author | oheimb |
Wed, 03 Apr 2002 10:21:13 +0200 | |
changeset 13076 | 70704dd48bd5 |
parent 11539 | 0f17da240450 |
child 13641 | 63d1790a43ed |
permissions | -rw-r--r-- |
5177 | 1 |
(* Title: HOL/Tools/datatype_aux.ML |
2 |
ID: $Id$ |
|
11539 | 3 |
Author: Stefan Berghofer, TU Muenchen |
4 |
License: GPL (GNU GENERAL PUBLIC LICENSE) |
|
5177 | 5 |
|
11539 | 6 |
Auxiliary functions for defining datatypes. |
5177 | 7 |
*) |
8 |
||
9 |
signature DATATYPE_AUX = |
|
10 |
sig |
|
5661 | 11 |
val quiet_mode : bool ref |
12 |
val message : string -> unit |
|
13 |
||
5177 | 14 |
val foldl1 : ('a * 'a -> 'a) -> 'a list -> 'a |
15 |
||
5661 | 16 |
val add_path : bool -> string -> theory -> theory |
17 |
val parent_path : bool -> theory -> theory |
|
18 |
||
8435 | 19 |
val store_thmss : string -> string list -> thm list list -> theory -> theory * thm list list |
20 |
val store_thms_atts : string -> string list -> theory attribute list list -> thm list |
|
21 |
-> theory -> theory * thm list |
|
22 |
val store_thms : string -> string list -> thm list -> theory -> theory * thm list |
|
5177 | 23 |
|
24 |
val split_conj_thm : thm -> thm list |
|
25 |
val mk_conj : term list -> term |
|
26 |
val mk_disj : term list -> term |
|
27 |
||
28 |
val indtac : thm -> int -> tactic |
|
29 |
val exh_tac : (string -> thm) -> int -> tactic |
|
30 |
||
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
31 |
datatype simproc_dist = QuickAndDirty |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
32 |
| FewConstrs of thm list |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
33 |
| ManyConstrs of thm * simpset; |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
34 |
|
5177 | 35 |
datatype dtyp = |
36 |
DtTFree of string |
|
37 |
| DtType of string * (dtyp list) |
|
38 |
| DtRec of int; |
|
8404 | 39 |
type descr |
5177 | 40 |
type datatype_info |
41 |
||
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
42 |
exception Datatype |
9740 | 43 |
val name_of_typ : typ -> string |
5177 | 44 |
val dtyp_of_typ : (string * string list) list -> typ -> dtyp |
45 |
val mk_Free : string -> typ -> int -> term |
|
46 |
val is_rec_type : dtyp -> bool |
|
47 |
val typ_of_dtyp : (int * (string * dtyp list * |
|
48 |
(string * dtyp list) list)) list -> (string * sort) list -> dtyp -> typ |
|
49 |
val dest_DtTFree : dtyp -> string |
|
50 |
val dest_DtRec : dtyp -> int |
|
51 |
val dest_TFree : typ -> string |
|
52 |
val get_nonrec_types : (int * (string * dtyp list * |
|
53 |
(string * dtyp list) list)) list -> (string * sort) list -> typ list |
|
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
54 |
val get_branching_types : (int * (string * dtyp list * |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
55 |
(string * dtyp list) list)) list -> (string * sort) list -> typ list |
5177 | 56 |
val get_rec_types : (int * (string * dtyp list * |
57 |
(string * dtyp list) list)) list -> (string * sort) list -> typ list |
|
58 |
val check_nonempty : (int * (string * dtyp list * |
|
59 |
(string * dtyp list) list)) list list -> unit |
|
60 |
val unfold_datatypes : |
|
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
61 |
Sign.sg -> (int * (string * dtyp list * (string * dtyp list) list)) list -> |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
62 |
(string * sort) list -> datatype_info Symtab.table -> |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
63 |
(int * (string * dtyp list * (string * dtyp list) list)) list -> int -> |
