(*  Title:      Tools/Code/code_namespace.ML

    Author:     Florian Haftmann, TU Muenchen

Mastering target language namespaces.

*)

signature CODE_NAMESPACE =

sig

  datatype export = Private | Opaque | Public

  val is_public: export -> bool

  val not_private: export -> bool

  val join_exports: export list -> export

  type flat_program

  val flat_program: Proof.context

    -> { module_prefix: string, module_name: string,

    reserved: Name.context, identifiers: Code_Target.identifier_data, empty_nsp: 'a,

    namify_stmt: Code_Thingol.stmt -> string -> 'a -> string * 'a,

    modify_stmt: Code_Thingol.stmt -> Code_Thingol.stmt option }

      -> Code_Symbol.T list -> Code_Thingol.program

      -> { deresolver: string -> Code_Symbol.T -> string,

           flat_program: flat_program }

  datatype ('a, 'b) node =

      Dummy

    | Stmt of export * 'a

    | Module of ('b * (string * ('a, 'b) node) Code_Symbol.Graph.T)

  type ('a, 'b) hierarchical_program

  val hierarchical_program: Proof.context

    -> { module_name: string,

    reserved: Name.context, identifiers: Code_Target.identifier_data,

    empty_nsp: 'c, namify_module: string -> 'c -> string * 'c,

    namify_stmt: Code_Thingol.stmt -> string -> 'c -> string * 'c,

    cyclic_modules: bool,

    class_transitive: bool, class_relation_public: bool,

    empty_data: 'b, memorize_data: Code_Symbol.T -> 'b -> 'b,

    modify_stmts: (Code_Symbol.T * (export * Code_Thingol.stmt)) list -> (export * 'a) option list }

      -> Code_Symbol.T list -> Code_Thingol.program

      -> { deresolver: string list -> Code_Symbol.T -> string,

           hierarchical_program: ('a, 'b) hierarchical_program }

  val print_hierarchical: { print_module: string list -> string -> 'b -> 'c list -> 'c,

    print_stmt: string list -> Code_Symbol.T * (export * 'a) -> 'c,

    lift_markup: (Pretty.T -> Pretty.T) -> 'c -> 'c }

      -> ('a, 'b) hierarchical_program -> 'c list

end;

structure Code_Namespace : CODE_NAMESPACE =

struct

(** export **)

datatype export = Private | Opaque | Public;

fun is_public Public = true

  | is_public _ = false;

fun not_private Public = true

  | not_private Opaque = true

  | not_private _ = false;

fun mark_export Public _ = Public

  | mark_export _ Public = Public

  | mark_export Opaque _ = Opaque

  | mark_export _ Opaque = Opaque

  | mark_export _ _ = Private;

fun join_exports exports = fold mark_export exports Private;

fun dependent_exports { program = program, class_transitive = class_transitive } =

  let

    fun is_datatype_or_class (Code_Symbol.Type_Constructor _) = true

      | is_datatype_or_class (Code_Symbol.Type_Class _) = true

      | is_datatype_or_class _ = false;

    fun is_relevant (Code_Symbol.Class_Relation _) = true

      | is_relevant sym = is_datatype_or_class sym;

    val proto_gr = Code_Symbol.Graph.restrict is_relevant program;

    val gr =

      proto_gr

      |> Code_Symbol.Graph.fold

          (fn (sym, (_, (_, deps))) =>

            if is_relevant sym

            then I

            else

              Code_Symbol.Graph.new_node (sym, Code_Thingol.NoStmt)

              #> Code_Symbol.Graph.Keys.fold

               (fn sym' =>

                if is_relevant sym'

                then Code_Symbol.Graph.add_edge (sym, sym')

                else I) deps) program

      |> class_transitive ?

