src/HOL/Tools/Nitpick/nitpick_scope.ML

minor fixes to Nitpick

(*  Title:      HOL/Tools/Nitpick/nitpick_scope.ML
    Author:     Jasmin Blanchette, TU Muenchen
    Copyright   2008, 2009, 2010

Scope enumerator for Nitpick.
*)

signature NITPICK_SCOPE =
sig
  type styp = Nitpick_Util.styp
  type hol_context = Nitpick_HOL.hol_context

  type constr_spec = {
    const: styp,
    delta: int,
    epsilon: int,
    exclusive: bool,
    explicit_max: int,
    total: bool}

  type dtype_spec = {
    typ: typ,
    card: int,
    co: bool,
    complete: bool,
    concrete: bool,
    deep: bool,
    constrs: constr_spec list}

  type scope = {
    hol_ctxt: hol_context,
    card_assigns: (typ * int) list,
    bits: int,
    bisim_depth: int,
    datatypes: dtype_spec list,
    ofs: int Typtab.table}

  val datatype_spec : dtype_spec list -> typ -> dtype_spec option
  val constr_spec : dtype_spec list -> styp -> constr_spec
  val is_complete_type : dtype_spec list -> typ -> bool
  val is_concrete_type : dtype_spec list -> typ -> bool
  val is_exact_type : dtype_spec list -> typ -> bool
  val offset_of_type : int Typtab.table -> typ -> int
  val spec_of_type : scope -> typ -> int * int
  val pretties_for_scope : scope -> bool -> Pretty.T list
  val multiline_string_for_scope : scope -> string
  val scopes_equivalent : scope -> scope -> bool
  val scope_less_eq : scope -> scope -> bool
  val all_scopes :
    hol_context -> int -> (typ option * int list) list
    -> (styp option * int list) list -> (styp option * int list) list
    -> int list -> int list -> typ list -> typ list -> typ list
    -> int * scope list
end;

structure Nitpick_Scope : NITPICK_SCOPE =
struct

open Nitpick_Util
open Nitpick_HOL

type constr_spec = {
  const: styp,
  delta: int,
  epsilon: int,
  exclusive: bool,
  explicit_max: int,
  total: bool}

type dtype_spec = {
  typ: typ,
  card: int,
  co: bool,
  complete: bool,
  concrete: bool,
  deep: bool,
  constrs: constr_spec list}

type scope = {
  hol_ctxt: hol_context,
  card_assigns: (typ * int) list,
  bits: int,
  bisim_depth: int,
  datatypes: dtype_spec list,
  ofs: int Typtab.table}

datatype row_kind = Card of typ | Max of styp

type row = row_kind * int list
type block = row list

(* dtype_spec list -> typ -> dtype_spec option *)
fun datatype_spec (dtypes : dtype_spec list) T =
  List.find (curry (op =) T o #typ) dtypes

(* dtype_spec list -> styp -> constr_spec *)
fun constr_spec [] x = raise TERM ("Nitpick_Scope.constr_spec", [Const x])
  | constr_spec ({constrs, ...} :: dtypes : dtype_spec list) (x as (s, T)) =
    case List.find (curry (op =) (s, body_type T) o (apsnd body_type o #const))
                   constrs of
      SOME c => c
    | NONE => constr_spec dtypes x

(* dtype_spec list -> typ -> bool *)
fun is_complete_type dtypes (Type ("fun", [T1, T2])) =
    is_concrete_type dtypes T1 andalso is_complete_type dtypes T2
  | is_complete_type dtypes (Type ("*", Ts)) =
    forall (is_complete_type dtypes) Ts
  | is_complete_type dtypes T =
    not (is_integer_type T) andalso not (is_bit_type T) andalso
    #complete (the (datatype_spec dtypes T))
    handle Option.Option => true
and is_concrete_type dtypes (Type ("fun", [T1, T2])) =
    is_complete_type dtypes T1 andalso is_concrete_type dtypes T2
  | is_concrete_type dtypes (Type ("*", Ts)) =
    forall (is_concrete_type dtypes) Ts
  | is_concrete_type dtypes T =
    #concrete (the (datatype_spec dtypes T)) handle Option.Option => true
fun is_exact_type dtypes = is_complete_type dtypes andf is_concrete_type dtypes

