(*  Title:      Pure/Thy/thy_info.ML

    ID:         $Id$

    Author:     Markus Wenzel, TU Muenchen

Main part of theory loader database, including handling of theory and

file dependencies.

*)

signature BASIC_THY_INFO =

sig

  val theory: string -> theory

(*val use: string -> unit*)             (*exported later*)

  val time_use: string -> unit

  val touch_thy: string -> unit

  val use_thy: string -> unit

  val update_thy: string -> unit

  val remove_thy: string -> unit

  val time_use_thy: string -> unit

end;

signature THY_INFO =

sig

  include BASIC_THY_INFO

  datatype action = Update | Outdate | Remove

  val str_of_action: action -> string

  val add_hook: (action -> string -> unit) -> unit

  val names: unit -> string list

  val known_thy: string -> bool

  val check_known_thy: string -> bool

  val if_known_thy: (string -> unit) -> string -> unit

  val lookup_theory: string -> theory option

  val get_theory: string -> theory

  val the_theory: string -> theory -> theory

  val get_parents: string -> string list

  val loaded_files: string -> Path.T list

  val touch_child_thys: string -> unit

  val touch_all_thys: unit -> unit

  val load_file: bool -> Path.T -> unit

  val use: string -> unit

  val pretend_use_thy_only: string -> unit

  val begin_theory: (Path.T list -> string -> string list ->

      (Path.T * bool) list -> theory -> theory) ->

    string -> string list -> (Path.T * bool) list -> bool -> theory

  val end_theory: theory -> theory

  val finish: unit -> unit

  val register_theory: theory -> unit

  val pretty_theory: theory -> Pretty.T

end;

structure ThyInfo: THY_INFO =

struct

(** theory loader actions and hooks **)

datatype action = Update | Outdate | Remove;

val str_of_action = fn Update => "Update" | Outdate => "Outdate" | Remove => "Remove";

local

  val hooks = ref ([]: (action -> string -> unit) list);

in

  fun add_hook f = hooks := f :: ! hooks;

  fun perform action name = List.app (fn f => (try (fn () => f action name) (); ())) (! hooks);

end;

(** thy database **)

(* messages *)

fun loader_msg txt [] = "Theory loader: " ^ txt

  | loader_msg txt names = "Theory loader: " ^ txt ^ " " ^ commas_quote names;

val show_path = space_implode " via " o map quote;

fun cycle_msg names = loader_msg ("cyclic dependency of " ^ show_path names) [];

(* derived graph operations *)

fun add_deps name parents G = Graph.add_deps_acyclic (name, parents) G

  handle Graph.CYCLES namess => error (cat_lines (map cycle_msg namess));

fun upd_deps name entry G =

  fold (fn parent => Graph.del_edge (parent, name)) (Graph.imm_preds G name) G

  |> Graph.map_node name (K entry);

fun update_node name parents entry G =

  (if can (Graph.get_node G) name then upd_deps name entry G else Graph.new_node (name, entry) G)

  |> add_deps name parents;

(* thy database *)

type master = (Path.T * File.ident) * (Path.T * File.ident) option;

type deps =

  {present: bool,

    outdated: bool,

    master: master option,

    files: (Path.T * (Path.T * File.ident) option) list};

fun master_idents (NONE: master option) = []

  | master_idents (SOME ((_, thy_id), NONE)) = [thy_id]

  | master_idents (SOME ((_, thy_id), SOME (_, ml_id))) = [thy_id, ml_id];

fun master_path (m: master option) = map (Path.dir o fst o fst) (the_list m);

fun master_path' (d: deps option) = maps (master_path o #master) (the_list d);

fun master_path'' d = maps master_path' (the_list d);

fun make_deps present outdated master files =

  {present = present, outdated = outdated, master = master, files = files}: deps;

fun init_deps master files = SOME (make_deps false true master (map (rpair NONE) files));

type thy = deps option * theory option;

local

  val database = ref (Graph.empty: thy Graph.T);

in

  fun get_thys () = ! database;

  val change_thys = Library.change database;

end;

(* access thy graph *)

fun thy_graph f x = f (get_thys ()) x;