          Code_Symbol.Graph.fold (fn (sym as Code_Symbol.Type_Class _, _) =>

            fold (curry Code_Symbol.Graph.add_edge sym)

              ((remove (op =) sym o Code_Symbol.Graph.all_succs proto_gr) [sym]) | _ => I) proto_gr

    fun deps_of sym =

      let

        val succs = Code_Symbol.Graph.Keys.dest o Code_Symbol.Graph.imm_succs gr;

        val deps1 = succs sym;

        val deps2 = [] |> fold (union (op =)) (map succs deps1) |> subtract (op =) deps1

      in (deps1, deps2) end;

  in

    { is_datatype_or_class = is_datatype_or_class,

      deps_of = deps_of }

  end;

fun mark_exports_aux { program = program, prefix_of = prefix_of, map_export = map_export,

    is_datatype_or_class = is_datatype_or_class, deps_of = deps_of,

    class_relation_public = class_relation_public } prefix sym =

  let

    val export = (if is_datatype_or_class sym then Opaque else Public);

    val (dependent_export1, dependent_export2) =

      case Code_Symbol.Graph.get_node program sym of

          Code_Thingol.Fun _ => (SOME Opaque, NONE)

        | Code_Thingol.Classinst _ => (SOME Opaque, NONE)

        | Code_Thingol.Datatypecons _ => (SOME Public, SOME Opaque)

        | Code_Thingol.Classparam _ => (SOME Public, SOME Opaque)

        | Code_Thingol.Class _ => (SOME Opaque, NONE)

        | Code_Thingol.Classrel _ =>

           (if class_relation_public

            then (SOME Public, SOME Opaque)

            else (SOME Opaque, NONE))

        | _ => (NONE, NONE);

    val dependent_exports =

      case dependent_export1 of

        SOME export1 => (case dependent_export2 of

          SOME export2 =>

            let

              val (deps1, deps2) = deps_of sym

            in map (rpair export1) deps1 @ map (rpair export2) deps2 end

        | NONE => map (rpair export1) (fst (deps_of sym)))

      | NONE => [];

  in 

    map_export prefix sym (mark_export export)

    #> fold (fn (sym, export) => map_export (prefix_of sym) sym (mark_export export))

      dependent_exports

  end;

fun mark_exports { program = program, prefix_of = prefix_of, map_export = map_export,

    class_transitive = class_transitive, class_relation_public = class_relation_public } =

  let

    val { is_datatype_or_class, deps_of } =

      dependent_exports { program = program, class_transitive = class_transitive };

  in

    mark_exports_aux { program = program, prefix_of = prefix_of, map_export = map_export,

      is_datatype_or_class = is_datatype_or_class, deps_of = deps_of,

      class_relation_public = class_relation_public }

  end;

(** fundamental module name hierarchy **)

fun module_fragments' { identifiers, reserved } name =

  case Code_Symbol.lookup_module_data identifiers name of

      SOME (fragments, _) => fragments

    | NONE => map (fn fragment => fst (Name.variant fragment reserved)) (Long_Name.explode name);

fun module_fragments { module_name, identifiers, reserved } =

  if module_name = ""

  then module_fragments' { identifiers = identifiers, reserved = reserved }

  else K (Long_Name.explode module_name);

fun build_module_namespace ctxt enforce_upper { module_prefix, module_name, identifiers, reserved } program =

  let

    val module_names = Code_Symbol.Graph.fold (insert (op =) o Code_Symbol.default_prefix ctxt o fst) program [];

    val module_fragments' = module_fragments

      { module_name = module_name, identifiers = identifiers, reserved = reserved };

    val adjust_case = if enforce_upper then map (Name.enforce_case true) else I;

  in

    fold (fn name => Symtab.update (name, adjust_case (Long_Name.explode module_prefix @ module_fragments' name)))

      module_names Symtab.empty

  end;

fun prep_symbol ctxt { module_namespace, force_module, identifiers } sym =

  case Code_Symbol.lookup identifiers sym of

      NONE => ((the o Symtab.lookup module_namespace o Code_Symbol.default_prefix ctxt) sym,

        Code_Symbol.default_base sym)

    | SOME prefix_name => if null force_module then prefix_name

        else (force_module, snd prefix_name);

fun has_priority identifiers = is_some o Code_Symbol.lookup identifiers;

fun build_proto_program { empty, add_stmt, add_dep } program =

  empty

  |> Code_Symbol.Graph.fold (fn (sym, (stmt, _)) => add_stmt sym stmt) program

  |> Code_Symbol.Graph.fold (fn (sym, (_, (_, syms))) =>

      Code_Symbol.Graph.Keys.fold (add_dep sym) syms) program;

fun prioritize has_priority = uncurry append o List.partition has_priority;