(* int Typtab.table -> typ -> int *)
fun offset_of_type ofs T =
  case Typtab.lookup ofs T of
    SOME j0 => j0
  | NONE => Typtab.lookup ofs dummyT |> the_default 0

(* scope -> typ -> int * int *)
fun spec_of_type ({card_assigns, ofs, ...} : scope) T =
  (card_of_type card_assigns T
   handle TYPE ("Nitpick_HOL.card_of_type", _, _) => ~1, offset_of_type ofs T)

(* (string -> string) -> scope
   -> string list * string list * string list * string list * string list *)
fun quintuple_for_scope quote ({hol_ctxt as {thy, ctxt, ...}, card_assigns,
                                bits, bisim_depth, datatypes, ...} : scope) =
  let
    val boring_Ts = [@{typ unsigned_bit}, @{typ signed_bit},
                     @{typ bisim_iterator}]
    val (iter_assigns, card_assigns) =
      card_assigns |> filter_out (member (op =) boring_Ts o fst)
                   |> List.partition (is_fp_iterator_type o fst)
    val (secondary_card_assigns, primary_card_assigns) =
      card_assigns |> List.partition ((is_integer_type orf is_datatype thy)
                                      o fst)
    val cards =
      map (fn (T, k) => quote (string_for_type ctxt T) ^ " = " ^
                        string_of_int k)
    fun maxes () =
      maps (map_filter
                (fn {const, explicit_max, ...} =>
                    if explicit_max < 0 then
                      NONE
                    else
                      SOME (Syntax.string_of_term ctxt (Const const) ^ " = " ^
                            string_of_int explicit_max))
                 o #constrs) datatypes
    fun iters () =
      map (fn (T, k) =>
              quote (Syntax.string_of_term ctxt
                         (Const (const_for_iterator_type T))) ^ " = " ^
              string_of_int (k - 1)) iter_assigns
    fun miscs () =
      (if bits = 0 then [] else ["bits = " ^ string_of_int bits]) @
      (if bisim_depth < 0 andalso forall (not o #co) datatypes then []
       else ["bisim_depth = " ^ signed_string_of_int bisim_depth])
  in
    setmp_show_all_types
        (fn () => (cards primary_card_assigns, cards secondary_card_assigns,
                   maxes (), iters (), miscs ())) ()
  end

(* scope -> bool -> Pretty.T list *)
fun pretties_for_scope scope verbose =
  let
    val (primary_cards, secondary_cards, maxes, iters, bisim_depths) =
      quintuple_for_scope maybe_quote scope
    val ss = map (prefix "card ") primary_cards @
             (if verbose then
                map (prefix "card ") secondary_cards @
                map (prefix "max ") maxes @
                map (prefix "iter ") iters @
                bisim_depths
              else
                [])
  in
    if null ss then []
    else serial_commas "and" ss |> map Pretty.str |> Pretty.breaks
  end

(* scope -> string *)
fun multiline_string_for_scope scope =
  let
    val (primary_cards, secondary_cards, maxes, iters, bisim_depths) =
      quintuple_for_scope I scope
    val cards = primary_cards @ secondary_cards
  in
    case (if null cards then [] else ["card: " ^ commas cards]) @
         (if null maxes then [] else ["max: " ^ commas maxes]) @
         (if null iters then [] else ["iter: " ^ commas iters]) @
         bisim_depths of
      [] => "empty"
    | lines => space_implode "\n" lines
  end

(* scope -> scope -> bool *)
fun scopes_equivalent (s1 : scope) (s2 : scope) =
  #datatypes s1 = #datatypes s2 andalso #card_assigns s1 = #card_assigns s2
fun scope_less_eq (s1 : scope) (s2 : scope) =
  (s1, s2) |> pairself (map snd o #card_assigns) |> op ~~ |> forall (op <=)

