src/Tools/quickcheck.ML
author blanchet
Thu Oct 29 12:09:32 2009 +0100 (2009-10-29)
changeset 33566 1c62ac4ef6d1
parent 33291 93f0238151f6
parent 33561 ab01b72715ef
child 33583 b5e0909cd5ea
permissions -rw-r--r--
merged
     1 (*  Title:      Tools/quickcheck.ML
     2     Author:     Stefan Berghofer, Florian Haftmann, TU Muenchen
     3 
     4 Generic counterexample search engine.
     5 *)
     6 
     7 signature QUICKCHECK =
     8 sig
     9   val auto: bool Unsynchronized.ref
    10   val test_term: Proof.context -> bool -> string option -> int -> int -> term ->
    11     (string * term) list option
    12   val add_generator: string * (Proof.context -> term -> int -> term list option) -> theory -> theory
    13   val setup: theory -> theory
    14   val quickcheck: (string * string) list -> int -> Proof.state -> (string * term) list option
    15 end;
    16 
    17 structure Quickcheck : QUICKCHECK =
    18 struct
    19 
    20 (* preferences *)
    21 
    22 val auto = Unsynchronized.ref false;
    23 
    24 val _ =
    25   ProofGeneralPgip.add_preference Preferences.category_tracing
    26   (setmp_CRITICAL auto true (fn () =>
    27     Preferences.bool_pref auto
    28       "auto-quickcheck"
    29       "Whether to run Quickcheck automatically.") ());
    30 
    31 
    32 (* quickcheck configuration -- default parameters, test generators *)
    33 
    34 datatype test_params = Test_Params of
    35   { size: int, iterations: int, default_type: typ option };
    36 
    37 fun dest_test_params (Test_Params { size, iterations, default_type }) =
    38   ((size, iterations), default_type);
    39 fun make_test_params ((size, iterations), default_type) =
    40   Test_Params { size = size, iterations = iterations, default_type = default_type };
    41 fun map_test_params f (Test_Params { size, iterations, default_type}) =
    42   make_test_params (f ((size, iterations), default_type));
    43 fun merge_test_params (Test_Params { size = size1, iterations = iterations1, default_type = default_type1 },
    44   Test_Params { size = size2, iterations = iterations2, default_type = default_type2 }) =
    45   make_test_params ((Int.max (size1, size2), Int.max (iterations1, iterations2)),
    46     case default_type1 of NONE => default_type2 | _ => default_type1);
    47 
    48 structure Data = TheoryDataFun(
    49   type T = (string * (Proof.context -> term -> int -> term list option)) list
    50     * test_params;
    51   val empty = ([], Test_Params { size = 10, iterations = 100, default_type = NONE });
    52   val copy = I;
    53   val extend = I;
    54   fun merge pp ((generators1, params1), (generators2, params2)) =
    55     (AList.merge (op = : string * string -> bool) (K true) (generators1, generators2),
    56       merge_test_params (params1, params2));
    57 )
    58 
    59 val add_generator = Data.map o apfst o AList.update (op =);
    60 
    61 
    62 (* generating tests *)
    63 
    64 fun mk_tester_select name ctxt =
    65   case AList.lookup (op =) ((fst o Data.get o ProofContext.theory_of) ctxt) name
    66    of NONE => error ("No such quickcheck generator: " ^ name)
    67     | SOME generator => generator ctxt;
    68 
    69 fun mk_testers ctxt t =
    70   (map snd o fst o Data.get o ProofContext.theory_of) ctxt
    71   |> map_filter (fn generator => try (generator ctxt) t);
    72 
    73 fun mk_testers_strict ctxt t =
    74   let
