(*  Title:      Pure/Syntax/syn_ext.ML

    ID:         $Id$

    Author:     Markus Wenzel and Carsten Clasohm, TU Muenchen

Syntax extension (internal interface).

*)

signature SYN_EXT0 =

  sig

  val typeT: typ

  val constrainC: string

  end;

signature SYN_EXT =

  sig

  include SYN_EXT0

  val logic: string

  val args: string

  val cargs: string

  val any: string

  val sprop: string

  val typ_to_nonterm: typ -> string

  datatype xsymb =

    Delim of string |

    Argument of string * int |

    Space of string |

    Bg of int | Brk of int | En

  datatype xprod = XProd of string * xsymb list * string * int

  val max_pri: int

  val chain_pri: int

  val delims_of: xprod list -> string list

  datatype mfix = Mfix of string * typ * string * int list * int

  datatype syn_ext =

    SynExt of {

      logtypes: string list,

      xprods: xprod list,

      consts: string list,

      parse_ast_translation: (string * (Ast.ast list -> Ast.ast)) list,

      parse_rules: (Ast.ast * Ast.ast) list,

      parse_translation: (string * (term list -> term)) list,

      print_translation: (string * (term list -> term)) list,

      print_rules: (Ast.ast * Ast.ast) list,

      print_ast_translation: (string * (Ast.ast list -> Ast.ast)) list}

  val mk_syn_ext: bool -> string list -> mfix list ->

    string list -> (string * (Ast.ast list -> Ast.ast)) list *

    (string * (term list -> term)) list *

    (string * (term list -> term)) list * (string * (Ast.ast list -> Ast.ast)) list

    -> (Ast.ast * Ast.ast) list * (Ast.ast * Ast.ast) list -> syn_ext

  val syn_ext: string list -> mfix list -> string list ->

    (string * (Ast.ast list -> Ast.ast)) list * (string * (term list -> term)) list *

    (string * (term list -> term)) list * (string * (Ast.ast list -> Ast.ast)) list

    -> (Ast.ast * Ast.ast) list * (Ast.ast * Ast.ast) list -> syn_ext

  val syn_ext_logtypes: string list -> syn_ext

  val syn_ext_const_names: string list -> string list -> syn_ext

  val syn_ext_rules: string list -> (Ast.ast * Ast.ast) list * (Ast.ast * Ast.ast) list -> syn_ext

  val syn_ext_trfuns: string list ->

    (string * (Ast.ast list -> Ast.ast)) list * (string * (term list -> term)) list *

    (string * (term list -> term)) list * (string * (Ast.ast list -> Ast.ast)) list

    -> syn_ext

  val pure_ext: syn_ext

  end;

structure SynExt : SYN_EXT =

struct

open Lexicon Ast;

(** misc definitions **)

(* syntactic categories *)

val logic = "logic";

val logicT = Type (logic, []);

val args = "args";

val cargs = "cargs";

val typeT = Type ("type", []);

val sprop = "#prop";

val spropT = Type (sprop, []);

val any = "any";

val anyT = Type (any, []);

(* constants *)

val constrainC = "_constrain";

(** datatype xprod **)

(*Delim s: delimiter s

  Argument (s, p): nonterminal s requiring priority >= p, or valued token

  Space s: some white space for printing

  Bg, Brk, En: blocks and breaks for pretty printing*)

datatype xsymb =

  Delim of string |

  Argument of string * int |

  Space of string |

  Bg of int | Brk of int | En;

(*XProd (lhs, syms, c, p):

    lhs: name of nonterminal on the lhs of the production

    syms: list of symbols on the rhs of the production

    c: head of parse tree

    p: priority of this production*)

datatype xprod = XProd of string * xsymb list * string * int;

val max_pri = 1000;   (*maximum legal priority*)

val chain_pri = ~1;   (*dummy for chain productions*)

