2 /* --------------------------------------------------------------------------
3 * Static Analysis for Hugs
5 * The Hugs 98 system is Copyright (c) Mark P Jones, Alastair Reid, the
6 * Yale Haskell Group, and the Oregon Graduate Institute of Science and
7 * Technology, 1994-1999, All rights reserved. It is distributed as
8 * free software under the license in the file "License", which is
9 * included in the distribution.
11 * $RCSfile: static.c,v $
13 * $Date: 2000/02/04 13:41:00 $
14 * ------------------------------------------------------------------------*/
24 /* --------------------------------------------------------------------------
25 * local function prototypes:
26 * ------------------------------------------------------------------------*/
28 static Void local kindError Args((Int,Constr,Constr,String,Kind,Int));
29 static Void local checkQualImport Args((Pair));
30 static Void local checkUnqualImport Args((Triple));
32 static Name local lookupName Args((Text,List));
33 static List local checkSubentities Args((List,List,List,String,Text));
34 static List local checkExportTycon Args((List,Text,Cell,Tycon));
35 static List local checkExportClass Args((List,Text,Cell,Class));
36 static List local checkExport Args((List,Text,Cell));
37 static List local checkImportEntity Args((List,Module,Cell));
38 static List local resolveImportList Args((Module,Cell));
39 static Void local checkImportList Args((Pair));
41 static Void local importEntity Args((Module,Cell));
42 static Void local importName Args((Module,Name));
43 static Void local importTycon Args((Module,Tycon));
44 static Void local importClass Args((Module,Class));
45 static List local checkExports Args((List));
47 static Void local checkTyconDefn Args((Tycon));
48 static Void local depConstrs Args((Tycon,List,Cell));
49 static List local addSels Args((Int,Name,List,List));
50 static List local selectCtxt Args((List,List));
51 static Void local checkSynonyms Args((List));
52 static List local visitSyn Args((List,Tycon,List));
53 static Type local instantiateSyn Args((Type,Type));
55 static Void local checkClassDefn Args((Class));
56 static Cell local depPredExp Args((Int,List,Cell));
57 static Void local checkMems Args((Class,List,Cell));
58 static Void local checkMems2 Args((Class,Cell));
59 static Void local addMembers Args((Class));
60 static Name local newMember Args((Int,Int,Cell,Type,Class));
61 Name newDSel Args((Class,Int));
62 static Text local generateText Args((String,Class));
63 Int visitClass Args((Class));
65 static List local classBindings Args((String,Class,List));
66 static Name local memberName Args((Class,Text));
67 static List local numInsert Args((Int,Cell,List));
69 static List local maybeAppendVar Args((Cell,List));
71 static Type local checkSigType Args((Int,String,Cell,Type));
72 static Void local checkOptQuantVars Args((Int,List,List));
73 static Type local depTopType Args((Int,List,Type));
74 static Type local depCompType Args((Int,List,Type));
75 static Type local depTypeExp Args((Int,List,Type));
76 static Type local depTypeVar Args((Int,List,Text));
77 static List local checkQuantVars Args((Int,List,List,Cell));
78 static List local otvars Args((Cell,List));
79 static Bool local osubset Args((List,List));
80 static Void local kindConstr Args((Int,Int,Int,Constr));
81 static Kind local kindAtom Args((Int,Constr));
82 static Void local kindPred Args((Int,Int,Int,Cell));
83 static Void local kindType Args((Int,String,Type));
84 static Void local fixKinds Args((Void));
86 static Void local kindTCGroup Args((List));
87 static Void local initTCKind Args((Cell));
88 static Void local kindTC Args((Cell));
89 static Void local genTC Args((Cell));
91 static Void local checkInstDefn Args((Inst));
92 static Void local insertInst Args((Inst));
93 static Bool local instCompare Args((Inst,Inst));
94 static Name local newInstImp Args((Inst));
95 static Void local kindInst Args((Inst,Int));
96 static Void local checkDerive Args((Tycon,List,List,Cell));
97 static Void local addDerInst Args((Int,Class,List,List,Type,Int));
98 static Void local deriveContexts Args((List));
99 static Void local initDerInst Args((Inst));
100 static Void local calcInstPreds Args((Inst));
101 static Void local maybeAddPred Args((Cell,Int,Int,List));
102 static List local calcFunDeps Args((List));
103 static Cell local copyAdj Args((Cell,Int,Int));
104 static Void local tidyDerInst Args((Inst));
105 static List local otvarsZonk Args((Cell,List,Int));
107 static Void local addDerivImp Args((Inst));
109 static Void local checkDefaultDefns Args((Void));
111 static Void local checkForeignImport Args((Name));
112 static Void local checkForeignExport Args((Name));
114 static Cell local tidyInfix Args((Int,Cell));
115 static Pair local attachFixity Args((Int,Cell));
116 static Syntax local lookupSyntax Args((Text));
118 static Cell local checkPat Args((Int,Cell));
119 static Cell local checkMaybeCnkPat Args((Int,Cell));
120 static Cell local checkApPat Args((Int,Int,Cell));
121 static Void local addToPatVars Args((Int,Cell));
122 static Name local conDefined Args((Int,Cell));
123 static Void local checkIsCfun Args((Int,Name));
124 static Void local checkCfunArgs Args((Int,Cell,Int));
125 static Cell local checkPatType Args((Int,String,Cell,Type));
126 static Cell local applyBtyvs Args((Cell));
127 static Cell local bindPat Args((Int,Cell));
128 static Void local bindPats Args((Int,List));
130 static List local extractSigdecls Args((List));
131 static List local extractFixdecls Args((List));
132 static List local extractBindings Args((List));
133 static List local getPatVars Args((Int,Cell,List));
134 static List local addPatVar Args((Int,Cell,List));
135 static List local eqnsToBindings Args((List,List,List,List));
136 static Void local notDefined Args((Int,List,Cell));
137 static Cell local findBinding Args((Text,List));
138 static Cell local getAttr Args((List,Cell));
139 static Void local addSigdecl Args((List,Cell));
140 static Void local addFixdecl Args((List,List,List,List,Triple));
141 static Void local dupFixity Args((Int,Text));
142 static Void local missFixity Args((Int,Text));
144 static List local dependencyAnal Args((List));
145 static List local topDependAnal Args((List));
146 static Void local addDepField Args((Cell));
147 static Void local remDepField Args((List));
148 static Void local remDepField1 Args((Cell));
149 static Void local clearScope Args((Void));
150 static Void local withinScope Args((List));
151 static Void local leaveScope Args((Void));
152 static Void local saveSyntax Args((Cell,Cell));
154 static Void local depBinding Args((Cell));
155 static Void local depDefaults Args((Class));
156 static Void local depInsts Args((Inst));
157 static Void local depClassBindings Args((List));
158 static Void local depAlt Args((Cell));
159 static Void local depRhs Args((Cell));
160 static Void local depGuard Args((Cell));
161 static Cell local depExpr Args((Int,Cell));
162 static Void local depPair Args((Int,Cell));
163 static Void local depTriple Args((Int,Cell));
164 static Void local depComp Args((Int,Cell,List));
165 static Void local depCaseAlt Args((Int,Cell));
166 static Cell local depVar Args((Int,Cell));
167 static Cell local depQVar Args((Int,Cell));
168 static Void local depConFlds Args((Int,Cell,Bool));
169 static Void local depUpdFlds Args((Int,Cell));
170 static List local depFields Args((Int,Cell,List,Bool));
172 static Void local depWith Args((Int,Cell));
173 static List local depDwFlds Args((Int,Cell,List));
176 static Cell local depRecord Args((Int,Cell));
179 static List local tcscc Args((List,List));
180 static List local bscc Args((List));
182 static Void local addRSsigdecls Args((Pair));
183 static Void local allNoPrevDef Args((Cell));
184 static Void local noPrevDef Args((Int,Cell));
185 static Bool local odiff Args((List,List));
187 static Void local duplicateErrorAux Args((Int,Module,Text,String));
188 #define duplicateError(l,m,t,k) duplicateErrorAux(l,m,t,k)
189 static Void local checkTypeIn Args((Pair));
191 /* --------------------------------------------------------------------------
192 * The code in this file is arranged in roughly the following order:
193 * - Kind inference preliminaries
194 * - Module declarations
195 * - Type declarations (data, type, newtype, type in)
196 * - Class declarations
198 * - Instance declarations
199 * - Default declarations
200 * - Primitive definitions
202 * - Infix expressions
203 * - Value definitions
204 * - Top-level static analysis and control
205 * - Haskell 98 compatibility tests
206 * ------------------------------------------------------------------------*/
208 /* --------------------------------------------------------------------------
209 * Kind checking preliminaries:
210 * ------------------------------------------------------------------------*/
212 Bool kindExpert = FALSE; /* TRUE => display kind errors in */
215 static Void local kindError(l,c,in,wh,k,o)
216 Int l; /* line number near constuctor exp */
217 Constr c; /* constructor */
218 Constr in; /* context (if any) */
219 String wh; /* place in which error occurs */
220 Kind k; /* expected kind (k,o) */
221 Int o; { /* inferred kind (typeIs,typeOff) */
224 if (!kindExpert) { /* for those with a fear of kinds */
225 ERRMSG(l) "Illegal type" ETHEN
227 ERRTEXT " \"" ETHEN ERRTYPE(in);
230 ERRTEXT " in %s\n", wh
234 ERRMSG(l) "Kind error in %s", wh ETHEN
236 ERRTEXT "\n*** expression : " ETHEN ERRTYPE(in);
238 ERRTEXT "\n*** constructor : " ETHEN ERRTYPE(c);
239 ERRTEXT "\n*** kind : " ETHEN ERRKIND(copyType(typeIs,typeOff));
240 ERRTEXT "\n*** does not match : " ETHEN ERRKIND(copyType(k,o));
242 ERRTEXT "\n*** because : %s", unifyFails ETHEN
248 #define shouldKind(l,c,in,wh,k,o) if (!kunify(typeIs,typeOff,k,o)) \
249 kindError(l,c,in,wh,k,o)
250 #define checkKind(l,a,m,c,in,wh,k,o) kindConstr(l,a,m,c); \
251 shouldKind(l,c,in,wh,k,o)
252 #define inferKind(k,o) typeIs=k; typeOff=o
254 static List unkindTypes; /* types in need of kind annotation*/
256 Kind extKind; /* Kind of extension, *->row->row */
259 /* --------------------------------------------------------------------------
260 * Static analysis of modules:
261 * ------------------------------------------------------------------------*/
267 Void startModule(nm) /* switch to a new module */
270 if (!isCon(nm)) internal("startModule");
271 if (isNull(m = findModule(textOf(nm))))
272 m = newModule(textOf(nm));
273 else if (!isPreludeScript()) {
274 /* You're allowed to break the rules in the Prelude! */
276 reloadModule = textToStr(textOf(nm));
278 ERRMSG(0) "Module \"%s\" already loaded", textToStr(textOf(nm))
284 Void setExportList(exps) /* Add export list to current module */
286 module(currentModule).exports = exps;
289 Void addQualImport(orig,new) /* Add to qualified import list */
290 Cell orig; /* Original name of module */
291 Cell new; { /* Name module is called within this module (or NIL) */
292 module(currentModule).qualImports =
293 cons(pair(isNull(new)?orig:new,orig),module(currentModule).qualImports);
296 Void addUnqualImport(mod,entities) /* Add to unqualified import list */
297 Cell mod; /* Name of module */
298 List entities; { /* List of entity names */
299 unqualImports = cons(pair(mod,entities),unqualImports);
302 static Void local checkQualImport(i) /* Process qualified import */
304 Module m = findModid(snd(i));
306 ERRMSG(0) "Module \"%s\" not previously loaded",
307 textToStr(textOf(snd(i)))
313 static Void local checkUnqualImport(i) /* Process unqualified import */
315 Module m = findModid(fst(i));
317 ERRMSG(0) "Module \"%s\" not previously loaded",
318 textToStr(textOf(fst(i)))
324 static Name local lookupName(t,nms) /* find text t in list of Names */
326 List nms; { /* :: [Name] */
327 for(; nonNull(nms); nms=tl(nms)) {
328 if (t == name(hd(nms)).text)
334 static List local checkSubentities(imports,named,wanted,description,textParent)
336 List named; /* :: [ Q?(Var|Con)(Id|Op) ] */
337 List wanted; /* :: [Name] */
338 String description; /* "<constructor>|<member> of <type>|<class>" */
340 for(; nonNull(named); named=tl(named)) {
342 /* ToDo: ignores qualifier; doesn't check that entity is in scope */
343 Text t = isPair(snd(x)) ? qtextOf(x) : textOf(x);
344 Name n = lookupName(t,wanted);
346 ERRMSG(0) "Entity \"%s\" is not a %s \"%s\"",
349 textToStr(textParent)
352 imports = cons(n,imports);
357 static List local checkImportEntity(imports,exporter,entity)
358 List imports; /* Accumulated list of things to import */
360 Cell entity; { /* Entry from import list */
361 List oldImports = imports;
362 Text t = isIdent(entity) ? textOf(entity) : textOf(fst(entity));
363 List es = module(exporter).exports;
364 for(; nonNull(es); es=tl(es)) {
365 Cell e = hd(es); /* :: Entity | (Entity, NIL|DOTDOT) */
369 if (tycon(f).text == t) {
370 imports = cons(f,imports);
371 if (!isIdent(entity)) {
372 switch (tycon(f).what) {
375 if (DOTDOT == snd(entity)) {
376 imports=dupOnto(tycon(f).defn,imports);
378 imports=checkSubentities(imports,snd(entity),tycon(f).defn,
379 "constructor of type",t);
383 /* deliberate fall thru */
387 } else if (isClass(f)) {
388 if (cclass(f).text == t) {
389 imports = cons(f,imports);
390 if (!isIdent(entity)) {
391 if (DOTDOT == snd(entity)) {
392 return dupOnto(cclass(f).members,imports);
394 return checkSubentities(imports,snd(entity),cclass(f).members,
395 "member of class",t);
400 internal("checkImportEntity2");
402 } else if (isName(e)) {
403 if (isIdent(entity) && name(e).text == t) {
404 imports = cons(e,imports);
407 internal("checkImportEntity3");
410 if (imports == oldImports) {
411 ERRMSG(0) "Unknown entity \"%s\" imported from module \"%s\"",
413 textToStr(module(exporter ).text)
419 static List local resolveImportList(m,impList)
420 Module m; /* exporting module */
423 if (DOTDOT == impList) {
424 List es = module(m).exports;
425 for(; nonNull(es); es=tl(es)) {
428 imports = cons(e,imports);
431 List subentities = NIL;
432 imports = cons(c,imports);
434 && (tycon(c).what == DATATYPE
435 || tycon(c).what == NEWTYPE))
436 subentities = tycon(c).defn;
438 subentities = cclass(c).members;
439 if (DOTDOT == snd(e)) {
440 imports = dupOnto(subentities,imports);
445 map1Accum(checkImportEntity,imports,m,impList);
450 static Void local checkImportList(importSpec) /*Import a module unqualified*/
452 Module m = fst(importSpec);
453 Cell impList = snd(importSpec);
455 List imports = NIL; /* entities we want to import */
456 List hidden = NIL; /* entities we want to hide */
458 if (moduleThisScript(m)) {
459 ERRMSG(0) "Module \"%s\" recursively imports itself",
460 textToStr(module(m).text)
463 if (isPair(impList) && HIDDEN == fst(impList)) {
464 /* Somewhat inefficient - but obviously correct:
465 * imports = importsOf("module Foo") `setDifference` hidden;
467 hidden = resolveImportList(m, snd(impList));
468 imports = resolveImportList(m, DOTDOT);
470 imports = resolveImportList(m, impList);
473 for(; nonNull(imports); imports=tl(imports)) {
474 Cell e = hd(imports);
475 if (!cellIsMember(e,hidden))
478 /* ToDo: hang onto the imports list for processing export list entries
479 * of the form "module Foo"
483 static Void local importEntity(source,e)
487 case NAME : importName(source,e);
490 case TYCON : importTycon(source,e);
492 case CLASS : importClass(source,e);
494 default: internal("importEntity");
498 static Void local importName(source,n)
501 Name clash = addName(n);
502 if (nonNull(clash) && clash!=n) {
503 ERRMSG(0) "Entity \"%s\" imported from module \"%s\" already defined in module \"%s\"",
504 textToStr(name(n).text),
505 textToStr(module(source).text),
506 textToStr(module(name(clash).mod).text)
511 static Void local importTycon(source,tc)
514 Tycon clash=addTycon(tc);
515 if (nonNull(clash) && clash!=tc) {
516 ERRMSG(0) "Tycon \"%s\" imported from \"%s\" already defined in module \"%s\"",
517 textToStr(tycon(tc).text),
518 textToStr(module(source).text),
519 textToStr(module(tycon(clash).mod).text)
522 if (nonNull(findClass(tycon(tc).text))) {
523 ERRMSG(0) "Import of type constructor \"%s\" clashes with class in module \"%s\"",
524 textToStr(tycon(tc).text),
525 textToStr(module(tycon(tc).mod).text)
530 static Void local importClass(source,c)
533 Class clash=addClass(c);
534 if (nonNull(clash) && clash!=c) {
535 ERRMSG(0) "Class \"%s\" imported from \"%s\" already defined in module \"%s\"",
536 textToStr(cclass(c).text),
537 textToStr(module(source).text),
538 textToStr(module(cclass(clash).mod).text)
541 if (nonNull(findTycon(cclass(c).text))) {
542 ERRMSG(0) "Import of class \"%s\" clashes with type constructor in module \"%s\"",
543 textToStr(cclass(c).text),
544 textToStr(module(source).text)
549 static List local checkExportTycon(exports,mt,spec,tc)
554 if (DOTDOT == spec || SYNONYM == tycon(tc).what) {
555 return cons(pair(tc,DOTDOT), exports);
557 return cons(pair(tc,NIL), exports);
561 static List local checkExportClass(exports,mt,spec,cl)
566 if (DOTDOT == spec) {
567 return cons(pair(cl,DOTDOT), exports);
569 return cons(pair(cl,NIL), exports);
573 static List local checkExport(exports,mt,e) /* Process entry in export list*/
579 List origExports = exports;
580 if (nonNull(export=findQualName(e))) {
581 exports=cons(export,exports);
583 if (isQCon(e) && nonNull(export=findQualTycon(e))) {
584 exports = checkExportTycon(exports,mt,NIL,export);
586 if (isQCon(e) && nonNull(export=findQualClass(e))) {
587 /* opaque class export */
588 exports = checkExportClass(exports,mt,NIL,export);
590 if (exports == origExports) {
591 ERRMSG(0) "Unknown entity \"%s\" exported from module \"%s\"",
597 } else if (MODULEENT == fst(e)) {
598 Module m = findModid(snd(e));
599 /* ToDo: shouldn't allow export of module we didn't import */
601 ERRMSG(0) "Unknown module \"%s\" exported from module \"%s\"",
602 textToStr(textOf(snd(e))),
606 if (m == currentModule) {
607 /* Exporting the current module exports local definitions */
609 for(xs=module(m).classes; nonNull(xs); xs=tl(xs)) {
610 if (cclass(hd(xs)).mod==m)
611 exports = checkExportClass(exports,mt,DOTDOT,hd(xs));
613 for(xs=module(m).tycons; nonNull(xs); xs=tl(xs)) {
614 if (tycon(hd(xs)).mod==m)
615 exports = checkExportTycon(exports,mt,DOTDOT,hd(xs));
617 for(xs=module(m).names; nonNull(xs); xs=tl(xs)) {
618 if (name(hd(xs)).mod==m)
619 exports = cons(hd(xs),exports);
622 /* Exporting other modules imports all things imported
623 * unqualified from it.