(* row -> int *)
fun rank_of_row (_, ks) = length ks
(* block -> int *)
fun rank_of_block block = fold Integer.max (map rank_of_row block) 1
(* int -> typ * int list -> typ * int list *)
fun project_row column (y, ks) = (y, [nth ks (Int.min (column, length ks - 1))])
(* int -> block -> block *)
fun project_block (column, block) = map (project_row column) block

(* (''a * ''a -> bool) -> (''a option * int list) list -> ''a -> int list *)
fun lookup_ints_assign eq assigns key =
  case triple_lookup eq assigns key of
    SOME ks => ks
  | NONE => raise ARG ("Nitpick_Scope.lookup_ints_assign", "")
(* theory -> (typ option * int list) list -> typ -> int list *)
fun lookup_type_ints_assign thy assigns T =
  map (curry Int.max 1) (lookup_ints_assign (type_match thy) assigns T)
  handle ARG ("Nitpick_Scope.lookup_ints_assign", _) =>
         raise TYPE ("Nitpick_Scope.lookup_type_ints_assign", [T], [])
(* theory -> (styp option * int list) list -> styp -> int list *)
fun lookup_const_ints_assign thy assigns x =
  lookup_ints_assign (const_match thy) assigns x
  handle ARG ("Nitpick_Scope.lookup_ints_assign", _) =>
         raise TERM ("Nitpick_Scope.lookup_const_ints_assign", [Const x])

(* theory -> (styp option * int list) list -> styp -> row option *)
fun row_for_constr thy maxes_assigns constr =
  SOME (Max constr, lookup_const_ints_assign thy maxes_assigns constr)
  handle TERM ("lookup_const_ints_assign", _) => NONE

val max_bits = 31 (* Kodkod limit *)

(* hol_context -> (typ option * int list) list -> (styp option * int list) list
   -> (styp option * int list) list -> int list -> int list -> typ -> block *)
fun block_for_type (hol_ctxt as {thy, ...}) cards_assigns maxes_assigns
                   iters_assigns bitss bisim_depths T =
  if T = @{typ unsigned_bit} then
    [(Card T, map (Integer.min max_bits o Integer.max 1) bitss)]
  else if T = @{typ signed_bit} then
    [(Card T, map (Integer.add 1 o Integer.min max_bits o Integer.max 1) bitss)]
  else if T = @{typ "unsigned_bit word"} then
    [(Card T, lookup_type_ints_assign thy cards_assigns nat_T)]
  else if T = @{typ "signed_bit word"} then
    [(Card T, lookup_type_ints_assign thy cards_assigns int_T)]
  else if T = @{typ bisim_iterator} then
    [(Card T, map (Integer.add 1 o Integer.max 0) bisim_depths)]
  else if is_fp_iterator_type T then
    [(Card T, map (Integer.add 1 o Integer.max 0)
                  (lookup_const_ints_assign thy iters_assigns
                                            (const_for_iterator_type T)))]
  else
    (Card T, lookup_type_ints_assign thy cards_assigns T) ::
    (case datatype_constrs hol_ctxt T of
       [_] => []
     | constrs => map_filter (row_for_constr thy maxes_assigns) constrs)

(* hol_context -> (typ option * int list) list -> (styp option * int list) list
   -> (styp option * int list) list -> int list -> int list -> typ list
   -> typ list -> block list *)
fun blocks_for_types hol_ctxt cards_assigns maxes_assigns iters_assigns bitss
                     bisim_depths mono_Ts nonmono_Ts =
  let
    (* typ -> block *)
    val block_for = block_for_type hol_ctxt cards_assigns maxes_assigns
                                   iters_assigns bitss bisim_depths
    val mono_block = maps block_for mono_Ts
    val nonmono_blocks = map block_for nonmono_Ts
  in mono_block :: nonmono_blocks end

val sync_threshold = 5

(* int list -> int list list *)
fun all_combinations_ordered_smartly ks =
  let
    (* int list -> int *)
    fun cost_with_monos [] = 0
      | cost_with_monos (k :: ks) =
        if k < sync_threshold andalso forall (curry (op =) k) ks then
          k - sync_threshold
        else
          k * (k + 1) div 2 + Integer.sum ks
    fun cost_without_monos [] = 0
      | cost_without_monos [k] = k
      | cost_without_monos (_ :: k :: ks) =
        if k < sync_threshold andalso forall (curry (op =) k) ks then
          k - sync_threshold
        else
          Integer.sum (k :: ks)
  in
    ks |> all_combinations
       |> map (`(if fst (hd ks) > 1 then cost_with_monos
                 else cost_without_monos))
       |> sort (int_ord o pairself fst) |> map snd
  end

