author  traytel 
Mon, 29 Nov 2010 16:53:08 +0100  
changeset 40836  a81d66d72e70 
parent 40297  c753e3f8b4d6 
child 40838  d9bd6df700a8 
permissions  rwrr 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

1 
(* Title: Tools/subtyping.ML 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

2 
Author: Dmitriy Traytel, TU Muenchen 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

3 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

4 
Coercive subtyping via subtype constraints. 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

5 
*) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

6 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

7 
signature SUBTYPING = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

8 
sig 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

9 
datatype variance = COVARIANT  CONTRAVARIANT  INVARIANT 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

10 
val infer_types: Proof.context > (string > typ option) > (indexname > typ option) > 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

11 
term list > term list 
40284
c9acf88447e6
export declarations by default, to allow other ML packages bypass concrete syntax;
wenzelm
parents:
40283
diff
changeset

12 
val add_type_map: term > Context.generic > Context.generic 
c9acf88447e6
export declarations by default, to allow other ML packages bypass concrete syntax;
wenzelm
parents:
40283
diff
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13 
val add_coercion: term > Context.generic > Context.generic 
40836  14 
val gen_coercion: Proof.context > typ Vartab.table > (typ * typ) > term 
40283  15 
val setup: theory > theory 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

16 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

17 

40283  18 
structure Subtyping: SUBTYPING = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

19 
struct 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

20 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

21 
(** coercions data **) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

22 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

23 
datatype variance = COVARIANT  CONTRAVARIANT  INVARIANT 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

24 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

25 
datatype data = Data of 
40282  26 
{coes: term Symreltab.table, (*coercions table*) 
27 
coes_graph: unit Graph.T, (*coercions graph*) 

28 
tmaps: (term * variance list) Symtab.table}; (*map functions*) 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

29 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

30 
fun make_data (coes, coes_graph, tmaps) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

31 
Data {coes = coes, coes_graph = coes_graph, tmaps = tmaps}; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

32 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

33 
structure Data = Generic_Data 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

34 
( 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

35 
type T = data; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

36 
val empty = make_data (Symreltab.empty, Graph.empty, Symtab.empty); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

37 
val extend = I; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

38 
fun merge 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

39 
(Data {coes = coes1, coes_graph = coes_graph1, tmaps = tmaps1}, 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

40 
Data {coes = coes2, coes_graph = coes_graph2, tmaps = tmaps2}) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

41 
make_data (Symreltab.merge (op aconv) (coes1, coes2), 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

42 
Graph.merge (op =) (coes_graph1, coes_graph2), 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

43 
Symtab.merge (eq_pair (op aconv) (op =)) (tmaps1, tmaps2)); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

44 
); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

45 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

46 
fun map_data f = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

47 
Data.map (fn Data {coes, coes_graph, tmaps} => 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

48 
make_data (f (coes, coes_graph, tmaps))); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

49 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

50 
fun map_coes f = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

51 
map_data (fn (coes, coes_graph, tmaps) => 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

52 
(f coes, coes_graph, tmaps)); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

53 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

54 
fun map_coes_graph f = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

55 
map_data (fn (coes, coes_graph, tmaps) => 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

56 
(coes, f coes_graph, tmaps)); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

57 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

58 
fun map_coes_and_graph f = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

59 
map_data (fn (coes, coes_graph, tmaps) => 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

60 
let val (coes', coes_graph') = f (coes, coes_graph); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

61 
in (coes', coes_graph', tmaps) end); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

62 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

63 
fun map_tmaps f = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

64 
map_data (fn (coes, coes_graph, tmaps) => 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

65 
(coes, coes_graph, f tmaps)); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

66 

40285  67 
val rep_data = (fn Data args => args) o Data.get o Context.Proof; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

68 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

69 
val coes_of = #coes o rep_data; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

70 
val coes_graph_of = #coes_graph o rep_data; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

71 
val tmaps_of = #tmaps o rep_data; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

72 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

73 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

74 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

75 
(** utils **) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

76 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

77 
fun nameT (Type (s, [])) = s; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

78 
fun t_of s = Type (s, []); 
40286  79 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

80 
fun sort_of (TFree (_, S)) = SOME S 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

81 
 sort_of (TVar (_, S)) = SOME S 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

82 
 sort_of _ = NONE; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

83 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

84 
val is_typeT = fn (Type _) => true  _ => false; 
40282  85 
val is_compT = fn (Type (_, _ :: _)) => true  _ => false; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

86 
val is_freeT = fn (TFree _) => true  _ => false; 
40286  87 
val is_fixedvarT = fn (TVar (xi, _)) => not (Type_Infer.is_param xi)  _ => false; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

88 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

89 

40836  90 
(* unification *) 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

91 

40836  92 
exception TYPE_INFERENCE_ERROR of unit > string; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

93 
exception NO_UNIFIER of string * typ Vartab.table; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

94 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

95 
fun unify weak ctxt = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

96 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

97 
val thy = ProofContext.theory_of ctxt; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

98 
val pp = Syntax.pp ctxt; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

99 
val arity_sorts = Type.arity_sorts pp (Sign.tsig_of thy); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

100 

40282  101 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

102 
(* adjust sorts of parameters *) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

103 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

104 
fun not_of_sort x S' S = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

105 
"Variable " ^ x ^ "::" ^ Syntax.string_of_sort ctxt S' ^ " not of sort " ^ 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

106 
Syntax.string_of_sort ctxt S; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

107 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

108 
fun meet (_, []) tye_idx = tye_idx 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

109 
 meet (Type (a, Ts), S) (tye_idx as (tye, _)) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