624 * ToDo: we reexport everything exported by a module -
625 * whether we imported it or not. This gives the wrong
626 * result for "module M(module N) where import N(x)"
628 exports = dupOnto(module(m).exports,exports);
632 Cell ident = fst(e); /* class name or type name */
633 Cell parts = snd(e); /* members or constructors */
635 if (isQCon(ident) && nonNull(nm=findQualTycon(ident))) {
636 switch (tycon(nm).what) {
639 ERRMSG(0) "Explicit constructor list given for type synonym"
640 " \"%s\" in export list of module \"%s\"",
645 return cons(pair(nm,DOTDOT),exports);
647 ERRMSG(0) "Transparent export of restricted type synonym"
648 " \"%s\" in export list of module \"%s\"",
652 return exports; /* Not reached */
656 return cons(pair(nm,DOTDOT),exports);
658 exports = checkSubentities(exports,parts,tycon(nm).defn,
659 "constructor of type",
661 return cons(pair(nm,DOTDOT), exports);
664 internal("checkExport1");
666 } else if (isQCon(ident) && nonNull(nm=findQualClass(ident))) {
667 if (DOTDOT == parts) {
668 return cons(pair(nm,DOTDOT),exports);
670 exports = checkSubentities(exports,parts,cclass(nm).members,
671 "member of class",cclass(nm).text);
672 return cons(pair(nm,DOTDOT), exports);
675 ERRMSG(0) "Explicit export list given for non-class/datatype \"%s\" in export list of module \"%s\"",
681 return exports; /* NOTUSED */
684 static List local checkExports(exports)
686 Module m = lastModule();
687 Text mt = module(m).text;
690 map1Accum(checkExport,es,mt,exports);
693 for(xs=es; nonNull(xs); xs=tl(xs)) {
694 Printf(" %s", textToStr(textOfEntity(hd(xs))));
701 /* --------------------------------------------------------------------------
702 * Static analysis of type declarations:
704 * Type declarations come in two forms:
705 * - data declarations - define new constructed data types
706 * - type declarations - define new type synonyms
708 * A certain amount of work is carried out as the declarations are
709 * read during parsing. In particular, for each type constructor
710 * definition encountered:
711 * - check that there is no previous definition of constructor
712 * - ensure type constructor not previously used as a class name
713 * - make a new entry in the type constructor table
714 * - record line number of declaration
715 * - Build separate lists of newly defined constructors for later use.
716 * ------------------------------------------------------------------------*/
718 Void tyconDefn(line,lhs,rhs,what) /* process new type definition */
719 Int line; /* definition line number */
720 Cell lhs; /* left hand side of definition */
721 Cell rhs; /* right hand side of definition */
722 Cell what; { /* SYNONYM/DATATYPE/etc... */
723 Text t = textOf(getHead(lhs));
725 if (nonNull(findTycon(t))) {
726 ERRMSG(line) "Repeated definition of type constructor \"%s\"",
730 else if (nonNull(findClass(t))) {
731 ERRMSG(line) "\"%s\" used as both class and type constructor",
736 Tycon nw = newTycon(t);
737 tyconDefns = cons(nw,tyconDefns);
738 tycon(nw).line = line;
739 tycon(nw).arity = argCount;
740 tycon(nw).what = what;
741 if (what==RESTRICTSYN) {
742 h98DoesntSupport(line,"restricted type synonyms");
743 typeInDefns = cons(pair(nw,snd(rhs)),typeInDefns);
746 tycon(nw).defn = pair(lhs,rhs);
750 Void setTypeIns(bs) /* set local synonyms for given */
751 List bs; { /* binding group */
752 List cvs = typeInDefns;
753 for (; nonNull(cvs); cvs=tl(cvs)) {
754 Tycon c = fst(hd(cvs));
755 List vs = snd(hd(cvs));
756 for (tycon(c).what = RESTRICTSYN; nonNull(vs); vs=tl(vs)) {
757 if (nonNull(findBinding(textOf(hd(vs)),bs))) {
758 tycon(c).what = SYNONYM;
765 Void clearTypeIns() { /* clear list of local synonyms */
766 for (; nonNull(typeInDefns); typeInDefns=tl(typeInDefns))
767 tycon(fst(hd(typeInDefns))).what = RESTRICTSYN;
770 /* --------------------------------------------------------------------------
771 * Further analysis of Type declarations:
773 * In order to allow the definition of mutually recursive families of
774 * data types, the static analysis of the right hand sides of type
775 * declarations cannot be performed until all of the type declarations
778 * Once parsing is complete, we carry out the following:
780 * - check format of lhs, extracting list of bound vars and ensuring that
781 * there are no repeated variables and no Skolem variables.
782 * - run dependency analysis on rhs to check that only bound type vars
783 * appear in type and that all constructors are defined.
784 * Replace type variables by offsets, constructors by Tycons.
785 * - use list of dependents to sort into strongly connected components.
786 * - ensure that there is not more than one synonym in each group.
787 * - kind-check each group of type definitions.
789 * - check that there are no previous definitions for constructor
790 * functions in data type definitions.
791 * - install synonym expansions and constructor definitions.
792 * ------------------------------------------------------------------------*/
794 static List tcDeps = NIL; /* list of dependent tycons/classes*/
796 static Void local checkTyconDefn(d) /* validate type constructor defn */
798 Cell lhs = fst(tycon(d).defn);
799 Cell rhs = snd(tycon(d).defn);
800 Int line = tycon(d).line;
801 List tyvars = getArgs(lhs);
803 /* check for repeated tyvars on lhs*/
804 for (temp=tyvars; nonNull(temp); temp=tl(temp))
805 if (nonNull(varIsMember(textOf(hd(temp)),tl(temp)))) {
806 ERRMSG(line) "Repeated type variable \"%s\" on left hand side",
807 textToStr(textOf(hd(temp)))
811 tcDeps = NIL; /* find dependents */
812 switch (whatIs(tycon(d).what)) {
814 case SYNONYM : rhs = depTypeExp(line,tyvars,rhs);
815 if (cellIsMember(d,tcDeps)) {
816 ERRMSG(line) "Recursive type synonym \"%s\"",
817 textToStr(tycon(d).text)
823 case NEWTYPE : depConstrs(d,tyvars,rhs);
827 default : internal("checkTyconDefn");
832 tycon(d).kind = tcDeps;
836 static Void local depConstrs(t,tyvars,cd)
837 Tycon t; /* Define constructor functions and*/
838 List tyvars; /* do dependency analysis for data */
839 Cell cd; { /* definitions (w or w/o deriving) */
840 Int line = tycon(t).line;
845 List derivs = snd(cd);
846 List compTypes = NIL;
850 for (i=0; i<tycon(t).arity; ++i) /* build representation for tycon */
851 lhs = ap(lhs,mkOffset(i)); /* applied to full comp. of args */
853 if (isQualType(cs)) { /* allow for possible context */
856 map2Over(depPredExp,line,tyvars,ctxt);
857 h98CheckCtxt(line,"context",TRUE,ctxt,NIL);
860 if (nonNull(cs) && isNull(tl(cs))) /* Single constructor datatype? */
863 for (; nonNull(cs); cs=tl(cs)) { /* For each constructor function: */
865 List sig = dupList(tyvars);
866 List evs = NIL; /* locally quantified vars */
867 List lps = NIL; /* locally bound predicates */
868 List ctxt1 = ctxt; /* constructor function context */
869 List scs = NIL; /* strict components */
870 List fs = NONE; /* selector names */
871 Type type = lhs; /* constructor function type */
872 Int arity = 0; /* arity of constructor function */
873 Int nr2 = 0; /* Number of rank 2 args */
874 Name n; /* name for constructor function */
876 if (whatIs(con)==POLYTYPE) { /* Locally quantified vars */
879 sig = checkQuantVars(line,evs,sig,con);
882 if (isQualType(con)) { /* Local predicates */
885 for (us = typeVarsIn(lps,NIL,NIL,NIL); nonNull(us); us=tl(us))
886 if (!varIsMember(textOf(hd(us)),evs)) {
888 "Variable \"%s\" in constraint is not locally bound",
889 textToStr(textOf(hd(us)))
892 map2Over(depPredExp,line,sig,lps);
897 if (whatIs(con)==LABC) { /* Skeletize constr components */
898 Cell fls = snd(snd(con)); /* get field specifications */
901 for (; nonNull(fls); fls=tl(fls)) { /* for each field spec: */
902 List vs = fst(hd(fls));
903 Type t = snd(hd(fls)); /* - scrutinize type */
904 Bool banged = whatIs(t)==BANG;
905 t = depCompType(line,sig,(banged ? arg(t) : t));
906 while (nonNull(vs)) { /* - add named components */
914 scs = cons(mkInt(arity),scs);
918 scs = rev(scs); /* put strict comps in ascend ord */
920 else { /* Non-labelled constructor */
923 for (; isAp(c); c=fun(c))
925 for (compNo=arity, c=con; isAp(c); c=fun(c)) {
927 if (whatIs(t)==BANG) {
928 scs = cons(mkInt(compNo),scs);
932 arg(c) = depCompType(line,sig,t);
936 if (nonNull(ctxt1)) /* Extract relevant part of context*/
937 ctxt1 = selectCtxt(ctxt1,offsetTyvarsIn(con,NIL));
939 for (i=arity; isAp(con); i--) { /* Calculate type of constructor */
942 fun(con) = typeArrow;
943 if (isPolyOrQualType(cmp)) {
944 if (nonNull(derivs)) {
945 ERRMSG(line) "Cannot derive instances for types" ETHEN
946 ERRTEXT " with polymorphic or qualified components"
952 if (nonNull(derivs)) /* and build list of components */
953 compTypes = cons(cmp,compTypes);
958 if (nr2>0) { /* Add rank 2 annotation */
959 type = ap(RANK2,pair(mkInt(nr2-length(lps)),type));
962 if (nonNull(evs)) { /* Add existential annotation */
963 if (nonNull(derivs)) {
964 ERRMSG(line) "Cannot derive instances for types" ETHEN
965 ERRTEXT " with existentially typed components"
970 "Cannot use selectors with existentially typed components"
973 type = ap(EXIST,pair(mkInt(length(evs)),type));
976 if (nonNull(lps)) { /* Add local preds part to type */
977 type = ap(CDICTS,pair(lps,type));
980 if (nonNull(ctxt1)) { /* Add context part to type */
981 type = ap(QUAL,pair(ctxt1,type));
984 if (nonNull(sig)) { /* Add quantifiers to type */
986 for (; nonNull(ts1); ts1=tl(ts1)) {
989 type = mkPolyType(sig,type);
992 n = findName(textOf(con)); /* Allocate constructor fun name */
994 n = newName(textOf(con),NIL);
995 } else if (name(n).defn!=PREDEFINED) {
996 duplicateError(line,name(n).mod,name(n).text,
997 "constructor function");
999 name(n).arity = arity; /* Save constructor fun details */
1000 name(n).line = line;
1002 name(n).number = cfunNo(conNo++);
1003 name(n).type = type;
1004 if (tycon(t).what==NEWTYPE) {
1007 "A newtype constructor cannot have class constraints"
1012 "A newtype constructor must have exactly one argument"
1017 "Illegal strictess annotation for newtype constructor"
1020 name(n).defn = nameId;
1022 implementCfun(n,scs);
1027 sels = addSels(line,n,fs,sels);
1031 if (nonNull(sels)) {
1033 fst(cd) = appendOnto(fst(cd),sels);
1034 selDefns = cons(sels,selDefns);
1037 if (nonNull(derivs)) { /* Generate derived instances */
1038 map3Proc(checkDerive,t,ctxt,compTypes,derivs);
1042 Int userArity(c) /* Find arity for cfun, ignoring */
1043 Name c; { /* CDICTS parameters */
1044 Int a = name(c).arity;
1045 Type t = name(c).type;
1047 if (isPolyType(t)) {
1050 if ((w=whatIs(t))==QUAL) {
1051 w = whatIs(t=snd(snd(t)));
1054 a -= length(fst(snd(t)));
1060 static List local addSels(line,c,fs,ss) /* Add fields to selector list */
1061 Int line; /* line number of constructor */
1062 Name c; /* corresponding constr function */
1063 List fs; /* list of fields (varids) */
1064 List ss; { /* list of existing selectors */
1066 cfunSfuns = cons(pair(c,fs),cfunSfuns);
1067 for (; nonNull(fs); fs=tl(fs), ++sn) {
1069 Text t = textOf(hd(fs));
1071 if (nonNull(varIsMember(t,tl(fs)))) {
1072 ERRMSG(line) "Repeated field name \"%s\" for constructor \"%s\"",
1073 textToStr(t), textToStr(name(c).text)
1077 while (nonNull(ns) && t!=name(hd(ns)).text) {
1082 name(hd(ns)).defn = cons(pair(c,mkInt(sn)),name(hd(ns)).defn);
1084 Name n = findName(t);
1086 ERRMSG(line) "Repeated definition for selector \"%s\"",
1091 name(n).line = line;
1092 name(n).number = SELNAME;
1093 name(n).defn = singleton(pair(c,mkInt(sn)));
1100 static List local selectCtxt(ctxt,vs) /* calculate subset of context */
1107 for (; nonNull(ctxt); ctxt=tl(ctxt)) {
1108 List us = offsetTyvarsIn(hd(ctxt),NIL);
1109 for (; nonNull(us) && cellIsMember(hd(us),vs); us=tl(us)) {
1112 ps = cons(hd(ctxt),ps);
1119 static Void local checkSynonyms(ts) /* Check for mutually recursive */
1120 List ts; { /* synonyms */
1122 for (; nonNull(ts); ts=tl(ts)) { /* build list of all synonyms */
1124 switch (whatIs(tycon(t).what)) {
1126 case RESTRICTSYN : syns = cons(t,syns);
1130 while (nonNull(syns)) { /* then visit each synonym */
1131 syns = visitSyn(NIL,hd(syns),syns);
1135 static List local visitSyn(path,t,syns) /* visit synonym definition to look*/
1136 List path; /* for cycles */
1139 if (cellIsMember(t,path)) { /* every elt in path depends on t */
1140 ERRMSG(tycon(t).line)
1141 "Type synonyms \"%s\" and \"%s\" are mutually recursive",
1142 textToStr(tycon(t).text), textToStr(tycon(hd(path)).text)
1145 List ds = tycon(t).kind;
1147 for (; nonNull(ds); ds=tl(ds)) {
1148 if (cellIsMember(hd(ds),syns)) {
1149 if (isNull(path1)) {
1150 path1 = cons(t,path);
1152 syns = visitSyn(path1,hd(ds),syns);
1156 tycon(t).defn = fullExpand(tycon(t).defn);
1157 return removeCell(t,syns);
1160 /* --------------------------------------------------------------------------
1161 * Expanding out all type synonyms in a type expression:
1162 * ------------------------------------------------------------------------*/
1164 Type fullExpand(t) /* find full expansion of type exp */
1165 Type t; { /* assuming that all relevant */
1166 Cell h = t; /* synonym defns of lower rank have*/
1167 Int n = 0; /* already been fully expanded */
1169 for (args=NIL; isAp(h); h=fun(h), n++) {
1170 args = cons(fullExpand(arg(h)),args);
1172 t = applyToArgs(h,args);
1173 if (isSynonym(h) && n>=tycon(h).arity) {
1174 if (n==tycon(h).arity) {
1175 t = instantiateSyn(tycon(h).defn,t);
1178 while (--n > tycon(h).arity) {
1181 fun(p) = instantiateSyn(tycon(h).defn,fun(p));
1187 static Type local instantiateSyn(t,env) /* instantiate type according using*/
1188 Type t; /* env to determine appropriate */
1189 Type env; { /* values for OFFSET type vars */
1190 switch (whatIs(t)) {
1191 case AP : return ap(instantiateSyn(fun(t),env),
1192 instantiateSyn(arg(t),env));
1194 case OFFSET : return nthArg(offsetOf(t),env);
1200 /* --------------------------------------------------------------------------
1201 * Static analysis of class declarations:
1203 * Performed in a similar manner to that used for type declarations.
1205 * The first part of the static analysis is performed as the declarations
1206 * are read during parsing. The parser ensures that:
1207 * - the class header and all superclass predicates are of the form
1210 * The classDefn() function:
1211 * - ensures that there is no previous definition for class
1212 * - checks that class name has not previously been used as a type constr.
1213 * - make new entry in class table
1214 * - record line number of declaration
1215 * - build list of classes defined in current script for use in later
1216 * stages of static analysis.
1217 * ------------------------------------------------------------------------*/
1219 Void classDefn(line,head,ms,fds) /* process new class definition */
1220 Int line; /* definition line number */
1221 Cell head; /* class header :: ([Supers],Class) */
1222 List ms; /* class definition body */
1223 List fds; { /* functional dependencies */
1224 Text ct = textOf(getHead(snd(head)));
1225 Int arity = argCount;
1227 if (nonNull(findClass(ct))) {
1228 ERRMSG(line) "Repeated definition of class \"%s\"",
1231 } else if (nonNull(findTycon(ct))) {
1232 ERRMSG(line) "\"%s\" used as both class and type constructor",
1236 Class nw = newClass(ct);
1237 cclass(nw).line = line;
1238 cclass(nw).arity = arity;
1239 cclass(nw).head = snd(head);
1240 cclass(nw).supers = fst(head);
1241 cclass(nw).members = ms;
1242 cclass(nw).level = 0;
1243 cclass(nw).fds = fds;
1244 cclass(nw).xfds = NIL;
1245 classDefns = cons(nw,classDefns);
1247 h98DoesntSupport(line,"multiple parameter classes");
1251 /* --------------------------------------------------------------------------
1252 * Further analysis of class declarations:
1254 * Full static analysis of class definitions must be postponed until the
1255 * complete script has been read and all static analysis on type definitions
1256 * has been completed.
1258 * Once this has been achieved, we carry out the following checks on each
1260 * - check that variables in header are distinct
1261 * - replace head by skeleton
1262 * - check superclass declarations, replace by skeletons
1263 * - split body of class into members and declarations
1264 * - make new name entry for each member function
1265 * - record member function number (eventually an offset into dictionary!)
1266 * - no member function has a previous definition ...