    75     val generators = ((map snd o fst o Data.get o ProofContext.theory_of) ctxt)
    76     val testers = map (fn generator => Exn.capture (generator ctxt) t) generators;
    77   in if forall (is_none o Exn.get_result) testers
    78     then [(Exn.release o snd o split_last) testers]
    79     else map_filter Exn.get_result testers
    80   end;
    81 
    82 
    83 (* testing propositions *)
    84 
    85 fun prep_test_term t =
    86   let
    87     val _ = (null (Term.add_tvars t []) andalso null (Term.add_tfrees t [])) orelse
    88       error "Term to be tested contains type variables";
    89     val _ = null (Term.add_vars t []) orelse
    90       error "Term to be tested contains schematic variables";
    91     val frees = Term.add_frees t [];
    92   in (map fst frees, list_abs_free (frees, t)) end
    93 
    94 fun test_term ctxt quiet generator_name size i t =
    95   let
    96     val (names, t') = prep_test_term t;
    97     val testers = case generator_name
    98      of NONE => if quiet then mk_testers ctxt t' else mk_testers_strict ctxt t'
    99       | SOME name => [mk_tester_select name ctxt t'];
   100     fun iterate f 0 = NONE
   101       | iterate f j = case f () handle Match => (if quiet then ()
   102              else warning "Exception Match raised during quickcheck"; NONE)
   103           of NONE => iterate f (j - 1) | SOME q => SOME q;
   104     fun with_testers k [] = NONE
   105       | with_testers k (tester :: testers) =
   106           case iterate (fn () => tester (k - 1)) i
   107            of NONE => with_testers k testers
   108             | SOME q => SOME q;
   109     fun with_size k = if k > size then NONE
   110       else (if quiet then () else priority ("Test data size: " ^ string_of_int k);
   111         case with_testers k testers
   112          of NONE => with_size (k + 1) | SOME q => SOME q);
   113   in case with_size 1
   114    of NONE => NONE
   115     | SOME ts => SOME (names ~~ ts)
   116   end;
   117 
   118 fun monomorphic_term thy insts default_T = 
   119   let
   120     fun subst (T as TFree (v, S)) =
   121           let
   122             val T' = AList.lookup (op =) insts v
   123               |> the_default (the_default T default_T)
   124           in if Sign.of_sort thy (T, S) then T'
   125             else error ("Type " ^ Syntax.string_of_typ_global thy T ^
   126               " to be substituted for variable " ^
   127               Syntax.string_of_typ_global thy T ^ "\ndoes not have sort " ^
   128               Syntax.string_of_sort_global thy S)
   129           end
   130       | subst T = T;
   131   in (map_types o map_atyps) subst end;
   132 
   133 fun test_goal quiet generator_name size iterations default_T insts i assms state =
   134   let
   135     val ctxt = Proof.context_of state;
   136     val thy = Proof.theory_of state;
   137     fun strip (Const ("all", _) $ Abs (_, _, t)) = strip t
   138       | strip t = t;
   139     val {goal = st, ...} = Proof.raw_goal state;
   140     val (gi, frees) = Logic.goal_params (prop_of st) i;
   141     val gi' = Logic.list_implies (assms, subst_bounds (frees, strip gi))
   142       |> monomorphic_term thy insts default_T
   143       |> ObjectLogic.atomize_term thy;
   144   in test_term ctxt quiet generator_name size iterations gi' end;
   145 
   146 fun pretty_counterex ctxt NONE = Pretty.str "No counterexamples found."