(*theory names in topological order*)

fun get_names () =

  let val G = get_thys ()

  in Graph.all_succs G (Graph.minimals G) end;

(* access thy *)

fun lookup_thy name =

  SOME (thy_graph Graph.get_node name) handle Graph.UNDEF _ => NONE;

val known_thy = is_some o lookup_thy;

fun check_known_thy name = known_thy name orelse (warning ("Unknown theory " ^ quote name); false);

fun if_known_thy f name = if check_known_thy name then f name else ();

fun get_thy name =

  (case lookup_thy name of

    SOME thy => thy

  | NONE => error (loader_msg "nothing known about theory" [name]));

fun change_thy name f = (get_thy name; change_thys (Graph.map_node name f));

(* access deps *)

val lookup_deps = Option.map #1 o lookup_thy;

val get_deps = #1 o get_thy;

fun change_deps name f = change_thy name (fn (deps, x) => (f deps, x));

fun is_finished name = is_none (get_deps name);

fun get_files name = (case get_deps name of SOME {files, ...} => files | _ => []);

fun loaded_files name =

  (case get_deps name of

    NONE => []

  | SOME {master, files, ...} =>

      (case master of SOME ((thy_path, _), _) => [thy_path] | NONE => []) @

      (map_filter (Option.map #1 o #2) files));

fun get_parents name =

  (thy_graph Graph.imm_preds name) handle Graph.UNDEF _ =>

    error (loader_msg "nothing known about theory" [name]);

(* pretty printing a theory *)

local

fun relevant_names names =

  let

    val (finished, unfinished) =

      List.filter (fn name => name = Context.draftN orelse known_thy name) names

      |> List.partition (fn name => name <> Context.draftN andalso is_finished name);

  in (if not (null finished) then [List.last finished] else []) @ unfinished end;

in

fun pretty_theory thy =

  Pretty.str_list "{" "}" (relevant_names (Context.names_of thy));

end;

(* access theory *)

fun lookup_theory name =

  (case lookup_thy name of

    SOME (_, SOME thy) => SOME thy

  | _ => NONE);

fun get_theory name =

  (case lookup_theory name of

    SOME theory => theory

  | _ => error (loader_msg "undefined theory entry for" [name]));

fun the_theory name thy =

  if Context.theory_name thy = name then thy

  else get_theory name;

fun put_theory name theory = change_thy name (fn (deps, _) => (deps, SOME theory));

val _ = ML_Context.value_antiq "theory"

  (Scan.lift Args.name

    >> (fn name => (name ^ "_thy", "ThyInfo.theory " ^ ML_Syntax.print_string name))

  || Scan.succeed ("thy", "ML_Context.the_context ()"));

(** thy operations **)

(* maintain 'outdated' flag *)

local

fun is_outdated name =

  (case lookup_deps name of

    SOME (SOME {outdated, ...}) => outdated

  | _ => false);

fun outdate_thy name =

  if is_finished name orelse is_outdated name then ()

  else (change_deps name (Option.map (fn {present, outdated = _, master, files} =>

    make_deps present true master files)); perform Outdate name);

fun check_unfinished name =

  if is_finished name then (warning (loader_msg "tried to touch finished theory" [name]); NONE)

  else SOME name;

in

fun touch_thys names =

  List.app outdate_thy (thy_graph Graph.all_succs (map_filter check_unfinished names));

fun touch_thy name = touch_thys [name];

fun touch_child_thys name = touch_thys (thy_graph Graph.imm_succs name);

fun touch_all_thys () = List.app outdate_thy (get_names ());

end;

(* check 'finished' state *)

fun check_unfinished fail name =

  if known_thy name andalso is_finished name then

    fail (loader_msg "cannot update finished theory" [name])

  else ();

(* load_file *)

local

fun provide path name info (deps as SOME {present, outdated, master, files}) =

     (if AList.defined (op =) files path then ()

      else warning (loader_msg "undeclared dependency of theory" [name] ^

        " on file: " ^ quote (Path.implode path));

      SOME (make_deps present outdated master (AList.update (op =) (path, SOME info) files)))

  | provide _ _ _ NONE = NONE;

fun run_file path =

  (case Option.map (Context.theory_name o Context.the_theory) (ML_Context.get_context ()) of

