->
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      let n = Number.compute_int_constant ic in
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      let e = C.(Econst (Cint (BigInt.to_string n))) in
      ([], return_or_expr env e)
    | Eapp (rs, el) ->
       if is_rs_tuple rs && env.computes_return_value
	 then begin
	     match env.returns_tuple with
	     | true, rl ->
		let args =
                  List.filter
                    (fun e ->
                      assert (not e.e_effect.eff_ghost);
                      match e.e_ity with
                      | I i when ity_equal i Ity.ity_unit -> false
                      | _ -> true)
		    el
                in
		assert (List.length rl = List.length args);
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                let env_f = { env with computes_return_value = false } in
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		C.([],
		   List.fold_right2
                     (fun res arg acc ->
                       let d,s = expr info env_f arg in
                       let s = assignify (Eunop(Ustar,Evar(res))) s in
		       Sseq(Sblock(d,s),
			    acc))
		     rl args (Sreturn(Enothing)))
	     | _ -> assert false
	   end
       else
	   let e =
             match
               (query_syntax info.syntax rs.rs_name,
                query_syntax info.converter rs.rs_name) with
               | _, Some s
               | Some s, _ ->
                 begin
                   try
                     let _ =
                       Str.search_forward
                         (Str.regexp "[%]\\([tv]?\\)[0-9]+") s 0 in
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                     let env_f =
                       { env with computes_return_value = false } in
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                     let params =
		       List.map
                         (fun e ->
                           (simplify_expr (expr info env_f e),
                            ty_of_ty info (ty_of_ity (ity_of_expr e))))
		         el in
		     let rty = ty_of_ity (match e.e_ity with
                                           | C _ -> assert false
                                           | I i -> i) in
		     let rtyargs = match rty.ty_node with
		       | Tyvar _ -> [||]
		       | Tyapp (_,args) ->
                         Array.of_list (List.map (ty_of_ty info) args)
		     in
		     C.Esyntax(s,ty_of_ty info rty, rtyargs, params,
                               Mid.mem rs.rs_name info.converter)
                   with Not_found ->
		     let args =
                       List.filter
                         (fun e ->
                           assert (not e.e_effect.eff_ghost);
                           match e.e_ity with
                           | I i when ity_equal i Ity.ity_unit -> false
                           | _ -> true)
		         el
                     in
                     if args=[]
                     then C.(Esyntax(s, Tnosyntax, [||], [], true)) (*constant*)
                     else
                       (*function defined in the prelude *)
                       let env_f =
                         { env with computes_return_value = false } in
		     C.(Ecall(Esyntax(s, Tnosyntax, [||], [], true),
			      List.map
                                (fun e ->
                                  simplify_expr (expr info env_f e))
                                el))
                 end
               | _ ->
                  let args =
                    List.filter
                      (fun e ->
                        assert (not e.e_effect.eff_ghost);
                        match e.e_ity with
                        | I i when ity_equal i Ity.ity_unit -> false
                        | _ -> true)
		      el in
                  let env_f =
                    { env with computes_return_value = false } in
		 C.(Ecall(Evar(rs.rs_name), List.map
                                (fun e ->
                                  simplify_expr (expr info env_f e))
                                args))
         in
	   C.([],
              if env.computes_return_value
	      then
                if (ity_equal rs.rs_cty.cty_result Ity.ity_unit)
                then Sseq(Sexpr e, Sreturn Enothing)
                else Sreturn e
              else Sexpr e)
    | Elet (ld,e) ->
       begin match ld with
       | Lvar (pv,le) -> (* not a block *)
          begin
          match le.e_node with
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          | Mltree.Econst ic ->
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            let n = Number.compute_int_constant ic in
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            let ce = C.(Econst (Cint (BigInt.to_string n))) in
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	    if debug then Format.printf "propagate constant %s for var %s@."