1267 * - no member function is mentioned more than once in the list of members
1268 * - each member function type is valid, replace vars by offsets
1269 * - qualify each member function type by class header
1270 * - only bindings for members appear in defaults
1271 * - only function bindings appear in defaults
1272 * - check that extended class hierarchy does not contain any cycles
1273 * ------------------------------------------------------------------------*/
1275 static Void local checkClassDefn(c) /* validate class definition */
1278 Int args = cclass(c).arity - 1;
1279 Cell temp = cclass(c).head;
1283 for (; isAp(temp); temp=fun(temp)) {
1284 if (!isVar(arg(temp))) {
1285 ERRMSG(cclass(c).line) "Type variable required in class head"
1288 if (nonNull(varIsMember(textOf(arg(temp)),tyvars))) {
1289 ERRMSG(cclass(c).line)
1290 "Repeated type variable \"%s\" in class head",
1291 textToStr(textOf(arg(temp)))
1294 tyvars = cons(arg(temp),tyvars);
1297 for (fs=cclass(c).fds; nonNull(fs); fs=tl(fs)) {
1301 /* Check for trivial dependency
1304 ERRMSG(cclass(c).line) "Functional dependency is trivial"
1308 /* Check for duplicated vars on right hand side, and for vars on
1309 * right that also appear on the left:
1311 for (vs=snd(fd); nonNull(vs); vs=tl(vs)) {
1312 if (varIsMember(textOf(hd(vs)),fst(fd))) {
1313 ERRMSG(cclass(c).line)
1314 "Trivial dependency for variable \"%s\"",
1315 textToStr(textOf(hd(vs)))
1318 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1319 ERRMSG(cclass(c).line)
1320 "Repeated variable \"%s\" in functional dependency",
1321 textToStr(textOf(hd(vs)))
1324 hd(vs) = depTypeVar(cclass(c).line,tyvars,textOf(hd(vs)));
1327 /* Check for duplicated vars on left hand side:
1329 for (vs=fst(fd); nonNull(vs); vs=tl(vs)) {
1330 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1331 ERRMSG(cclass(c).line)
1332 "Repeated variable \"%s\" in functional dependency",
1333 textToStr(textOf(hd(vs)))
1336 hd(vs) = depTypeVar(cclass(c).line,tyvars,textOf(hd(vs)));
1340 if (cclass(c).arity==0) {
1343 Int args = cclass(c).arity - 1;
1344 for (temp=cclass(c).head; args>0; temp=fun(temp), args--) {
1345 arg(temp) = mkOffset(args);
1347 arg(temp) = mkOffset(0);
1351 tcDeps = NIL; /* find dependents */
1352 map2Over(depPredExp,cclass(c).line,tyvars,cclass(c).supers);
1353 h98CheckCtxt(cclass(c).line,"class definition",FALSE,cclass(c).supers,NIL);
1354 cclass(c).numSupers = length(cclass(c).supers);
1355 cclass(c).defaults = extractBindings(cclass(c).members); /* defaults*/
1356 ss = extractSigdecls(cclass(c).members);
1357 fs = extractFixdecls(cclass(c).members);
1358 cclass(c).members = pair(ss,fs);
1359 map2Proc(checkMems,c,tyvars,ss);
1361 cclass(c).kinds = tcDeps;
1366 /* --------------------------------------------------------------------------
1367 * Functional dependencies are inherited from superclasses.
1368 * For example, if I've got the following classes:
1370 * class C a b | a -> b
1371 * class C [b] a => D a b
1373 * then C will have the dependency ([a], [b]) as expected, and D will inherit
1374 * the dependency ([b], [a]) from C.
1375 * When doing pairwise improvement, we have to consider not just improving
1376 * when we see a pair of Cs or a pair of Ds in the context, but when we've
1377 * got a C and a D as well. In this case, we only improve when the
1378 * predicate in question matches the type skeleton in the relevant superclass
1379 * constraint. E.g., we improve the pair (C [Int] a, D b Int) (unifying
1380 * a and b), but we don't improve the pair (C Int a, D b Int).
1381 * To implement functional dependency inheritance, we calculate
1382 * the closure of all functional dependencies, and store the result
1383 * in an additional field `xfds' (extended functional dependencies).
1384 * The `xfds' field is a list of functional dependency lists, annotated
1385 * with a list of predicate skeletons constraining when improvement can
1386 * happen against this dependency list. For example, the xfds field
1387 * for C above would be:
1388 * [([C a b], [([a], [b])])]
1389 * and the xfds field for D would be:
1390 * [([C [b] a, D a b], [([b], [a])])]
1391 * Self-improvement (of a C with a C, or a D with a D) is treated as a
1392 * special case of an inherited dependency.
1393 * ------------------------------------------------------------------------*/
1394 static List local inheritFundeps ( Class c, Cell pi, Int o )
1396 Int alpha = newKindedVars(cclass(c).kinds);
1397 List scs = cclass(c).supers;
1400 /* better not fail ;-) */
1401 if (!matchPred(pi,o,cclass(c).head,alpha))
1402 internal("inheritFundeps - predicate failed to match it's own head!");
1403 this = copyPred(pi,o);
1404 for (; nonNull(scs); scs=tl(scs)) {
1405 Class s = getHead(hd(scs));
1407 List sfds = inheritFundeps(s,hd(scs),alpha);
1408 for (; nonNull(sfds); sfds=tl(sfds)) {
1410 xfds = cons(pair(cons(this,fst(h)),snd(h)),xfds);
1414 if (nonNull(cclass(c).fds)) {
1415 List fds = NIL, fs = cclass(c).fds;
1416 for (; nonNull(fs); fs=tl(fs)) {
1417 fds = cons(pair(otvars(this,fst(hd(fs))),
1418 otvars(this,snd(hd(fs)))),fds);
1420 xfds = cons(pair(cons(this,NIL),fds),xfds);
1425 static Void local extendFundeps ( Class c )
1428 emptySubstitution();
1429 alpha = newKindedVars(cclass(c).kinds);
1430 cclass(c).xfds = inheritFundeps(c,cclass(c).head,alpha);
1432 /* we can now check for ambiguity */
1433 map1Proc(checkMems2,c,fst(cclass(c).members));
1437 static Cell local depPredExp(line,tyvars,pred)
1444 for (; isAp(h); args++) {
1445 arg(h) = depTypeExp(line,tyvars,arg(h));
1451 h98DoesntSupport(line,"tag classes");
1452 } else if (args!=1) {
1453 h98DoesntSupport(line,"multiple parameter classes");
1456 if (isQCon(h)) { /* standard class constraint */
1457 Class c = findQualClass(h);
1459 ERRMSG(line) "Undefined class \"%s\"", identToStr(h)
1467 if (args!=cclass(c).arity) {
1468 ERRMSG(line) "Wrong number of arguments for class \"%s\"",
1469 textToStr(cclass(c).text)
1472 if (cellIsMember(c,classDefns) && !cellIsMember(c,tcDeps)) {
1473 tcDeps = cons(c,tcDeps);
1477 else if (isExt(h)) { /* Lacks predicate */
1478 if (args!=1) { /* parser shouldn't let this happen*/
1479 ERRMSG(line) "Wrong number of arguments for lacks predicate"
1486 if (whatIs(h) != IPCELL)
1489 internal("depPredExp");
1494 static Void local checkMems(c,tyvars,m) /* check member function details */
1498 Int line = intOf(fst3(m));
1505 if (isPolyType(t)) {
1511 tyvars = typeVarsIn(t,NIL,xtvs,tyvars);
1512 /* Look for extra type vars. */
1513 checkOptQuantVars(line,xtvs,tyvars);
1515 if (isQualType(t)) { /* Overloaded member signatures? */
1516 map2Over(depPredExp,line,tyvars,fst(snd(t)));
1518 t = ap(QUAL,pair(NIL,t));
1521 fst(snd(t)) = cons(cclass(c).head,fst(snd(t)));/* Add main predicate */
1522 snd(snd(t)) = depTopType(line,tyvars,snd(snd(t)));
1524 for (tvs=tyvars; nonNull(tvs); tvs=tl(tvs)){/* Quantify */
1528 t = mkPolyType(sig,t);
1530 thd3(m) = t; /* Save type */
1531 take(cclass(c).arity,tyvars); /* Delete extra type vars */
1533 if (isAmbiguous(t)) {
1534 ambigError(line,"class declaration",hd(vs),t);
1536 h98CheckType(line,"member type",hd(vs),t);
1539 static Void local checkMems2(c,m) /* check member function details */
1542 Int line = intOf(fst3(m));
1547 static Void local addMembers(c) /* Add definitions of member funs */
1548 Class c; { /* and other parts of class struct.*/
1549 List ms = fst(cclass(c).members);
1550 List fs = snd(cclass(c).members);
1551 List ns = NIL; /* List of names */
1552 Int mno; /* Member function number */
1554 for (mno=0; mno<cclass(c).numSupers; mno++) {
1555 ns = cons(newDSel(c,mno),ns);
1557 cclass(c).dsels = rev(ns); /* Save dictionary selectors */
1559 for (mno=1, ns=NIL; nonNull(ms); ms=tl(ms)) {
1560 Int line = intOf(fst3(hd(ms)));
1561 List vs = rev(snd3(hd(ms)));
1562 Type t = thd3(hd(ms));
1563 for (; nonNull(vs); vs=tl(vs)) {
1564 ns = cons(newMember(line,mno++,hd(vs),t,c),ns);
1567 cclass(c).members = rev(ns); /* Save list of members */
1568 cclass(c).numMembers = length(cclass(c).members);
1570 for (; nonNull(fs); fs=tl(fs)) { /* fixity declarations */
1571 Int line = intOf(fst3(hd(fs)));
1572 List ops = snd3(hd(fs));
1573 Syntax s = intOf(thd3(hd(fs)));
1574 for (; nonNull(ops); ops=tl(ops)) {
1575 Name n = nameIsMember(textOf(hd(ops)),cclass(c).members);
1577 missFixity(line,textOf(hd(ops)));
1578 } else if (name(n).syntax!=NO_SYNTAX) {
1579 dupFixity(line,textOf(hd(ops)));
1585 /* Not actually needed just yet; for the time being, dictionary code will
1586 not be passed through the type checker.
1588 cclass(c).dtycon = addPrimTycon(generateText("Dict.%s",c),
1595 mno = cclass(c).numSupers + cclass(c).numMembers;
1596 /* cclass(c).dcon = addPrimCfun(generateText("Make.%s",c),mno,0,NIL); */
1597 cclass(c).dcon = addPrimCfun(generateText(":D%s",c),mno,0,NIL);
1598 /* implementCfun(cclass(c).dcon,NIL);
1599 Don't manufacture a wrapper fn for dictionary constructors.
1600 Applications of dictionary constructors are always saturated,
1601 and translate.c:stgExpr() special-cases saturated constructor apps.
1604 if (mno==1) { /* Single entry dicts use newtype */
1605 name(cclass(c).dcon).defn = nameId;
1606 if (nonNull(cclass(c).members)) {
1607 name(hd(cclass(c).members)).number = mfunNo(0);
1610 cclass(c).defaults = classBindings("class",c,cclass(c).defaults);
1613 static Name local newMember(l,no,v,t,parent)
1614 Int l; /* Make definition for member fn */
1619 Name m = findName(textOf(v));
1622 m = newName(textOf(v),parent);
1623 } else if (name(m).defn!=PREDEFINED) {
1624 ERRMSG(l) "Repeated definition for member function \"%s\"",
1625 textToStr(name(m).text)
1631 name(m).number = mfunNo(no);
1636 Name newDSel(c,no) /* Make definition for dict selectr*/
1642 /* sprintf(buf,"sc%d.%s",no,"%s"); */
1643 sprintf(buf,"$p%d%s",no+1,"%s");
1644 s = newName(generateText(buf,c),c);
1645 name(s).line = cclass(c).line;
1647 name(s).number = DFUNNAME;
1653 static Text local generateText(sk,c) /* We need to generate names for */
1654 String sk; /* certain objects corresponding */
1655 Class c; { /* to each class. */
1656 String cname = textToStr(cclass(c).text);
1657 char buffer[MAX_GEN+1];
1659 if ((strlen(sk)+strlen(cname))>=MAX_GEN) {
1660 ERRMSG(0) "Please use a shorter name for class \"%s\"", cname
1663 sprintf(buffer,sk,cname);
1664 return findText(buffer);
1667 Int visitClass(c) /* visit class defn to check that */
1668 Class c; { /* class hierarchy is acyclic */
1670 if (isExt(c)) { /* special case for lacks preds */
1674 if (cclass(c).level < 0) { /* already visiting this class? */
1675 ERRMSG(cclass(c).line) "Class hierarchy for \"%s\" is not acyclic",
1676 textToStr(cclass(c).text)
1678 } else if (cclass(c).level == 0) { /* visiting class for first time */
1679 List scs = cclass(c).supers;
1681 cclass(c).level = (-1);
1682 for (; nonNull(scs); scs=tl(scs)) {
1683 Int l = visitClass(getHead(hd(scs)));
1686 cclass(c).level = 1+lev; /* level = 1 + max level of supers */
1688 return cclass(c).level;
1691 /* --------------------------------------------------------------------------
1692 * Process class and instance declaration binding groups:
1693 * ------------------------------------------------------------------------*/
1695 static List local classBindings(where,c,bs)
1696 String where; /* Check validity of bindings bs */
1697 Class c; /* for class c (or an inst of c) */
1698 List bs; { /* sort into approp. member order */
1701 for (; nonNull(bs); bs=tl(bs)) {
1703 Cell body = snd(snd(b));
1706 if (!isVar(fst(b))) { /* Only allow function bindings */
1707 ERRMSG(rhsLine(snd(body)))
1708 "Pattern binding illegal in %s declaration", where
1712 if (isNull(mnm=memberName(c,textOf(fst(b))))) {
1713 ERRMSG(rhsLine(snd(hd(body))))
1714 "No member \"%s\" in class \"%s\"",
1715 textToStr(textOf(fst(b))), textToStr(cclass(c).text)
1719 nbs = numInsert(mfunOf(mnm)-1,b,nbs);
1724 static Name local memberName(c,t) /* return name of member function */
1725 Class c; /* with name t in class c */
1726 Text t; { /* return NIL if not a member */
1727 List ms = cclass(c).members;
1728 for (; nonNull(ms); ms=tl(ms)) {
1729 if (t==name(hd(ms)).text) {
1736 static List local numInsert(n,x,xs) /* insert x at nth position in xs, */
1737 Int n; /* filling gaps with NIL */
1740 List start = isNull(xs) ? cons(NIL,NIL) : xs;
1742 for (xs=start; 0<n--; xs=tl(xs)) {
1743 if (isNull(tl(xs))) {
1744 tl(xs) = cons(NIL,NIL);
1751 /* --------------------------------------------------------------------------
1752 * Calculate set of variables appearing in a given type expression (possibly
1753 * qualified) as a list of distinct values. The order in which variables
1754 * appear in the list is the same as the order in which those variables
1755 * occur in the type expression when read from left to right.
1756 * ------------------------------------------------------------------------*/
1758 List local typeVarsIn(ty,us,ws,vs) /*Calculate list of type variables*/
1759 Cell ty; /* used in type expression, reading*/
1760 List us; /* from left to right ignoring any */
1761 List ws; /* listed in us. */
1762 List vs; { /* ws = explicitly quantified vars */
1763 if (isNull(ty)) return vs;
1764 switch (whatIs(ty)) {
1765 case DICTAP : return typeVarsIn(snd(snd(ty)),us,ws,vs);
1766 case UNBOXEDTUP: return typeVarsIn(snd(ty),us,ws,vs);
1768 case AP : return typeVarsIn(snd(ty),us,ws,
1769 typeVarsIn(fst(ty),us,ws,vs));
1772 case VAROPCELL : if ((nonNull(findBtyvs(textOf(ty)))
1773 && !varIsMember(textOf(ty),ws))
1774 || varIsMember(textOf(ty),us)) {
1777 return maybeAppendVar(ty,vs);
1780 case POLYTYPE : return typeVarsIn(monotypeOf(ty),polySigOf(ty),ws,vs);
1782 case QUAL : { vs = typeVarsIn(fst(snd(ty)),us,ws,vs);
1783 return typeVarsIn(snd(snd(ty)),us,ws,vs);
1786 case BANG : return typeVarsIn(snd(ty),us,ws,vs);
1788 case LABC : { List fs = snd(snd(ty));
1789 for (; nonNull(fs); fs=tl(fs)) {
1790 vs = typeVarsIn(snd(hd(fs)),us,ws,vs);
1797 case QUALIDENT: return vs;
1799 default: fprintf(stderr, " bad tag = %d\n", whatIs(ty));internal("typeVarsIn");
1804 static List local maybeAppendVar(v,vs) /* append variable to list if not */
1805 Cell v; /* already included */
1811 while (nonNull(c)) {
1812 if (textOf(hd(c))==t) {
1820 tl(p) = cons(v,NIL);
1828 /* --------------------------------------------------------------------------
1829 * Static analysis for type expressions is required to:
1830 * - ensure that each type constructor or class used has been defined.
1831 * - replace type variables by offsets, constructor names by Tycons.
1832 * - ensure that the type is well-kinded.
