(* XXX this is copy-pasted from pretty_printer.ml with the following
 * changes:
 * - open Interp_ast instead of Ast; don't open Type_internals
 * - string_of_big_int instead of string_of_int
 * - annot does not contain type annotations anymore, so E_internal_cast
 *   is ignored
 * - don't print E_cast either by default (controlled by ignore_casts)
 * - special case for holes in doc_id
 * - pp_exp returns a string instead of working on a buffer (should
 *   change this in the original as well, probably)
 * - pp_defs deleted
 * - the pretty-printer does not support DeIid; here, we add a
 *   work-around to make it work, converting back to Id with parens,
 *   because the stack/continuation contains operators in DeIid form.
 *   Should maybe backport this one to the original p-p.
 *)

open Interp_ast
open Format
open Big_int

let ignore_casts = ref true

let pp_format_id (Id_aux(i,_)) =
  match i with
  | Id(i) -> i
  | DeIid(x) -> "(deinfix " ^ x ^ ")"

(****************************************************************************
 * PPrint-based source-to-source pretty printer
****************************************************************************)

open PPrint

let doc_id (Id_aux(i,_)) =
  match i with
  | Id "0" -> string "\x1b[1;31m[_]\x1b[m" (* internal representation of a hole *)
  | Id i -> string i
  | DeIid x ->
      (* add an extra space through empty to avoid a closing-comment
       * token in case of x ending with star. *)
      parens (separate space [string "deinfix"; string x; empty])

let doc_var (Kid_aux(Var v,_)) = string v

let doc_int i = string (string_of_big_int i)

let doc_bkind (BK_aux(k,_)) =
  string (match k with
  | BK_type -> "Type"
  | BK_nat -> "Nat"
  | BK_order -> "Order"
  | BK_effect -> "Effect")

let doc_op symb a b = infix 2 1 symb a b
let doc_unop symb a = prefix 2 1 symb a

let arrow = string "->"
let dotdot = string ".."
let coloneq = string ":="
let lsquarebar = string "[|"
let rsquarebar = string "|]"
let squarebars = enclose lsquarebar rsquarebar
let lsquarebarbar = string "[||"
let rsquarebarbar = string "||]"
let squarebarbars = enclose lsquarebarbar rsquarebarbar
let spaces op = enclose space space op
let semi_sp = semi ^^ space
let comma_sp = comma ^^ space
let colon_sp = spaces colon

let doc_kind (K_aux(K_kind(klst),_)) =
  separate_map (spaces arrow) doc_bkind klst

let doc_effect (BE_aux (e,_)) =
  string (match e with
  | BE_rreg -> "rreg"
  | BE_wreg -> "wreg"
  | BE_rmem -> "rmem"
  | BE_wmem -> "wmem"
  | BE_barr -> "barr"
  | BE_undef -> "undef"
  | BE_unspec -> "unspec"
  | BE_nondet -> "nondet")

let doc_effects (Effect_aux(e,_)) = match e with
  | Effect_var v -> doc_var v
  | Effect_set [] -> string "pure"
  | Effect_set s -> braces (separate_map comma_sp doc_effect s)

let doc_ord (Ord_aux(o,_)) = match o with
  | Ord_var v -> doc_var v
  | Ord_inc -> string "inc"
  | Ord_dec -> string "dec"