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			  (BigInt.to_string n) (pv_name pv).id_string;
            C.propagate_in_block (pv_name pv) ce (expr info env e)
          | Eapp (rs,_) when Mid.mem rs.rs_name info.converter ->
            begin match expr info {env with computes_return_value = false} le
              with
            | [], C.Sexpr(se) ->
              C.propagate_in_block (pv_name pv) se (expr info env e)
            | _ -> assert false
            end
          | _->
            let t = ty_of_ty info (ty_of_ity pv.pv_ity) in
            match expr info {env with computes_return_value = false} le with
            | [], C.Sexpr((C.Esyntax(_,_,_,_,b) as se))
                when b (* converter *) ->
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              if debug then Format.printf "propagate converter for var %s@."
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                (pv_name pv).id_string;
              C.propagate_in_block (pv_name pv) se (expr info env e)
            | d,s ->
              let initblock = d, C.assignify (Evar (pv_name pv)) s in
              [ C.Ddecl (t, [pv_name pv, C.Enothing]) ],
              C.Sseq (C.Sblock initblock, C.Sblock (expr info env e))
          end
      | Lsym _ -> raise (Unsupported "LDsym")
      | Lrec _ -> raise (Unsupported "LDrec") (* TODO for rec at least*)
       end
    | Eif (cond, th, el) ->
       let c = expr info {env with computes_return_value = false} cond in
       let t = expr info env th in
       let e = expr info env el in
       begin match c with
	     | [], C.Sexpr c ->
		if is_false th && is_true el
		then C.([], Sexpr(Eunop(Unot, c)))
		else [], C.Sif(c,C.Sblock t, C.Sblock e)
	     | cdef, cs ->
		let cid = id_register (id_fresh "cond") in (* ? *)
		C.Ddecl (C.Tsyntax ("int",[]), [cid, C.Enothing])::cdef,
		C.Sseq (C.assignify (Evar cid) cs,
                        C.Sif (C.Evar cid, C.Sblock t, C.Sblock e))
       (* TODO detect empty branches and replace with Snop, detect and/or*)
       end
    | Ewhile (c,b) ->
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       if debug then Format.printf "while@.";
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      let cd, cs = expr info {env with computes_return_value = false} c in
      (* this is needed so that the extracted expression has all
         needed variables in its scope *)
      let cd, cs = C.flatten_defs cd cs in
      let cd = C.group_defs_by_type cd in
      let env' = { computes_return_value = false;
                   in_unguarded_loop = true;
		   returns_tuple = env.returns_tuple;
                   returns = env.returns;
                   breaks =
                     if env.in_unguarded_loop
                     then Sid.empty else env.breaks } in
      let b = expr info  env' b in
      begin match cs with
      | C.Sexpr ce -> cd, C.Swhile (ce, C.Sblock b)
      | _ ->
        begin match C.get_last_expr cs with
        | C.Snop, e -> cd, C.(Swhile(e, C.Sblock b))
        | s,e -> cd, C.(Swhile(Econst (Cint "1"),
                     Sseq(s,
                          Sseq(Sif(Eunop(Unot, e), Sbreak, Snop),
                               C.Sblock b))))
        end
      end
    | Etry (b,xl) ->
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      if debug then Format.printf "TRY@.";
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      let is_while = match b.e_node with Ewhile _ -> true | _-> false in
      let breaks, returns = List.fold_left
        (fun (bs,rs) (xs, pvsl, r) ->
          let id = xs.xs_name in
          match pvsl, r.e_node with
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          | [pv], Mltree.Evar pv'
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            when pv_equal pv pv' && env.computes_return_value ->
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            (bs, Sid.add id rs)
          | [], (Eblock []) when is_unit r.e_ity && is_while ->
            (Sid.add id bs, rs)
          |_ -> raise (Unsupported "non break/return exception in try"))
        (Sid.empty, env.returns) xl
      in
      let env' = { computes_return_value = env.computes_return_value;
                   in_unguarded_loop = false;
		   returns_tuple = env.returns_tuple;
                   breaks = breaks;
                   returns = returns;
                 } in
      expr info env' b