(* delims_of *)

fun delims_of xprods =

  let

    fun del_of (Delim s) = Some s

      | del_of _ = None;

    fun dels_of (XProd (_, xsymbs, _, _)) =

      mapfilter del_of xsymbs;

  in

    distinct (flat (map dels_of xprods))

  end;

(** datatype mfix **)

(*Mfix (sy, ty, c, ps, p):

    sy: rhs of production as symbolic string

    ty: type description of production

    c: head of parse tree

    ps: priorities of arguments in sy

    p: priority of production*)

datatype mfix = Mfix of string * typ * string * int list * int;

(* typ_to_nonterm *)

fun typ_to_nt _ (Type (c, _)) = c

  | typ_to_nt default _ = default;

(*get nonterminal for rhs*)

val typ_to_nonterm = typ_to_nt any;

(*get nonterminal for lhs*)

val typ_to_nonterm1 = typ_to_nt logic;

(* mfix_to_xprod *)

fun mfix_to_xprod convert logtypes (Mfix (sy, typ, const, pris, pri)) =

  let

    fun err msg =

      (writeln ("Error in mixfix annotation " ^ quote sy ^ " for "

                ^ quote const);

        error msg);

    fun check_pri p =

      if p >= 0 andalso p <= max_pri then ()

      else err ("precedence out of range: " ^ string_of_int p);

    fun blocks_ok [] 0 = true

      | blocks_ok [] _ = false

      | blocks_ok (Bg _ :: syms) n = blocks_ok syms (n + 1)

      | blocks_ok (En :: _) 0 = false

      | blocks_ok (En :: syms) n = blocks_ok syms (n - 1)

      | blocks_ok (_ :: syms) n = blocks_ok syms n;

    fun check_blocks syms =

      if blocks_ok syms 0 then ()

      else err "unbalanced block parentheses";

    local

      fun is_meta c = c mem ["(", ")", "/", "_"];

      fun scan_delim_char ("'" :: c :: cs) =

            if is_blank c then raise LEXICAL_ERROR else (c, cs)

        | scan_delim_char ["'"] = err "trailing escape character"

        | scan_delim_char (chs as c :: cs) =

            if is_blank c orelse is_meta c then raise LEXICAL_ERROR else (c, cs)

        | scan_delim_char [] = raise LEXICAL_ERROR;

      val scan_sym =

        $$ "_" >> K (Argument ("", 0)) ||

        $$ "(" -- scan_int >> (Bg o #2) ||

        $$ ")" >> K En ||

        $$ "/" -- $$ "/" >> K (Brk ~1) ||

        $$ "/" -- scan_any is_blank >> (Brk o length o #2) ||

        scan_any1 is_blank >> (Space o implode) ||

        repeat1 scan_delim_char >> (Delim o implode);

      val scan_symb =

        scan_sym >> Some ||

        $$ "'" -- scan_one is_blank >> K None;

    in

      val scan_symbs = mapfilter I o #1 o repeat scan_symb;

    end;

    val cons_fst = apfst o cons;

    fun add_args [] ty [] = ([], typ_to_nonterm1 ty)

      | add_args [] _ _ = err "too many precedences"

      | add_args (Argument _ :: syms) (Type ("fun", [ty, tys])) [] =

          cons_fst (Argument (typ_to_nonterm ty, 0)) (add_args syms tys [])

      | add_args (Argument _ :: syms) (Type ("fun", [ty, tys])) (p :: ps) =

          cons_fst (Argument (typ_to_nonterm ty, p)) (add_args syms tys ps)

      | add_args (Argument _ :: _) _ _ =

          err "more arguments than in corresponding type"

      | add_args (sym :: syms) ty ps = cons_fst sym (add_args syms ty ps);

    fun is_arg (Argument _) = true

      | is_arg _ = false;

    fun is_term (Delim _) = true

      | is_term (Argument (s, _)) = is_terminal s

      | is_term _ = false;

    fun rem_pri (Argument (s, _)) = Argument (s, chain_pri)

      | rem_pri sym = sym;

    fun is_delim (Delim _) = true

      | is_delim _ = false;