1833 * ------------------------------------------------------------------------*/
1835 static Type local checkSigType(line,where,e,type)
1836 Int line; /* Check validity of type expr in */
1837 String where; /* explicit type signature */
1844 if (isPolyType(type)) {
1845 xtvs = fst(snd(type));
1846 type = monotypeOf(type);
1848 tvs = typeVarsIn(type,NIL,xtvs,NIL);
1850 checkOptQuantVars(line,xtvs,tvs);
1852 if (isQualType(type)) {
1853 map2Over(depPredExp,line,tvs,fst(snd(type)));
1854 snd(snd(type)) = depTopType(line,tvs,snd(snd(type)));
1856 if (isAmbiguous(type)) {
1857 ambigError(line,where,e,type);
1860 type = depTopType(line,tvs,type);
1864 if (length(tvs)>=NUM_OFFSETS) {
1865 ERRMSG(line) "Too many type variables in %s\n", where
1869 for (; nonNull(ts); ts=tl(ts)) {
1872 type = mkPolyType(tvs,type);
1877 kindType(line,"type expression",type);
1881 h98CheckType(line,where,e,type);
1885 static Void local checkOptQuantVars(line,xtvs,tvs)
1887 List xtvs; /* Explicitly quantified vars */
1888 List tvs; { /* Implicitly quantified vars */
1889 if (nonNull(xtvs)) {
1891 for (; nonNull(vs); vs=tl(vs)) {
1892 if (!varIsMember(textOf(hd(vs)),xtvs)) {
1893 ERRMSG(line) "Quantifier does not mention type variable \"%s\"",
1894 textToStr(textOf(hd(vs)))
1898 for (vs=xtvs; nonNull(vs); vs=tl(vs)) {
1899 if (!varIsMember(textOf(hd(vs)),tvs)) {
1900 ERRMSG(line) "Quantified type variable \"%s\" is not used",
1901 textToStr(textOf(hd(vs)))
1904 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1905 ERRMSG(line) "Quantified type variable \"%s\" is repeated",
1906 textToStr(textOf(hd(vs)))
1913 static Type local depTopType(l,tvs,t) /* Check top-level of type sig */
1921 for (; getHead(t1)==typeArrow && argCount==2; ++i) {
1922 arg(fun(t1)) = depCompType(l,tvs,arg(fun(t1)));
1923 if (isPolyOrQualType(arg(fun(t1)))) {
1929 if (nonNull(prev)) {
1930 arg(prev) = depTypeExp(l,tvs,t1);
1932 t = depTypeExp(l,tvs,t1);
1935 t = ap(RANK2,pair(mkInt(nr2),t));
1940 static Type local depCompType(l,tvs,t) /* Check component type for constr */
1944 Int ntvs = length(tvs);
1946 if (isPolyType(t)) {
1947 List vs = fst(snd(t));
1949 tvs = checkQuantVars(l,vs,tvs,t);
1950 nfr = replicate(length(vs),NIL);
1952 if (isQualType(t)) {
1953 map2Over(depPredExp,l,tvs,fst(snd(t)));
1954 snd(snd(t)) = depTypeExp(l,tvs,snd(snd(t)));
1955 if (isAmbiguous(t)) {
1956 ambigError(l,"type component",NIL,t);
1959 t = depTypeExp(l,tvs,t);
1965 return mkPolyType(nfr,t);
1968 static Type local depTypeExp(line,tyvars,type)
1972 switch (whatIs(type)) {
1973 case AP : fst(type) = depTypeExp(line,tyvars,fst(type));
1974 snd(type) = depTypeExp(line,tyvars,snd(type));
1977 case VARIDCELL : return depTypeVar(line,tyvars,textOf(type));
1979 case QUALIDENT : if (isQVar(type)) {
1980 ERRMSG(line) "Qualified type variables not allowed"
1983 /* deliberate fall through */
1984 case CONIDCELL : { Tycon tc = findQualTycon(type);
1987 "Undefined type constructor \"%s\"",
1991 if (cellIsMember(tc,tyconDefns) &&
1992 !cellIsMember(tc,tcDeps)) {
1993 tcDeps = cons(tc,tcDeps);
1999 case EXT : h98DoesntSupport(line,"extensible records");
2004 default : internal("depTypeExp");
2009 static Type local depTypeVar(line,tyvars,tv)
2016 for (; nonNull(tyvars); offset++) {
2017 if (tv==textOf(hd(tyvars))) {
2020 tyvars = tl(tyvars);
2023 Cell vt = findBtyvs(tv);
2027 ERRMSG(line) "Undefined type variable \"%s\"", textToStr(tv)
2030 return mkOffset(found);
2033 static List local checkQuantVars(line,vs,tvs,body)
2035 List vs; /* variables to quantify over */
2036 List tvs; /* variables already in scope */
2037 Cell body; { /* type/constr for scope of vars */
2039 List bvs = typeVarsIn(body,NIL,NIL,NIL);
2041 for (; nonNull(us); us=tl(us)) {
2042 Text u = textOf(hd(us));
2043 if (varIsMember(u,tl(us))) {
2044 ERRMSG(line) "Duplicated quantified variable %s",
2049 if (varIsMember(u,tvs)) {
2050 ERRMSG(line) "Local quantifier for %s hides an outer use",
2055 if (!varIsMember(u,bvs)) {
2056 ERRMSG(line) "Locally quantified variable %s is not used",
2061 tvs = appendOnto(tvs,vs);
2066 /* --------------------------------------------------------------------------
2067 * Check for ambiguous types:
2068 * A type Preds => type is ambiguous if not (TV(P) `subset` TV(type))
2069 * ------------------------------------------------------------------------*/
2071 List offsetTyvarsIn(t,vs) /* add list of offset tyvars in t */
2072 Type t; /* to list vs */
2074 switch (whatIs(t)) {
2075 case AP : return offsetTyvarsIn(fun(t),
2076 offsetTyvarsIn(arg(t),vs));
2078 case OFFSET : if (cellIsMember(t,vs))
2083 case QUAL : return offsetTyvarsIn(snd(t),vs);
2085 case POLYTYPE : return offsetTyvarsIn(monotypeOf(t),vs);
2086 /* slightly inaccurate, but won't matter here */
2089 case RANK2 : return offsetTyvarsIn(snd(snd(t)),vs);
2091 default : return vs;
2095 List zonkTyvarsIn(t,vs)
2098 switch (whatIs(t)) {
2099 case AP : return zonkTyvarsIn(fun(t),
2100 zonkTyvarsIn(arg(t),vs));
2102 case INTCELL : if (cellIsMember(t,vs))
2107 /* this case will lead to a type error --
2108 much better than reporting an internal error ;-) */
2109 /* case OFFSET : internal("zonkTyvarsIn"); */
2111 default : return vs;
2115 static List local otvars(pi,os) /* os is a list of offsets that */
2116 Cell pi; /* refer to the arguments of pi; */
2117 List os; { /* find list of offsets in those */
2118 List us = NIL; /* positions */
2119 for (; nonNull(os); os=tl(os)) {
2120 us = offsetTyvarsIn(nthArg(offsetOf(hd(os)),pi),us);
2125 static List local otvarsZonk(pi,os,o) /* same as above, but zonks */
2129 for (; nonNull(os); os=tl(os)) {
2130 Type t = zonkType(nthArg(offsetOf(hd(os)),pi),o);
2131 us = zonkTyvarsIn(t,us);
2136 static Bool local odiff(us,vs)
2138 while (nonNull(us) && cellIsMember(hd(us),vs)) {
2144 static Bool local osubset(us,vs) /* Determine whether us is subset */
2145 List us, vs; { /* of vs */
2146 while (nonNull(us) && cellIsMember(hd(us),vs)) {
2152 List oclose(fds,vs) /* Compute closure of vs wrt to fds*/
2155 Bool changed = TRUE;
2159 while (nonNull(fds)) {
2161 List next = tl(fds);
2162 if (osubset(fst(fd),vs)) { /* Test if fd applies */
2164 for (; nonNull(os); os=tl(os)) {
2165 if (!cellIsMember(hd(os),vs)) {
2166 vs = cons(hd(os),vs);
2170 } else { /* Didn't apply this time, so keep */
2181 Bool isAmbiguous(type) /* Determine whether type is */
2182 Type type; { /* ambiguous */
2183 if (isPolyType(type)) {
2184 type = monotypeOf(type);
2186 if (isQualType(type)) { /* only qualified types can be */
2187 List ps = fst(snd(type)); /* ambiguous */
2188 List tvps = offsetTyvarsIn(ps,NIL);
2189 List tvts = offsetTyvarsIn(snd(snd(type)),NIL);
2190 List fds = calcFunDeps(ps);
2192 tvts = oclose(fds,tvts); /* Close tvts under fds */
2193 return !osubset(tvps,tvts);
2198 List calcFunDeps(ps)
2201 for (; nonNull(ps); ps=tl(ps)) {/* Calc functional dependencies */
2203 Cell c = getHead(pi);
2205 List xfs = cclass(c).xfds;
2206 for (; nonNull(xfs); xfs=tl(xfs)) {
2207 List fs = snd(hd(xfs));
2208 for (; nonNull(fs); fs=tl(fs)) {
2209 fds = cons(pair(otvars(pi,fst(hd(fs))),
2210 otvars(pi,snd(hd(fs)))),fds);
2216 fds = cons(pair(NIL,offsetTyvarsIn(arg(pi),NIL)),fds);
2223 List calcFunDepsPreds(ps)
2226 for (; nonNull(ps); ps=tl(ps)) {/* Calc functional dependencies */
2228 Cell pi = fst3(pi3);
2229 Cell c = getHead(pi);
2230 Int o = intOf(snd3(pi3));
2232 List xfs = cclass(c).xfds;
2233 for (; nonNull(xfs); xfs=tl(xfs)) {
2234 List fs = snd(hd(xfs));
2235 for (; nonNull(fs); fs=tl(fs)) {
2236 fds = cons(pair(otvarsZonk(pi,fst(hd(fs)),o),
2237 otvarsZonk(pi,snd(hd(fs)),o)),fds);
2243 fds = cons(pair(NIL,zonkTyvarsIn(arg(pi),NIL)),fds);
2250 Void ambigError(line,where,e,type) /* produce error message for */
2251 Int line; /* ambiguity */
2255 ERRMSG(line) "Ambiguous type signature in %s", where ETHEN
2256 ERRTEXT "\n*** ambiguous type : " ETHEN ERRTYPE(type);
2258 ERRTEXT "\n*** assigned to : " ETHEN ERREXPR(e);
2264 /* --------------------------------------------------------------------------
2265 * Kind inference for simple types:
2266 * ------------------------------------------------------------------------*/
2268 static Void local kindConstr(line,alpha,m,c)
2269 Int line; /* Determine kind of constructor */
2273 Cell h = getHead(c);
2277 Printf("kindConstr: alpha=%d, m=%d, c=",alpha,m);
2278 printType(stdout,c);
2282 switch (whatIs(h)) {
2283 case POLYTYPE : if (n!=0) {
2284 internal("kindConstr1");
2286 static String pt = "polymorphic type";
2287 Type t = dropRank1(c,alpha,m);
2288 Kinds ks = polySigOf(t);
2291 for (; isAp(ks); ks=tl(ks)) {
2294 beta = newKindvars(m1);
2295 unkindTypes = cons(pair(mkInt(beta),t),unkindTypes);
2296 checkKind(line,beta,m1,monotypeOf(t),NIL,pt,STAR,0);
2301 case QUAL : if (n!=0) {
2302 internal("kindConstr2");
2304 map3Proc(kindPred,line,alpha,m,fst(snd(c)));
2305 kindConstr(line,alpha,m,snd(snd(c)));
2309 case RANK2 : kindConstr(line,alpha,m,snd(snd(c)));
2313 case EXT : if (n!=2) {
2315 "Illegal use of row in " ETHEN ERRTYPE(c);
2322 case TYCON : if (isSynonym(h) && n<tycon(h).arity) {
2324 "Not enough arguments for type synonym \"%s\"",
2325 textToStr(tycon(h).text)
2331 if (n==0) { /* trivial case, no arguments */
2332 typeIs = kindAtom(alpha,c);
2333 } else { /* non-trivial application */
2334 static String app = "constructor application";
2344 typeIs = kindAtom(alpha,h); /* h :: v1 -> ... -> vn -> w */
2345 shouldKind(line,h,c,app,k,beta);
2347 for (i=n; i>0; --i) { /* ci :: vi for each 1 <- 1..n */
2348 checkKind(line,alpha,m,arg(a),c,app,aVar,beta+i-1);
2351 tyvarType(beta+n); /* inferred kind is w */
2355 static Kind local kindAtom(alpha,c) /* Find kind of atomic constructor */
2358 switch (whatIs(c)) {
2359 case TUPLE : return simpleKind(tupleOf(c)); /*(,)::* -> * -> * */
2360 case OFFSET : return mkInt(alpha+offsetOf(c));
2361 case TYCON : return tycon(c).kind;
2362 case INTCELL : return c;
2364 case VAROPCELL : { Cell vt = findBtyvs(textOf(c));
2370 case EXT : return extKind;
2374 Printf("kindAtom(%d,whatIs(%d)) on ",alpha,whatIs(c));
2375 printType(stdout,c);
2378 internal("kindAtom");
2379 return STAR;/* not reached */
2382 static Void local kindPred(l,alpha,m,pi)/* Check kinds of arguments in pred*/
2388 if (isAp(pi) && isExt(fun(pi))) {
2389 static String lackspred = "lacks predicate";
2390 checkKind(l,alpha,m,arg(pi),NIL,lackspred,ROW,0);
2395 if (isAp(pi) && whatIs(fun(pi)) == IPCELL) {
2396 static String ippred = "iparam predicate";
2397 checkKind(l,alpha,m,arg(pi),NIL,ippred,STAR,0);
2401 { static String predicate = "class constraint";
2402 Class c = getHead(pi);
2403 List as = getArgs(pi);
2404 Kinds ks = cclass(c).kinds;
2406 while (nonNull(ks)) {
2407 checkKind(l,alpha,m,hd(as),NIL,predicate,hd(ks),0);
2414 static Void local kindType(line,wh,type)/* check that (poss qualified) type*/
2415 Int line; /* is well-kinded */
2418 checkKind(line,0,0,type,NIL,wh,STAR,0);
2421 static Void local fixKinds() { /* add kind annotations to types */
2422 for (; nonNull(unkindTypes); unkindTypes=tl(unkindTypes)) {
2423 Pair pr = hd(unkindTypes);
2424 Int beta = intOf(fst(pr));
2425 Cell qts = polySigOf(snd(pr));
2427 if (isNull(hd(qts))) {
2428 hd(qts) = copyKindvar(beta++);
2430 internal("fixKinds");
2432 if (nonNull(tl(qts))) {
2440 Printf("Type expression: ");
2441 printType(stdout,snd(pr));
2443 printKind(stdout,polySigOf(snd(pr)));
2449 /* --------------------------------------------------------------------------
2450 * Kind checking of groups of type constructors and classes:
2451 * ------------------------------------------------------------------------*/
2453 static Void local kindTCGroup(tcs) /* find kinds for mutually rec. gp */
2454 List tcs; { /* of tycons and classes */
2455 emptySubstitution();
2457 mapProc(initTCKind,tcs);
2458 mapProc(kindTC,tcs);
2461 emptySubstitution();
2464 static Void local initTCKind(c) /* build initial kind/arity for c */
2466 if (isTycon(c)) { /* Initial kind of tycon is: */
2467 Int beta = newKindvars(1); /* v1 -> ... -> vn -> vn+1 */
2468 varKind(tycon(c).arity); /* where n is the arity of c. */
2469 bindTv(beta,typeIs,typeOff); /* For data definitions, vn+1 == * */
2470 switch (whatIs(tycon(c).what)) {
2472 case DATATYPE : bindTv(typeOff+tycon(c).arity,STAR,0);
2474 tycon(c).kind = mkInt(beta);
2476 Int n = cclass(c).arity;
2477 Int beta = newKindvars(n);
2478 cclass(c).kinds = NIL;
2481 cclass(c).kinds = pair(mkInt(beta+n),cclass(c).kinds);
2486 static Void local kindTC(c) /* check each part of a tycon/class*/
2487 Cell c; { /* is well-kinded */
2489 static String cfun = "constructor function";
2490 static String tsyn = "synonym definition";
2491 Int line = tycon(c).line;
2492 Int beta = tyvar(intOf(tycon(c).kind))->offs;
2493 Int m = tycon(c).arity;
2494 switch (whatIs(tycon(c).what)) {
2496 case DATATYPE : { List cs = tycon(c).defn;
2497 if (isQualType(cs)) {
2498 map3Proc(kindPred,line,beta,m,
2500 tycon(c).defn = cs = snd(snd(cs));
2502 for (; hasCfun(cs); cs=tl(cs)) {
2503 kindType(line,cfun,name(hd(cs)).type);
2508 default : checkKind(line,beta,m,tycon(c).defn,NIL,
2512 else { /* scan type exprs in class defn to*/
2513 List ms = fst(cclass(c).members);
2514 Int m = cclass(c).arity; /* determine the class signature */
2515 Int beta = newKindvars(m);
2516 kindPred(cclass(c).line,beta,m,cclass(c).head);
2517 map3Proc(kindPred,cclass(c).line,beta,m,cclass(c).supers);
2518 for (; nonNull(ms); ms=tl(ms)) {
2519 Int line = intOf(fst3(hd(ms)));
2520 Type type = thd3(hd(ms));
2521 kindType(line,"member function type signature",type);
2526 static Void local genTC(c) /* generalise kind inferred for */
2527 Cell c; { /* given tycon/class */
2529 tycon(c).kind = copyKindvar(intOf(tycon(c).kind));
2531 Printf("%s :: ",textToStr(tycon(c).text));
2532 printKind(stdout,tycon(c).kind);
2536 Kinds ks = cclass(c).kinds;
2537 for (; nonNull(ks); ks=tl(ks)) {
2538 hd(ks) = copyKindvar(intOf(hd(ks)));
2541 Printf("%s :: ",textToStr(cclass(c).text));
2542 printKinds(stdout,cclass(c).kinds);
2548 /* --------------------------------------------------------------------------
2549 * Static analysis of instance declarations:
2551 * The first part of the static analysis is performed as the declarations
2552 * are read during parsing:
2553 * - make new entry in instance table
2554 * - record line number of declaration
2555 * - build list of instances defined in current script for use in later
2556 * stages of static analysis.
2557 * ------------------------------------------------------------------------*/
2559 Void instDefn(line,head,ms) /* process new instance definition */
2560 Int line; /* definition line number */
2561 Cell head; /* inst header :: (context,Class) */
2562 List ms; { /* instance members */
2563 Inst nw = newInst();
2564 inst(nw).line = line;
2565 inst(nw).specifics = fst(head);
2566 inst(nw).head = snd(head);
2567 inst(nw).implements = ms;
2568 instDefns = cons(nw,instDefns);
2571 /* --------------------------------------------------------------------------
2572 * Further static analysis of instance declarations:
2574 * Makes the following checks:
2575 * - Class part of header has form C (T a1 ... an) where C is a known
2576 * class, and T is a known datatype constructor (or restricted synonym),
2577 * and there is no previous C-T instance, and (T a1 ... an) has a kind
2578 * appropriate for the class C.
2579 * - Each element of context is a valid class expression, with type vars
2580 * drawn from a1, ..., an.