110 
meets (Ts, arity_sorts a S handle ERROR msg => raise NO_UNIFIER (msg, tye)) tye_idx 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

111 
 meet (TFree (x, S'), S) (tye_idx as (tye, _)) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

112 
if Sign.subsort thy (S', S) then tye_idx 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

113 
else raise NO_UNIFIER (not_of_sort x S' S, tye) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

114 
 meet (TVar (xi, S'), S) (tye_idx as (tye, idx)) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

115 
if Sign.subsort thy (S', S) then tye_idx 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

116 
else if Type_Infer.is_param xi then 
40286  117 
(Vartab.update_new 
118 
(xi, Type_Infer.mk_param idx (Sign.inter_sort thy (S', S))) tye, idx + 1) 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

119 
else raise NO_UNIFIER (not_of_sort (Term.string_of_vname xi) S' S, tye) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

120 
and meets (T :: Ts, S :: Ss) (tye_idx as (tye, _)) = 
40286  121 
meets (Ts, Ss) (meet (Type_Infer.deref tye T, S) tye_idx) 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

122 
 meets _ tye_idx = tye_idx; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

123 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

124 
val weak_meet = if weak then fn _ => I else meet 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

125 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

126 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

127 
(* occurs check and assignment *) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

128 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

129 
fun occurs_check tye xi (TVar (xi', _)) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

130 
if xi = xi' then raise NO_UNIFIER ("Occurs check!", tye) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

131 
else 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

132 
(case Vartab.lookup tye xi' of 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

133 
NONE => () 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

134 
 SOME T => occurs_check tye xi T) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

135 
 occurs_check tye xi (Type (_, Ts)) = List.app (occurs_check tye xi) Ts 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

136 
 occurs_check _ _ _ = (); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

137 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

138 
fun assign xi (T as TVar (xi', _)) S env = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

139 
if xi = xi' then env 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

140 
else env > weak_meet (T, S) >> Vartab.update_new (xi, T) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

141 
 assign xi T S (env as (tye, _)) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

142 
(occurs_check tye xi T; env > weak_meet (T, S) >> Vartab.update_new (xi, T)); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

143 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

144 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

145 
(* unification *) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

146 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

147 
fun show_tycon (a, Ts) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

148 
quote (Syntax.string_of_typ ctxt (Type (a, replicate (length Ts) dummyT))); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

149 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

150 
fun unif (T1, T2) (env as (tye, _)) = 
40286  151 
(case pairself (`Type_Infer.is_paramT o Type_Infer.deref tye) (T1, T2) of 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

152 
((true, TVar (xi, S)), (_, T)) => assign xi T S env 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

153 
 ((_, T), (true, TVar (xi, S))) => assign xi T S env 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

154 
 ((_, Type (a, Ts)), (_, Type (b, Us))) => 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

155 
if weak andalso null Ts andalso null Us then env 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

156 
else if a <> b then 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

157 
raise NO_UNIFIER 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

158 
("Clash of types " ^ show_tycon (a, Ts) ^ " and " ^ show_tycon (b, Us), tye) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

159 
else fold unif (Ts ~~ Us) env 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

160 
 ((_, T), (_, U)) => if T = U then env else raise NO_UNIFIER ("", tye)); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

161 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

162 
in unif end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

163 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

164 
val weak_unify = unify true; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

165 
val strong_unify = unify false; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

166 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

167 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

168 
(* Typ_Graph shortcuts *) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

169 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

170 
val add_edge = Typ_Graph.add_edge_acyclic; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

171 
fun get_preds G T = Typ_Graph.all_preds G [T]; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

172 
fun get_succs G T = Typ_Graph.all_succs G [T]; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

173 
fun maybe_new_typnode T G = perhaps (try (Typ_Graph.new_node (T, ()))) G; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

174 
fun maybe_new_typnodes Ts G = fold maybe_new_typnode Ts G; 
40282  175 
fun new_imm_preds G Ts = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

176 
subtract (op =) Ts (distinct (op =) (maps (Typ_Graph.imm_preds G) Ts)); 
40282  177 
fun new_imm_succs G Ts = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

178 
subtract op= Ts (distinct (op =) (maps (Typ_Graph.imm_succs G) Ts)); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

179 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

180 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

181 
(* Graph shortcuts *) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

182 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

183 
fun maybe_new_node s G = perhaps (try (Graph.new_node (s, ()))) G 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

184 
fun maybe_new_nodes ss G = fold maybe_new_node ss G 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

185 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

186 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

187 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

188 
(** error messages **) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

189 

40836  190 
fun gen_msg err msg = 
191 
err () ^ "\nNow trying to infer coercions:\n\nCoercion inference failed" ^ 

192 
(if msg = "" then "" else ": " ^ msg) ^ "\n"; 

193 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

194 
fun prep_output ctxt tye bs ts Ts = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

195 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

196 
val (Ts_bTs', ts') = Type_Infer.finish ctxt tye (Ts @ map snd bs, ts); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

197 
val (Ts', Ts'') = chop (length Ts) Ts_bTs'; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

198 
fun prep t = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

199 
let val xs = rev (Term.variant_frees t (rev (map fst bs ~~ Ts''))) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

200 
in Term.subst_bounds (map Syntax.mark_boundT xs, t) end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

201 
in (map prep ts', Ts') end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

202 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

203 
fun err_loose i = error ("Loose bound variable: B." ^ string_of_int i); 
40836  204 

205 
fun unif_failed msg = 

206 
"Type unification failed" ^ (if msg = "" then "" else ": " ^ msg) ^ "\n\n"; 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