5177 | 64 |
(int * (string * dtyp list * |
65 |
(string * dtyp list) list)) list list * int |
|
66 |
end; |
|
67 |
||
68 |
structure DatatypeAux : DATATYPE_AUX = |
|
69 |
struct |
|
70 |
||
5661 | 71 |
val quiet_mode = ref false; |
72 |
fun message s = if !quiet_mode then () else writeln s; |
|
73 |
||
5177 | 74 |
(* FIXME: move to library ? *) |
75 |
fun foldl1 f (x::xs) = foldl f (x, xs); |
|
76 |
||
5661 | 77 |
fun add_path flat_names s = if flat_names then I else Theory.add_path s; |
78 |
fun parent_path flat_names = if flat_names then I else Theory.parent_path; |
|
79 |
||
8435 | 80 |
|
5177 | 81 |
(* store theorems in theory *) |
82 |
||
83 |
fun store_thmss label tnames thmss thy = |
|
8435 | 84 |
(thy, tnames ~~ thmss) |> |
85 |
foldl_map (fn (thy', (tname, thms)) => thy' |> |
|
5661 | 86 |
Theory.add_path tname |> |
8435 | 87 |
(apsnd hd o PureThy.add_thmss [((label, thms), [])]) |>> |
88 |
Theory.parent_path); |
|
5177 | 89 |
|
8435 | 90 |
fun store_thms_atts label tnames attss thms thy = |
91 |
(thy, tnames ~~ attss ~~ thms) |> |
|
92 |
foldl_map (fn (thy', ((tname, atts), thm)) => thy' |> |
|
5661 | 93 |
Theory.add_path tname |> |
8435 | 94 |
(apsnd hd o PureThy.add_thms [((label, thm), atts)]) |>> |
95 |
Theory.parent_path); |
|
96 |
||
97 |
fun store_thms label tnames = store_thms_atts label tnames (replicate (length tnames) []); |
|
98 |
||
5177 | 99 |
|
100 |
(* split theorem thm_1 & ... & thm_n into n theorems *) |
|
101 |
||
102 |
fun split_conj_thm th = |
|
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
103 |
((th RS conjunct1)::(split_conj_thm (th RS conjunct2))) handle THM _ => [th]; |
5177 | 104 |
|
105 |
val mk_conj = foldr1 (HOLogic.mk_binop "op &"); |
|
106 |
val mk_disj = foldr1 (HOLogic.mk_binop "op |"); |
|
107 |
||
108 |
||
109 |
(* instantiate induction rule *) |
|
110 |
||
111 |
fun indtac indrule i st = |
|
112 |
let |
|
8305 | 113 |
val ts = HOLogic.dest_conj (HOLogic.dest_Trueprop (concl_of indrule)); |
114 |
val ts' = HOLogic.dest_conj (HOLogic.dest_Trueprop |
|
5177 | 115 |
(Logic.strip_imp_concl (nth_elem (i - 1, prems_of st)))); |
116 |
val getP = if can HOLogic.dest_imp (hd ts) then |
|
117 |
(apfst Some) o HOLogic.dest_imp else pair None; |
|
118 |
fun abstr (t1, t2) = (case t1 of |
|
119 |
None => let val [Free (s, T)] = add_term_frees (t2, []) |
|
120 |
in absfree (s, T, t2) end |
|
121 |
| Some (_ $ t' $ _) => Abs ("x", fastype_of t', abstract_over (t', t2))) |
|
6394 | 122 |
val cert = cterm_of (Thm.sign_of_thm st); |
5177 | 123 |
val Ps = map (cert o head_of o snd o getP) ts; |
124 |
val indrule' = cterm_instantiate (Ps ~~ |
|
125 |
(map (cert o abstr o getP) ts')) indrule |
|
126 |
in |
|
127 |
rtac indrule' i st |
|
128 |
end; |
|
129 |
||
130 |
(* perform exhaustive case analysis on last parameter of subgoal i *) |
|
131 |
||
132 |
fun exh_tac exh_thm_of i state = |
|
133 |
let |
|
6394 | 134 |
val sg = Thm.sign_of_thm state; |
5177 | 135 |
val prem = nth_elem (i - 1, prems_of state); |
136 |
val params = Logic.strip_params prem; |
|
137 |
val (_, Type (tname, _)) = hd (rev params); |
|
138 |
val exhaustion = lift_rule (state, i) (exh_thm_of tname); |
|
139 |
val prem' = hd (prems_of exhaustion); |
|
140 |
val _ $ (_ $ lhs $ _) = hd (rev (Logic.strip_assums_hyp prem')); |
|
141 |
val exhaustion' = cterm_instantiate [(cterm_of sg (head_of lhs), |
|
142 |
cterm_of sg (foldr (fn ((_, T), t) => Abs ("z", T, t)) |