2581 * - All bindings are function bindings
2582 * - All bindings define member functions for class C
2583 * - Arrange bindings into appropriate order for member list
2584 * - No top level type signature declarations
2585 * ------------------------------------------------------------------------*/
2587 Bool allowOverlap = FALSE; /* TRUE => allow overlapping insts */
2588 Name nameListMonad = NIL; /* builder function for List Monad */
2590 static Void local checkInstDefn(in) /* Validate instance declaration */
2592 Int line = inst(in).line;
2593 List tyvars = typeVarsIn(inst(in).head,NIL,NIL,NIL);
2594 List tvps = NIL, tvts = NIL;
2597 if (haskell98) { /* Check for `simple' type */
2599 Cell t = arg(inst(in).head);
2600 for (; isAp(t); t=fun(t)) {
2601 if (!isVar(arg(t))) {
2603 "syntax error in instance head (variable expected)"
2606 if (varIsMember(textOf(arg(t)),tvs)) {
2607 ERRMSG(line) "repeated type variable \"%s\" in instance head",
2608 textToStr(textOf(arg(t)))
2611 tvs = cons(arg(t),tvs);
2615 "syntax error in instance head (constructor expected)"
2620 /* add in the tyvars from the `specifics' so that we don't
2621 prematurely complain about undefined tyvars */
2622 tyvars = typeVarsIn(inst(in).specifics,NIL,NIL,tyvars);
2623 inst(in).head = depPredExp(line,tyvars,inst(in).head);
2626 Type h = getHead(arg(inst(in).head));
2628 ERRMSG(line) "Cannot use type synonym in instance head"
2633 map2Over(depPredExp,line,tyvars,inst(in).specifics);
2635 /* OK, now we start over, and test for ambiguity */
2636 tvts = offsetTyvarsIn(inst(in).head,NIL);
2637 tvps = offsetTyvarsIn(inst(in).specifics,NIL);
2638 fds = calcFunDeps(inst(in).specifics);
2639 tvts = oclose(fds,tvts);
2640 tvts = odiff(tvps,tvts);
2641 if (!isNull(tvts)) {
2642 ERRMSG(line) "Undefined type variable \"%s\"",
2643 textToStr(textOf(nth(offsetOf(hd(tvts)),tyvars)))
2647 h98CheckCtxt(line,"instance definition",FALSE,inst(in).specifics,NIL);
2648 inst(in).numSpecifics = length(inst(in).specifics);
2649 inst(in).c = getHead(inst(in).head);
2650 if (!isClass(inst(in).c)) {
2651 ERRMSG(line) "Illegal predicate in instance declaration"
2655 if (nonNull(cclass(inst(in).c).fds)) {
2656 List fds = cclass(inst(in).c).fds;
2657 for (; nonNull(fds); fds=tl(fds)) {
2658 List as = otvars(inst(in).head, fst(hd(fds)));
2659 List bs = otvars(inst(in).head, snd(hd(fds)));
2660 List fs = calcFunDeps(inst(in).specifics);
2662 if (!osubset(bs,as)) {
2663 ERRMSG(inst(in).line)
2664 "Instance is more general than a dependency allows"
2666 ERRTEXT "\n*** Instance : "
2667 ETHEN ERRPRED(inst(in).head);
2668 ERRTEXT "\n*** For class : "
2669 ETHEN ERRPRED(cclass(inst(in).c).head);
2670 ERRTEXT "\n*** Under dependency : "
2671 ETHEN ERRFD(hd(fds));
2678 kindInst(in,length(tyvars));
2681 if (nonNull(extractSigdecls(inst(in).implements))) {
2683 "Type signature declarations not permitted in instance declaration"
2686 if (nonNull(extractFixdecls(inst(in).implements))) {
2688 "Fixity declarations not permitted in instance declaration"
2691 inst(in).implements = classBindings("instance",
2693 extractBindings(inst(in).implements));
2694 inst(in).builder = newInstImp(in);
2695 if (!preludeLoaded && isNull(nameListMonad) && isAp(inst(in).head)
2696 && fun(inst(in).head)==classMonad && arg(inst(in).head)==typeList) {
2697 nameListMonad = inst(in).builder;
2701 static Void local insertInst(in) /* Insert instance into class */
2703 Class c = inst(in).c;
2704 List ins = cclass(c).instances;
2707 if (nonNull(cclass(c).fds)) { /* Check for conflicts with fds */
2708 List ins1 = cclass(c).instances;
2709 for (; nonNull(ins1); ins1=tl(ins1)) {
2710 List fds = cclass(c).fds;
2711 substitution(RESET);
2712 for (; nonNull(fds); fds=tl(fds)) {
2713 Int alpha = newKindedVars(inst(in).kinds);
2714 Int beta = newKindedVars(inst(hd(ins1)).kinds);
2715 List as = fst(hd(fds));
2717 for (; same && nonNull(as); as=tl(as)) {
2718 Int n = offsetOf(hd(as));
2719 same &= unify(nthArg(n,inst(in).head),alpha,
2720 nthArg(n,inst(hd(ins1)).head),beta);
2722 if (isNull(as) && same) {
2723 for (as=snd(hd(fds)); same && nonNull(as); as=tl(as)) {
2724 Int n = offsetOf(hd(as));
2725 same &= sameType(nthArg(n,inst(in).head),alpha,
2726 nthArg(n,inst(hd(ins1)).head),beta);
2729 ERRMSG(inst(in).line)
2730 "Instances are not consistent with dependencies"
2732 ERRTEXT "\n*** This instance : "
2733 ETHEN ERRPRED(inst(in).head);
2734 ERRTEXT "\n*** Conflicts with : "
2735 ETHEN ERRPRED(inst(hd(ins)).head);
2736 ERRTEXT "\n*** For class : "
2737 ETHEN ERRPRED(cclass(c).head);
2738 ERRTEXT "\n*** Under dependency : "
2739 ETHEN ERRFD(hd(fds));
2749 substitution(RESET);
2750 while (nonNull(ins)) { /* Look for overlap w/ other insts */
2751 Int alpha = newKindedVars(inst(in).kinds);
2752 Int beta = newKindedVars(inst(hd(ins)).kinds);
2753 if (unifyPred(inst(in).head,alpha,inst(hd(ins)).head,beta)) {
2754 Cell pi = copyPred(inst(in).head,alpha);
2755 if (allowOverlap && !haskell98) {
2756 Bool bef = instCompare(in,hd(ins));
2757 Bool aft = instCompare(hd(ins),in);
2758 if (bef && !aft) { /* in comes strictly before hd(ins)*/
2761 if (aft && !bef) { /* in comes strictly after hd(ins) */
2768 if (multiInstRes && nonNull(inst(in).specifics)) {
2772 ERRMSG(inst(in).line) "Overlapping instances for class \"%s\"",
2773 textToStr(cclass(c).text)
2775 ERRTEXT "\n*** This instance : " ETHEN ERRPRED(inst(in).head);
2776 ERRTEXT "\n*** Overlaps with : " ETHEN
2777 ERRPRED(inst(hd(ins)).head);
2778 ERRTEXT "\n*** Common instance : " ETHEN
2786 prev = ins; /* No overlap detected, so move on */
2787 ins = tl(ins); /* to next instance */
2789 substitution(RESET);
2791 if (nonNull(prev)) { /* Insert instance at this point */
2792 tl(prev) = cons(in,ins);
2794 cclass(c).instances = cons(in,ins);
2798 static Bool local instCompare(ia,ib) /* See if ia is an instance of ib */
2800 Int alpha = newKindedVars(inst(ia).kinds);
2801 Int beta = newKindedVars(inst(ib).kinds);
2802 return matchPred(inst(ia).head,alpha,inst(ib).head,beta);
2805 static Name local newInstImp(in) /* Make definition for inst builder*/
2807 Name b = newName(inventText(),in);
2808 name(b).line = inst(in).line;
2809 name(b).arity = inst(in).numSpecifics;
2810 name(b).number = DFUNNAME;
2814 /* --------------------------------------------------------------------------
2815 * Kind checking of instance declaration headers:
2816 * ------------------------------------------------------------------------*/
2818 static Void local kindInst(in,freedom) /* check predicates in instance */
2823 emptySubstitution();
2824 beta = newKindvars(freedom);
2825 kindPred(inst(in).line,beta,freedom,inst(in).head);
2826 if (whatIs(inst(in).specifics)!=DERIVE) {
2827 map3Proc(kindPred,inst(in).line,beta,freedom,inst(in).specifics);
2829 for (inst(in).kinds = NIL; 0<freedom--; ) {
2830 inst(in).kinds = cons(copyKindvar(beta+freedom),inst(in).kinds);
2833 Printf("instance ");
2834 printPred(stdout,inst(in).head);
2836 printKinds(stdout,inst(in).kinds);
2839 emptySubstitution();
2842 /* --------------------------------------------------------------------------
2843 * Process derived instance requests:
2844 * ------------------------------------------------------------------------*/
2846 static List derivedInsts; /* list of derived instances */
2848 static Void local checkDerive(t,p,ts,ct)/* verify derived instance request */
2849 Tycon t; /* for tycon t, with explicit */
2850 List p; /* context p, component types ts */
2851 List ts; /* and named class ct */
2853 Int line = tycon(t).line;
2854 Class c = findQualClass(ct);
2856 ERRMSG(line) "Unknown class \"%s\" in derived instance",
2860 addDerInst(line,c,p,dupList(ts),t,tycon(t).arity);
2863 static Void local addDerInst(line,c,p,cts,t,a) /* Add a derived instance */
2870 Cell head = t; /* Build instance head */
2874 head = ap(head,mkOffset(i));
2880 inst(in).line = line;
2881 inst(in).head = head;
2882 inst(in).specifics = ap(DERIVE,pair(dupList(p),cts));
2883 inst(in).implements = NIL;
2884 inst(in).kinds = mkInt(a);
2885 derivedInsts = cons(in,derivedInsts);
2888 Void addTupInst(c,n) /* Request derived instance of c */
2889 Class c; /* for mkTuple(n) constructor */
2894 cts = cons(mkOffset(m),cts);
2897 addDerInst(0,c,NIL,cts,mkTuple(n),n);
2901 Inst addRecShowInst(c,e) /* Generate instance for ShowRecRow*/
2902 Class c; /* c *must* be ShowRecRow */
2904 Inst in = newInst();
2906 inst(in).head = ap(c,ap2(e,aVar,bVar));
2907 inst(in).kinds = extKind;
2908 inst(in).specifics = cons(ap(classShow,aVar),
2910 cons(ap(c,bVar),NIL)));
2911 inst(in).numSpecifics = 3;
2912 inst(in).builder = implementRecShw(extText(e),in);
2913 cclass(c).instances = appendOnto(cclass(c).instances,singleton(in));
2917 Inst addRecEqInst(c,e) /* Generate instance for EqRecRow */
2918 Class c; /* c *must* be EqRecRow */
2920 Inst in = newInst();
2922 inst(in).head = ap(c,ap2(e,aVar,bVar));
2923 inst(in).kinds = extKind;
2924 inst(in).specifics = cons(ap(classEq,aVar),
2926 cons(ap(c,bVar),NIL)));
2927 inst(in).numSpecifics = 3;
2928 inst(in).builder = implementRecEq(extText(e),in);
2929 cclass(c).instances = appendOnto(cclass(c).instances,singleton(in));
2934 /* --------------------------------------------------------------------------
2935 * Calculation of contexts for derived instances:
2937 * Allowing arbitrary types to appear in contexts makes it rather harder
2938 * to decide what the context for a derived instance should be. For
2941 * data T a = MkT [a] deriving Show,
2943 * we could have either of the following:
2945 * instance (Show [a]) => Show (T a) where ...
2946 * instance (Show a) => Show (T a) where ...
2948 * (assuming, of course, that instance (Show a) => Show [a]). For now, we
2949 * choose to reduce contexts in the hope of detecting errors at an earlier
2950 * stage---in contrast with value definitions, there is no way for a user
2951 * to provide something analogous to a `type signature' by which they might
2952 * be able to control this behaviour themselves. We eliminate tautological
2953 * predicates, but only allow predicates to appear in the final result if
2954 * they have at least one argument with a variable at its head.
2956 * In general, we have to deal with mutually recursive instance declarations.
2957 * We find a solution in the obvious way by iterating to find a fixed point.
2958 * Of course, without restrictions on the form of instance declarations, we
2959 * cannot be sure that this will always terminate!
2961 * For each instance we maintain a pair of the form DERIVE (ctxt,ps).
2962 * Ctxt is a list giving the parts of the context that have been produced
2963 * so far in the form of predicate skeletons. During the calculation of
2964 * derived instances, we attach a dummy NIL value to the end of the list
2965 * which acts as a kind of `variable': other parts of the system maintain
2966 * pointers to this variable, and use it to detect when the context has
2967 * been extended with new elements. Meanwhile, ps is a list containing
2968 * predicates (pi,o) together with (delayed) substitutions of the form
2969 * (o,xs) where o is an offset and xs is one of the context variables
2970 * described above, which may have been partially instantiated.
2971 * ------------------------------------------------------------------------*/
2973 static Bool instsChanged;
2975 static Void local deriveContexts(is) /* Calc contexts for derived insts */
2977 emptySubstitution();
2978 mapProc(initDerInst,is); /* Prepare derived instances */
2980 do { /* Main calculation of contexts */
2981 instsChanged = FALSE;
2982 mapProc(calcInstPreds,is);
2983 } while (instsChanged);
2985 mapProc(tidyDerInst,is); /* Tidy up results */
2988 static Void local initDerInst(in) /* Prepare instance for calculation*/
2989 Inst in; { /* of derived instance context */
2990 Cell spcs = inst(in).specifics;
2991 Int beta = newKindedVars(inst(in).kinds);
2992 if (whatIs(spcs)!=DERIVE) {
2993 internal("initDerInst");
2995 fst(snd(spcs)) = appendOnto(fst(snd(spcs)),singleton(NIL));
2996 for (spcs=snd(snd(spcs)); nonNull(spcs); spcs=tl(spcs)) {
2997 hd(spcs) = ap2(inst(in).c,hd(spcs),mkInt(beta));
2999 inst(in).numSpecifics = beta;
3001 #ifdef DEBUG_DERIVING
3002 Printf("initDerInst: ");
3003 printPred(stdout,inst(in).head);
3005 printContext(stdout,snd(snd(inst(in).specifics)));
3010 static Void local calcInstPreds(in) /* Calculate next approximation */
3011 Inst in; { /* of the context for a derived */
3012 List retain = NIL; /* instance */
3013 List ps = snd(snd(inst(in).specifics));
3014 List spcs = fst(snd(inst(in).specifics));
3015 Int beta = inst(in).numSpecifics;
3017 Int factor = 1+length(ps);
3019 #ifdef DEBUG_DERIVING
3020 Printf("calcInstPreds: ");
3021 printPred(stdout,inst(in).head);
3025 while (nonNull(ps)) {
3028 if (its++ >= factor*cutoff) {
3029 Cell bpi = inst(in).head;
3030 Cell pi = copyPred(fun(p),intOf(snd(p)));
3031 ERRMSG(inst(in).line) "\n*** Cannot derive " ETHEN ERRPRED(bpi);
3032 ERRTEXT " after %d iterations.", its-1 ETHEN
3034 "\n*** This may indicate that the problem is undecidable. However,\n"
3036 "*** you may still try to increase the cutoff limit using the -c\n"
3038 "*** option and then try again. (The current setting is -c%d)\n",
3042 if (isInt(fst(p))) { /* Delayed substitution? */
3044 for (; nonNull(hd(qs)); qs=tl(qs)) {
3045 ps = cons(pair(hd(qs),fst(p)),ps);
3047 retain = cons(pair(fst(p),qs),retain);
3050 else if (isExt(fun(fst(p)))) { /* Lacks predicate */
3051 Text l = extText(fun(fst(p)));
3052 Type t = arg(fst(p));
3053 Int o = intOf(snd(p));
3058 h = getDerefHead(t,o);
3059 while (isExt(h) && argCount==2 && l!=extText(h)) {
3062 h = getDerefHead(t,o);
3064 if (argCount==0 && isOffset(h)) {
3065 maybeAddPred(ap(fun(fun(p)),h),o,beta,spcs);
3066 } else if (argCount!=0 || h!=typeNoRow) {
3067 Cell bpi = inst(in).head;
3068 Cell pi = copyPred(fun(p),intOf(snd(p)));
3069 ERRMSG(inst(in).line) "Cannot derive " ETHEN ERRPRED(bpi);
3070 ERRTEXT " because predicate " ETHEN ERRPRED(pi);
3071 ERRTEXT " does not hold\n"
3076 else { /* Class predicate */
3078 Int o = intOf(snd(p));
3079 Inst in1 = findInstFor(pi,o);
3081 List qs = inst(in1).specifics;
3082 Int off = mkInt(typeOff);
3083 if (whatIs(qs)==DERIVE) { /* Still being derived */
3084 for (qs=fst(snd(qs)); nonNull(hd(qs)); qs=tl(qs)) {
3085 ps = cons(pair(hd(qs),off),ps);
3087 retain = cons(pair(off,qs),retain);
3088 } else { /* Previously def'd inst */
3089 for (; nonNull(qs); qs=tl(qs)) {
3090 ps = cons(pair(hd(qs),off),ps);
3093 } else { /* No matching instance */
3095 while (isAp(qi) && isOffset(getDerefHead(arg(qi),o))) {
3099 Cell bpi = inst(in).head;
3100 pi = copyPred(pi,o);
3101 ERRMSG(inst(in).line) "An instance of " ETHEN ERRPRED(pi);
3102 ERRTEXT " is required to derive " ETHEN ERRPRED(bpi);
3106 maybeAddPred(pi,o,beta,spcs);
3111 snd(snd(inst(in).specifics)) = retain;
3114 static Void local maybeAddPred(pi,o,beta,ps)
3115 Cell pi; /* Add predicate pi to the list ps,*/
3116 Int o; /* setting the instsChanged flag if*/
3117 Int beta; /* pi is not already a member and */
3118 List ps; { /* using beta to adjust vars */
3119 Cell c = getHead(pi);
3120 for (; nonNull(ps); ps=tl(ps)) {
3121 if (isNull(hd(ps))) { /* reached the `dummy' end of list?*/
3122 hd(ps) = copyAdj(pi,o,beta);
3123 tl(ps) = pair(NIL,NIL);
3124 instsChanged = TRUE;
3126 } else if (c==getHead(hd(ps)) && samePred(pi,o,hd(ps),beta)) {
3132 static Cell local copyAdj(c,o,beta) /* Copy (c,o), replacing vars with */
3133 Cell c; /* offsets relative to beta. */
3136 switch (whatIs(c)) {
3137 case AP : { Cell l = copyAdj(fst(c),o,beta);
3138 Cell r = copyAdj(snd(c),o,beta);
3142 case OFFSET : { Int vn = o+offsetOf(c);
3143 Tyvar *tyv = tyvar(vn);
3145 return copyAdj(tyv->bound,tyv->offs,beta);
3148 if (vn<0 || vn>=NUM_OFFSETS) {
3149 internal("copyAdj");
3151 return mkOffset(vn);
3157 static Void local tidyDerInst(in) /* Tidy up results of derived inst */
3158 Inst in; { /* calculations */
3159 Int o = inst(in).numSpecifics;
3160 List ps = tl(rev(fst(snd(inst(in).specifics))));
3162 copyPred(inst(in).head,o);
3163 inst(in).specifics = simpleContext(ps,o);
3164 h98CheckCtxt(inst(in).line,"derived instance",FALSE,inst(in).specifics,in);
3165 inst(in).numSpecifics = length(inst(in).specifics);
3167 #ifdef DEBUG_DERIVING
3168 Printf("Derived instance: ");
3169 printContext(stdout,inst(in).specifics);
3171 printPred(stdout,inst(in).head);
3176 /* --------------------------------------------------------------------------
3177 * Generate code for derived instances:
3178 * ------------------------------------------------------------------------*/
3180 static Void local addDerivImp(in)
3183 Type t = getHead(arg(inst(in).head));
3184 Class c = inst(in).c;
3187 } else if (c==classOrd) {
3189 } else if (c==classEnum) {
3190 imp = deriveEnum(t);
3191 } else if (c==classIx) {
3193 } else if (c==classShow) {
3194 imp = deriveShow(t);
3195 } else if (c==classRead) {
3196 imp = deriveRead(t);
3197 } else if (c==classBounded) {
3198 imp = deriveBounded(t);
3200 ERRMSG(inst(in).line) "Cannot derive instances of class \"%s\"",
3201 textToStr(cclass(inst(in).c).text)
3205 kindInst(in,intOf(inst(in).kinds));
3207 inst(in).builder = newInstImp(in);
3208 inst(in).implements = classBindings("derived instance",
3214 /* --------------------------------------------------------------------------
3215 * Default definitions; only one default definition is permitted in a
3216 * given script file. If no default is supplied, then a standard system
3217 * default will be used where necessary.
3218 * ------------------------------------------------------------------------*/
3220 Void defaultDefn(line,defs) /* Handle default types definition */
3223 if (defaultLine!=0) {
3224 ERRMSG(line) "Multiple default declarations are not permitted in" ETHEN
3225 ERRTEXT "a single script file.\n"
3228 defaultDefns = defs;
3232 static Void local checkDefaultDefns() { /* check that default types are */
3233 List ds = NIL; /* well-kinded instances of Num */
3235 if (defaultLine!=0) {
3236 map2Over(depTypeExp,defaultLine,NIL,defaultDefns);
3237 emptySubstitution();
3239 map2Proc(kindType,defaultLine,"default type",defaultDefns);
3241 emptySubstitution();
3242 mapOver(fullExpand,defaultDefns);
3244 defaultDefns = stdDefaults;
3247 if (isNull(classNum)) {
3248 classNum = findClass(findText("Num"));
3251 for (ds=defaultDefns; nonNull(ds); ds=tl(ds)) {
3252 if (isNull(provePred(NIL,NIL,ap(classNum,hd(ds))))) {
3254 "Default types must be instances of the Num class"
3261 /* --------------------------------------------------------------------------
3262 * Foreign import declarations are Hugs' equivalent of GHC's ccall mechanism.