let doc_typ, doc_atomic_typ, doc_nexp =
  (* following the structure of parser for precedence *)
  let rec typ ty = fn_typ ty
  and fn_typ ((Typ_aux (t, _)) as ty) = match t with
  | Typ_fn(arg,ret,efct) ->
      separate space [tup_typ arg; arrow; fn_typ ret; string "effect"; doc_effects efct]
  | _ -> tup_typ ty
  and tup_typ ((Typ_aux (t, _)) as ty) = match t with
  | Typ_tup typs -> parens (separate_map comma_sp app_typ typs)
  | _ -> app_typ ty
  and app_typ ((Typ_aux (t, _)) as ty) = match t with
  | Typ_app(id,args) ->
      (* trailing space to avoid >> token in case of nested app types *)
      (doc_id id) ^^ (angles (separate_map comma_sp doc_typ_arg args)) ^^ space
  | Typ_app(Id_aux (Id "vector", _), [
    Typ_arg_aux(Typ_arg_nexp (Nexp_aux(Nexp_constant n, _)), _);
    Typ_arg_aux(Typ_arg_nexp (Nexp_aux(Nexp_constant m, _)), _);
    Typ_arg_aux (Typ_arg_order (Ord_aux (Ord_inc, _)), _);
    Typ_arg_aux (Typ_arg_typ (Typ_aux (Typ_id id, _)), _)]) ->
    (doc_id id) ^^ 
      (brackets (if eq_big_int n zero_big_int then doc_int m 
	         else doc_op colon (doc_int n) (doc_int (add_big_int n (sub_big_int m unit_big_int)))))
  | Typ_app(Id_aux (Id "range", _), [
    Typ_arg_aux(Typ_arg_nexp (Nexp_aux(Nexp_constant n, _)), _);
    Typ_arg_aux(Typ_arg_nexp m, _);]) ->
    (squarebars (if eq_big_int n zero_big_int then nexp m else doc_op colon (doc_int n) (nexp m))) 
  | _ -> atomic_typ ty 
  and atomic_typ ((Typ_aux (t, _)) as ty) = match t with
  | Typ_id id  -> doc_id id
  | Typ_var v  -> doc_var v
  | Typ_wild -> underscore
  | Typ_app _ | Typ_tup _ | Typ_fn _ ->
      (* exhaustiveness matters here to avoid infinite loops
       * if we add a new Typ constructor *)
      group (parens (typ ty))
  and doc_typ_arg (Typ_arg_aux(t,_)) = match t with
  (* Be careful here because typ_arg is implemented as nexp in the
   * parser - in practice falling through app_typ after all the proper nexp
   * cases; so Typ_arg_typ has the same precedence as a Typ_app *)
  | Typ_arg_typ t -> app_typ t
  | Typ_arg_nexp n -> nexp n
  | Typ_arg_order o -> doc_ord o
  | Typ_arg_effect e -> doc_effects e

  (* same trick to handle precedence of nexp *)
  and nexp ne = sum_typ ne
  and sum_typ ((Nexp_aux(n,_)) as ne) = match n with
  | Nexp_sum(n1,n2) -> doc_op plus (sum_typ n1) (star_typ n2)
  | _ -> star_typ ne
  and star_typ ((Nexp_aux(n,_)) as ne) = match n with
  | Nexp_times(n1,n2) -> doc_op star (star_typ n1) (exp_typ n2)
  | _ -> exp_typ ne
  and exp_typ ((Nexp_aux(n,_)) as ne) = match n with
  | Nexp_exp n1 -> doc_unop (string "2**") (neg_typ n1)
  | _ -> neg_typ ne
  and neg_typ ((Nexp_aux(n,_)) as ne) = match n with
  | Nexp_neg n1 ->
      (* XXX this is not valid Sail, only an internal representation -
       * work around by commenting it *)
      let minus = concat [string "(*"; minus; string "*)"] in
      minus ^^ (atomic_nexp_typ n1)
  | _ -> atomic_nexp_typ ne
  and atomic_nexp_typ ((Nexp_aux(n,_)) as ne) = match n with
  | Nexp_var v -> doc_var v
  | Nexp_constant i -> doc_int i
  | Nexp_neg _ | Nexp_exp _ | Nexp_times _ | Nexp_sum _ ->
      group (parens (nexp ne))