207 

40836  208 
fun subtyping_err_appl_msg ctxt msg tye bs t T u U () = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

209 
let val ([t', u'], [T', U']) = prep_output ctxt tye bs [t, u] [T, U] 
40836  210 
in msg ^ Type.appl_error (Syntax.pp ctxt) t' T' u' U' ^ "\n" end; 
211 

212 
fun err_appl_msg ctxt msg tye bs t T u U () = 

213 
let val ([t', u'], [T', U']) = prep_output ctxt tye bs [t, u] [T, U] 

214 
in unif_failed msg ^ Type.appl_error (Syntax.pp ctxt) t' T' u' U' ^ "\n" end; 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

215 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

216 
fun err_list ctxt msg tye Ts = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

217 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

218 
val (_, Ts') = prep_output ctxt tye [] [] Ts; 
40836  219 
val text = cat_lines ([msg, 
220 
"Cannot unify a list of types that should be the same:", 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

221 
(Pretty.string_of (Pretty.list "[" "]" (map (Pretty.typ (Syntax.pp ctxt)) Ts')))]); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

222 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

223 
error text 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

224 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

225 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

226 
fun err_bound ctxt msg tye packs = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

227 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

228 
val pp = Syntax.pp ctxt; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

229 
val (ts, Ts) = fold 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

230 
(fn (bs, t $ u, U, _, U') => fn (ts, Ts) => 
40836  231 
let val (t', T') = prep_output ctxt tye bs [t, u] [U', U] 
40282  232 
in (t' :: ts, T' :: Ts) end) 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

233 
packs ([], []); 
40836  234 
val text = cat_lines ([msg, "Cannot fulfil subtype constraints:"] @ 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

235 
(map2 (fn [t, u] => fn [T, U] => Pretty.string_of ( 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

236 
Pretty.block [ 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

237 
Pretty.typ pp T, Pretty.brk 2, Pretty.str "<:", Pretty.brk 2, Pretty.typ pp U, 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

238 
Pretty.brk 3, Pretty.str "from function application", Pretty.brk 2, 
40836  239 
Pretty.block [Pretty.term pp (t $ u)]])) 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

240 
ts Ts)) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

241 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

242 
error text 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

243 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

244 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

245 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

246 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

247 
(** constraint generation **) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

248 

40836  249 
fun generate_constraints ctxt err = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

250 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

251 
fun gen cs _ (Const (_, T)) tye_idx = (T, tye_idx, cs) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

252 
 gen cs _ (Free (_, T)) tye_idx = (T, tye_idx, cs) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

253 
 gen cs _ (Var (_, T)) tye_idx = (T, tye_idx, cs) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

254 
 gen cs bs (Bound i) tye_idx = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

255 
(snd (nth bs i handle Subscript => err_loose i), tye_idx, cs) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

256 
 gen cs bs (Abs (x, T, t)) tye_idx = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

257 
let val (U, tye_idx', cs') = gen cs ((x, T) :: bs) t tye_idx 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

258 
in (T > U, tye_idx', cs') end 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

259 
 gen cs bs (t $ u) tye_idx = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

260 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

261 
val (T, tye_idx', cs') = gen cs bs t tye_idx; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

262 
val (U', (tye, idx), cs'') = gen cs' bs u tye_idx'; 
40286  263 
val U = Type_Infer.mk_param idx []; 
264 
val V = Type_Infer.mk_param (idx + 1) []; 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

265 
val tye_idx''= strong_unify ctxt (U > V, T) (tye, idx + 2) 
40836  266 
handle NO_UNIFIER (msg, tye') => error (gen_msg err msg); 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

267 
val error_pack = (bs, t $ u, U, V, U'); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

268 
in (V, tye_idx'', ((U', U), error_pack) :: cs'') end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

269 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

270 
gen [] [] 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

271 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

272 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

273 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

274 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

275 
(** constraint resolution **) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

276 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

277 
exception BOUND_ERROR of string; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

278 

40836  279 
fun process_constraints ctxt err cs tye_idx = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

280 
let 
40285  281 
val coes_graph = coes_graph_of ctxt; 
282 
val tmaps = tmaps_of ctxt; 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

283 
val tsig = Sign.tsig_of (ProofContext.theory_of ctxt); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

284 
val pp = Syntax.pp ctxt; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

285 
val arity_sorts = Type.arity_sorts pp tsig; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

286 
val subsort = Type.subsort tsig; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

287 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

288 
fun split_cs _ [] = ([], []) 
40282  289 
 split_cs f (c :: cs) = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

290 
(case pairself f (fst c) of 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

291 
(false, false) => apsnd (cons c) (split_cs f cs) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

292 
 _ => apfst (cons c) (split_cs f cs)); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

293 

40282  294 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

295 
(* check whether constraint simplification will terminate using weak unification *) 
40282  296 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

297 
val _ = fold (fn (TU, error_pack) => fn tye_idx => 
40836  298 
weak_unify ctxt TU tye_idx handle NO_UNIFIER (msg, tye) => 
299 
error (gen_msg err ("weak unification of subtype constraints fails\n" ^ msg))) cs tye_idx; 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

300 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

301 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

302 
(* simplify constraints *) 
40282  303 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

304 
fun simplify_constraints cs tye_idx = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

305 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

306 
fun contract a Ts Us error_pack done todo tye idx = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

307 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

308 
val arg_var = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

309 
(case Symtab.lookup tmaps a of 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

310 
(*everything is invariant for unknown constructors*) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

311 
NONE => replicate (length Ts) INVARIANT 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

312 
 SOME av => snd av); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

313 
fun new_constraints (variance, constraint) (cs, tye_idx) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