3263 * They are used to "import" C functions into a module.
3264 * They are usually not written by hand but, rather, generated automatically
3265 * by GreenCard, IDL compilers or whatever. We support foreign import
3266 * (static) and foreign import dynamic. In the latter case, extName==NIL.
3268 * Foreign export declarations generate C wrappers for Hugs functions.
3269 * Hugs only provides "foreign export dynamic" because it's not obvious
3270 * what "foreign export static" would mean in an interactive setting.
3271 * ------------------------------------------------------------------------*/
3273 Void foreignImport(line,callconv,extName,intName,type)
3274 /* Handle foreign imports */
3280 Text t = textOf(intName);
3281 Name n = findName(t);
3282 Int l = intOf(line);
3286 } else if (name(n).defn!=PREDEFINED) {
3287 ERRMSG(l) "Redeclaration of foreign \"%s\"", textToStr(t)
3291 name(n).defn = extName;
3292 name(n).type = type;
3293 name(n).callconv = callconv;
3294 foreignImports = cons(n,foreignImports);
3297 static Void local checkForeignImport(p) /* Check foreign import */
3299 emptySubstitution();
3300 name(p).type = checkSigType(name(p).line,
3301 "foreign import declaration",
3304 /* We don't expand synonyms here because we don't want the IO
3305 * part to be expanded.
3306 * name(p).type = fullExpand(name(p).type);
3308 implementForeignImport(p);
3311 Void foreignExport(line,callconv,extName,intName,type)
3312 /* Handle foreign exports */
3318 Text t = textOf(intName);
3319 Name n = findName(t);
3320 Int l = intOf(line);
3324 } else if (name(n).defn!=PREDEFINED) {
3325 ERRMSG(l) "Redeclaration of foreign \"%s\"", textToStr(t)
3329 name(n).defn = NIL; /* nothing to say */
3330 name(n).type = type;
3331 name(n).callconv = callconv;
3332 foreignExports = cons(n,foreignExports);
3335 static Void local checkForeignExport(p) /* Check foreign export */
3337 emptySubstitution();
3338 name(p).type = checkSigType(name(p).line,
3339 "foreign export declaration",
3342 implementForeignExport(p);
3347 /* --------------------------------------------------------------------------
3348 * Static analysis of patterns:
3350 * Patterns are parsed as ordinary (atomic) expressions. Static analysis
3351 * makes the following checks:
3352 * - Patterns are well formed (according to pattern syntax), including the
3353 * special case of (n+k) patterns.
3354 * - All constructor functions have been defined and are used with the
3355 * correct number of arguments.
3356 * - No variable name is used more than once in a pattern.
3358 * The list of pattern variables occuring in each pattern is accumulated in
3359 * a global list `patVars', which must be initialised to NIL at appropriate
3360 * points before using these routines to check for valid patterns. This
3361 * mechanism enables the pattern checking routine to be mapped over a list
3362 * of patterns, ensuring that no variable occurs more than once in the
3363 * complete pattern list (as is required on the lhs of a function defn).
3364 * ------------------------------------------------------------------------*/
3366 static List patVars; /* List of vars bound in pattern */
3368 static Cell local checkPat(line,p) /* Check valid pattern syntax */
3371 switch (whatIs(p)) {
3373 case VAROPCELL : addToPatVars(line,p);
3376 case INFIX : return checkPat(line,tidyInfix(line,snd(p)));
3378 case AP : return checkMaybeCnkPat(line,p);
3383 case CONOPCELL : return checkApPat(line,0,p);
3388 case FLOATCELL : break;
3389 case INTCELL : break;
3391 case ASPAT : addToPatVars(line,fst(snd(p)));
3392 snd(snd(p)) = checkPat(line,snd(snd(p)));
3395 case LAZYPAT : snd(p) = checkPat(line,snd(p));
3398 case FINLIST : map1Over(checkPat,line,snd(p));
3401 case CONFLDS : depConFlds(line,p,TRUE);
3404 case ESIGN : snd(snd(p)) = checkPatType(line,
3408 fst(snd(p)) = checkPat(line,fst(snd(p)));
3411 default : ERRMSG(line) "Illegal pattern syntax"
3417 static Cell local checkMaybeCnkPat(l,p)/* Check applicative pattern with */
3418 Int l; /* the possibility of n+k pattern */
3421 Cell h = getHead(p);
3423 if (argCount==2 && isVar(h) && textOf(h)==textPlus) { /* n+k */
3424 Cell v = arg(fun(p));
3425 if (!isInt(arg(p))) {
3426 ERRMSG(l) "Second argument in (n+k) pattern must be an integer"
3429 if (intOf(arg(p))<=0) {
3430 ERRMSG(l) "Integer k in (n+k) pattern must be > 0"
3433 fst(fun(p)) = ADDPAT;
3434 intValOf(fun(p)) = intOf(arg(p));
3435 arg(p) = checkPat(l,v);
3439 return checkApPat(l,0,p);
3442 static Cell local checkApPat(line,args,p)
3443 Int line; /* check validity of application */
3444 Int args; /* of constructor to arguments */
3446 switch (whatIs(p)) {
3447 case AP : fun(p) = checkApPat(line,args+1,fun(p));
3448 arg(p) = checkPat(line,arg(p));
3451 case TUPLE : if (tupleOf(p)!=args) {
3452 ERRMSG(line) "Illegal tuple pattern"
3458 case EXT : h98DoesntSupport(line,"extensible records");
3460 ERRMSG(line) "Illegal record pattern"
3466 case QUALIDENT : if (!isQCon(p)) {
3468 "Illegal use of qualified variable in pattern"
3471 /* deliberate fall through */
3473 case CONOPCELL : p = conDefined(line,p);
3474 checkCfunArgs(line,p,args);
3477 case NAME : checkIsCfun(line,p);
3478 checkCfunArgs(line,p,args);
3481 default : ERRMSG(line) "Illegal pattern syntax"
3487 static Void local addToPatVars(line,v) /* Add variable v to list of vars */
3488 Int line; /* in current pattern, checking */
3489 Cell v; { /* for repeated variables. */
3494 for (; nonNull(n); p=n, n=tl(n)) {
3495 if (textOf(hd(n))==t) {
3496 ERRMSG(line) "Repeated variable \"%s\" in pattern",
3503 patVars = cons(v,NIL);
3505 tl(p) = cons(v,NIL);
3509 static Name local conDefined(line,nm) /* check that nm is the name of a */
3510 Int line; /* previously defined constructor */
3511 Cell nm; { /* function. */
3512 Name n = findQualName(nm);
3514 ERRMSG(line) "Undefined constructor function \"%s\"", identToStr(nm)
3517 checkIsCfun(line,n);
3521 static Void local checkIsCfun(line,c) /* Check that c is a constructor fn */
3525 ERRMSG(line) "\"%s\" is not a constructor function",
3526 textToStr(name(c).text)
3531 static Void local checkCfunArgs(line,c,args)
3532 Int line; /* Check constructor applied with */
3533 Cell c; /* correct number of arguments */
3535 Int a = userArity(c);
3538 "Constructor \"%s\" must have exactly %d argument%s in pattern",
3539 textToStr(name(c).text), a, ((a==1)?"":"s")
3544 static Cell local checkPatType(l,wh,e,t)/* Check type appearing in pattern */
3549 List tvs = typeVarsIn(t,NIL,NIL,NIL);
3550 h98DoesntSupport(l,"pattern type annotations");
3551 for (; nonNull(tvs); tvs=tl(tvs)) {
3552 Int beta = newKindvars(1);
3553 hd(btyvars) = cons(pair(hd(tvs),mkInt(beta)), hd(btyvars));
3555 t = checkSigType(l,"pattern type",e,t);
3556 if (isPolyOrQualType(t) || whatIs(t)==RANK2) {
3557 ERRMSG(l) "Illegal syntax in %s type annotation", wh
3563 static Cell local applyBtyvs(pat) /* Record bound type vars in pat */
3565 List bts = hd(btyvars);
3568 pat = ap(BIGLAM,pair(bts,pat));
3569 for (; nonNull(bts); bts=tl(bts)) {
3570 snd(hd(bts)) = copyKindvar(intOf(snd(hd(bts))));
3576 /* --------------------------------------------------------------------------
3577 * Maintaining lists of bound variables and local definitions, for
3578 * dependency and scope analysis.
3579 * ------------------------------------------------------------------------*/
3581 static List bounds; /* list of lists of bound vars */
3582 static List bindings; /* list of lists of binds in scope */
3583 static List depends; /* list of lists of dependents */
3585 /* bounds :: [[Var]] -- var equality used on Vars */
3586 /* bindings :: [[([Var],?)]] -- var equality used on Vars */
3587 /* depends :: [[Var]] -- pointer equality used on Vars */
3589 #define saveBvars() hd(bounds) /* list of bvars in current scope */
3590 #define restoreBvars(bs) hd(bounds)=bs /* restore list of bound variables */
3592 static Cell local bindPat(line,p) /* add new bound vars for pattern */
3596 p = checkPat(line,p);
3597 hd(bounds) = revOnto(patVars,hd(bounds));
3601 static Void local bindPats(line,ps) /* add new bound vars for patterns */
3605 map1Over(checkPat,line,ps);
3606 hd(bounds) = revOnto(patVars,hd(bounds));
3609 /* --------------------------------------------------------------------------
3610 * Before processing value and type signature declarations, all data and
3611 * type definitions have been processed so that:
3612 * - all valid type constructors (with their arities) are known.
3613 * - all valid constructor functions (with their arities and types) are
3616 * The result of parsing a list of value declarations is a list of Eqns:
3617 * Eqn ::= (SIGDECL,(Line,[Var],type))
3618 * | (FIXDECL,(Line,[Op],SyntaxInt))
3620 * The ordering of the equations in this list is the reverse of the original
3621 * ordering in the script parsed. This is a consequence of the structure of
3622 * the parser ... but also turns out to be most convenient for the static
3625 * As the first stage of the static analysis of value declarations, each
3626 * list of Eqns is converted to a list of Bindings. As part of this
3628 * - The ordering of the list of Bindings produced is the same as in the
3630 * - When a variable (function) is defined over a number of lines, all
3631 * of the definitions should appear together and each should give the
3632 * same arity to the variable being defined.
3633 * - No variable can have more than one definition.
3634 * - For pattern bindings:
3635 * - Each lhs is a valid pattern/function lhs, all constructor functions
3636 * have been defined and are used with the correct number of arguments.
3637 * - Each lhs contains no repeated pattern variables.
3638 * - Each equation defines at least one variable (e.g. True = False is
3640 * - Types appearing in type signatures are well formed:
3641 * - Type constructors used are defined and used with correct number
3643 * - type variables are replaced by offsets, type constructor names
3645 * - Every variable named in a type signature declaration is defined by
3646 * one or more equations elsewhere in the script.
3647 * - No variable has more than one type declaration.
3648 * - Similar properties for fixity declarations.
3650 * ------------------------------------------------------------------------*/
3652 #define bindingAttr(b) fst(snd(b)) /* type(s)/fixity(ies) for binding */
3653 #define fbindAlts(b) snd(snd(b)) /* alternatives for function binding*/
3655 static List local extractSigdecls(es) /* Extract the SIGDECLS from list */
3656 List es; { /* of equations */
3657 List sigdecls = NIL; /* :: [(Line,[Var],Type)] */
3659 for(; nonNull(es); es=tl(es)) {
3660 if (fst(hd(es))==SIGDECL) { /* type-declaration? */
3661 Pair sig = snd(hd(es));
3662 Int line = intOf(fst3(sig));
3663 List vs = snd3(sig);
3664 for(; nonNull(vs); vs=tl(vs)) {
3665 if (isQualIdent(hd(vs))) {
3666 ERRMSG(line) "Type signature for qualified variable \"%s\" is not allowed",
3671 sigdecls = cons(sig,sigdecls); /* discard SIGDECL tag*/
3677 static List local extractFixdecls(es) /* Extract the FIXDECLS from list */
3678 List es; { /* of equations */
3679 List fixdecls = NIL; /* :: [(Line,SyntaxInt,[Op])] */
3681 for(; nonNull(es); es=tl(es)) {
3682 if (fst(hd(es))==FIXDECL) { /* fixity declaration?*/
3683 fixdecls = cons(snd(hd(es)),fixdecls); /* discard FIXDECL tag*/
3689 static List local extractBindings(ds) /* extract untyped bindings from */
3690 List ds; { /* given list of equations */
3691 Cell lastVar = NIL; /* = var def'd in last eqn (if any)*/
3692 Int lastArity = 0; /* = number of args in last defn */
3693 List bs = NIL; /* :: [Binding] */
3695 for(; nonNull(ds); ds=tl(ds)) {
3697 if (fst(d)==FUNBIND) { /* Function bindings */
3698 Cell rhs = snd(snd(d));
3699 Int line = rhsLine(rhs);
3700 Cell lhs = fst(snd(d));
3701 Cell v = getHead(lhs);
3702 Cell newAlt = pair(getArgs(lhs),rhs);
3704 internal("FUNBIND");
3706 if (nonNull(lastVar) && textOf(v)==textOf(lastVar)) {
3707 if (argCount!=lastArity) {
3708 ERRMSG(line) "Equations give different arities for \"%s\"",
3709 textToStr(textOf(v))
3712 fbindAlts(hd(bs)) = cons(newAlt,fbindAlts(hd(bs)));
3716 lastArity = argCount;
3717 notDefined(line,bs,v);
3718 bs = cons(pair(v,pair(NIL,singleton(newAlt))),bs);
3721 } else if (fst(d)==PATBIND) { /* Pattern bindings */
3722 Cell rhs = snd(snd(d));
3723 Int line = rhsLine(rhs);
3724 Cell pat = fst(snd(d));
3725 while (whatIs(pat)==ESIGN) {/* Move type annotations to rhs */
3726 Cell p = fst(snd(pat));
3727 fst(snd(pat)) = rhs;
3728 snd(snd(d)) = rhs = pat;
3729 fst(snd(d)) = pat = p;
3732 if (isVar(pat)) { /* Convert simple pattern bind to */
3733 notDefined(line,bs,pat);/* a function binding */
3734 bs = cons(pair(pat,pair(NIL,singleton(pair(NIL,rhs)))),bs);
3736 List vs = getPatVars(line,pat,NIL);
3738 ERRMSG(line) "No variables defined in lhs pattern"
3741 map2Proc(notDefined,line,bs,vs);
3742 bs = cons(pair(vs,pair(NIL,snd(d))),bs);
3750 static List local getPatVars(line,p,vs) /* Find list of variables bound in */
3751 Int line; /* pattern p */
3754 switch (whatIs(p)) {
3756 vs = getPatVars(line,arg(p),vs);
3759 return vs; /* Ignore head of application */
3761 case CONFLDS : { List pfs = snd(snd(p));
3762 for (; nonNull(pfs); pfs=tl(pfs)) {
3763 if (isVar(hd(pfs))) {
3764 vs = addPatVar(line,hd(pfs),vs);
3766 vs = getPatVars(line,snd(hd(pfs)),vs);
3772 case FINLIST : { List ps = snd(p);
3773 for (; nonNull(ps); ps=tl(ps)) {
3774 vs = getPatVars(line,hd(ps),vs);
3779 case ESIGN : return getPatVars(line,fst(snd(p)),vs);
3784 case INFIX : return getPatVars(line,snd(p),vs);
3786 case ASPAT : return addPatVar(line,fst(snd(p)),
3787 getPatVars(line,snd(snd(p)),vs));
3790 case VAROPCELL : return addPatVar(line,p,vs);
3800 case WILDCARD : return vs;
3802 default : internal("getPatVars");
3807 static List local addPatVar(line,v,vs) /* Add var to list of previously */
3808 Int line; /* encountered variables */
3811 if (varIsMember(textOf(v),vs)) {
3812 ERRMSG(line) "Repeated use of variable \"%s\" in pattern binding",
3813 textToStr(textOf(v))
3819 static List local eqnsToBindings(es,ts,cs,ps)
3820 List es; /* Convert list of equations to */
3821 List ts; /* list of typed bindings */
3824 List bs = extractBindings(es);
3825 map1Proc(addSigdecl,bs,extractSigdecls(es));
3826 map4Proc(addFixdecl,bs,ts,cs,ps,extractFixdecls(es));
3830 static Void local notDefined(line,bs,v)/* check if name already defined in */
3831 Int line; /* list of bindings */
3834 if (nonNull(findBinding(textOf(v),bs))) {
3835 ERRMSG(line) "\"%s\" multiply defined", textToStr(textOf(v))
3840 static Cell local findBinding(t,bs) /* look for binding for variable t */
3841 Text t; /* in list of bindings bs */
3843 for (; nonNull(bs); bs=tl(bs)) {
3844 if (isVar(fst(hd(bs)))) { /* function-binding? */
3845 if (textOf(fst(hd(bs)))==t) {
3848 } else if (nonNull(varIsMember(t,fst(hd(bs))))){/* pattern-binding?*/
3855 static Cell local getAttr(bs,v) /* Locate type/fixity attribute */
3856 List bs; /* for variable v in bindings bs */
3859 Cell b = findBinding(t,bs);
3861 if (isNull(b)) { /* No binding */
3863 } else if (isVar(fst(b))) { /* func binding? */
3864 if (isNull(bindingAttr(b))) {
3865 bindingAttr(b) = pair(NIL,NIL);
3867 return bindingAttr(b);
3868 } else { /* pat binding? */
3870 List as = bindingAttr(b);
3873 bindingAttr(b) = as = replicate(length(vs),NIL);
3876 while (nonNull(vs) && t!=textOf(hd(vs))) {
3882 internal("getAttr");
3883 } else if (isNull(hd(as))) {
3884 hd(as) = pair(NIL,NIL);
3890 static Void local addSigdecl(bs,sigdecl)/* add type information to bindings*/
3891 List bs; /* :: [Binding] */
3892 Cell sigdecl; { /* :: (Line,[Var],Type) */
3893 Int l = intOf(fst3(sigdecl));
3894 List vs = snd3(sigdecl);
3895 Type type = checkSigType(l,"type declaration",hd(vs),thd3(sigdecl));
3897 for (; nonNull(vs); vs=tl(vs)) {
3899 Pair attr = getAttr(bs,v);
3901 ERRMSG(l) "Missing binding for variable \"%s\" in type signature",
3902 textToStr(textOf(v))
3904 } else if (nonNull(fst(attr))) {
3905 ERRMSG(l) "Repeated type signature for \"%s\"",
3906 textToStr(textOf(v))
3913 static Void local addFixdecl(bs,ts,cs,ps,fixdecl)
3919 Int line = intOf(fst3(fixdecl));
3920 List ops = snd3(fixdecl);
3921 Cell sy = thd3(fixdecl);
3923 for (; nonNull(ops); ops=tl(ops)) {
3925 Text t = textOf(op);
3926 Cell attr = getAttr(bs,op);
3927 if (nonNull(attr)) { /* Found name in binding? */
3928 if (nonNull(snd(attr))) {
3932 } else { /* Look in tycons, classes, prims */
3937 for (; isNull(n) && nonNull(ts1); ts1=tl(ts1)) { /* tycons */
3939 if (tycon(tc).what==DATATYPE || tycon(tc).what==NEWTYPE) {
3940 n = nameIsMember(t,tycon(tc).defn);
3943 for (; isNull(n) && nonNull(cs1); cs1=tl(cs1)) { /* classes */
3944 n = nameIsMember(t,cclass(hd(cs1)).members);
3946 for (; isNull(n) && nonNull(ps1); ps1=tl(ps1)) { /* prims */
3947 n = nameIsMember(t,hd(ps1));
3952 } else if (name(n).syntax!=NO_SYNTAX) {
3955 name(n).syntax = intOf(sy);
3960 static Void local dupFixity(line,t) /* Report repeated fixity decl */
3964 "Repeated fixity declaration for operator \"%s\"", textToStr(t)
3968 static Void local missFixity(line,t) /* Report missing op for fixity */
3972 "Cannot find binding for operator \"%s\" in fixity declaration",
3977 /* --------------------------------------------------------------------------
3978 * Dealing with infix operators:
3980 * Expressions involving infix operators or unary minus are parsed as
3981 * elements of the following type:
3983 * data InfixExp = Only Exp | Neg InfixExp | Infix InfixExp Op Exp
3985 * (The algorithms here do not assume that negation can be applied only once,
3986 * i.e., that - - x is a syntax error, as required by the Haskell report.