  (* expose doc_typ, doc_atomic_typ and doc_nexp *)
  in typ, atomic_typ, nexp

let doc_nexp_constraint (NC_aux(nc,_)) = match nc with
  | NC_fixed(n1,n2) -> doc_op equals (doc_nexp n1) (doc_nexp n2)
  | NC_bounded_ge(n1,n2) -> doc_op (string ">=") (doc_nexp n1) (doc_nexp n2)
  | NC_bounded_le(n1,n2) -> doc_op (string "<=") (doc_nexp n1) (doc_nexp n2)
  | NC_nat_set_bounded(v,bounds) ->
      doc_op (string "IN") (doc_var v)
        (braces (separate_map comma_sp doc_int bounds))

let doc_qi (QI_aux(qi,_)) = match qi with
  | QI_const n_const -> doc_nexp_constraint n_const
  | QI_id(KOpt_aux(ki,_)) ->
    match ki with
    | KOpt_none v -> doc_var v
    | KOpt_kind(k,v) -> separate space [doc_kind k; doc_var v]

(* typ_doc is the doc for the type being quantified *)
let doc_typquant (TypQ_aux(tq,_)) typ_doc = match tq with
  | TypQ_no_forall -> typ_doc
  | TypQ_tq [] -> failwith "TypQ_tq with empty list"
  | TypQ_tq qlist ->
    (* include trailing break because the caller doesn't know if tq is empty *)
    doc_op dot
      (separate space [string "forall"; separate_map comma_sp doc_qi qlist])
      typ_doc

let doc_typscm (TypSchm_aux(TypSchm_ts(tq,t),_)) =
  (doc_typquant tq (doc_typ t))

let doc_typscm_atomic (TypSchm_aux(TypSchm_ts(tq,t),_)) =
  (doc_typquant tq (doc_atomic_typ t))

let doc_lit (L_aux(l,_)) =
  utf8string (match l with
  | L_unit  -> "()"
  | L_zero  -> "bitzero"
  | L_one   -> "bitone"
  | L_true  -> "true"
  | L_false -> "false"
  | L_num i -> string_of_big_int i
  | L_hex n -> "0x" ^ n
  | L_bin n -> "0b" ^ n
  | L_undef -> "undefined"
  | L_string s -> "\"" ^ s ^ "\"")

let doc_pat, doc_atomic_pat =
  let rec pat pa = pat_colons pa
  and pat_colons ((P_aux(p,l)) as pa) = match p with
  | P_vector_concat pats  -> separate_map colon_sp atomic_pat pats
  | _ -> app_pat pa
  and app_pat ((P_aux(p,l)) as pa) = match p with
  | P_app(id, ((_ :: _) as pats)) -> doc_unop (doc_id id) (parens (separate_map comma_sp atomic_pat pats))
  | _ -> atomic_pat pa
  and atomic_pat ((P_aux(p,l)) as pa) = match p with
  | P_lit lit  -> doc_lit lit
  | P_wild -> underscore
  | P_id id -> doc_id id
  | P_as(p,id) -> parens (separate space [pat p; string "as"; doc_id id])
  | P_typ(typ,p) -> separate space [parens (doc_typ typ); atomic_pat p]
  | P_app(id,[]) -> doc_id id
  | P_record(fpats,_) -> braces (separate_map semi_sp fpat fpats)
  | P_vector pats  -> brackets (separate_map comma_sp atomic_pat pats)
  | P_vector_indexed ipats  -> brackets (separate_map comma_sp npat ipats)
  | P_tup pats  -> parens (separate_map comma_sp atomic_pat pats)
  | P_list pats  -> squarebarbars (separate_map semi_sp atomic_pat pats)
  | P_app(_, _ :: _) | P_vector_concat _ ->
      group (parens (pat pa))
  and fpat (FP_aux(FP_Fpat(id,fpat),_)) = doc_op equals (doc_id id) (pat fpat)
  and npat (i,p) = doc_op equals (doc_int i) (pat p)