314 
(case variance of 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

315 
COVARIANT => (constraint :: cs, tye_idx) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

316 
 CONTRAVARIANT => (swap constraint :: cs, tye_idx) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

317 
 INVARIANT => (cs, strong_unify ctxt constraint tye_idx 
40836  318 
handle NO_UNIFIER (msg, tye) => 
319 
error (gen_msg err ("failed to unify invariant arguments\n" ^ msg)))); 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

320 
val (new, (tye', idx')) = apfst (fn cs => (cs ~~ replicate (length cs) error_pack)) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

321 
(fold new_constraints (arg_var ~~ (Ts ~~ Us)) ([], (tye, idx))); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

322 
val test_update = is_compT orf is_freeT orf is_fixedvarT; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

323 
val (ch, done') = 
40286  324 
if not (null new) then ([], done) 
325 
else split_cs (test_update o Type_Infer.deref tye') done; 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

326 
val todo' = ch @ todo; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

327 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

328 
simplify done' (new @ todo') (tye', idx') 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

329 
end 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

330 
(*xi is definitely a parameter*) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

331 
and expand varleq xi S a Ts error_pack done todo tye idx = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

332 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

333 
val n = length Ts; 
40286  334 
val args = map2 Type_Infer.mk_param (idx upto idx + n  1) (arity_sorts a S); 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

335 
val tye' = Vartab.update_new (xi, Type(a, args)) tye; 
40286  336 
val (ch, done') = split_cs (is_compT o Type_Infer.deref tye') done; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

337 
val todo' = ch @ todo; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

338 
val new = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

339 
if varleq then (Type(a, args), Type (a, Ts)) 
40286  340 
else (Type (a, Ts), Type (a, args)); 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

341 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

342 
simplify done' ((new, error_pack) :: todo') (tye', idx + n) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

343 
end 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

344 
(*TU is a pair of a parameter and a free/fixed variable*) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

345 
and eliminate TU error_pack done todo tye idx = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

346 
let 
40286  347 
val [TVar (xi, S)] = filter Type_Infer.is_paramT TU; 
348 
val [T] = filter_out Type_Infer.is_paramT TU; 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

349 
val SOME S' = sort_of T; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

350 
val test_update = if is_freeT T then is_freeT else is_fixedvarT; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

351 
val tye' = Vartab.update_new (xi, T) tye; 
40286  352 
val (ch, done') = split_cs (test_update o Type_Infer.deref tye') done; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

353 
val todo' = ch @ todo; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

354 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

355 
if subsort (S', S) (*TODO check this*) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

356 
then simplify done' todo' (tye', idx) 
40836  357 
else error (gen_msg err "sort mismatch") 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

358 
end 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

359 
and simplify done [] tye_idx = (done, tye_idx) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

360 
 simplify done (((T, U), error_pack) :: todo) (tye_idx as (tye, idx)) = 
40286  361 
(case (Type_Infer.deref tye T, Type_Infer.deref tye U) of 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

362 
(Type (a, []), Type (b, [])) => 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

363 
if a = b then simplify done todo tye_idx 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

364 
else if Graph.is_edge coes_graph (a, b) then simplify done todo tye_idx 
40836  365 
else error (gen_msg err (a ^ " is not a subtype of " ^ b)) 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

366 
 (Type (a, Ts), Type (b, Us)) => 
40836  367 
if a <> b then error (gen_msg err "different constructors") 
368 
(fst tye_idx) error_pack 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

369 
else contract a Ts Us error_pack done todo tye idx 
40282  370 
 (TVar (xi, S), Type (a, Ts as (_ :: _))) => 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

371 
expand true xi S a Ts error_pack done todo tye idx 
40282  372 
 (Type (a, Ts as (_ :: _)), TVar (xi, S)) => 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

373 
expand false xi S a Ts error_pack done todo tye idx 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

374 
 (T, U) => 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

375 
if T = U then simplify done todo tye_idx 
40282  376 
else if exists (is_freeT orf is_fixedvarT) [T, U] andalso 
40286  377 
exists Type_Infer.is_paramT [T, U] 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

378 
then eliminate [T, U] error_pack done todo tye idx 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

379 
else if exists (is_freeT orf is_fixedvarT) [T, U] 
40836  380 
then error (gen_msg err "not eliminated free/fixed variables") 
40282  381 
else simplify (((T, U), error_pack) :: done) todo tye_idx); 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

382 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

383 
simplify [] cs tye_idx 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

384 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

385 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

386 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

387 
(* do simplification *) 
40282  388 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

389 
val (cs', tye_idx') = simplify_constraints cs tye_idx; 
40836  390 

391 
fun find_error_pack lower T' = map_filter 

392 
(fn ((T, U), pack) => if if lower then T' = U else T' = T then SOME pack else NONE) cs'; 

393 

394 
fun find_cycle_packs nodes = 

395 
let 

396 
val (but_last, last) = split_last nodes 

397 
val pairs = (last, hd nodes) :: (but_last ~~ tl nodes); 

398 
in 

399 
map_filter 

400 
(fn (TU, pack) => if member (eq_pair (op =) (op =)) pairs TU then SOME pack else NONE) 

401 
cs' 

402 
end; 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

403 

40282  404 
fun unify_list (T :: Ts) tye_idx = 
40836  405 
fold (fn U => fn tye_idx' => strong_unify ctxt (T, U) tye_idx') Ts tye_idx; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

406 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

407 
(*styps stands either for supertypes or for subtypes of a type T 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

408 
in terms of the subtyperelation (excluding T itself)*) 
40282  409 
fun styps super T = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