    | Eraise (xs,_) when Sid.mem xs.xs_name env.breaks ->
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      if debug then Format.printf "BREAK@.";
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      ([], C.Sbreak)
    | Eraise (xs, Some r) when Sid.mem xs.xs_name env.returns ->
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      if debug then Format.printf "RETURN@.";
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      expr info {env with computes_return_value = true} r
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    | Eraise (_, None) -> assert false (* nothing to pass to return *)
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    | Eraise _ -> raise (Unsupported "non break/return exception raised")
    | Efor _ -> raise (Unsupported "for loops")  (*TODO*)
    | Ematch (e1, [Ptuple rets,e2])
         when List.for_all
                (function Pvar _ -> true |_-> false)
                rets
      ->
      let rets, defs = List.fold_right
        (fun p (r, d)-> match p with
        | Pvar vs -> (C.(Eunop(Uaddr,Evar vs.vs_name))::r,
		        C.Ddecl(ty_of_ty info vs.vs_ty,
                                [vs.vs_name, C.Enothing])::d)
        | _ -> assert false )
        rets ([], []) in
      let d,s = expr info {env with computes_return_value = false} e1 in
      let s' = C.add_to_last_call rets s in
      let b = expr info env e2 in
      d@defs, C.(Sseq(s', Sblock b))
    | Ematch _ -> raise (Unsupported "pattern matching")
    | Eabsurd -> assert false
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    | Eassign ([pv, ({rs_field = Some _} as rs), v]) ->
       let t =
         match (query_syntax info.syntax rs.rs_name,
                      query_syntax info.converter rs.rs_name) with
         | _, Some s | Some s, _ ->
            let _ =
              try
                Str.search_forward
                  (Str.regexp "[%]\\([tv]?\\)[0-9]+") s 0
              with Not_found -> raise (Unsupported "assign field format")  in
            let params = [ C.Evar pv.pv_vs.vs_name,
                           ty_of_ty info (ty_of_ity pv.pv_ity) ] in
            let rty = ty_of_ity rs.rs_cty.cty_result in
            let rtyargs = match rty.ty_node with
	      | Tyvar _ -> [||]
	      | Tyapp (_,args) ->
                 Array.of_list (List.map (ty_of_ty info) args)
	    in
            C.Esyntax(s,ty_of_ty info rty, rtyargs, params,
                      Mid.mem rs.rs_name info.converter)
         | None, None -> raise (Unsupported ("assign not in driver")) in
       [], C.(Sexpr(Ebinop(Bassign, t, C.Evar v.pv_vs.vs_name)))
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    | Eassign _ -> raise (Unsupported "assign")
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    | Ehole -> assert false
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    | Eexn _ -> raise (Unsupported "exception")
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    | Eignore e ->
       [], C.Sseq(C.Sblock(expr info {env with computes_return_value = false} e),
              if env.computes_return_value
              then C.Sreturn(Enothing)
              else C.Snop)
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    | Efun _ -> raise (Unsupported "higher order")

  let translate_decl (info:info) (d:decl) : C.definition option
    =
    match d with
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    | Dlet (Lsym(rs, _, vl, e)) ->
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       if rs_ghost rs
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       then begin if debug then Format.printf "is ghost@."; None end
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       else
         begin try
           let params =
             List.map (fun (id, ty, _gh) -> (ty_of_mlty info ty, id))
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                      (List.filter (fun (_,_, gh) -> not gh) vl) in
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	   let env = { computes_return_value = true;
		       in_unguarded_loop = false;
		       returns_tuple = false, [];
		       returns = Sid.empty;
		       breaks = Sid.empty; } in
	   let rity = rs.rs_cty.cty_result in
	   let is_simple_tuple ity =
	     let arity_zero = function
	       | Ityapp(_,a,r) -> a = [] && r = []
	       | Ityreg { reg_args = a; reg_regs = r } ->
                  a = [] && r = []
