(* Title: HOL/Tools/Quickcheck/abstract_generators.ML
Author: Lukas Bulwahn, TU Muenchen
Quickcheck generators for abstract types.
*)
signature ABSTRACT_GENERATORS =
sig
val quickcheck_generator : string -> term option -> term list -> theory -> theory
end
structure Abstract_Generators : ABSTRACT_GENERATORS =
struct
fun check_constrs ctxt tyco constrs =
let
fun check_type c =
(case try (dest_Type o body_type o fastype_of) c of
NONE => error (Syntax.string_of_term ctxt c ^ " has mismatching result type.")
| SOME (tyco', vs) => if not (tyco' = tyco) then
error (Syntax.string_of_term ctxt c ^ " has mismatching result type. " ^
"Expected type constructor " ^ quote tyco ^ ", but found " ^ quote tyco' ^ ".")
else
(case try (map dest_TFree) vs of
NONE => error (Syntax.string_of_term ctxt c ^ " has mismatching result type.")
| SOME _ => ()))
in map check_type constrs end
fun gen_quickcheck_generator prep_tyco prep_term tyco_raw opt_pred_raw constrs_raw thy =
let
val ctxt = Proof_Context.init_global thy
val tyco = prep_tyco ctxt tyco_raw
val opt_pred = Option.map (prep_term ctxt) opt_pred_raw
val constrs = map (prep_term ctxt) constrs_raw
val _ = check_constrs ctxt tyco constrs
val vs = map dest_TFree (snd (dest_Type (body_type (fastype_of (hd constrs)))))
val name = Long_Name.base_name tyco
fun mk_dconstrs (Const (s, T)) =
(s, map (Old_Datatype_Aux.dtyp_of_typ [(tyco, vs)]) (binder_types T))
| mk_dconstrs t =
error (Syntax.string_of_term ctxt t ^
" is not a valid constructor for quickcheck_generator, which expects a constant.")
fun the_descr _ _ =
let val descr = [(0, (tyco, map Old_Datatype_Aux.DtTFree vs, map mk_dconstrs constrs))]
in (descr, vs, [tyco], name, ([name], []), ([Type (tyco, map TFree vs)], [])) end
fun ensure_sort (sort, instantiate) =
Quickcheck_Common.ensure_sort
(((@{sort typerep}, @{sort term_of}), sort), (the_descr, instantiate))
Old_Datatype_Aux.default_config [tyco]
in
thy
|> ensure_sort
(@{sort full_exhaustive}, Exhaustive_Generators.instantiate_full_exhaustive_datatype)
|> ensure_sort (@{sort exhaustive}, Exhaustive_Generators.instantiate_exhaustive_datatype)
|> ensure_sort (@{sort random}, Random_Generators.instantiate_random_datatype)
|> (case opt_pred of NONE => I
| SOME t => Context.theory_map (Quickcheck_Common.register_predicate (t, tyco)))
end
val quickcheck_generator = gen_quickcheck_generator (K I) (K I)
val quickcheck_generator_cmd =
gen_quickcheck_generator
((#1 o dest_Type) oo Proof_Context.read_type_name {proper = true, strict = true})
Syntax.read_term
val _ =
Outer_Syntax.command @{command_keyword quickcheck_generator}
"define quickcheck generators for abstract types"
((Parse.type_const --
Scan.option (Args.$$$ "predicate" |-- @{keyword ":"} |-- Parse.term)) --
(Args.$$$ "constructors" |-- @{keyword ":"} |-- Parse.list1 Parse.term)
>> (fn ((tyco, opt_pred), constrs) =>
Toplevel.theory (quickcheck_generator_cmd tyco opt_pred constrs)))
end