  (* expose doc_pat and doc_atomic_pat *)
  in pat, atomic_pat

let doc_exp, doc_let =
  let rec exp env add_red e = group (or_exp env add_red e)
  and or_exp env add_red ((E_aux(e,_)) as expr) = match e with
  | E_app_infix(l,(Id_aux(Id ("|" | "||"),_) as op),r) ->
      doc_op (doc_id op) (and_exp env add_red l) (or_exp env add_red r)
  | _ -> and_exp env add_red expr
  and and_exp env add_red ((E_aux(e,_)) as expr) = match e with
  | E_app_infix(l,(Id_aux(Id ("&" | "&&"),_) as op),r) ->
    doc_op (doc_id op) (eq_exp env add_red l) (and_exp env add_red r)
  | _ -> eq_exp env add_red expr
  and eq_exp env add_red ((E_aux(e,_)) as expr) = match e with
  | E_app_infix(l,(Id_aux(Id (
    (* XXX this is not very consistent - is the parser bogus here? *)
      "=" | "==" | "!="
    | ">=" | ">=_s" | ">=_u" | ">" | ">_s" | ">_u"
    | "<=" | "<=_s" | "<" | "<_s" | "<_si" | "<_u"
    ),_) as op),r) ->
      doc_op (doc_id op) (eq_exp env add_red l) (at_exp env add_red r)
  (* XXX assignment should not have the same precedence as equal etc. *)
  | E_assign(le,exp) -> doc_op coloneq (doc_lexp env add_red le) (at_exp env add_red exp)
  | _ -> at_exp env add_red expr
  and at_exp env add_red ((E_aux(e,_)) as expr) = match e with
  | E_app_infix(l,(Id_aux(Id ("@" | "^^" | "^" | "~^"),_) as op),r) ->
      doc_op (doc_id op) (cons_exp env add_red l) (at_exp env add_red r)
  | _ -> cons_exp env add_red expr
  and cons_exp env add_red ((E_aux(e,_)) as expr) = match e with
  | E_vector_append(l,r) ->
      doc_op colon (shift_exp env add_red l) (cons_exp env add_red r)
  | E_cons(l,r) ->
      doc_op colon (shift_exp env add_red l) (cons_exp env add_red r)
  | _ -> shift_exp env add_red expr
  and shift_exp env add_red ((E_aux(e,_)) as expr) = match e with
  | E_app_infix(l,(Id_aux(Id (">>" | ">>>" | "<<" | "<<<"),_) as op),r) ->
      doc_op (doc_id op) (shift_exp env add_red l) (plus_exp env add_red r)
  | _ -> plus_exp env add_red expr
  and plus_exp env add_red ((E_aux(e,_)) as expr) = match e with
  | E_app_infix(l,(Id_aux(Id ("+" | "-"| "+_s" | "-_s" ),_) as op),r) ->
      doc_op (doc_id op) (plus_exp env add_red l) (star_exp env add_red r)
  | _ -> star_exp env add_red expr
  and star_exp env add_red ((E_aux(e,_)) as expr) = match e with
  | E_app_infix(l,(Id_aux(Id (
      "*" | "/"
    | "div" | "quot" | "rem" | "mod" | "quot_s"
    | "*_s" | "*_si" | "*_u" | "*_ui"),_) as op),r) ->
      doc_op (doc_id op) (star_exp env add_red l) (starstar_exp env add_red r)
  | _ -> starstar_exp env add_red expr
  and starstar_exp env add_red ((E_aux(e,_)) as expr) = match e with
  | E_app_infix(l,(Id_aux(Id "**",_) as op),r) ->
      doc_op (doc_id op) (starstar_exp env add_red l) (app_exp env add_red r)
  | E_if _ | E_for _ | E_let _ -> right_atomic_exp env add_red expr
  | _ -> app_exp env add_red expr
  and right_atomic_exp env add_red ((E_aux(e,_)) as expr) = match e with
  (* Special case: omit "else ()" when the else branch is empty. *)