410 
(if super then Graph.imm_succs else Graph.imm_preds) coes_graph T 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

411 
handle Graph.UNDEF _ => []; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

412 

40282  413 
fun minmax sup (T :: Ts) = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

414 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

415 
fun adjust T U = if sup then (T, U) else (U, T); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

416 
fun extract T [] = T 
40282  417 
 extract T (U :: Us) = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

418 
if Graph.is_edge coes_graph (adjust T U) then extract T Us 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

419 
else if Graph.is_edge coes_graph (adjust U T) then extract U Us 
40836  420 
else raise BOUND_ERROR "uncomparable types in type list"; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

421 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

422 
t_of (extract T Ts) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

423 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

424 

40282  425 
fun ex_styp_of_sort super T styps_and_sorts = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

426 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

427 
fun adjust T U = if super then (T, U) else (U, T); 
40282  428 
fun styp_test U Ts = forall 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

429 
(fn T => T = U orelse Graph.is_edge coes_graph (adjust U T)) Ts; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

430 
fun fitting Ts S U = Type.of_sort tsig (t_of U, S) andalso styp_test U Ts 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

431 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

432 
forall (fn (Ts, S) => exists (fitting Ts S) (T :: styps super T)) styps_and_sorts 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

433 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

434 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

435 
(* computes the tightest possible, correct assignment for 'a::S 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

436 
e.g. in the supremum case (sup = true): 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

437 
 'a::S 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

438 
/ / \ \ 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

439 
/ / \ \ 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

440 
'b::C1 'c::C2 ... T1 T2 ... 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

441 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

442 
sorts  list of sorts [C1, C2, ...] 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

443 
T::Ts  nonempty list of base types [T1, T2, ...] 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

444 
*) 
40282  445 
fun tightest sup S styps_and_sorts (T :: Ts) = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

446 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

447 
fun restriction T = Type.of_sort tsig (t_of T, S) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

448 
andalso ex_styp_of_sort (not sup) T styps_and_sorts; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

449 
fun candidates T = inter (op =) (filter restriction (T :: styps sup T)); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

450 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

451 
(case fold candidates Ts (filter restriction (T :: styps sup T)) of 
40836  452 
[] => raise BOUND_ERROR ("no " ^ (if sup then "supremum" else "infimum")) 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

453 
 [T] => t_of T 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

454 
 Ts => minmax sup Ts) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

455 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

456 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

457 
fun build_graph G [] tye_idx = (G, tye_idx) 
40282  458 
 build_graph G ((T, U) :: cs) tye_idx = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

459 
if T = U then build_graph G cs tye_idx 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

460 
else 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

461 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

462 
val G' = maybe_new_typnodes [T, U] G; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

463 
val (G'', tye_idx') = (add_edge (T, U) G', tye_idx) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

464 
handle Typ_Graph.CYCLES cycles => 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

465 
let 
40836  466 
val (tye, idx) = 
467 
fold 

468 
(fn cycle => fn tye_idx' => (unify_list cycle tye_idx' 

469 
handle NO_UNIFIER (msg, tye) => 

470 
err_bound ctxt 

471 
(gen_msg err ("constraint cycle not unifiable" ^ msg)) (fst tye_idx) 

472 
(find_cycle_packs cycle))) 

473 
cycles tye_idx 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

474 
in 
40836  475 
collapse (tye, idx) cycles G 
476 
end 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

477 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

478 
build_graph G'' cs tye_idx' 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

479 
end 
40836  480 
and collapse (tye, idx) cycles G = (*nodes nonempty list*) 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

481 
let 
40836  482 
(*all cycles collapse to one node, 
483 
because all of them share at least the nodes x and y*) 

484 
val nodes = (distinct (op =) (flat cycles)); 

485 
val T = Type_Infer.deref tye (hd nodes); 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

486 
val P = new_imm_preds G nodes; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

487 
val S = new_imm_succs G nodes; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

488 
val G' = Typ_Graph.del_nodes (tl nodes) G; 
40836  489 
fun check_and_gen super T' = 
490 
let val U = Type_Infer.deref tye T'; 

491 
in 

492 
if not (is_typeT T) orelse not (is_typeT U) orelse T = U 

493 
then if super then (hd nodes, T') else (T', hd nodes) 

494 
else 

495 
if super andalso 

496 
Graph.is_edge coes_graph (nameT T, nameT U) then (hd nodes, T') 

497 
else if not super andalso 

498 
Graph.is_edge coes_graph (nameT U, nameT T) then (T', hd nodes) 

499 
else err_bound ctxt (gen_msg err "cycle elimination produces inconsistent graph") 

500 
(fst tye_idx) 

501 
(maps find_cycle_packs cycles @ find_error_pack super T') 

502 
end; 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

503 
in 
40836  504 
build_graph G' (map (check_and_gen false) P @ map (check_and_gen true) S) (tye, idx) 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

505 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

506 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

507 
fun assign_bound lower G key (tye_idx as (tye, _)) = 
40286  508 
if Type_Infer.is_paramT (Type_Infer.deref tye key) then 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

509 
let 
40286  510 
val TVar (xi, S) = Type_Infer.deref tye key; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

511 
val get_bound = if lower then get_preds else get_succs; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

512 
val raw_bound = get_bound G key; 
40286  513 
val bound = map (Type_Infer.deref tye) raw_bound; 
514 
val not_params = filter_out Type_Infer.is_paramT bound; 

40282  515 
fun to_fulfil T = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