|
143 |
(params, Bound 0)))] exhaustion |
|
144 |
in compose_tac (false, exhaustion', nprems_of exhaustion) i state |
|
145 |
end; |
|
146 |
||
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
147 |
(* handling of distinctness theorems *) |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
148 |
|
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
149 |
datatype simproc_dist = QuickAndDirty |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
150 |
| FewConstrs of thm list |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
151 |
| ManyConstrs of thm * simpset; |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
152 |
|
5177 | 153 |
(********************** Internal description of datatypes *********************) |
154 |
||
155 |
datatype dtyp = |
|
156 |
DtTFree of string |
|
157 |
| DtType of string * (dtyp list) |
|
158 |
| DtRec of int; |
|
159 |
||
160 |
(* information about datatypes *) |
|
161 |
||
8404 | 162 |
type descr = (int * (string * dtyp list * (string * dtyp list) list)) list; |
163 |
||
5177 | 164 |
type datatype_info = |
165 |
{index : int, |
|
8404 | 166 |
descr : descr, |
5177 | 167 |
rec_names : string list, |
168 |
rec_rewrites : thm list, |
|
169 |
case_name : string, |
|
170 |
case_rewrites : thm list, |
|
171 |
induction : thm, |
|
172 |
exhaustion : thm, |
|
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
173 |
distinct : simproc_dist, |
5177 | 174 |
inject : thm list, |
175 |
nchotomy : thm, |
|
10120 | 176 |
case_cong : thm, |
177 |
weak_case_cong : thm}; |
|
5177 | 178 |
|
179 |
fun mk_Free s T i = Free (s ^ (string_of_int i), T); |
|
180 |
||
181 |
fun subst_DtTFree _ substs (T as (DtTFree name)) = |
|
182 |
(case assoc (substs, name) of |
|
183 |
None => T |
|
184 |
| Some U => U) |
|
185 |
| subst_DtTFree i substs (DtType (name, ts)) = |
|
186 |
DtType (name, map (subst_DtTFree i substs) ts) |
|
187 |
| subst_DtTFree i _ (DtRec j) = DtRec (i + j); |
|
188 |
||
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
189 |
exception Datatype; |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
190 |
|
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
191 |
fun dest_DtTFree (DtTFree a) = a |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
192 |
| dest_DtTFree _ = raise Datatype; |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
193 |
|
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
194 |
fun dest_DtRec (DtRec i) = i |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
195 |
| dest_DtRec _ = raise Datatype; |
5177 | 196 |
|
197 |
fun is_rec_type (DtType (_, dts)) = exists is_rec_type dts |
|
198 |
| is_rec_type (DtRec _) = true |
|
199 |
| is_rec_type _ = false; |
|
200 |
||
201 |
fun dest_TFree (TFree (n, _)) = n; |
|
202 |
||
9740 | 203 |
fun name_of_typ (Type (s, Ts)) = space_implode "_" |
204 |
(filter (not o equal "") (map name_of_typ Ts) @ [Sign.base_name s]) |
|
205 |
| name_of_typ _ = ""; |
|
206 |
||
5177 | 207 |
fun dtyp_of_typ _ (TFree (n, _)) = DtTFree n |
208 |
| dtyp_of_typ _ (TVar _) = error "Illegal schematic type variable(s)" |
|
209 |
| dtyp_of_typ new_dts (Type (tname, Ts)) = |
|
210 |
(case assoc (new_dts, tname) of |
|
211 |
None => DtType (tname, map (dtyp_of_typ new_dts) Ts) |
|
212 |
| Some vs => if map (try dest_TFree) Ts = map Some vs then |
|
213 |
DtRec (find_index (curry op = tname o fst) new_dts) |
|
214 |
else error ("Illegal occurence of recursive type " ^ tname)); |
|