  | E_if(c,t,E_aux(E_block [], _)) ->
      string "if" ^^ space ^^ group (exp env add_red c) ^/^
      string "then" ^^ space ^^ group (exp env add_red t)
  | E_if(c,t,e) ->
      string "if" ^^ space ^^ group (exp env add_red c) ^/^
      string "then" ^^ space ^^ group (exp env add_red t) ^/^
      string "else" ^^ space ^^ group (exp env add_red e)
  | E_for(id,exp1,exp2,exp3,order,exp4) ->
      string "foreach" ^^ space ^^
      group (parens (
        separate (break 1) [
          doc_id id;
          string "from " ^^ (atomic_exp env add_red exp1);
          string "to " ^^ (atomic_exp env add_red exp2);
          string "by " ^^ (atomic_exp env add_red exp3);
          string "in " ^^ doc_ord order
        ]
      )) ^/^
	(exp env add_red exp4)
  | E_let(leb,e) -> doc_op (string "in") (let_exp env add_red leb) (exp env add_red e)
  | _ -> group (parens (exp env add_red expr))
  and app_exp env add_red ((E_aux(e,_)) as expr) = match e with
  | E_app(f,args) ->
      doc_unop (doc_id f) (parens (separate_map comma (exp env add_red) args))
  | _ -> vaccess_exp env add_red expr
  and vaccess_exp env add_red ((E_aux(e,_)) as expr) = match e with
  | E_vector_access(v,e) ->
    (atomic_exp env add_red v) ^^ brackets (exp env add_red e)
  | E_vector_subrange(v,e1,e2) ->
    (atomic_exp env add_red v) ^^ brackets (doc_op dotdot (exp env add_red e1) (exp env add_red e2))
  | _ -> field_exp env add_red expr
  and field_exp env add_red ((E_aux(e,_)) as expr) = match e with
  | E_field(fexp,id) -> (atomic_exp env add_red fexp) ^^ dot ^^ doc_id id
  | _ -> atomic_exp env add_red expr
  and atomic_exp env add_red ((E_aux(e,annot)) as expr) = match e with
  (* Special case: an empty block is equivalent to unit, but { } is a syntactic struct *)
  | E_block [] -> string "()"
  | E_block exps ->
      let exps_doc = separate_map (semi ^^ hardline) (exp env add_red) exps in
      surround 2 1 lbrace exps_doc rbrace
  | E_nondet exps ->
    let exps_doc = separate_map (semi ^^ hardline) (exp env add_red) exps in
    string "nondet" ^^ space ^^ (surround 2 1 lbrace exps_doc rbrace)
  | E_id id -> 
    (match id with
      | Id_aux(Id("0"), _) -> 
	(match Interp.in_lenv env id with
	  | Interp.V_unknown -> string (add_red "[_]")
	  | v -> (*string ("\x1b[1;31m" ^ Interp.string_of_value v ^ "\x1b[m")*)
	    string (add_red (Interp.string_of_value v)))
      | _ -> doc_id id)
  | E_lit lit -> doc_lit lit
  | E_cast(typ,e) ->
      if !ignore_casts then
        atomic_exp env add_red e
      else
        prefix 2 1 (parens (doc_typ typ)) (group (atomic_exp env add_red e))
  | E_internal_cast(_,e) ->
      (* XXX ignore internal casts in the interpreter *)
      atomic_exp env add_red e
  | E_tuple exps ->
      parens (separate_map comma (exp env add_red) exps)
  | E_record(FES_aux(FES_Fexps(fexps,_),_)) ->
      braces (separate_map semi_sp (doc_fexp env add_red) fexps)
  | E_record_update(e,(FES_aux(FES_Fexps(fexps,_),_))) ->