516 
(case sort_of T of 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

517 
NONE => NONE 
40282  518 
 SOME S => 
40286  519 
SOME 
520 
(map nameT 

521 
(filter_out Type_Infer.is_paramT (map (Type_Infer.deref tye) (get_bound G T))), 

522 
S)); 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

523 
val styps_and_sorts = distinct (op =) (map_filter to_fulfil raw_bound); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

524 
val assignment = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

525 
if null bound orelse null not_params then NONE 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

526 
else SOME (tightest lower S styps_and_sorts (map nameT not_params) 
40836  527 
handle BOUND_ERROR msg => 
528 
err_bound ctxt (gen_msg err msg) tye (find_error_pack lower key)) 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

529 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

530 
(case assignment of 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

531 
NONE => tye_idx 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

532 
 SOME T => 
40286  533 
if Type_Infer.is_paramT T then tye_idx 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

534 
else if lower then (*upper bound check*) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

535 
let 
40286  536 
val other_bound = map (Type_Infer.deref tye) (get_succs G key); 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

537 
val s = nameT T; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

538 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

539 
if subset (op = o apfst nameT) (filter is_typeT other_bound, s :: styps true s) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

540 
then apfst (Vartab.update (xi, T)) tye_idx 
40836  541 
else err_bound ctxt (gen_msg err ("assigned simple type " ^ s ^ 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

542 
" clashes with the upper bound of variable " ^ 
40836  543 
Syntax.string_of_typ ctxt (TVar(xi, S)))) tye (find_error_pack (not lower) key) 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

544 
end 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

545 
else apfst (Vartab.update (xi, T)) tye_idx) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

546 
end 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

547 
else tye_idx; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

548 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

549 
val assign_lb = assign_bound true; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

550 
val assign_ub = assign_bound false; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

551 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

552 
fun assign_alternating ts' ts G tye_idx = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

553 
if ts' = ts then tye_idx 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

554 
else 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

555 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

556 
val (tye_idx' as (tye, _)) = fold (assign_lb G) ts tye_idx 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

557 
> fold (assign_ub G) ts; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

558 
in 
40836  559 
assign_alternating ts 
560 
(filter (Type_Infer.is_paramT o Type_Infer.deref tye) ts) G tye_idx' 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

561 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

562 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

563 
(*Unify all weakly connected components of the constraint forest, 
40282  564 
that contain only params. These are the only WCCs that contain 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

565 
params anyway.*) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

566 
fun unify_params G (tye_idx as (tye, _)) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

567 
let 
40286  568 
val max_params = 
569 
filter (Type_Infer.is_paramT o Type_Infer.deref tye) (Typ_Graph.maximals G); 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

570 
val to_unify = map (fn T => T :: get_preds G T) max_params; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

571 
in 
40836  572 
fold 
573 
(fn Ts => fn tye_idx' => unify_list Ts tye_idx' 

574 
handle NO_UNIFIER (msg, tye) => err_list ctxt (gen_msg err msg) (fst tye_idx) Ts) 

575 
to_unify tye_idx 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

576 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

577 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

578 
fun solve_constraints G tye_idx = tye_idx 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

579 
> assign_alternating [] (Typ_Graph.keys G) G 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

580 
> unify_params G; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

581 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

582 
build_graph Typ_Graph.empty (map fst cs') tye_idx' 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

583 
> solve_constraints 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

584 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

585 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

586 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

587 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

588 
(** coercion insertion **) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

589 

40836  590 
fun gen_coercion ctxt tye (T1, T2) = 
591 
(case pairself (Type_Infer.deref tye) (T1, T2) of 

592 
((Type (a, [])), (Type (b, []))) => 

593 
if a = b 

594 
then Abs (Name.uu, Type (a, []), Bound 0) 

595 
else 

596 
(case Symreltab.lookup (coes_of ctxt) (a, b) of 

597 
NONE => raise Fail (a ^ " is not a subtype of " ^ b) 

598 
 SOME co => co) 

599 
 ((Type (a, Ts)), (Type (b, Us))) => 

600 
if a <> b 

601 
then raise Fail ("Different constructors: " ^ a ^ " and " ^ b) 

602 
else 

603 
let 

604 
fun inst t Ts = 

605 
Term.subst_vars 

606 
(((Term.add_tvar_namesT (fastype_of t) []) ~~ rev Ts), []) t; 

607 
fun sub_co (COVARIANT, TU) = gen_coercion ctxt tye TU 

608 
 sub_co (CONTRAVARIANT, TU) = gen_coercion ctxt tye (swap TU); 

609 
fun ts_of [] = [] 

610 
 ts_of (Type ("fun", [x1, x2]) :: xs) = x1 :: x2 :: (ts_of xs); 

611 
in 

612 
(case Symtab.lookup (tmaps_of ctxt) a of 

613 
NONE => raise Fail ("No map function for " ^ a ^ " known") 

614 
 SOME tmap => 

615 
let 

616 
val used_coes = map sub_co ((snd tmap) ~~ (Ts ~~ Us)); 

617 
in 

618 
Term.list_comb 

619 
(inst (fst tmap) (ts_of (map fastype_of used_coes)), used_coes) 

620 
end) 

621 
end 

622 
 (T, U) => 

623 
if Type.could_unify (T, U) 

624 
then Abs (Name.uu, T, Bound 0) 

625 
else raise Fail ("Cannot generate coercion from " 

626 
^ Syntax.string_of_typ ctxt T ^ " to " ^ Syntax.string_of_typ ctxt U)); 

627 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

628 
fun insert_coercions ctxt tye ts = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

629 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

630 
fun insert _ (Const (c, T)) = 
40836  631 
let val T' = T; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

632 
in (Const (c, T'), T') end 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