215 |
||
216 |
fun typ_of_dtyp descr sorts (DtTFree a) = TFree (a, the (assoc (sorts, a))) |
|
217 |
| typ_of_dtyp descr sorts (DtRec i) = |
|
218 |
let val (s, ds, _) = the (assoc (descr, i)) |
|
219 |
in Type (s, map (typ_of_dtyp descr sorts) ds) end |
|
220 |
| typ_of_dtyp descr sorts (DtType (s, ds)) = |
|
221 |
Type (s, map (typ_of_dtyp descr sorts) ds); |
|
222 |
||
223 |
(* find all non-recursive types in datatype description *) |
|
224 |
||
225 |
fun get_nonrec_types descr sorts = |
|
226 |
let fun add (Ts, T as DtTFree _) = T ins Ts |
|
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
227 |
| add (Ts, T as DtType ("fun", [_, DtRec _])) = Ts |
5177 | 228 |
| add (Ts, T as DtType _) = T ins Ts |
229 |
| add (Ts, _) = Ts |
|
230 |
in map (typ_of_dtyp descr sorts) (foldl (fn (Ts, (_, (_, _, constrs))) => |
|
231 |
foldl (fn (Ts', (_, cargs)) => |
|
232 |
foldl add (Ts', cargs)) (Ts, constrs)) ([], descr)) |
|
233 |
end; |
|
234 |
||
235 |
(* get all recursive types in datatype description *) |
|
236 |
||
237 |
fun get_rec_types descr sorts = map (fn (_ , (s, ds, _)) => |
|
238 |
Type (s, map (typ_of_dtyp descr sorts) ds)) descr; |
|
239 |
||
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
240 |
(* get all branching types *) |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
241 |
|
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
242 |
fun get_branching_types descr sorts = |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
243 |
let fun add (Ts, DtType ("fun", [T, DtRec _])) = T ins Ts |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
244 |
| add (Ts, _) = Ts |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
245 |
in map (typ_of_dtyp descr sorts) (foldl (fn (Ts, (_, (_, _, constrs))) => |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
246 |
foldl (fn (Ts', (_, cargs)) => |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
247 |
foldl add (Ts', cargs)) (Ts, constrs)) ([], descr)) |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
248 |
end; |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
249 |
|
5177 | 250 |
(* nonemptiness check for datatypes *) |
251 |
||
252 |
fun check_nonempty descr = |
|
253 |
let |
|
254 |
val descr' = flat descr; |
|
255 |
fun is_nonempty_dt is i = |
|
256 |
let |
|
257 |
val (_, _, constrs) = the (assoc (descr', i)); |
|
258 |
fun arg_nonempty (DtRec i) = if i mem is then false |
|
259 |
else is_nonempty_dt (i::is) i |
|
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
260 |
| arg_nonempty (DtType ("fun", [_, T])) = arg_nonempty T |
5177 | 261 |
| arg_nonempty _ = true; |
262 |
in exists ((forall arg_nonempty) o snd) constrs |
|
263 |
end |
|
264 |
in assert_all (fn (i, _) => is_nonempty_dt [i] i) (hd descr) |
|
265 |
(fn (_, (s, _, _)) => "Nonemptiness check failed for datatype " ^ s) |
|
266 |
end; |
|
267 |
||
268 |
(* unfold a list of mutually recursive datatype specifications *) |
|
269 |
(* all types of the form DtType (dt_name, [..., DtRec _, ...]) *) |
|
270 |
(* need to be unfolded *) |
|
271 |
||
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
272 |
fun unfold_datatypes sign orig_descr sorts (dt_info : datatype_info Symtab.table) descr i = |
5177 | 273 |
let |
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
274 |
fun typ_error T msg = error ("Non-admissible type expression\n" ^ |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
275 |