	       | Ityvar _ -> true
	     in
	     (match ity.ity_node with
	      | Ityapp ({its_ts = s},_,_)
                | Ityreg { reg_its = {its_ts = s}; }
		-> is_ts_tuple s
	      | _ -> false)
	     && (ity_fold
                   (fun acc ity ->
                     acc && arity_zero ity.ity_node) true ity)
	   in
	   (* FIXME is it necessary to have arity 0 in regions ?*)
	   let rtype =
	     if ity_equal rity Ity.ity_unit
	     then C.Tvoid
	     else ty_of_ty info (ty_of_ity rity) in
	   let env, rtype, params = match rtype with
	     | C.Tnosyntax when is_simple_tuple rity ->
		(* instead of returning a tuple, return
			      void and assign the result to addresses
			      passed as parameters *)
		let returns =
		  let f ity b acc =
		    if b.its_visible
		    then (C.Tptr(ty_of_ty info (ty_of_ity ity)),
			  id_register (id_fresh "result"))::acc
		    else acc
		  in
		  match rity.ity_node with
		  | Ityapp(s, tl,_)
		    | Ityreg { reg_its = s; reg_args = tl } ->
		     List.fold_right2 f tl s.its_arg_flg []
		  | Ityvar _ -> assert false
		in
		{env with returns_tuple = true, List.map snd returns},
		C.Tvoid,
		returns@params
	     | _ -> env, rtype, params
	   in
	   let d,s = expr info env e in
           (*TODO check if we want this flatten*)
	   let d,s = C.flatten_defs d s in
           let d = C.group_defs_by_type d in
	   let s = C.elim_nop s in
	   let s = C.elim_empty_blocks s in
	   Some
             (C.Dfun (rs.rs_name, (rtype,params), (d,s)))
           with  Unsupported s ->
             Format.printf "Unsupported : %s@." s; None
         end
    | Dtype [{its_name=id; its_def=idef}] ->
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      if debug then Format.printf "PDtype %s@." id.id_string;
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      begin
        match idef with
        | Some (Dalias ty) -> Some (C.Dtypedef (ty_of_mlty info ty, id))
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        | Some _ -> raise (Unsupported "Ddata/Drecord@.")
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        | None ->
          begin match query_syntax info.syntax id with
          | Some _ -> None
          | None ->
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             raise (Unsupported ("type declaration without syntax or alias: "^id.id_string))
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          end
      end

    | _ -> None (*TODO exn ? *)

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  let translate_decl (info:info) (d:Mltree.decl) : C.definition option
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    =
    let decide_print id = query_syntax info.syntax id = None in
    match Compile.ML.get_decl_name d with
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    | [id] when decide_print id ->
       if debug then Format.printf "print %s@." id.id_string;
       translate_decl info d
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    | [_] -> None
    | _ -> raise (Unsupported "no name or recursive defs")


end


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let fg ?fname m =
  let n = m.Pmodule.mod_theory.Theory.th_name.Ident.id_string in
  match fname with
  | None -> n ^ ".c"
  | Some f -> f ^ "__" ^ n ^ ".c"
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(*
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let pr args ?old ?fname ~flat m fmt _d =
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  ignore(old);
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  let ast = Translate.translate args m in
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  try Print.print_file fmt args ast
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  with Print.Unprinted s -> (Format.printf "Could not print: %s@." s;
		       Format.fprintf fmt "/* Dummy file */@.")
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*)
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let print_decl args ?old ?fname ~flat m fmt d =
  ignore old;
  ignore fname;
  ignore flat; (*FIXME*)
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  ignore m;
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  let cds = MLToC.translate_decl args d in
  match cds with
  | None -> ()
  | Some cd -> Format.fprintf fmt "%a@." Print.print_def cd

let () =
  Pdriver.register_printer "c" ~desc:"printer for C code" fg print_decl