(* typ -> bool *)
fun is_self_recursive_constr_type T =
  exists (exists_subtype (curry (op =) (body_type T))) (binder_types T)

(* (styp * int) list -> styp -> int *)
fun constr_max maxes x = the_default ~1 (AList.lookup (op =) maxes x)

type scope_desc = (typ * int) list * (styp * int) list

(* hol_context -> scope_desc -> typ * int -> bool *)
fun is_surely_inconsistent_card_assign hol_ctxt (card_assigns, max_assigns)
                                       (T, k) =
  case datatype_constrs hol_ctxt T of
    [] => false
  | xs =>
    let
      val dom_cards =
        map (Integer.prod o map (bounded_card_of_type k ~1 card_assigns)
             o binder_types o snd) xs
      val maxes = map (constr_max max_assigns) xs
      (* int -> int -> int *)
      fun effective_max card ~1 = card
        | effective_max card max = Int.min (card, max)
      val max = map2 effective_max dom_cards maxes |> Integer.sum
    in max < k end
(* hol_context -> (typ * int) list -> (typ * int) list -> (styp * int) list
   -> bool *)
fun is_surely_inconsistent_scope_description hol_ctxt seen rest max_assigns =
  exists (is_surely_inconsistent_card_assign hol_ctxt
                                             (seen @ rest, max_assigns)) seen

(* hol_context -> scope_desc -> (typ * int) list option *)
fun repair_card_assigns hol_ctxt (card_assigns, max_assigns) =
  let
    (* (typ * int) list -> (typ * int) list -> (typ * int) list option *)
    fun aux seen [] = SOME seen
      | aux seen ((T, 0) :: _) = NONE
      | aux seen ((T, k) :: rest) =
        (if is_surely_inconsistent_scope_description hol_ctxt ((T, k) :: seen)
                                                     rest max_assigns then
           raise SAME ()
         else
           case aux ((T, k) :: seen) rest of
             SOME assigns => SOME assigns
           | NONE => raise SAME ())
        handle SAME () => aux seen ((T, k - 1) :: rest)
  in aux [] (rev card_assigns) end

(* theory -> (typ * int) list -> typ * int -> typ * int *)
fun repair_iterator_assign thy assigns (T as Type (s, Ts), k) =
    (T, if T = @{typ bisim_iterator} then
          let
            val co_cards = map snd (filter (is_codatatype thy o fst) assigns)
          in Int.min (k, Integer.sum co_cards) end
        else if is_fp_iterator_type T then
          case Ts of
            [] => 1
          | _ => bounded_card_of_type k ~1 assigns (foldr1 HOLogic.mk_prodT Ts)
        else
          k)
  | repair_iterator_assign _ _ assign = assign

(* row -> scope_desc -> scope_desc *)
fun add_row_to_scope_descriptor (kind, ks) (card_assigns, max_assigns) =
  case kind of
    Card T => ((T, the_single ks) :: card_assigns, max_assigns)
  | Max x => (card_assigns, (x, the_single ks) :: max_assigns)
(* block -> scope_desc *)
fun scope_descriptor_from_block block =
  fold_rev add_row_to_scope_descriptor block ([], [])
(* hol_context -> block list -> int list -> scope_desc option *)
fun scope_descriptor_from_combination (hol_ctxt as {thy, ...}) blocks columns =
  let
    val (card_assigns, max_assigns) =
      maps project_block (columns ~~ blocks) |> scope_descriptor_from_block
    val card_assigns = repair_card_assigns hol_ctxt (card_assigns, max_assigns)
                       |> the
  in
    SOME (map (repair_iterator_assign thy card_assigns) card_assigns,
          max_assigns)
  end
  handle Option.Option => NONE

