1 /* -*- mode: hugs-c; -*- */
2 /* --------------------------------------------------------------------------
3 * subst.h: Copyright (c) Mark P Jones 1991-1998. All rights reserved.
4 * See NOTICE for details and conditions of use etc...
5 * Hugs version 1.3c, March 1998
7 * Definitions for substitution data structure and operations.
8 * ------------------------------------------------------------------------*/
10 typedef struct { /* Each type variable contains: */
11 Type bound; /* A type skeleton (unbound==NIL) */
12 Int offs; /* Offset for skeleton */
13 Kind kind; /* kind annotation */
16 #if FIXED_SUBST /* storage for type variables */
17 extern Tyvar tyvars[];
19 extern Tyvar *tyvars; /* storage for type variables */
21 extern Int typeOff; /* offset of result type */
22 extern Type typeIs; /* skeleton of result type */
23 extern Int typeFree; /* freedom in instantiated type */
24 extern List predsAre; /* list of predicates in type */
25 extern List genericVars; /* list of generic vars */
26 extern List btyvars; /* explicitly scoped type vars */
28 #define tyvar(n) (tyvars+(n)) /* nth type variable */
29 #define tyvNum(t) ((t)-tyvars) /* and the corresp. inverse funct. */
30 #define isBound(t) (((t)->bound) && ((t)->bound!=SKOLEM))
31 #define aVar mkOffset(0) /* Simple skeleton for type var */
32 #define bVar mkOffset(1) /* Simple skeleton for type var */
33 #define enterBtyvs() btyvars = cons(NIL,btyvars)
34 #define leaveBtyvs() btyvars = tl(btyvars)
36 #define deRef(tyv,t,o) while ((tyv=getTypeVar(t,o)) && isBound(tyv)) { \
41 /* offs values when isNull(bound): */
42 #define FIXED_TYVAR 0 /* fixed in current assumption */
43 #define UNUSED_GENERIC 1 /* not fixed, not yet encountered */
44 #define GENERIC 2 /* GENERIC+n==nth generic var found*/
46 extern char *unifyFails; /* Unification error message */
48 extern Void emptySubstitution Args((Void));
49 extern Int newTyvars Args((Int));
50 #define newKindvars(n) newTyvars(n)
51 extern Int newKindedVars Args((Kind));
52 extern Void instantiate Args((Type));
54 extern Pair findBtyvs Args((Text));
55 extern Void markBtyvs Args((Void));
56 extern Type localizeBtyvs Args((Type));
58 extern Tyvar *getTypeVar Args((Type,Int));
59 extern Void tyvarType Args((Int));
60 extern Void bindTv Args((Int,Type,Int));
61 extern Cell getDerefHead Args((Type,Int));
62 extern Void expandSyn Args((Tycon, Int, Type *, Int *));
64 extern Void clearMarks Args((Void));
65 extern Void resetGenerics Args((Void));
66 extern Void markTyvar Args((Int));
67 extern Void markType Args((Type,Int));
68 extern Void markPred Args((Cell));
70 extern Type copyTyvar Args((Int));
71 extern Type copyType Args((Type,Int));
72 extern Cell copyPred Args((Cell,Int));
73 extern Type dropRank2 Args((Type,Int,Int));
74 extern Type dropRank1 Args((Type,Int,Int));
75 extern Void liftRank2Args Args((List,Int,Int));
76 extern Type liftRank2 Args((Type,Int,Int));
77 extern Type liftRank1 Args((Type,Int,Int));
79 extern Type debugTyvar Args((Int));
80 extern Type debugType Args((Type,Int));
82 extern Kind copyKindvar Args((Int));
83 extern Kind copyKind Args((Kind,Int));
85 extern Bool eqKind Args((Kind,Kind));
86 extern Kind getKind Args((Cell,Int));
88 extern List genvarTyvar Args((Int,List));
89 extern List genvarType Args((Type,Int,List));
91 extern Bool doesntOccurIn Args((Tyvar*,Type,Int));
92 extern Bool unify Args((Type,Int,Type,Int));
93 extern Bool kunify Args((Kind,Int,Kind,Int));
95 extern Void typeTuple Args((Cell));
96 extern Kind simpleKind Args((Int));
97 extern Void varKind Args((Int));
99 extern Bool samePred Args((Cell,Int,Cell,Int));
100 extern Bool matchPred Args((Cell,Int,Cell,Int));
101 extern Bool unifyPred Args((Cell,Int,Cell,Int));
102 extern Inst findInstFor Args((Cell,Int));
104 extern Bool sameSchemes Args((Type,Type));
106 extern Bool typeMatches Args((Type,Type));
108 /*-------------------------------------------------------------------------*/