3987 * Instead, that restriction is captured by the grammar itself, given above.)
3989 * There are rules of precedence and grouping, expressed by two functions:
3991 * prec :: Op -> Int; assoc :: Op -> Assoc (Assoc = {L, N, R})
3993 * InfixExp values are rearranged accordingly when a complete expression
3994 * has been read using a simple shift-reduce parser whose result may be taken
3995 * to be a value of the following type:
3997 * data Exp = Atom Int | Negate Exp | Apply Op Exp Exp | Error String
3999 * The machine on which this parser is based can be defined as follows:
4001 * tidy :: InfixExp -> [(Op,Exp)] -> Exp
4002 * tidy (Only a) [] = a
4003 * tidy (Only a) ((o,b):ss) = tidy (Only (Apply o a b)) ss
4004 * tidy (Infix a o b) [] = tidy a [(o,b)]
4005 * tidy (Infix a o b) ((p,c):ss)
4006 * | shift o p = tidy a ((o,b):(p,c):ss)
4007 * | red o p = tidy (Infix a o (Apply p b c)) ss
4008 * | ambig o p = Error "ambiguous use of operators"
4009 * tidy (Neg e) [] = tidy (tidyNeg e) []
4010 * tidy (Neg e) ((o,b):ss)
4011 * | nshift o = tidy (Neg (underNeg o b e)) ss
4012 * | nred o = tidy (tidyNeg e) ((o,b):ss)
4013 * | nambig o = Error "illegal use of negation"
4015 * At each stage, the parser can either shift, reduce, accept, or error.
4016 * The transitions when dealing with juxtaposed operators o and p are
4017 * determined by the following rules:
4019 * shift o p = (prec o > prec p)
4020 * || (prec o == prec p && assoc o == L && assoc p == L)
4022 * red o p = (prec o < prec p)
4023 * || (prec o == prec p && assoc o == R && assoc p == R)
4025 * ambig o p = (prec o == prec p)
4026 * && (assoc o == N || assoc p == N || assoc o /= assoc p)
4028 * The transitions when dealing with juxtaposed unary minus and infix
4029 * operators are as follows. The precedence of unary minus (infixl 6) is
4030 * hardwired in to these definitions, as it is to the definitions of the
4031 * Haskell grammar in the official report.
4033 * nshift o = (prec o > 6)
4034 * nred o = (prec o < 6) || (prec o == 6 && assoc o == L)
4035 * nambig o = prec o == 6 && (assoc o == R || assoc o == N)
4037 * An InfixExp of the form (Neg e) means negate the last thing in
4038 * the InfixExp e; we can force this negation using:
4040 * tidyNeg :: OpExp -> OpExp
4041 * tidyNeg (Only e) = Only (Negate e)
4042 * tidyNeg (Infix a o b) = Infix a o (Negate b)
4043 * tidyNeg (Neg e) = tidyNeg (tidyNeg e)
4045 * On the other hand, if we want to sneak application of an infix operator
4046 * under a negation, then we use:
4048 * underNeg :: Op -> Exp -> OpExp -> OpExp
4049 * underNeg o b (Only e) = Only (Apply o e b)
4050 * underNeg o b (Neg e) = Neg (underNeg o b e)
4051 * underNeg o b (Infix e p f) = Infix e p (Apply o f b)
4053 * As a concession to efficiency, we lower the number of calls to syntaxOf
4054 * by keeping track of the values of sye, sys throughout the process. The
4055 * value APPLIC is used to indicate that the syntax value is unknown.
4056 * ------------------------------------------------------------------------*/
4058 static Cell local tidyInfix(line,e) /* Convert infixExp to Exp */
4060 Cell e; { /* :: OpExp */
4061 Cell s = NIL; /* :: [(Op,Exp)] */
4062 Syntax sye = APPLIC; /* Syntax of op in e (init unknown)*/
4063 Syntax sys = APPLIC; /* Syntax of op in s (init unknown)*/
4066 while (fst(d)!=ONLY) { /* Attach fixities to operators */
4070 fun(fun(d)) = attachFixity(line,fun(fun(d)));
4076 switch (whatIs(e)) {
4077 case ONLY : e = snd(e);
4078 while (nonNull(s)) {
4079 Cell next = arg(fun(s));
4081 fun(fun(s)) = snd(fun(fun(s)));
4087 case NEG : if (nonNull(s)) {
4088 if (sys==APPLIC) { /* calculate sys */
4089 sys = intOf(fst(fun(fun(s))));
4092 if (precOf(sys)==UMINUS_PREC && /* nambig */
4093 assocOf(sys)!=UMINUS_ASSOC) {
4095 "Ambiguous use of unary minus with \""
4096 ETHEN ERREXPR(snd(fun(fun(s))));
4101 if (precOf(sys)>UMINUS_PREC) { /* nshift */
4105 while (whatIs(e1)==NEG)
4107 arg(fun(t)) = arg(e1);
4108 fun(fun(t)) = snd(fun(fun(t)));
4115 /* Intentional fall-thru for nreduce and isNull(s) */
4117 { Cell prev = e; /* e := tidyNeg e */
4118 Cell temp = arg(prev);
4120 for (; whatIs(temp)==NEG; nneg++) {
4121 fun(prev) = nameNegate;
4125 if (isInt(arg(temp))) { /* special cases */
4126 if (nneg&1) /* for literals */
4127 arg(temp) = mkInt(-intOf(arg(temp)));
4129 else if (isFloat(arg(temp))) {
4131 arg(temp) = floatNegate(arg(temp));
4132 //mkFloat(-floatOf(arg(temp)));
4135 fun(prev) = nameNegate;
4136 arg(prev) = arg(temp);
4143 default : if (isNull(s)) {/* Move operation onto empty stack */
4144 Cell next = arg(fun(e));
4151 else { /* deal with pair of operators */
4153 if (sye==APPLIC) { /* calculate sys and sye */
4154 sye = intOf(fst(fun(fun(e))));
4157 sys = intOf(fst(fun(fun(s))));
4160 if (precOf(sye)==precOf(sys) && /* ambig */
4161 (assocOf(sye)!=assocOf(sys) ||
4162 assocOf(sye)==NON_ASS)) {
4163 ERRMSG(line) "Ambiguous use of operator \""
4164 ETHEN ERREXPR(snd(fun(fun(e))));
4165 ERRTEXT "\" with \""
4166 ETHEN ERREXPR(snd(fun(fun(s))));
4171 if (precOf(sye)>precOf(sys) || /* shift */
4172 (precOf(sye)==precOf(sys) &&
4173 assocOf(sye)==LEFT_ASS &&
4174 assocOf(sys)==LEFT_ASS)) {
4175 Cell next = arg(fun(e));
4183 Cell next = arg(fun(s));
4184 arg(fun(s)) = arg(e);
4185 fun(fun(s)) = snd(fun(fun(s)));
4196 static Pair local attachFixity(line,op) /* Attach fixity to operator in an */
4197 Int line; /* infix expression */
4199 Syntax sy = DEF_OPSYNTAX;
4201 switch (whatIs(op)) {
4203 case VARIDCELL : if ((sy=lookupSyntax(textOf(op)))==NO_SYNTAX) {
4204 Name n = findName(textOf(op));
4206 ERRMSG(line) "Undefined variable \"%s\"",
4207 textToStr(textOf(op))
4216 case CONIDCELL : sy = syntaxOf(op = conDefined(line,op));
4219 case QUALIDENT : { Name n = findQualName(op);
4225 "Undefined qualified variable \"%s\"",
4235 return pair(mkInt(sy),op); /* Pair fixity with (possibly) */
4236 /* translated operator */
4239 static Syntax local lookupSyntax(t) /* Try to find fixity for var in */
4240 Text t; { /* enclosing bindings */
4241 List bounds1 = bounds;
4242 List bindings1 = bindings;
4244 while (nonNull(bindings1)) {
4245 if (nonNull(varIsMember(t,hd(bounds1)))) {
4246 return DEF_OPSYNTAX;
4248 Cell b = findBinding(t,hd(bindings1));
4250 Cell a = fst(snd(b));
4251 if (isVar(fst(b))) { /* Function binding */
4252 if (nonNull(a) && nonNull(snd(a))) {
4253 return intOf(snd(a));
4255 } else { /* Pattern binding */
4257 while (nonNull(vs) && nonNull(a)) {
4258 if (t==textOf(hd(vs))) {
4259 if (nonNull(hd(a)) && isInt(snd(hd(a)))) {
4260 return intOf(snd(hd(a)));
4268 return DEF_OPSYNTAX;
4271 bounds1 = tl(bounds1);
4272 bindings1 = tl(bindings1);
4277 /* --------------------------------------------------------------------------
4278 * To facilitate dependency analysis, lists of bindings are temporarily
4279 * augmented with an additional field, which is used in two ways:
4280 * - to build the `adjacency lists' for the dependency graph. Represented by
4281 * a list of pointers to other bindings in the same list of bindings.
4282 * - to hold strictly positive integer values (depth first search numbers) of
4283 * elements `on the stack' during the strongly connected components search
4284 * algorithm, or a special value mkInt(0), once the binding has been added
4285 * to a particular strongly connected component.
4287 * Using this extra field, the type of each list of declarations during
4288 * dependency analysis is [Binding'] where:
4290 * Binding' ::= (Var, (Attr, (Dep, [Alt]))) -- function binding
4291 * | ([Var], ([Attr], (Dep, (Pat,Rhs)))) -- pattern binding
4293 * ------------------------------------------------------------------------*/
4295 #define depVal(d) (fst(snd(snd(d)))) /* Access to dependency information*/
4297 static List local dependencyAnal(bs) /* Separate lists of bindings into */
4298 List bs; { /* mutually recursive groups in */
4299 /* order of dependency */
4300 mapProc(addDepField,bs); /* add extra field for dependents */
4301 mapProc(depBinding,bs); /* find dependents of each binding */
4302 bs = bscc(bs); /* sort to strongly connected comps*/
4303 mapProc(remDepField,bs); /* remove dependency info field */
4307 static List local topDependAnal(bs) /* Like dependencyAnal(), but at */
4308 List bs; { /* top level, reporting on progress*/
4312 setGoal("Dependency analysis",(Target)(length(bs)));
4314 mapProc(addDepField,bs); /* add extra field for dependents */
4315 for (xs=bs; nonNull(xs); xs=tl(xs)) {
4316 emptySubstitution();
4318 soFar((Target)(i++));
4320 bs = bscc(bs); /* sort to strongly connected comps */
4321 mapProc(remDepField,bs); /* remove dependency info field */
4326 static Void local addDepField(b) /* add extra field to binding to */
4327 Cell b; { /* hold list of dependents */
4328 snd(snd(b)) = pair(NIL,snd(snd(b)));
4331 static Void local remDepField(bs) /* remove dependency field from */
4332 List bs; { /* list of bindings */
4333 mapProc(remDepField1,bs);
4336 static Void local remDepField1(b) /* remove dependency field from */
4337 Cell b; { /* single binding */
4338 snd(snd(b)) = snd(snd(snd(b)));
4341 static Void local clearScope() { /* initialise dependency scoping */
4347 static Void local withinScope(bs) /* Enter scope of bindings bs */
4349 bounds = cons(NIL,bounds);
4350 bindings = cons(bs,bindings);
4351 depends = cons(NIL,depends);
4354 static Void local leaveScope() { /* Leave scope of last withinScope */
4355 List bs = hd(bindings); /* Remove fixity info from binds */
4356 Bool toplevel = isNull(tl(bindings));
4357 for (; nonNull(bs); bs=tl(bs)) {
4359 if (isVar(fst(b))) { /* Variable binding */
4360 Cell a = fst(snd(b));
4363 saveSyntax(fst(b),snd(a));
4365 fst(snd(b)) = fst(a);
4367 } else { /* Pattern binding */
4369 List as = fst(snd(b));
4370 while (nonNull(vs) && nonNull(as)) {
4371 if (isPair(hd(as))) {
4373 saveSyntax(hd(vs),snd(hd(as)));
4375 hd(as) = fst(hd(as));
4382 bounds = tl(bounds);
4383 bindings = tl(bindings);
4384 depends = tl(depends);
4387 static Void local saveSyntax(v,sy) /* Save syntax of top-level var */
4388 Cell v; /* in corresponding Name */
4390 Name n = findName(textOf(v));
4391 if (isNull(n) || name(n).syntax!=NO_SYNTAX) {
4392 internal("saveSyntax");
4395 name(n).syntax = intOf(sy);
4399 /* --------------------------------------------------------------------------
4400 * As a side effect of the dependency analysis we also make the following
4402 * - Each lhs is a valid pattern/function lhs, all constructor functions
4403 * have been defined and are used with the correct number of arguments.
4404 * - No lhs contains repeated pattern variables.
4405 * - Expressions used on the rhs of an eqn should be well formed. This
4407 * - Checking for valid patterns (including repeated vars) in lambda,
4408 * case, and list comprehension expressions.
4409 * - Recursively checking local lists of equations.
4410 * - No free (i.e. unbound) variables are used in the declaration list.
4411 * ------------------------------------------------------------------------*/
4413 static Void local depBinding(b) /* find dependents of binding */
4415 Cell defpart = snd(snd(snd(b))); /* definition part of binding */
4419 if (isVar(fst(b))) { /* function-binding? */
4420 mapProc(depAlt,defpart);
4421 if (isNull(fst(snd(b)))) { /* Save dep info if no type sig */
4422 fst(snd(b)) = pair(ap(IMPDEPS,hd(depends)),NIL);
4423 } else if (isNull(fst(fst(snd(b))))) {
4424 fst(fst(snd(b))) = ap(IMPDEPS,hd(depends));
4426 } else { /* pattern-binding? */
4427 Int line = rhsLine(snd(defpart));
4430 fst(defpart) = checkPat(line,fst(defpart));
4431 depRhs(snd(defpart));
4433 if (nonNull(hd(btyvars))) {
4435 "Sorry, no type variables are allowed in pattern binding type annotations"
4439 fst(defpart) = applyBtyvs(fst(defpart));
4441 depVal(b) = hd(depends);
4444 static Void local depDefaults(c) /* dependency analysis on defaults */
4445 Class c; { /* from class definition */
4446 depClassBindings(cclass(c).defaults);
4449 static Void local depInsts(in) /* dependency analysis on instance */
4450 Inst in; { /* bindings */
4451 depClassBindings(inst(in).implements);
4454 static Void local depClassBindings(bs) /* dependency analysis on list of */
4455 List bs; { /* bindings, possibly containing */
4456 for (; nonNull(bs); bs=tl(bs)) { /* NIL bindings ... */
4457 if (nonNull(hd(bs))) { /* No need to add extra field for */
4458 mapProc(depAlt,snd(hd(bs)));/* dependency information... */
4463 static Void local depAlt(a) /* Find dependents of alternative */
4465 List obvs = saveBvars(); /* Save list of bound variables */
4467 bindPats(rhsLine(snd(a)),fst(a)); /* add new bound vars for patterns */
4468 depRhs(snd(a)); /* find dependents of rhs */
4469 fst(a) = applyBtyvs(fst(a));
4470 restoreBvars(obvs); /* restore original list of bvars */
4473 static Void local depRhs(r) /* Find dependents of rhs */
4475 switch (whatIs(r)) {
4476 case GUARDED : mapProc(depGuard,snd(r));
4479 case LETREC : fst(snd(r)) = eqnsToBindings(fst(snd(r)),NIL,NIL,NIL);
4480 withinScope(fst(snd(r)));
4481 fst(snd(r)) = dependencyAnal(fst(snd(r)));
4482 hd(depends) = fst(snd(r));
4483 depRhs(snd(snd(r)));
4487 case RSIGN : snd(snd(r)) = checkPatType(rhsLine(fst(snd(r))),
4489 rhsExpr(fst(snd(r))),
4491 depRhs(fst(snd(r)));
4494 default : snd(r) = depExpr(intOf(fst(r)),snd(r));
4499 static Void local depGuard(g) /* find dependents of single guarded*/
4500 Cell g; { /* expression */
4501 depPair(intOf(fst(g)),snd(g));
4504 static Cell local depExpr(line,e) /* find dependents of expression */
4507 // Printf( "\n\n"); print(e,100); Printf("\n");
4508 //printExp(stdout,e);
4509 switch (whatIs(e)) {
4512 case VAROPCELL : return depVar(line,e);
4515 case CONOPCELL : return conDefined(line,e);
4517 case QUALIDENT : if (isQVar(e)) {
4518 return depQVar(line,e);
4519 } else { /* QConOrConOp */
4520 return conDefined(line,e);
4523 case INFIX : return depExpr(line,tidyInfix(line,snd(e)));
4526 case RECSEL : break;
4528 case AP : if (isAp(e) && isAp(fun(e)) && isExt(fun(fun(e)))) {
4529 return depRecord(line,e);
4535 arg(a) = depExpr(line,arg(a));
4538 fun(a) = depExpr(line,fun(a));
4542 case AP : depPair(line,e);
4556 case INTCELL : break;
4558 case COND : depTriple(line,snd(e));
4561 case FINLIST : map1Over(depExpr,line,snd(e));
4564 case LETREC : fst(snd(e)) = eqnsToBindings(fst(snd(e)),NIL,NIL,NIL);
4565 withinScope(fst(snd(e)));
4566 fst(snd(e)) = dependencyAnal(fst(snd(e)));
4567 hd(depends) = fst(snd(e));
4568 snd(snd(e)) = depExpr(line,snd(snd(e)));
4572 case LAMBDA : depAlt(snd(e));
4575 case DOCOMP : /* fall-thru */
4576 case COMP : depComp(line,snd(e),snd(snd(e)));
4579 case ESIGN : fst(snd(e)) = depExpr(line,fst(snd(e)));
4580 snd(snd(e)) = checkSigType(line,
4586 case CASE : fst(snd(e)) = depExpr(line,fst(snd(e)));
4587 map1Proc(depCaseAlt,line,snd(snd(e)));
4590 case CONFLDS : depConFlds(line,e,FALSE);
4593 case UPDFLDS : depUpdFlds(line,e);
4597 case WITHEXP : depWith(line,e);
4601 case ASPAT : ERRMSG(line) "Illegal `@' in expression"
4604 case LAZYPAT : ERRMSG(line) "Illegal `~' in expression"
4607 case WILDCARD : ERRMSG(line) "Illegal `_' in expression"
4611 case EXT : ERRMSG(line) "Illegal application of record"
4615 default : internal("depExpr");
4620 static Void local depPair(line,e) /* find dependents of pair of exprs*/
4623 fst(e) = depExpr(line,fst(e));
4624 snd(e) = depExpr(line,snd(e));
4627 static Void local depTriple(line,e) /* find dependents of triple exprs */
4630 fst3(e) = depExpr(line,fst3(e));
4631 snd3(e) = depExpr(line,snd3(e));
4632 thd3(e) = depExpr(line,thd3(e));
4635 static Void local depComp(l,e,qs) /* find dependents of comprehension*/
4640 fst(e) = depExpr(l,fst(e));
4644 switch (whatIs(q)) {
4645 case FROMQUAL : { List obvs = saveBvars();
4646 snd(snd(q)) = depExpr(l,snd(snd(q)));
4648 fst(snd(q)) = bindPat(l,fst(snd(q)));
4650 fst(snd(q)) = applyBtyvs(fst(snd(q)));
4655 case QWHERE : snd(q) = eqnsToBindings(snd(q),NIL,NIL,NIL);
4656 withinScope(snd(q));
4657 snd(q) = dependencyAnal(snd(q));
4658 hd(depends) = snd(q);
4663 case DOQUAL : /* fall-thru */
4664 case BOOLQUAL : snd(q) = depExpr(l,snd(q));
4671 static Void local depCaseAlt(line,a) /* Find dependents of case altern. */
4674 List obvs = saveBvars(); /* Save list of bound variables */
4676 fst(a) = bindPat(line,fst(a)); /* Add new bound vars for pats */
4677 depRhs(snd(a)); /* Find dependents of rhs */
4678 fst(a) = applyBtyvs(fst(a));
4679 restoreBvars(obvs); /* Restore original list of bvars */
4682 static Cell local depVar(line,e) /* Register occurrence of variable */
4685 List bounds1 = bounds;
4686 List bindings1 = bindings;
4687 List depends1 = depends;
4691 while (nonNull(bindings1)) {
4692 n = varIsMember(t,hd(bounds1)); /* look for t in bound variables */
4696 n = findBinding(t,hd(bindings1)); /* look for t in var bindings */
4698 if (!cellIsMember(n,hd(depends1))) {
4699 hd(depends1) = cons(n,hd(depends1));
4701 return (isVar(fst(n)) ? fst(n) : e);
4704 bounds1 = tl(bounds1);
4705 bindings1 = tl(bindings1);
4706 depends1 = tl(depends1);
4709 if (isNull(n=findName(t))) { /* check global definitions */
4710 ERRMSG(line) "Undefined variable \"%s\"", textToStr(t)
4714 if (!moduleThisScript(name(n).mod)) {
4717 /* Later phases of the system cannot cope if we resolve references
4718 * to unprocessed objects too early. This is the main reason that
4719 * we cannot cope with recursive modules at the moment.
