2 /* --------------------------------------------------------------------------
3 * Definitions for substitution data structure and operations.
5 * Hugs 98 is Copyright (c) Mark P Jones, Alastair Reid and the Yale
6 * Haskell Group 1994-99, and is distributed as Open Source software
7 * under the Artistic License; see the file "Artistic" that is included
8 * in the distribution for details.
10 * $RCSfile: subst.h,v $
12 * $Date: 1999/02/03 17:08:43 $
13 * ------------------------------------------------------------------------*/
15 typedef struct { /* Each type variable contains: */
16 Type bound; /* A type skeleton (unbound==NIL) */
17 Int offs; /* Offset for skeleton */
18 Kind kind; /* kind annotation */
21 #if FIXED_SUBST /* storage for type variables */
22 extern Tyvar tyvars[];
24 extern Tyvar *tyvars; /* storage for type variables */
26 extern Int typeOff; /* offset of result type */
27 extern Type typeIs; /* skeleton of result type */
28 extern Int typeFree; /* freedom in instantiated type */
29 extern List predsAre; /* list of predicates in type */
30 extern List genericVars; /* list of generic vars */
31 extern List btyvars; /* explicitly scoped type vars */
33 #define tyvar(n) (tyvars+(n)) /* nth type variable */
34 #define tyvNum(t) ((t)-tyvars) /* and the corresp. inverse funct. */
35 #define isBound(t) (((t)->bound) && ((t)->bound!=SKOLEM))
36 #define aVar mkOffset(0) /* Simple skeletons for type vars */
37 #define bVar mkOffset(1)
38 #define enterBtyvs() btyvars = cons(NIL,btyvars)
39 #define leaveBtyvs() btyvars = tl(btyvars)
41 #define deRef(tyv,t,o) while ((tyv=getTypeVar(t,o)) && isBound(tyv)) { \
46 /* offs values when isNull(bound): */
47 #define FIXED_TYVAR 0 /* fixed in current assumption */
48 #define UNUSED_GENERIC 1 /* not fixed, not yet encountered */
49 #define GENERIC 2 /* GENERIC+n==nth generic var found*/
51 extern char *unifyFails; /* Unification error message */
53 extern Void emptySubstitution Args((Void));
54 extern Int newTyvars Args((Int));
55 #define newKindvars(n) newTyvars(n)
56 extern Int newKindedVars Args((Kind));
57 extern Void instantiate Args((Type));
59 extern Pair findBtyvs Args((Text));
60 extern Void markBtyvs Args((Void));
61 extern Type localizeBtyvs Args((Type));
63 extern Tyvar *getTypeVar Args((Type,Int));
64 extern Void tyvarType Args((Int));
65 extern Void bindTv Args((Int,Type,Int));
66 extern Cell getDerefHead Args((Type,Int));
67 extern Void expandSyn Args((Tycon, Int, Type *, Int *));
69 extern Void clearMarks Args((Void));
70 extern Void markAllVars Args((Void));
71 extern Void resetGenerics Args((Void));
72 extern Void markTyvar Args((Int));
73 extern Void markType Args((Type,Int));
74 extern Void markPred Args((Cell));
76 extern Type copyTyvar Args((Int));
77 extern Type copyType Args((Type,Int));
78 extern Cell copyPred Args((Cell,Int));
79 extern Type dropRank2 Args((Type,Int,Int));
80 extern Type dropRank1 Args((Type,Int,Int));
81 extern Void liftRank2Args Args((List,Int,Int));
82 extern Type liftRank2 Args((Type,Int,Int));
83 extern Type liftRank1 Args((Type,Int,Int));
85 extern Type debugTyvar Args((Int));
86 extern Type debugType Args((Type,Int));
88 extern Kind copyKindvar Args((Int));
89 extern Kind copyKind Args((Kind,Int));
91 extern Bool eqKind Args((Kind,Kind));
92 extern Kind getKind Args((Cell,Int));
94 extern List genvarTyvar Args((Int,List));
95 extern List genvarType Args((Type,Int,List));
97 extern Bool doesntOccurIn Args((Tyvar*,Type,Int));
98 extern Bool unify Args((Type,Int,Type,Int));
99 extern Bool kunify Args((Kind,Int,Kind,Int));
101 extern Void typeTuple Args((Cell));
102 extern Kind simpleKind Args((Int));
103 extern Void varKind Args((Int));
105 extern Bool samePred Args((Cell,Int,Cell,Int));
106 extern Bool matchPred Args((Cell,Int,Cell,Int));
107 extern Bool unifyPred Args((Cell,Int,Cell,Int));
108 extern Inst findInstFor Args((Cell,Int));
110 extern Bool sameSchemes Args((Type,Type));
112 /*-------------------------------------------------------------------------*/