    NONE => (ThyLoad.load_ml [] path; ())

  | SOME name =>

      (case lookup_deps name of

        SOME deps =>

          change_deps name (provide path name (ThyLoad.load_ml (master_path' deps) path))

      | NONE => (ThyLoad.load_ml [] path; ())));

in

fun load_file time path = Output.toplevel_errors (fn () =>

  if time then

    let val name = Path.implode path in

      timeit (fn () =>

       (priority ("\n**** Starting file " ^ quote name ^ " ****");

        run_file path;

        priority ("**** Finished file " ^ quote name ^ " ****\n")))

    end

  else run_file path) ();

val use = load_file false o Path.explode;

val time_use = load_file true o Path.explode;

end;

(* load_thy *)

fun required_by _ [] = ""

  | required_by s initiators = s ^ "(required by " ^ show_path (rev initiators) ^ ")";

fun load_thy really ml time initiators dirs name =

  let

    val _ =

      if really then priority ("Loading theory " ^ quote name ^ required_by " " initiators)

      else priority ("Registering theory " ^ quote name);

    val _ = touch_thy name;

    val master =

      if really then ThyLoad.load_thy dirs name ml time

      else #1 (ThyLoad.deps_thy dirs name ml);

    val files = get_files name;

    val missing_files = map_filter (fn (path, NONE) => SOME (Path.implode path) | _ => NONE) files;

  in

    if null missing_files then ()

    else warning (loader_msg "unresolved dependencies of theory" [name] ^

      " on file(s): " ^ commas_quote missing_files);

    change_deps name (fn _ => SOME (make_deps true false (SOME master) files));

    perform Update name

  end;

(* require_thy *)

fun base_name s = Path.implode (Path.base (Path.explode s));

local

fun check_ml master (path, info) =

  let val info' =

    (case info of NONE => NONE

    | SOME (_, id) =>

        (case ThyLoad.check_ml (master_path master) path of NONE => NONE

        | SOME (path', id') => if id <> id' then NONE else SOME (path', id')))

  in (path, info') end;

fun check_deps ml strict dirs name =

  (case lookup_deps name of

    NONE =>

      let val (master, (parents, files)) = ThyLoad.deps_thy dirs name ml |>> SOME

      in (false, (init_deps master files, parents)) end

  | SOME NONE => (true, (NONE, get_parents name))

  | SOME (deps as SOME {present, outdated, master, files}) =>

      if present andalso not strict then (true, (deps, get_parents name))

      else

        let val (master', (parents', files')) = ThyLoad.deps_thy dirs name ml |>> SOME in

          if master_idents master <> master_idents master'

          then (false, (init_deps master' files', parents'))

          else

            let

              val checked_files = map (check_ml master') files;

              val current = not outdated andalso forall (is_some o snd) checked_files;

              val deps' = SOME (make_deps present (not current) master' checked_files);

            in (current, (deps', parents')) end

        end);

fun require_thy really ml time strict keep_strict initiators dirs str visited =

  let

    val path = Path.expand (Path.explode str);

    val name = Path.implode (Path.base path);

    val dirs' = Path.dir path :: dirs;

    val _ = member (op =) initiators name andalso error (cycle_msg initiators);

  in

    if known_thy name andalso is_finished name orelse member (op =) visited name

    then ((true, name), visited)

    else

      let

        val (current, (deps, parents)) = check_deps ml strict dirs' name

          handle ERROR msg => cat_error msg

            (loader_msg "the error(s) above occurred while examining theory" [name] ^

              (if null initiators then "" else required_by "\n" initiators));

        val dirs'' = master_path' deps @ dirs;

        val req_parent = require_thy true true time (strict andalso keep_strict) keep_strict

