1 (* Title: Pure/data.ML |
|
2 ID: $Id$ |
|
3 Author: Markus Wenzel, TU Muenchen |
|
4 |
|
5 Arbitrarily typed data. Fools the ML type system via exception |
|
6 constructors. |
|
7 *) |
|
8 |
|
9 type object = exn; |
|
10 |
|
11 signature DATA = |
|
12 sig |
|
13 type T |
|
14 val empty: T |
|
15 val merge: T * T -> T |
|
16 val prep_ext: T -> T |
|
17 val kinds: T -> string list |
|
18 val init: T -> string -> object -> |
|
19 (object -> object) -> (object * object -> object) -> (object -> unit) -> T |
|
20 val get: T -> string -> object |
|
21 val put: T -> string -> object -> T |
|
22 val print: T -> string -> unit |
|
23 end; |
|
24 |
|
25 |
|
26 structure Data: DATA = |
|
27 struct |
|
28 |
|
29 |
|
30 (* datatype T *) |
|
31 |
|
32 datatype T = Data of |
|
33 (object * (*value*) |
|
34 ((object -> object) * (*prepare extend method*) |
|
35 (object * object -> object) * (*merge and prepare extend method*) |
|
36 (object -> unit))) (*print method*) |
|
37 Symtab.table; |
|
38 |
|
39 val empty = Data Symtab.null; |
|
40 |
|
41 fun kinds (Data tab) = map fst (Symtab.dest tab); |
|
42 |
|
43 |
|
44 (* errors *) |
|
45 |
|
46 fun err_method name kind = |
|
47 error ("Error while invoking " ^ quote kind ^ " " ^ name ^ " method"); |
|
48 |
|
49 fun err_dup_init kind = |
|
50 error ("Duplicate initialization of " ^ quote kind ^ " data"); |
|
51 |
|
52 fun err_uninit kind = |
|
53 error ("Tried to access uninitialized " ^ quote kind ^ " data"); |
|
54 |
|
55 |
|
56 (* prepare data *) |
|
57 |
|
58 fun merge (Data tab1, Data tab2) = |
|
59 let |
|
60 val data1 = Symtab.dest tab1; |
|
61 val data2 = Symtab.dest tab2; |
|
62 val all_data = data1 @ data2; |
|
63 val kinds = distinct (map fst all_data); |
|
64 |
|
65 fun entry data kind = |
|
66 (case assoc (data, kind) of |
|
67 None => [] |
|
68 | Some x => [(kind, x)]); |
|
69 |
|
70 fun merge_entries [(kind, (e, mths as (ext, _, _)))] = |
|
71 (kind, (ext e handle _ => err_method "prep_ext" kind, mths)) |
|
72 | merge_entries [(kind, (e1, mths as (_, mrg, _))), (_, (e2, _))] = |
|
73 (kind, (mrg (e1, e2) handle _ => err_method "merge" kind, mths)) |
|
74 | merge_entries _ = sys_error "merge_entries"; |
|
75 |
|
76 val data = map (fn k => merge_entries (entry data1 k @ entry data2 k)) kinds; |
|
77 in Data (Symtab.make data) end; |
|
78 |
|
79 |
|
80 fun prep_ext data = merge (data, empty); |
|
81 |
|
82 fun init (Data tab) kind e ext mrg prt = |
|
83 Data (Symtab.update_new ((kind, (e, (ext, mrg, prt))), tab)) |
|
84 handle Symtab.DUPLICATE _ => err_dup_init kind; |
|
85 |
|
86 |
|
87 (* access data *) |
|
88 |
|
89 fun lookup tab kind = |
|
90 (case Symtab.lookup (tab, kind) of |
|
91 Some x => x |
|
92 | None => err_uninit kind); |
|
93 |
|
94 fun get (Data tab) kind = fst (lookup tab kind); |
|
95 |
|
96 fun put (Data tab) kind e = |
|
97 Data (Symtab.update ((kind, (e, snd (lookup tab kind))), tab)); |
|
98 |
|
99 fun print (Data tab) kind = |
|
100 let val (e, (_, _, prt)) = lookup tab kind |
|
101 in prt e handle _ => err_method "print" kind end; |
|
102 |
|
103 |
|
104 end; |
|