Sign.string_of_typ sign (typ_of_dtyp (orig_descr @ descr) sorts T) ^ "\n" ^ msg); |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
276 |
|
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
277 |
fun get_dt_descr T i tname dts = |
5177 | 278 |
(case Symtab.lookup (dt_info, tname) of |
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
279 |
None => typ_error T (tname ^ " is not a datatype - can't use it in\ |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
280 |
\ nested recursion") |
5177 | 281 |
| (Some {index, descr, ...}) => |
282 |
let val (_, vars, _) = the (assoc (descr, index)); |
|
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
283 |
val subst = ((map dest_DtTFree vars) ~~ dts) handle LIST _ => |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
284 |
typ_error T ("Type constructor " ^ tname ^ " used with wrong\ |
5177 | 285 |
\ number of arguments") |
286 |
in (i + index, map (fn (j, (tn, args, cs)) => (i + j, |
|
287 |
(tn, map (subst_DtTFree i subst) args, |
|
288 |
map (apsnd (map (subst_DtTFree i subst))) cs))) descr) |
|
289 |
end); |
|
290 |
||
291 |
(* unfold a single constructor argument *) |
|
292 |
||
293 |
fun unfold_arg ((i, Ts, descrs), T as (DtType (tname, dts))) = |
|
294 |
if is_rec_type T then |
|
7015
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
295 |
if tname = "fun" then |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
296 |
if is_rec_type (hd dts) then |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
297 |
typ_error T "Non-strictly positive recursive occurrence of type" |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
298 |
else |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
299 |
(case hd (tl dts) of |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
300 |
DtType ("fun", _) => typ_error T "Curried function types not allowed" |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
301 |
| T' => let val (i', [T''], descrs') = unfold_arg ((i, [], descrs), T') |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
302 |
in (i', Ts @ [DtType (tname, [hd dts, T''])], descrs') end) |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
303 |
else |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
304 |
let val (index, descr) = get_dt_descr T i tname dts; |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
305 |
val (descr', i') = unfold_datatypes sign orig_descr sorts dt_info descr (i + length descr) |
85be09eb136c
- Datatype package now also supports arbitrarily branching datatypes
berghofe
parents:
6394
diff
changeset
|
306 |
in (i', Ts @ [DtRec index], descrs @ descr') end |
5177 | 307 |
else (i, Ts @ [T], descrs) |
308 |
| unfold_arg ((i, Ts, descrs), T) = (i, Ts @ [T], descrs); |
|
309 |
||
310 |
(* unfold a constructor *) |
|
311 |
||
312 |
fun unfold_constr ((i, constrs, descrs), (cname, cargs)) = |
|
313 |
let val (i', cargs', descrs') = foldl unfold_arg ((i, [], descrs), cargs) |
|
314 |
in (i', constrs @ [(cname, cargs')], descrs') end; |
|
315 |
||
316 |
(* unfold a single datatype *) |
|
317 |
||
318 |
fun unfold_datatype ((i, dtypes, descrs), (j, (tname, tvars, constrs))) = |
|
319 |
let val (i', constrs', descrs') = |
|
320 |
foldl unfold_constr ((i, [], descrs), constrs) |
|
321 |
in (i', dtypes @ [(j, (tname, tvars, constrs'))], descrs') |
|
322 |
end; |
|
323 |
||
324 |
val (i', descr', descrs) = foldl unfold_datatype ((i, [],[]), descr); |
|
325 |
||
326 |
in (descr' :: descrs, i') end; |
|
327 |
||
328 |
end; |