          (name :: initiators) dirs'';

        val (parent_results, visited') = fold_map req_parent parents (name :: visited);

        val all_current = current andalso forall fst parent_results;

        val thy = if all_current orelse not really then SOME (get_theory name) else NONE;

        val _ = change_thys (update_node name (map base_name parents) (deps, thy));

        val _ =

          if all_current then ()

          else load_thy really ml (time orelse ! Output.timing) initiators dirs' name;

      in ((all_current, name), visited') end

  end;

fun gen_use_thy' req dirs s = Output.toplevel_errors (fn () =>

  let val ((_, name), _) = req [] dirs s []

  in ML_Context.set_context (SOME (Context.Theory (get_theory name))) end) ();

fun gen_use_thy req = gen_use_thy' req [];

fun warn_finished f name = (check_unfinished warning name; f name);

in

val weak_use_thy     = gen_use_thy' (require_thy true true false false false);

val quiet_update_thy = gen_use_thy' (require_thy true true false true true);

val use_thy          = warn_finished (gen_use_thy (require_thy true true false true false));

val time_use_thy     = warn_finished (gen_use_thy (require_thy true true true true false));

val update_thy       = warn_finished (gen_use_thy (require_thy true true false true true));

val pretend_use_thy_only = warn_finished (gen_use_thy (require_thy false false false true false));

end;

(* remove_thy *)

fun remove_thy name =

  if is_finished name then error (loader_msg "cannot remove finished theory" [name])

  else

    let val succs = thy_graph Graph.all_succs [name] in

      priority (loader_msg "removing" succs);

      List.app (perform Remove) succs;

      change_thys (Graph.del_nodes succs)

    end;

(* begin / end theory *)

fun check_uses name uses =

  let val illegal = map (fn ext => Path.ext ext (Path.basic name)) ("" :: ThyLoad.ml_exts) in

    (case find_first (member (op =) illegal o Path.base o Path.expand o #1) uses of

      NONE => ()

    | SOME (path, _) => error ("Illegal use of theory ML file: " ^ quote (Path.implode path)))

  end;

fun begin_theory present name parents uses int =

  let

    val bparents = map base_name parents;

    val dirs' = master_path'' (lookup_deps name);

    val dirs = dirs' @ [Path.current];

    val _ = check_unfinished error name;

    val _ = List.app ((if int then quiet_update_thy else weak_use_thy) dirs) parents;

    val _ = check_uses name uses;

    val theory = Theory.begin_theory name (map get_theory bparents);

    val deps =

      if known_thy name then get_deps name

      else (init_deps NONE (map #1 uses));

    val uses_now = map_filter (fn (x, true) => SOME x | _ => NONE) uses;

    val _ = change_thys (update_node name bparents (deps, SOME (Theory.copy theory)));

    val theory' = theory |> present dirs' name bparents uses;

    val _ = put_theory name (Theory.copy theory');

    val ((), theory'') =

      ML_Context.pass_context (Context.Theory theory') (List.app (load_file false)) uses_now

      ||> Context.the_theory;

    val _ = put_theory name (Theory.copy theory'');

  in theory'' end;

fun end_theory theory =

  let

    val name = Context.theory_name theory;

    val theory' = Theory.end_theory theory;

  in put_theory name theory'; theory' end;

(* finish all theories *)

fun finish () = change_thys (Graph.map_nodes (fn (_, entry) => (NONE, entry)));

(* register existing theories *)

fun register_theory theory =

  let

    val name = Context.theory_name theory;

    val parents = Theory.parents_of theory;

    val parent_names = map Context.theory_name parents;

    fun err txt bads =

      error (loader_msg txt bads ^ "\ncannot register theory " ^ quote name);

    val nonfinished = filter_out is_finished parent_names;

    fun get_variant (x, y_name) =

      if Theory.eq_thy (x, get_theory y_name) then NONE

      else SOME y_name;

    val variants = map_filter get_variant (parents ~~ parent_names);

    fun register G =

      (Graph.new_node (name, (NONE, SOME theory)) G

        handle Graph.DUP _ => err "duplicate theory entry" [])

      |> add_deps name parent_names;

  in

    if not (null nonfinished) then err "non-finished parent theories" nonfinished

    else if not (null variants) then err "different versions of parent theories" variants

    else (change_thys register; perform Update name)

  end;

val _ = register_theory ProtoPure.thy;

(*final declarations of this structure*)

val theory = get_theory;

val names = get_names;

end;

structure BasicThyInfo: BASIC_THY_INFO = ThyInfo;

open BasicThyInfo;