633 
 insert _ (Free (x, T)) = 
40836  634 
let val T' = T; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

635 
in (Free (x, T'), T') end 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

636 
 insert _ (Var (xi, T)) = 
40836  637 
let val T' = T; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

638 
in (Var (xi, T'), T') end 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

639 
 insert bs (Bound i) = 
40836  640 
let val T = nth bs i handle Subscript => err_loose i; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

641 
in (Bound i, T) end 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

642 
 insert bs (Abs (x, T, t)) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

643 
let 
40836  644 
val T' = T; 
40282  645 
val (t', T'') = insert (T' :: bs) t; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

646 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

647 
(Abs (x, T', t'), T' > T'') 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

648 
end 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

649 
 insert bs (t $ u) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

650 
let 
40836  651 
val (t', Type ("fun", [U, T])) = apsnd (Type_Infer.deref tye) (insert bs t); 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

652 
val (u', U') = insert bs u; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

653 
in 
40836  654 
if can (fn TU => strong_unify ctxt TU (tye, 0)) (U, U') 
655 
then (t' $ u', T) 

656 
else (t' $ (gen_coercion ctxt tye (U', U) $ u'), T) 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

657 
end 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

658 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

659 
map (fst o insert []) ts 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

660 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

661 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

662 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

663 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

664 
(** assembling the pipeline **) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

665 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

666 
fun infer_types ctxt const_type var_type raw_ts = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

667 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

668 
val (idx, ts) = Type_Infer.prepare ctxt const_type var_type raw_ts; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

669 

40836  670 
fun inf _ (t as (Const (_, T))) tye_idx = (t, T, tye_idx) 
671 
 inf _ (t as (Free (_, T))) tye_idx = (t, T, tye_idx) 

672 
 inf _ (t as (Var (_, T))) tye_idx = (t, T, tye_idx) 

673 
 inf bs (t as (Bound i)) tye_idx = 

674 
(t, snd (nth bs i handle Subscript => err_loose i), tye_idx) 

675 
 inf bs (Abs (x, T, t)) tye_idx = 

676 
let val (t', U, tye_idx') = inf ((x, T) :: bs) t tye_idx 

677 
in (Abs (x, T, t'), T > U, tye_idx') end 

678 
 inf bs (t $ u) tye_idx = 

679 
let 

680 
val (t', T, tye_idx') = inf bs t tye_idx; 

681 
val (u', U, (tye, idx)) = inf bs u tye_idx'; 

682 
val V = Type_Infer.mk_param idx []; 

683 
val (tu, tye_idx'') = (t' $ u', strong_unify ctxt (U > V, T) (tye, idx + 1)) 

684 
handle NO_UNIFIER (msg, tye') => 

685 
raise TYPE_INFERENCE_ERROR (err_appl_msg ctxt msg tye' bs t T u U); 

686 
in (tu, V, tye_idx'') end; 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

687 

40836  688 
fun infer_single t (ts, tye_idx) = 
689 
let val (t, _, tye_idx') = inf [] t tye_idx; 

690 
in (ts @ [t], tye_idx') end; 

691 

692 
val (ts', (tye, _)) = (fold infer_single ts ([], (Vartab.empty, idx)) 

693 
handle TYPE_INFERENCE_ERROR err => 

694 
let 

695 
fun gen_single t (tye_idx, constraints) = 

696 
let val (_, tye_idx', constraints') = generate_constraints ctxt err t tye_idx 

697 
in (tye_idx', constraints' @ constraints) end; 

698 

699 
val (tye_idx, constraints) = fold gen_single ts ((Vartab.empty, idx), []); 

700 
val (tye, idx) = process_constraints ctxt err constraints tye_idx; 

701 
in 

702 
(insert_coercions ctxt tye ts, (tye, idx)) 

703 
end); 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

704 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

705 
val (_, ts'') = Type_Infer.finish ctxt tye ([], ts'); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

706 
in ts'' end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

707 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

708 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

709 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

710 
(** installation **) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

711 

40283  712 
(* term check *) 
713 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

714 
fun coercion_infer_types ctxt = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

715 
infer_types ctxt 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

716 
(try (Consts.the_constraint (ProofContext.consts_of ctxt))) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

717 
(ProofContext.def_type ctxt); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

718 

40283  719 
val add_term_check = 
720 
Syntax.add_term_check ~100 "coercions" 

721 
(fn xs => fn ctxt => 

722 
let val xs' = coercion_infer_types ctxt xs 

723 
in if eq_list (op aconv) (xs, xs') then NONE else SOME (xs', ctxt) end); 

40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

724 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

725 

40283  726 
(* declarations *) 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

727 

40284
c9acf88447e6
export declarations by default, to allow other ML packages bypass concrete syntax;
wenzelm
parents:
40283
diff
changeset

728 
fun add_type_map raw_t context = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

729 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

730 
val ctxt = Context.proof_of context; 
40284
c9acf88447e6
export declarations by default, to allow other ML packages bypass concrete syntax;
wenzelm
parents:
40283
diff
changeset

731 
val t = singleton (Variable.polymorphic ctxt) raw_t; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

732 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

733 
fun err_str () = "\n\nthe general type signature for a map function is" ^ 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

734 
"\nf1 => f2 => ... => fn => C [x1, ..., xn] => C [x1, ..., xn]" ^ 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

735 
"\nwhere C is a constructor and fi is of type (xi => yi) or (yi => xi)"; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

736 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

737 
fun gen_arg_var ([], []) = [] 
40282  738 
 gen_arg_var ((T, T') :: Ts, (U, U') :: Us) = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