(* theory -> (typ * int) list -> dtype_spec list -> int Typtab.table *)
fun offset_table_for_card_assigns thy assigns dtypes =
  let
    (* int -> (int * int) list -> (typ * int) list -> int Typtab.table
       -> int Typtab.table *)
    fun aux next _ [] = Typtab.update_new (dummyT, next)
      | aux next reusable ((T, k) :: assigns) =
        if k = 1 orelse is_integer_type T orelse is_bit_type T then
          aux next reusable assigns
        else if length (these (Option.map #constrs (datatype_spec dtypes T)))
                > 1 then
          Typtab.update_new (T, next) #> aux (next + k) reusable assigns
        else
          case AList.lookup (op =) reusable k of
            SOME j0 => Typtab.update_new (T, j0) #> aux next reusable assigns
          | NONE => Typtab.update_new (T, next)
                    #> aux (next + k) ((k, next) :: reusable) assigns
  in aux 0 [] assigns Typtab.empty end

(* int -> (typ * int) list -> typ -> int *)
fun domain_card max card_assigns =
  Integer.prod o map (bounded_card_of_type max max card_assigns) o binder_types

(* scope_desc -> bool -> int -> (int -> int) -> int -> int -> bool * styp
   -> constr_spec list -> constr_spec list *)
fun add_constr_spec (card_assigns, max_assigns) co card sum_dom_cards
                    num_self_recs num_non_self_recs (self_rec, x as (s, T))
                    constrs =
  let
    val max = constr_max max_assigns x
    (* int -> int *)
    fun bound k = Int.min (card, (max >= 0 ? curry Int.min max) k)
    (* unit -> int *)
    fun next_delta () = if null constrs then 0 else #epsilon (hd constrs)
    val {delta, epsilon, exclusive, total} =
      if max = 0 then
        let val delta = next_delta () in
          {delta = delta, epsilon = delta, exclusive = true, total = false}
        end
      else if not co andalso num_self_recs > 0 then
        (if num_self_recs = 1 andalso num_non_self_recs = 1 then
           if self_rec then
             case constrs of
               [{delta = 0, epsilon = 1, exclusive = true, ...}] =>
               {delta = 1, epsilon = card, exclusive = true, total = false}
             | _ => raise SAME ()
           else
             if domain_card 2 card_assigns T = 1 then
               {delta = 0, epsilon = 1, exclusive = true, total = true}
             else
               raise SAME ()
         else
           raise SAME ())
        handle SAME () =>
               {delta = 0, epsilon = card, exclusive = false, total = false}
      else if card = sum_dom_cards (card + 1) then
        let val delta = next_delta () in
          {delta = delta, epsilon = delta + domain_card card card_assigns T,
           exclusive = true, total = true}
        end
      else
        {delta = 0, epsilon = card,
         exclusive = (num_self_recs + num_non_self_recs = 1), total = false}
  in
    {const = x, delta = delta, epsilon = epsilon, exclusive = exclusive,
     explicit_max = max, total = total} :: constrs
  end

(* hol_context -> (typ * int) list -> typ -> bool *)
fun has_exact_card hol_ctxt card_assigns T =
  let val card = card_of_type card_assigns T in
    card = bounded_exact_card_of_type hol_ctxt (card + 1) 0 card_assigns T
  end

(* hol_context -> typ list -> scope_desc -> typ * int -> dtype_spec *)
fun datatype_spec_from_scope_descriptor (hol_ctxt as {thy, ...}) deep_dataTs
                                        (desc as (card_assigns, _)) (T, card) =
  let
    val deep = member (op =) deep_dataTs T
    val co = is_codatatype thy T
    val xs = boxed_datatype_constrs hol_ctxt T
    val self_recs = map (is_self_recursive_constr_type o snd) xs
    val (num_self_recs, num_non_self_recs) =
      List.partition I self_recs |> pairself length
    val complete = has_exact_card hol_ctxt card_assigns T
    val concrete = xs |> maps (binder_types o snd) |> maps binder_types
                      |> forall (has_exact_card hol_ctxt card_assigns)
    (* int -> int *)
    fun sum_dom_cards max =
      map (domain_card max card_assigns o snd) xs |> Integer.sum
    val constrs =
      fold_rev (add_constr_spec desc co card sum_dom_cards num_self_recs
                                num_non_self_recs)
               (sort (bool_ord o swap o pairself fst) (self_recs ~~ xs)) []
  in
    {typ = T, card = card, co = co, complete = complete, concrete = concrete,
     deep = deep, constrs = constrs}
  end