    (*replace logical types on rhs by "logic"*)

    fun unify_logtypes copy_prod (a as (Argument (s, p))) =

          if s mem logtypes then Argument (logic, p)

          else a

      | unify_logtypes _ a = a;

    val raw_symbs = scan_symbs (explode sy);

    val (symbs, lhs) = add_args raw_symbs typ pris;

    val copy_prod = lhs mem ["prop", "logic"]

          andalso const <> ""

          andalso not (null symbs)

          andalso not (exists is_delim symbs);

    val lhs' = if convert andalso not copy_prod then

                 (if lhs mem logtypes then logic

                  else if lhs = "prop" then sprop else lhs)

               else lhs;

    val symbs' = map (unify_logtypes copy_prod) symbs;

    val xprod = XProd (lhs', symbs', const, pri);

  in

    seq check_pri pris;

    check_pri pri;

    check_blocks symbs';

    if is_terminal lhs' then err ("illegal lhs: " ^ lhs')

    else if const <> "" then xprod

    else if length (filter is_arg symbs') <> 1 then

      err "copy production must have exactly one argument"

    else if exists is_term symbs' then xprod

    else XProd (lhs', map rem_pri symbs', "", chain_pri)

  end;

(** datatype syn_ext **)

datatype syn_ext =

  SynExt of {

    logtypes: string list,

    xprods: xprod list,

    consts: string list,

    parse_ast_translation: (string * (Ast.ast list -> Ast.ast)) list,

    parse_rules: (Ast.ast * Ast.ast) list,

    parse_translation: (string * (term list -> term)) list,

    print_translation: (string * (term list -> term)) list,

    print_rules: (Ast.ast * Ast.ast) list,

    print_ast_translation: (string * (Ast.ast list -> Ast.ast)) list};

(* syn_ext *)

fun mk_syn_ext convert logtypes mfixes consts trfuns rules =

  let

    val (parse_ast_translation, parse_translation, print_translation,

      print_ast_translation) = trfuns;

    val (parse_rules, print_rules) = rules;

    val logtypes' = logtypes \ "prop";

    val mfix_consts = distinct (map (fn (Mfix (_, _, c, _, _)) => c) mfixes);

    val xprods = map (mfix_to_xprod convert logtypes') mfixes;

  in

    SynExt {

      logtypes = logtypes',

      xprods = xprods,

      consts = filter is_xid (consts union mfix_consts),

      parse_ast_translation = parse_ast_translation,

      parse_rules = parse_rules,

      parse_translation = parse_translation,

      print_translation = print_translation,

      print_rules = print_rules,

      print_ast_translation = print_ast_translation}

  end;

val syn_ext = mk_syn_ext true;

fun syn_ext_logtypes logtypes =

  syn_ext logtypes [] [] ([], [], [], []) ([], []);

fun syn_ext_const_names logtypes cs =

  syn_ext logtypes [] cs ([], [], [], []) ([], []);

fun syn_ext_rules logtypes rules =

  syn_ext logtypes [] [] ([], [], [], []) rules;

fun syn_ext_trfuns logtypes trfuns =

  syn_ext logtypes [] [] trfuns ([], []);

(* pure_ext *)

val pure_ext = mk_syn_ext false []

  [Mfix ("_", spropT --> propT, "", [0], 0),

   Mfix ("_", logicT --> anyT, "", [0], 0),

   Mfix ("_", spropT --> anyT, "", [0], 0),

   Mfix ("'(_')", logicT --> logicT, "", [0], max_pri),

   Mfix ("'(_')", spropT --> spropT, "", [0], max_pri),

   Mfix ("_::_",  [logicT, typeT] ---> logicT, "_constrain", [4, 0], 3),

   Mfix ("_::_",  [spropT, typeT] ---> spropT, "_constrain", [4, 0], 3)]

  []

  ([], [], [], [])

  ([], []);

end;