      braces (doc_op (string "with") (exp env add_red e) (separate_map semi_sp (doc_fexp env add_red) fexps))
  | E_vector exps ->
    let default_print _ = brackets (separate_map comma (exp env add_red) exps) in
    (match exps with
      | [] -> default_print ()
      | E_aux(e,_)::es ->
	(match e with
	  | E_lit (L_aux(L_one, _)) | E_lit (L_aux(L_zero, _)) ->
	    utf8string
	      ("0b" ^ 
	       (List.fold_right (fun (E_aux(E_lit(L_aux(l, _)),_)) rst -> match l with | L_one -> "1"^rst | L_zero -> "0"^rst) exps "")) 
	  | _ -> default_print ()))
  | E_vector_indexed (iexps, (Def_val_aux(default,_))) ->
    let default_string = 
      (match default with
	| Def_val_empty -> string "" 
	| Def_val_dec e -> concat [semi; space; string "default"; equals; (exp env add_red e)]) in 
      let iexp (i,e) = doc_op equals (doc_int i) (exp env add_red e) in
      brackets (concat [(separate_map comma iexp iexps);default_string])
  | E_vector_update(v,e1,e2) ->
      brackets (doc_op (string "with") (exp env add_red v) (doc_op equals (atomic_exp env add_red e1) (exp env add_red e2)))
  | E_vector_update_subrange(v,e1,e2,e3) ->
      brackets (
        doc_op (string "with") (exp env add_red v)
        (doc_op equals ((atomic_exp env add_red e1) ^^ colon ^^ (atomic_exp env add_red e2)) (exp env add_red e3)))
  | E_list exps ->
      squarebarbars (separate_map comma (exp env add_red) exps)
  | E_case(e,pexps) ->
      let opening = separate space [string "switch"; exp env add_red e; lbrace] in
      let cases = separate_map (break 1) (doc_case env add_red) pexps in
      surround 2 1 opening cases rbrace
  | E_exit e -> separate space [string "exit"; exp env add_red e;]
  (* adding parens and loop for lower precedence *)
  | E_app (_, _)|E_vector_access (_, _)|E_vector_subrange (_, _, _)
  | E_cons (_, _)|E_field (_, _)|E_assign (_, _)
  | E_if _ | E_for _ | E_let _
  | E_vector_append _
  | E_app_infix (_,
    (* for every app_infix operator caught at a higher precedence,
     * we need to wrap around with parens *)
    (Id_aux(Id("|" | "||"
    | "&" | "&&"
    | "=" | "==" | "!="
    | ">=" | ">=_s" | ">=_u" | ">" | ">_s" | ">_u"
    | "<=" | "<=_s" | "<" | "<_s" | "<_si" | "<_u"
    | "@" | "^^" | "^" | "~^"
    | ">>" | ">>>" | "<<" | "<<<"
    | "+" | "+_s" | "-" | "-_s" 
    | "*" | "/"
    | "div" | "quot" | "quot_s" | "rem" | "mod"
    | "*_s" | "*_si" | "*_u" | "*_ui"
    | "**"), _))
    , _) ->
      group (parens (exp env add_red expr))
  (* XXX fixup deinfix into infix ones *)
  | E_app_infix(l, (Id_aux((DeIid op), annot')), r) ->
      group (parens (exp env add_red (E_aux ((E_app_infix (l, (Id_aux(Id op, annot')), r)), annot))))
  (* XXX default precedence for app_infix? *)
  | E_app_infix(l,op,r) ->
      failwith ("unexpected app_infix operator " ^ (pp_format_id op))
      (* doc_op (doc_id op) (exp l) (exp r) *)
  (* XXX missing case *)
  | E_internal_exp _ -> assert false