739 
if T = U andalso T' = U' then COVARIANT :: gen_arg_var (Ts, Us) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

740 
else if T = U' andalso T' = U then CONTRAVARIANT :: gen_arg_var (Ts, Us) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

741 
else error ("Functions do not apply to arguments correctly:" ^ err_str ()) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

742 
 gen_arg_var (_, _) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

743 
error ("Different numbers of functions and arguments\n" ^ err_str ()); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

744 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

745 
(* TODO: This function is only needed to introde the fun type map 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

746 
function: "% f g h . g o h o f". There must be a better solution. *) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

747 
fun balanced (Type (_, [])) (Type (_, [])) = true 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

748 
 balanced (Type (a, Ts)) (Type (b, Us)) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

749 
a = b andalso forall I (map2 balanced Ts Us) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

750 
 balanced (TFree _) (TFree _) = true 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

751 
 balanced (TVar _) (TVar _) = true 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

752 
 balanced _ _ = false; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

753 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

754 
fun check_map_fun (pairs, []) (Type ("fun", [T as Type (C, Ts), U as Type (_, Us)])) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

755 
if balanced T U 
40282  756 
then ((pairs, Ts ~~ Us), C) 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

757 
else if C = "fun" 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

758 
then check_map_fun (pairs @ [(hd Ts, hd (tl Ts))], []) U 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

759 
else error ("Not a proper map function:" ^ err_str ()) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

760 
 check_map_fun _ _ = error ("Not a proper map function:" ^ err_str ()); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

761 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

762 
val res = check_map_fun ([], []) (fastype_of t); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

763 
val res_av = gen_arg_var (fst res); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

764 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

765 
map_tmaps (Symtab.update (snd res, (t, res_av))) context 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

766 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

767 

40284
c9acf88447e6
export declarations by default, to allow other ML packages bypass concrete syntax;
wenzelm
parents:
40283
diff
changeset

768 
fun add_coercion raw_t context = 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

769 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

770 
val ctxt = Context.proof_of context; 
40284
c9acf88447e6
export declarations by default, to allow other ML packages bypass concrete syntax;
wenzelm
parents:
40283
diff
changeset

771 
val t = singleton (Variable.polymorphic ctxt) raw_t; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

772 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

773 
fun err_coercion () = error ("Bad type for coercion " ^ 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

774 
Syntax.string_of_term ctxt t ^ ":\n" ^ 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

775 
Syntax.string_of_typ ctxt (fastype_of t)); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

776 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

777 
val (Type ("fun", [T1, T2])) = fastype_of t 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

778 
handle Bind => err_coercion (); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

779 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

780 
val a = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

781 
(case T1 of 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

782 
Type (x, []) => x 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

783 
 _ => err_coercion ()); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

784 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

785 
val b = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

786 
(case T2 of 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

787 
Type (x, []) => x 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

788 
 _ => err_coercion ()); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

789 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

790 
fun coercion_data_update (tab, G) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

791 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

792 
val G' = maybe_new_nodes [a, b] G 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

793 
val G'' = Graph.add_edge_trans_acyclic (a, b) G' 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

794 
handle Graph.CYCLES _ => error (a ^ " is already a subtype of " ^ b ^ 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

795 
"!\n\nCannot add coercion of type: " ^ a ^ " => " ^ b); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

796 
val new_edges = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

797 
flat (Graph.dest G'' > map (fn (x, ys) => ys > map_filter (fn y => 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

798 
if Graph.is_edge G' (x, y) then NONE else SOME (x, y)))); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

799 
val G_and_new = Graph.add_edge (a, b) G'; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

800 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

801 
fun complex_coercion tab G (a, b) = 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

802 
let 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

803 
val path = hd (Graph.irreducible_paths G (a, b)) 
40836  804 
val path' = fst (split_last path) ~~ tl path 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

805 
in Abs (Name.uu, Type (a, []), 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

806 
fold (fn t => fn u => t $ u) (map (the o Symreltab.lookup tab) path') (Bound 0)) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

807 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

808 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

809 
val tab' = fold 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

810 
(fn pair => fn tab => Symreltab.update (pair, complex_coercion tab G_and_new pair) tab) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

811 
(filter (fn pair => pair <> (a, b)) new_edges) 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

812 
(Symreltab.update ((a, b), t) tab); 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

813 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

814 
(tab', G'') 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

815 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

816 
in 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

817 
map_coes_and_graph coercion_data_update context 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

818 
end; 
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

819 

40283  820 

821 
(* theory setup *) 

822 

823 
val setup = 

824 
Context.theory_map add_term_check #> 

40284
c9acf88447e6
export declarations by default, to allow other ML packages bypass concrete syntax;
wenzelm
parents:
40283
diff
changeset

825 
Attrib.setup @{binding coercion} 
c9acf88447e6
export declarations by default, to allow other ML packages bypass concrete syntax;
wenzelm
parents:
40283
diff
changeset

826 
(Args.term >> (fn t => Thm.declaration_attribute (K (add_coercion t)))) 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

827 
"declaration of new coercions" #> 
40297  828 
Attrib.setup @{binding coercion_map} 
40284
c9acf88447e6
export declarations by default, to allow other ML packages bypass concrete syntax;
wenzelm
parents:
40283
diff
changeset

829 
(Args.term >> (fn t => Thm.declaration_attribute (K (add_type_map t)))) 
40283  830 
"declaration of new map functions"; 
40281
3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

831 

3c6198fd0937
Coercive subtyping via subtype constraints, by Dmitriy Traytel (21Oct2010).
wenzelm
parents:
diff
changeset

832 
end; 