(* int -> int *)
fun min_bits_for_nat_value n = if n <= 0 then 0 else IntInf.log2 n + 1
(* scope_desc -> int *)
fun min_bits_for_max_assigns (_, []) = 0
  | min_bits_for_max_assigns (card_assigns, max_assigns) =
    min_bits_for_nat_value (fold Integer.max
        (map snd card_assigns @ map snd max_assigns) 0)

(* hol_context -> int -> typ list -> scope_desc -> scope *)
fun scope_from_descriptor (hol_ctxt as {thy, ...}) sym_break deep_dataTs
                          (desc as (card_assigns, _)) =
  let
    val datatypes =
      map (datatype_spec_from_scope_descriptor hol_ctxt deep_dataTs desc)
          (filter (is_datatype thy o fst) card_assigns)
    val bits = card_of_type card_assigns @{typ signed_bit} - 1
               handle TYPE ("Nitpick_HOL.card_of_type", _, _) =>
                      card_of_type card_assigns @{typ unsigned_bit}
                      handle TYPE ("Nitpick_HOL.card_of_type", _, _) => 0
    val bisim_depth = card_of_type card_assigns @{typ bisim_iterator} - 1
  in
    {hol_ctxt = hol_ctxt, card_assigns = card_assigns, datatypes = datatypes,
     bits = bits, bisim_depth = bisim_depth,
     ofs = if sym_break <= 0 then Typtab.empty
           else offset_table_for_card_assigns thy card_assigns datatypes}
  end

(* theory -> typ list -> (typ option * int list) list
   -> (typ option * int list) list *)
fun repair_cards_assigns_wrt_boxing _ _ [] = []
  | repair_cards_assigns_wrt_boxing thy Ts ((SOME T, ks) :: cards_assigns) =
    (if is_fun_type T orelse is_pair_type T then
       Ts |> filter (curry (type_match thy o swap) T o unbit_and_unbox_type)
          |> map (rpair ks o SOME)
     else
       [(SOME T, ks)]) @ repair_cards_assigns_wrt_boxing thy Ts cards_assigns
  | repair_cards_assigns_wrt_boxing thy Ts ((NONE, ks) :: cards_assigns) =
    (NONE, ks) :: repair_cards_assigns_wrt_boxing thy Ts cards_assigns

val max_scopes = 4096
val distinct_threshold = 512

(* hol_context -> int -> (typ option * int list) list
   -> (styp option * int list) list -> (styp option * int list) list -> int list
   -> typ list -> typ list -> typ list -> int * scope list *)
fun all_scopes (hol_ctxt as {thy, ...}) sym_break cards_assigns maxes_assigns
               iters_assigns bitss bisim_depths mono_Ts nonmono_Ts deep_dataTs =
  let
    val cards_assigns = repair_cards_assigns_wrt_boxing thy mono_Ts
                                                        cards_assigns
    val blocks = blocks_for_types hol_ctxt cards_assigns maxes_assigns
                                  iters_assigns bitss bisim_depths mono_Ts
                                  nonmono_Ts
    val ranks = map rank_of_block blocks
    val all = all_combinations_ordered_smartly (map (rpair 0) ranks)
    val head = take max_scopes all
    val descs = map_filter (scope_descriptor_from_combination hol_ctxt blocks)
                           head
  in
    (length all - length head,
     descs |> length descs <= distinct_threshold ? distinct (op =)
           |> map (scope_from_descriptor hol_ctxt sym_break deep_dataTs))
  end

end;