(** flat program structure **)

type flat_program = ((string * (export * Code_Thingol.stmt) option) Code_Symbol.Graph.T * (string * Code_Symbol.T list) list) Graph.T;

fun flat_program ctxt { module_prefix, module_name, reserved,

    identifiers, empty_nsp, namify_stmt, modify_stmt } exports program =

  let

    (* building module name hierarchy *)

    val module_namespace = build_module_namespace ctxt true { module_prefix = module_prefix,

      module_name = module_name, identifiers = identifiers, reserved = reserved } program;

    val prep_sym = prep_symbol ctxt { module_namespace = module_namespace,

      force_module = Long_Name.explode module_name, identifiers = identifiers }

      #>> Long_Name.implode;

    val sym_priority = has_priority identifiers;

    (* distribute statements over hierarchy *)

    val mark_exports = mark_exports { program = program, prefix_of = fst o prep_sym,

      map_export = fn module_name => fn sym =>

        Graph.map_node module_name o apfst o Code_Symbol.Graph.map_node sym o apsnd o apfst,

        class_transitive = false, class_relation_public = false };

    fun add_stmt sym stmt =

      let

        val (module_name, base) = prep_sym sym;

      in

        Graph.default_node (module_name, (Code_Symbol.Graph.empty, []))

        #> (Graph.map_node module_name o apfst)

          (Code_Symbol.Graph.new_node (sym, (base, (if null exports then Public else Private, stmt))))

      end;

    fun add_dep sym sym' =

      let

        val (module_name, _) = prep_sym sym;

        val (module_name', _) = prep_sym sym';

      in if module_name = module_name'

        then (Graph.map_node module_name o apfst) (Code_Symbol.Graph.add_edge (sym, sym'))

        else (Graph.map_node module_name o apsnd)

          (AList.map_default (op =) (module_name', []) (insert (op =) sym'))

          #> mark_exports module_name' sym'

      end;

    val proto_program = build_proto_program

      { empty = Graph.empty, add_stmt = add_stmt, add_dep = add_dep } program

      |> fold (fn sym => mark_exports ((fst o prep_sym) sym) sym) exports;

    (* name declarations and statement modifications *)

    fun declare sym (base, (_, stmt)) (gr, nsp) = 

      let

        val (base', nsp') = namify_stmt stmt base nsp;

        val gr' = (Code_Symbol.Graph.map_node sym o apfst) (K base') gr;

      in (gr', nsp') end;

    fun declarations gr = (gr, empty_nsp)

      |> fold (fn sym => declare sym (Code_Symbol.Graph.get_node gr sym))

          (prioritize sym_priority (Code_Symbol.Graph.keys gr))

      |> fst

      |> Code_Symbol.Graph.map_strong_conn (fn syms_bases_exports_stmts =>

        map snd syms_bases_exports_stmts

        |> (map o apsnd) (fn (export, stmt) => Option.map (pair export) (modify_stmt stmt)));

    val flat_program = proto_program

      |> (Graph.map o K o apfst) declarations;

    (* qualified and unqualified imports, deresolving *)

    fun base_deresolver sym = fst (Code_Symbol.Graph.get_node

      (fst (Graph.get_node flat_program (fst (prep_sym sym)))) sym);

    fun classify_names gr imports =

      let

        val import_tab = maps

          (fn (module_name, syms) => map (rpair module_name) syms) imports;

        val imported_syms = map fst import_tab;

        val here_syms = Code_Symbol.Graph.keys gr;

      in

        Code_Symbol.Table.empty

        |> fold (fn sym => Code_Symbol.Table.update (sym, base_deresolver sym)) here_syms

        |> fold (fn sym => Code_Symbol.Table.update (sym,

            Long_Name.append (the (AList.lookup (op =) import_tab sym))

              (base_deresolver sym))) imported_syms

      end;

    val deresolver_tab = Symtab.make (AList.make

      (uncurry classify_names o Graph.get_node flat_program)

        (Graph.keys flat_program));

    fun deresolver "" sym =

          Long_Name.append (fst (prep_sym sym)) (base_deresolver sym)

      | deresolver module_name sym =

          the (Code_Symbol.Table.lookup (the (Symtab.lookup deresolver_tab module_name)) sym)

          handle Option.Option => error ("Unknown statement name: "