   147   | pretty_counterex ctxt (SOME cex) =
   148       Pretty.chunks (Pretty.str "Counterexample found:\n" ::
   149         map (fn (s, t) =>
   150           Pretty.block [Pretty.str (s ^ " ="), Pretty.brk 1, Syntax.pretty_term ctxt t]) cex);
   151 
   152 
   153 (* automatic testing *)
   154 
   155 fun auto_quickcheck state =
   156   if not (!auto) then
   157     (false, state)
   158   else
   159     let
   160       val ctxt = Proof.context_of state;
   161       val assms = map term_of (Assumption.all_assms_of ctxt);
   162       val Test_Params { size, iterations, default_type } =
   163         (snd o Data.get o Proof.theory_of) state;
   164       val res =
   165         try (test_goal true NONE size iterations default_type [] 1 assms) state;
   166     in
   167       case res of
   168         NONE => (false, state)
   169       | SOME NONE => (false, state)
   170       | SOME cex => (true, Proof.goal_message (K (Pretty.chunks [Pretty.str "",
   171           Pretty.mark Markup.hilite (pretty_counterex ctxt cex)])) state)
   172     end
   173 
   174 val setup = Auto_Counterexample.register_tool ("quickcheck", auto_quickcheck)
   175 
   176 
   177 (* Isar commands *)
   178 
   179 fun read_nat s = case (Library.read_int o Symbol.explode) s
   180  of (k, []) => if k >= 0 then k
   181       else error ("Not a natural number: " ^ s)
   182   | (_, _ :: _) => error ("Not a natural number: " ^ s);
   183 
   184 fun parse_test_param ctxt ("size", arg) =
   185       (apfst o apfst o K) (read_nat arg)
   186   | parse_test_param ctxt ("iterations", arg) =
   187       (apfst o apsnd o K) (read_nat arg)
   188   | parse_test_param ctxt ("default_type", arg) =
   189       (apsnd o K o SOME) (ProofContext.read_typ ctxt arg)
   190   | parse_test_param ctxt (name, _) =
   191       error ("Bad test parameter: " ^ name);
   192 
   193 fun parse_test_param_inst ctxt ("generator", arg) =
   194       (apsnd o apfst o K o SOME) arg
   195   | parse_test_param_inst ctxt (name, arg) =
   196       case try (ProofContext.read_typ ctxt) name
   197        of SOME (TFree (v, _)) => (apsnd o apsnd o AList.update (op =))
   198               (v, ProofContext.read_typ ctxt arg)
   199         | _ => (apfst o parse_test_param ctxt) (name, arg);
   200 
   201 fun quickcheck_params_cmd args thy =
   202   let
   203     val ctxt = ProofContext.init thy;
   204     val f = fold (parse_test_param ctxt) args;
   205   in
   206     thy
   207     |> (Data.map o apsnd o map_test_params) f
   208   end;
   209 
   210 fun quickcheck args i state =
   211   let
   212     val thy = Proof.theory_of state;
   213     val ctxt = Proof.context_of state;
   214     val default_params = (dest_test_params o snd o Data.get) thy;
   215     val f = fold (parse_test_param_inst ctxt) args;
   216     val (((size, iterations), default_type), (generator_name, insts)) =
   217       f (default_params, (NONE, []));
   218   in
   219     test_goal false generator_name size iterations default_type insts i [] state
   220   end;
   221 
   222 fun quickcheck_cmd args i state =
   223   quickcheck args i (Toplevel.proof_of state)
   224   |> Pretty.writeln o pretty_counterex (Toplevel.context_of state);
   225 
   226 local structure P = OuterParse and K = OuterKeyword in
   227 
   228 val parse_arg = P.name --| P.$$$ "=" -- P.name;
   229 val parse_args = P.$$$ "[" |-- P.list1 parse_arg --| P.$$$ "]"
   230   || Scan.succeed [];
   231 
   232 val _ = OuterSyntax.command "quickcheck_params" "set parameters for random testing" K.thy_decl
   233   (parse_args >> (fn args => Toplevel.theory (quickcheck_params_cmd args)));
   234 
   235 val _ = OuterSyntax.improper_command "quickcheck" "try to find counterexample for subgoal" K.diag
   236   (parse_args -- Scan.optional P.nat 1
   237     >> (fn (args, i) => Toplevel.no_timing o Toplevel.keep (quickcheck_cmd args i)));
   238 
   239 end; (*local*)
   240 
   241 end;
   242 
   243 
   244 val auto_quickcheck = Quickcheck.auto;