4724 static Cell local depQVar(line,e)/* register occurrence of qualified variable */
4727 Name n = findQualName(e);
4728 if (isNull(n)) { /* check global definitions */
4729 ERRMSG(line) "Undefined qualified variable \"%s\"", identToStr(e)
4732 if (name(n).mod != currentModule) {
4735 if (fst(e) == VARIDCELL) {
4736 e = mkVar(qtextOf(e));
4738 e = mkVarop(qtextOf(e));
4740 return depVar(line,e);
4743 static Void local depConFlds(line,e,isP)/* check construction using fields */
4747 Name c = conDefined(line,fst(snd(e)));
4748 if (isNull(snd(snd(e))) ||
4749 nonNull(cellIsMember(c,depFields(line,e,snd(snd(e)),isP)))) {
4752 ERRMSG(line) "Constructor \"%s\" does not have selected fields in ",
4753 textToStr(name(c).text)
4758 if (!isP && isPair(name(c).defn)) { /* Check that banged fields defined*/
4759 List scs = fst(name(c).defn); /* List of strict components */
4760 Type t = name(c).type;
4761 Int a = userArity(c);
4762 List fs = snd(snd(e));
4764 if (isPolyType(t)) { /* Find tycon that c belongs to */
4767 if (isQualType(t)) {
4770 if (whatIs(t)==CDICTS) {
4779 for (ss=tycon(t).defn; hasCfun(ss); ss=tl(ss)) {
4781 /* Now we know the tycon t that c belongs to, and the corresponding
4782 * list of selectors for that type, ss. Now we have to check that
4783 * each of the fields identified by scs appears in fs, using ss to
4784 * cross reference, and convert integers to selector names.
4786 for (; nonNull(scs); scs=tl(scs)) {
4787 Int i = intOf(hd(scs));
4789 for (; nonNull(ss1); ss1=tl(ss1)) {
4790 List cns = name(hd(ss1)).defn;
4791 for (; nonNull(cns); cns=tl(cns)) {
4792 if (fst(hd(cns))==c) {
4796 if (nonNull(cns) && intOf(snd(hd(cns)))==i) {
4801 internal("depConFlds");
4805 for (; nonNull(fs1) && s!=fst(hd(fs1)); fs1=tl(fs1)) {
4808 ERRMSG(line) "Construction does not define strict field"
4810 ERRTEXT "\nExpression : " ETHEN ERREXPR(e);
4811 ERRTEXT "\nField : " ETHEN ERREXPR(s);
4820 static Void local depUpdFlds(line,e) /* check update using fields */
4823 if (isNull(thd3(snd(e)))) {
4824 ERRMSG(line) "Empty field list in update"
4827 fst3(snd(e)) = depExpr(line,fst3(snd(e)));
4828 snd3(snd(e)) = depFields(line,e,thd3(snd(e)),FALSE);
4831 static List local depFields(l,e,fs,isP) /* check field binding list */
4839 for (; nonNull(fs); fs=tl(fs)) { /* for each field binding */
4843 if (isVar(fb)) { /* expand var to var = var */
4844 h98DoesntSupport(l,"missing field bindings");
4845 fb = hd(fs) = pair(fb,fb);
4848 s = findQualName(fst(fb)); /* check for selector */
4849 if (nonNull(s) && isSfun(s)) {
4852 ERRMSG(l) "\"%s\" is not a selector function/field name",
4853 textToStr(textOf(fst(fb)))
4857 if (isNull(ss)) { /* for first named selector */
4858 List scs = name(s).defn; /* calculate list of constructors */
4859 for (; nonNull(scs); scs=tl(scs)) {
4860 cs = cons(fst(hd(scs)),cs);
4862 ss = singleton(s); /* initialize selector list */
4863 } else { /* for subsequent selectors */
4864 List ds = cs; /* intersect constructor lists */
4865 for (cs=NIL; nonNull(ds); ) {
4866 List scs = name(s).defn;
4867 while (nonNull(scs) && fst(hd(scs))!=hd(ds)) {
4880 if (cellIsMember(s,ss)) { /* check for repeated uses */
4881 ERRMSG(l) "Repeated field name \"%s\" in field list",
4882 textToStr(name(s).text)
4888 if (isNull(cs)) { /* Are there any matching constrs? */
4889 ERRMSG(l) "No constructor has all of the fields specified in "
4895 snd(fb) = (isP ? checkPat(l,snd(fb)) : depExpr(l,snd(fb)));
4901 static Void local depWith(line,e) /* check with using fields */
4904 fst(snd(e)) = depExpr(line,fst(snd(e)));
4905 snd(snd(e)) = depDwFlds(line,e,snd(snd(e)));
4908 static List local depDwFlds(l,e,fs)/* check field binding list */
4914 for (; nonNull(c); c=tl(c)) { /* for each field binding */
4915 snd(hd(c)) = depExpr(l,snd(hd(c)));
4922 static Cell local depRecord(line,e) /* find dependents of record and */
4923 Int line; /* sort fields into approp. order */
4924 Cell e; { /* to make construction and update */
4925 List exts = NIL; /* more efficient. */
4928 h98DoesntSupport(line,"extensible records");
4929 do { /* build up list of extensions */
4930 Text t = extText(fun(fun(r)));
4931 String s = textToStr(t);
4934 while (nonNull(nx) && strcmp(textToStr(extText(fun(fun(nx)))),s)>0) {
4938 if (nonNull(nx) && t==extText(fun(fun(nx)))) {
4939 ERRMSG(line) "Repeated label \"%s\" in record ", s
4945 exts = cons(fun(r),exts);
4947 tl(prev) = cons(fun(r),nx);
4949 extField(r) = depExpr(line,extField(r));
4951 } while (isAp(r) && isAp(fun(r)) && isExt(fun(fun(r))));
4952 r = depExpr(line,r);
4953 return revOnto(exts,r);
4958 /* --------------------------------------------------------------------------
4959 * Several parts of this program require an algorithm for sorting a list
4960 * of values (with some added dependency information) into a list of strongly
4961 * connected components in which each value appears before its dependents.
4963 * Each of these algorithms is obtained by parameterising a standard
4964 * algorithm in "scc.c" as shown below.
4965 * ------------------------------------------------------------------------*/
4967 #define SCC2 tcscc /* make scc algorithm for Tycons */
4968 #define LOWLINK tclowlink
4969 #define DEPENDS(c) (isTycon(c) ? tycon(c).kind : cclass(c).kinds)
4970 #define SETDEPENDS(c,v) if(isTycon(c)) tycon(c).kind=v; else cclass(c).kinds=v
4977 #define SCC bscc /* make scc algorithm for Bindings */
4978 #define LOWLINK blowlink
4979 #define DEPENDS(t) depVal(t)
4980 #define SETDEPENDS(c,v) depVal(c)=v
4987 /* --------------------------------------------------------------------------
4988 * Main static analysis:
4989 * ------------------------------------------------------------------------*/
4991 Void checkExp() { /* Top level static check on Expr */
4992 staticAnalysis(RESET);
4993 clearScope(); /* Analyse expression in the scope */
4994 withinScope(NIL); /* of no local bindings */
4995 inputExpr = depExpr(0,inputExpr);
4997 staticAnalysis(RESET);
5000 #if EXPLAIN_INSTANCE_RESOLUTION
5001 Void checkContext(void) { /* Top level static check on Expr */
5004 staticAnalysis(RESET);
5005 clearScope(); /* Analyse expression in the scope */
5006 withinScope(NIL); /* of no local bindings */
5008 for (vs = NIL; nonNull(qs); qs=tl(qs)) {
5009 vs = typeVarsIn(hd(qs),NIL,NIL,vs);
5011 map2Proc(depPredExp,0,vs,inputContext);
5013 staticAnalysis(RESET);
5017 Void checkDefns() { /* Top level static analysis */
5018 Module thisModule = lastModule();
5019 staticAnalysis(RESET);
5021 setCurrModule(thisModule);
5023 /* Resolve module references */
5024 mapProc(checkQualImport, module(thisModule).qualImports);
5025 mapProc(checkUnqualImport,unqualImports);
5026 /* Add "import Prelude" if there`s no explicit import */
5027 if (thisModule!=modulePrelude
5028 && isNull(cellAssoc(modulePrelude,unqualImports))
5029 && isNull(cellRevAssoc(modulePrelude,module(thisModule).qualImports))) {
5030 unqualImports = cons(pair(modulePrelude,DOTDOT),unqualImports);
5032 /* Every module (including the Prelude) implicitly contains
5033 * "import qualified Prelude"
5035 module(thisModule).qualImports=cons(pair(mkCon(textPrelude),modulePrelude),
5036 module(thisModule).qualImports);
5038 mapProc(checkImportList, unqualImports);
5040 if (!combined) linkPreludeTC(); /* Get prelude tycons and classes */
5042 mapProc(checkTyconDefn,tyconDefns); /* validate tycon definitions */
5043 checkSynonyms(tyconDefns); /* check synonym definitions */
5044 mapProc(checkClassDefn,classDefns); /* process class definitions */
5045 mapProc(kindTCGroup,tcscc(tyconDefns,classDefns)); /* attach kinds */
5046 mapProc(extendFundeps,classDefns); /* finish class definitions */
5047 mapProc(addMembers,classDefns); /* add definitions for member funs */
5048 mapProc(visitClass,classDefns); /* check class hierarchy */
5050 if (!combined) linkPreludeCM(); /* Get prelude cfuns and mfuns */
5052 instDefns = rev(instDefns); /* process instance definitions */
5053 mapProc(checkInstDefn,instDefns);
5055 setCurrModule(thisModule);
5056 mapProc(addRSsigdecls,typeInDefns); /* add sigdecls for RESTRICTSYN */
5057 valDefns = eqnsToBindings(valDefns,tyconDefns,classDefns,/*primDefns*/NIL);
5058 mapProc(allNoPrevDef,valDefns); /* check against previous defns */
5059 mapProc(addDerivImp,derivedInsts); /* Add impls for derived instances */
5060 deriveContexts(derivedInsts); /* Calculate derived inst contexts */
5061 instDefns = appendOnto(instDefns,derivedInsts);
5062 checkDefaultDefns(); /* validate default definitions */
5064 mapProc(allNoPrevDef,valDefns); /* check against previous defns */
5066 if (!combined) linkPreludeNames(); /* link names in Prelude */
5068 mapProc(checkForeignImport,foreignImports); /* check foreign imports */
5069 mapProc(checkForeignExport,foreignExports); /* check foreign exports */
5070 foreignImports = NIL;
5071 foreignExports = NIL;
5073 /* Every top-level name has now been created - so we can build the */
5074 /* export list. Note that this has to happen before dependency */
5075 /* analysis so that references to Prelude.foo will be resolved */
5076 /* when compiling the prelude. */
5077 module(thisModule).exports = checkExports(module(thisModule).exports);
5079 mapProc(checkTypeIn,typeInDefns); /* check restricted synonym defns */
5082 withinScope(valDefns);
5083 valDefns = topDependAnal(valDefns); /* top level dependency ordering */
5084 mapProc(depDefaults,classDefns); /* dep. analysis on class defaults */
5085 mapProc(depInsts,instDefns); /* dep. analysis on inst defns */
5088 /* ToDo: evalDefaults should match current evaluation module */
5089 evalDefaults = defaultDefns; /* Set defaults for evaluator */
5091 staticAnalysis(RESET);
5097 static Void local addRSsigdecls(pr) /* add sigdecls from TYPE ... IN ..*/
5099 List vs = snd(pr); /* get list of variables */
5100 for (; nonNull(vs); vs=tl(vs)) {
5101 if (fst(hd(vs))==SIGDECL) { /* find a sigdecl */
5102 valDefns = cons(hd(vs),valDefns); /* add to valDefns */
5103 hd(vs) = hd(snd3(snd(hd(vs)))); /* and replace with var */
5108 static Void local allNoPrevDef(b) /* ensure no previous bindings for*/
5109 Cell b; { /* variables in new binding */
5110 if (isVar(fst(b))) {
5111 noPrevDef(rhsLine(snd(hd(snd(snd(b))))),fst(b));
5113 Int line = rhsLine(snd(snd(snd(b))));
5114 map1Proc(noPrevDef,line,fst(b));
5118 static Void local noPrevDef(line,v) /* ensure no previous binding for */
5119 Int line; /* new variable */
5121 Name n = findName(textOf(v));
5124 n = newName(textOf(v),NIL);
5125 name(n).defn = PREDEFINED;
5126 } else if (name(n).defn!=PREDEFINED) {
5127 duplicateError(line,name(n).mod,name(n).text,"variable");
5129 name(n).line = line;
5132 static Void local duplicateErrorAux(line,mod,t,kind)/* report duplicate defn */
5137 if (mod == currentModule) {
5138 ERRMSG(line) "Repeated definition for %s \"%s\"", kind,
5142 ERRMSG(line) "Definition of %s \"%s\" clashes with import", kind,
5148 static Void local checkTypeIn(cvs) /* Check that vars in restricted */
5149 Pair cvs; { /* synonym are defined */
5153 for (; nonNull(vs); vs=tl(vs)) {
5154 if (isNull(findName(textOf(hd(vs))))) {
5155 ERRMSG(tycon(c).line)
5156 "No top level binding of \"%s\" for restricted synonym \"%s\"",
5157 textToStr(textOf(hd(vs))), textToStr(tycon(c).text)
5163 /* --------------------------------------------------------------------------
5164 * Haskell 98 compatibility tests:
5165 * ------------------------------------------------------------------------*/
5167 Bool h98Pred(allowArgs,pi) /* Check syntax of Hask98 predicate*/
5170 return isClass(getHead(pi)) && argCount==1 &&
5171 isOffset(getHead(arg(pi))) && (argCount==0 || allowArgs);
5174 Cell h98Context(allowArgs,ps) /* Check syntax of Hask98 context */
5177 for (; nonNull(ps); ps=tl(ps)) {
5178 if (!h98Pred(allowArgs,hd(ps))) {
5185 Void h98CheckCtxt(line,wh,allowArgs,ps,in)
5186 Int line; /* Report illegal context/predicate*/
5192 Cell pi = h98Context(allowArgs,ps);
5194 ERRMSG(line) "Illegal Haskell 98 class constraint in %s",wh ETHEN
5196 ERRTEXT "\n*** Instance : " ETHEN ERRPRED(inst(in).head);
5198 ERRTEXT "\n*** Constraint : " ETHEN ERRPRED(pi);
5199 if (nonNull(ps) && nonNull(tl(ps))) {
5200 ERRTEXT "\n*** Context : " ETHEN ERRCONTEXT(ps);
5208 Void h98CheckType(line,wh,e,t) /* Check for Haskell 98 type */
5217 if (isQualType(t)) {
5218 Cell pi = h98Context(TRUE,fst(snd(t)));
5220 ERRMSG(line) "Illegal Haskell 98 class constraint in %s",wh
5222 ERRTEXT "\n*** Expression : " ETHEN ERREXPR(e);
5223 ERRTEXT "\n*** Type : " ETHEN ERRTYPE(ty);
5231 Void h98DoesntSupport(line,wh) /* Report feature missing in H98 */
5235 ERRMSG(line) "Haskell 98 does not support %s", wh
5240 /* --------------------------------------------------------------------------
5241 * Static Analysis control:
5242 * ------------------------------------------------------------------------*/
5244 Void staticAnalysis(what)
5247 case RESET : cfunSfuns = NIL;
5260 case MARK : mark(daSccs);
5275 case POSTPREL: break;
5277 case PREPREL : staticAnalysis(RESET);
5279 extKind = pair(STAR,pair(ROW,ROW));
5284 /*-------------------------------------------------------------------------*/