  and let_exp env add_red (LB_aux(lb,_)) = match lb with
  | LB_val_explicit(ts,pat,e) ->
      prefix 2 1
        (separate space [string "let"; doc_typscm_atomic ts; doc_atomic_pat pat; equals])
        (exp env add_red e)
  | LB_val_implicit(pat,e) ->
      prefix 2 1
        (separate space [string "let"; doc_atomic_pat pat; equals])
        (exp env add_red e)

  and doc_fexp env add_red (FE_aux(FE_Fexp(id,e),_)) = doc_op equals (doc_id id) (exp env add_red e)

  and doc_case env add_red (Pat_aux(Pat_exp(pat,e),_)) =
    doc_op arrow (separate space [string "case"; doc_atomic_pat pat]) (group (exp env add_red e))

  (* lexps are parsed as eq_exp - we need to duplicate the precedence
   * structure for them *)
  and doc_lexp env add_red le = app_lexp env add_red le
  and app_lexp env add_red ((LEXP_aux(lexp,_)) as le) = match lexp with
  | LEXP_memory(id,args) -> doc_id id ^^ parens (separate_map comma (exp env add_red) args)
  | _ -> vaccess_lexp env add_red le
  and vaccess_lexp env add_red ((LEXP_aux(lexp,_)) as le) = match lexp with
  | LEXP_vector(v,e) -> (atomic_lexp env add_red v) ^^ brackets (exp env add_red e)
  | LEXP_vector_range(v,e1,e2) ->
      (atomic_lexp env add_red v) ^^ brackets ((exp env add_red e1) ^^ dotdot ^^ (exp env add_red e2))
  | _ -> field_lexp env add_red le
  and field_lexp env add_red ((LEXP_aux(lexp,_)) as le) = match lexp with
  | LEXP_field(v,id) -> (atomic_lexp env add_red v) ^^ dot ^^ doc_id id
  | _ -> atomic_lexp env add_red le
  and atomic_lexp env add_red ((LEXP_aux(lexp,_)) as le) = match lexp with
  | LEXP_id id -> doc_id id
  | LEXP_cast(typ,id) -> prefix 2 1 (parens (doc_typ typ)) (doc_id id)
  | LEXP_memory _ | LEXP_vector _ | LEXP_vector_range _
  | LEXP_field _ -> group (parens (doc_lexp env add_red le))

  (* expose doc_exp and doc_let *)
  in exp, let_exp

let doc_default (DT_aux(df,_)) = match df with
  | DT_kind(bk,v) -> separate space [string "default"; doc_bkind bk; doc_var v]
  | DT_typ(ts,id) -> separate space [string "default"; doc_typscm ts; doc_id id]

let doc_spec (VS_aux(v,_)) = match v with
  | VS_val_spec(ts,id) ->
      separate space [string "val"; doc_typscm ts; doc_id id]
  | VS_extern_no_rename(ts,id) ->
      separate space [string "val"; string "extern"; doc_typscm ts; doc_id id]
  | VS_extern_spec(ts,id,s) ->
      separate space [string "val"; string "extern"; doc_typscm ts;
      doc_op equals (doc_id id) (dquotes (string s))]

let doc_namescm (Name_sect_aux(ns,_)) = match ns with
  | Name_sect_none -> empty
  (* include leading space because the caller doesn't know if ns is
   * empty, and trailing break already added by the following equals *)
  | Name_sect_some s -> space ^^ brackets (doc_op equals (string "name") (dquotes (string s)))

let rec doc_range (BF_aux(r,_)) = match r with
  | BF_single i -> doc_int i
  | BF_range(i1,i2) -> doc_op dotdot (doc_int i1) (doc_int i2)
  | BF_concat(ir1,ir2) -> (doc_range ir1) ^^ comma ^^ (doc_range ir2)

let doc_type_union (Tu_aux(typ_u,_)) = match typ_u with
  | Tu_ty_id(typ,id) -> separate space [doc_typ typ; doc_id id]
  | Tu_id id -> doc_id id

let doc_typdef (TD_aux(td,_)) = match td with
  | TD_abbrev(id,nm,typschm) ->
      doc_op equals (concat [string "typedef"; space; doc_id id; doc_namescm nm]) (doc_typscm typschm)
  | TD_record(id,nm,typq,fs,_) ->
      let f_pp (typ,id) = concat [doc_typ typ; space; doc_id id; semi] in
      let fs_doc = group (separate_map (break 1) f_pp fs) in
      doc_op equals
        (concat [string "typedef"; space; doc_id id; doc_namescm nm])
        (string "const struct" ^^ space ^^ doc_typquant typq (braces fs_doc))
  | TD_variant(id,nm,typq,ar,_) ->
      let ar_doc = group (separate_map (semi ^^ break 1) doc_type_union ar) in
      doc_op equals
        (concat [string "typedef"; space; doc_id id; doc_namescm nm])
        (string "const union" ^^ space ^^ doc_typquant typq (braces ar_doc))
  | TD_enum(id,nm,enums,_) ->
      let enums_doc = group (separate_map (semi ^^ break 1) doc_id enums) in
      doc_op equals
        (concat [string "typedef"; space; doc_id id; doc_namescm nm])
        (string "enumerate" ^^ space ^^ braces enums_doc)
  | TD_register(id,n1,n2,rs) ->
      let doc_rid (r,id) = separate space [doc_range r; colon; doc_id id] ^^ semi in
      let doc_rids = group (separate_map (break 1) doc_rid rs) in
      doc_op equals
        (string "typedef" ^^ space ^^ doc_id id)
        (separate space [
          string "register bits";
          brackets (doc_nexp n1 ^^ colon ^^ doc_nexp n2);
          braces doc_rids;
        ])