            ^ Code_Symbol.quote ctxt sym);

  in { deresolver = deresolver, flat_program = flat_program } end;

(** hierarchical program structure **)

datatype ('a, 'b) node =

    Dummy

  | Stmt of export * 'a

  | Module of ('b * (string * ('a, 'b) node) Code_Symbol.Graph.T);

type ('a, 'b) hierarchical_program = (string * ('a, 'b) node) Code_Symbol.Graph.T;

fun the_stmt (Stmt (export, stmt)) = (export, stmt);

fun map_module_content f (Module content) = Module (f content);

fun map_module [] = I

  | map_module (name_fragment :: name_fragments) =

      apsnd o Code_Symbol.Graph.map_node (Code_Symbol.Module name_fragment) o apsnd o map_module_content

        o map_module name_fragments;

fun map_module_stmts f_module f_stmts sym_base_nodes =

  let

    val some_modules =

      sym_base_nodes

      |> map (fn (_, (base, Module content)) => SOME (base, content) | _ => NONE)

      |> (burrow_options o map o apsnd) f_module;

    val some_export_stmts =

      sym_base_nodes

      |> map (fn (sym, (base, Stmt export_stmt)) => SOME ((sym, export_stmt), base) | _ => NONE)

      |> (burrow_options o burrow_fst) (fn [] => [] | xs => f_stmts xs)

  in

    map2 (fn SOME (base, content) => (K (base, Module content))

      | NONE => fn SOME (some_export_stmt, base) =>

          (base, case some_export_stmt of SOME export_stmt => Stmt export_stmt | NONE => Dummy))

      some_modules some_export_stmts

  end;

fun hierarchical_program ctxt { module_name, reserved, identifiers, empty_nsp,

      namify_module, namify_stmt, cyclic_modules,

      class_transitive, class_relation_public,

      empty_data, memorize_data, modify_stmts }

      exports program =

  let

    (* building module name hierarchy *)

    val module_namespace = build_module_namespace ctxt false { module_prefix = "",

      module_name = module_name, identifiers = identifiers, reserved = reserved } program;

    val prep_sym = prep_symbol ctxt { module_namespace = module_namespace,

      force_module = Long_Name.explode module_name, identifiers = identifiers }

    val sym_priority = has_priority identifiers;

    (* building empty module hierarchy *)

    val empty_module = (empty_data, Code_Symbol.Graph.empty);

    fun ensure_module name_fragment (data, nodes) =

      if can (Code_Symbol.Graph.get_node nodes) (Code_Symbol.Module name_fragment) then (data, nodes)

      else (data,

        nodes |> Code_Symbol.Graph.new_node (Code_Symbol.Module name_fragment, (name_fragment, Module empty_module)));

    fun allocate_module [] = I

      | allocate_module (name_fragment :: name_fragments) =

          ensure_module name_fragment

          #> (apsnd o Code_Symbol.Graph.map_node (Code_Symbol.Module name_fragment) o apsnd o map_module_content o allocate_module) name_fragments;

    val empty_program =

      empty_module

      |> Symtab.fold (fn (_, fragments) => allocate_module fragments) module_namespace

      |> Code_Symbol.Graph.fold (allocate_module o these o Option.map fst

          o Code_Symbol.lookup identifiers o fst) program;

    (* distribute statements over hierarchy *)

    val mark_exports = mark_exports { program = program, prefix_of = fst o prep_sym,

      map_export = fn name_fragments => fn sym => fn f =>

        (map_module name_fragments o apsnd o Code_Symbol.Graph.map_node sym o apsnd)

          (fn Stmt (export, stmt) => Stmt (f export, stmt)),

      class_transitive = class_transitive, class_relation_public = class_relation_public };

    fun add_stmt sym stmt =

      let

        val (name_fragments, base) = prep_sym sym;

      in

        (map_module name_fragments o apsnd)

          (Code_Symbol.Graph.new_node (sym, (base, Stmt (if null exports then Public else Private, stmt))))

      end;

    fun add_edge_acyclic_error error_msg dep gr =

      Code_Symbol.Graph.add_edge_acyclic dep gr

        handle Code_Symbol.Graph.CYCLES _ => error (error_msg ())

    fun add_dep sym sym' =

      let

        val (name_fragments, _) = prep_sym sym;

        val (name_fragments', _) = prep_sym sym';

        val (name_fragments_common, (diff, diff')) =

          chop_prefix (op =) (name_fragments, name_fragments');

        val is_cross_module = not (null diff andalso null diff');

        val dep = pairself hd (map Code_Symbol.Module diff @ [sym], map Code_Symbol.Module diff' @ [sym']);

        val add_edge = if is_cross_module andalso not cyclic_modules

          then add_edge_acyclic_error (fn _ => "Dependency "