let doc_rec (Rec_aux(r,_)) = match r with
  | Rec_nonrec -> empty
  (* include trailing space because caller doesn't know if we return
   * empty *)
  | Rec_rec -> string "rec" ^^ space

let doc_tannot_opt (Typ_annot_opt_aux(t,_)) = match t with
  | Typ_annot_opt_some(tq,typ) -> doc_typquant tq (doc_typ typ)

let doc_effects_opt (Effect_opt_aux(e,_)) = match e with
  | Effect_opt_pure -> string "pure"
  | Effect_opt_effect e -> doc_effects e

let doc_funcl env add_red (FCL_aux(FCL_Funcl(id,pat,exp),_)) =
  group (doc_op equals (separate space [doc_id id; doc_atomic_pat pat]) (doc_exp env add_red exp))

let doc_fundef env add_red (FD_aux(FD_function(r, typa, efa, fcls),_)) =
  match fcls with
  | [] -> failwith "FD_function with empty function list"
  | _ ->
      let sep = hardline ^^ string "and" ^^ space in
      let clauses = separate_map sep (doc_funcl env add_red) fcls in
      separate space [string "function";
        doc_rec r ^^ doc_tannot_opt typa;
        string "effect"; doc_effects_opt efa;
        clauses]

let doc_dec (DEC_aux(DEC_reg(typ,id),_)) =
  separate space [string "register"; doc_atomic_typ typ; doc_id id]

let doc_scattered env add_red (SD_aux (sdef, _)) = match sdef with
 | SD_scattered_function (r, typa, efa, id) ->
     separate space [
       string "scattered function";
       doc_rec r ^^ doc_tannot_opt typa;
       string "effect"; doc_effects_opt efa;
       doc_id id]
 | SD_scattered_variant (id, ns, tq) ->
     doc_op equals
       (string "scattered typedef" ^^ space ^^ doc_id id ^^ doc_namescm ns)
       (doc_typquant tq empty)
 | SD_scattered_funcl funcl ->
     string "function clause" ^^ space ^^ doc_funcl env add_red funcl
 | SD_scattered_unioncl (id, tu) ->
     separate space [string "union"; doc_id id;
     string "member"; doc_type_union tu]
 | SD_scattered_end id -> string "end" ^^ space ^^ doc_id id

let doc_def env add_red def = group (match def with
  | DEF_default df -> doc_default df
  | DEF_spec v_spec -> doc_spec v_spec
  | DEF_type t_def -> doc_typdef t_def
  | DEF_fundef f_def -> doc_fundef env add_red f_def
  | DEF_val lbind -> doc_let env add_red lbind
  | DEF_reg_dec dec -> doc_dec dec
  | DEF_scattered sdef -> doc_scattered env add_red sdef
  ) ^^ hardline

let doc_defs env add_red (Defs(defs)) =
  separate_map hardline (doc_def env add_red) defs

let print ?(len=80) channel doc = ToChannel.pretty 1. len channel doc
let to_buf ?(len=80) buf doc = ToBuffer.pretty 1. len buf doc

let pp_exp env add_red e =
  let b = Buffer.create 20 in
  to_buf b (doc_exp env add_red e);
  Buffer.contents b