            ^ Code_Symbol.quote ctxt sym ^ " -> "

            ^ Code_Symbol.quote ctxt sym'

            ^ " would result in module dependency cycle") dep

          else Code_Symbol.Graph.add_edge dep;

      in

        (map_module name_fragments_common o apsnd) add_edge

        #> (if is_cross_module then mark_exports name_fragments' sym' else I)

      end;

    val proto_program = build_proto_program

      { empty = empty_program, add_stmt = add_stmt, add_dep = add_dep } program

      |> fold (fn sym => mark_exports ((fst o prep_sym) sym) sym) exports;

    (* name declarations, data and statement modifications *)

    fun make_declarations nsps (data, nodes) =

      let

        val (module_fragments, stmt_syms) =

          Code_Symbol.Graph.keys nodes

          |> List.partition

              (fn sym => case Code_Symbol.Graph.get_node nodes sym

                of (_, Module _) => true | _ => false)

          |> pairself (prioritize sym_priority)

        fun declare namify sym (nsps, nodes) =

          let

            val (base, node) = Code_Symbol.Graph.get_node nodes sym;

            val (base', nsps') = namify node base nsps;

            val nodes' = Code_Symbol.Graph.map_node sym (K (base', node)) nodes;

          in (nsps', nodes') end;

        val (nsps', nodes') = (nsps, nodes)

          |> fold (declare (K namify_module)) module_fragments

          |> fold (declare (namify_stmt o snd o the_stmt)) stmt_syms;

        fun modify_stmts' syms_stmts =

          let

            val stmts' = modify_stmts syms_stmts

          in stmts' @ replicate (length syms_stmts - length stmts') NONE end;

        val nodes'' =

          nodes'

          |> Code_Symbol.Graph.map_strong_conn (map_module_stmts (make_declarations nsps') modify_stmts');

        val data' = fold memorize_data stmt_syms data;

      in (data', nodes'') end;

    val (_, hierarchical_program) = make_declarations empty_nsp proto_program;

    (* deresolving *)

    fun deresolver prefix_fragments sym =

      let

        val (name_fragments, _) = prep_sym sym;

        val (_, (_, remainder)) = chop_prefix (op =) (prefix_fragments, name_fragments);

        val nodes = fold (fn name_fragment => fn nodes => case Code_Symbol.Graph.get_node nodes (Code_Symbol.Module name_fragment)

         of (_, Module (_, nodes)) => nodes) name_fragments hierarchical_program;

        val (base', _) = Code_Symbol.Graph.get_node nodes sym;

      in Long_Name.implode (remainder @ [base']) end

        handle Code_Symbol.Graph.UNDEF _ => error ("Unknown statement name: "

          ^ Code_Symbol.quote ctxt sym);

  in { deresolver = deresolver, hierarchical_program = hierarchical_program } end;

fun print_hierarchical { print_module, print_stmt, lift_markup } =

  let

    fun print_node _ (_, Dummy) =

          NONE

      | print_node prefix_fragments (sym, Stmt stmt) =

          SOME (lift_markup (Code_Printer.markup_stmt sym)

            (print_stmt prefix_fragments (sym, stmt)))

      | print_node prefix_fragments (Code_Symbol.Module name_fragment, Module (data, nodes)) =

          let

            val prefix_fragments' = prefix_fragments @ [name_fragment]

          in

            Option.map (print_module prefix_fragments'

              name_fragment data) (print_nodes prefix_fragments' nodes)

          end

    and print_nodes prefix_fragments nodes =

      let

        val xs = (map_filter (fn sym => print_node prefix_fragments

          (sym, snd (Code_Symbol.Graph.get_node nodes sym))) o rev o flat o Code_Symbol.Graph.strong_conn) nodes

      in if null xs then NONE else SOME xs end;

  in these o print_nodes [] end;

end;