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: 2000/03/09 06:14:38 $
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,Bool,Cell));
38 static List local resolveImportList Args((Module,Cell,Bool));
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,priv,entity)
358 List imports; /* Accumulated list of things to import */
361 Cell entity; { /* Entry from import list */
362 List oldImports = imports;
363 Text t = isIdent(entity) ? textOf(entity) : textOf(fst(entity));
366 es = module(exporter).names;
367 es = dupOnto(module(exporter).tycons,es);
368 es = dupOnto(module(exporter).classes,es);
370 es = module(exporter).exports;
373 for(; nonNull(es); es=tl(es)) {
374 Cell e = hd(es); /* :: Entity
375 | (Entity, NIL|DOTDOT)
382 if (tycon(f).text == t) {
383 imports = cons(f,imports);
384 if (!isIdent(entity)) {
385 switch (tycon(f).what) {
388 if (DOTDOT == snd(entity)) {
389 imports=dupOnto(tycon(f).defn,imports);
391 imports=checkSubentities(imports,snd(entity),tycon(f).defn,
392 "constructor of type",t);
396 /* deliberate fall thru */
400 } else if (isClass(f)) {
401 if (cclass(f).text == t) {
402 imports = cons(f,imports);
403 if (!isIdent(entity)) {
404 if (DOTDOT == snd(entity)) {
405 return dupOnto(cclass(f).members,imports);
407 return checkSubentities(imports,snd(entity),cclass(f).members,
408 "member of class",t);
413 internal("checkImportEntity2");
415 } else if (isName(e)) {
416 if (isIdent(entity) && name(e).text == t) {
417 imports = cons(e,imports);
419 } else if (isTycon(e) && priv) {
420 if (tycon(e).text == t) {
421 imports = cons(e,imports);
422 return dupOnto(tycon(e).defn,imports);
424 } else if (isClass(e) && priv) {
425 if (cclass(e).text == t) {
426 imports = cons(e,imports);
427 return dupOnto(cclass(e).members,imports);
429 } else if (whatIs(e) == TUPLE && priv) {
432 internal("checkImportEntity3");
435 if (imports == oldImports) {
436 ERRMSG(0) "Unknown entity \"%s\" imported from module \"%s\"",
438 textToStr(module(exporter ).text)
444 static List local resolveImportList(m,impList,priv)
445 Module m; /* exporting module */
449 if (DOTDOT == impList) {
450 List es = module(m).exports;
451 for(; nonNull(es); es=tl(es)) {
454 imports = cons(e,imports);
457 List subentities = NIL;
458 imports = cons(c,imports);
460 && (tycon(c).what == DATATYPE
461 || tycon(c).what == NEWTYPE))
462 subentities = tycon(c).defn;
464 subentities = cclass(c).members;
465 if (DOTDOT == snd(e)) {
466 imports = dupOnto(subentities,imports);
471 } else if (STAR == impList) {
473 for(xs=module(m).names; nonNull(xs); xs=tl(xs)) {
475 imports = cons(e,imports);
477 for(xs=module(m).classes; nonNull(xs); xs=tl(xs)) {
479 imports = cons(cl,imports);
480 imports = dupOnto(cclass(cl).members,imports);
482 for(xs=module(m).tycons; nonNull(xs); xs=tl(xs)) {
484 imports = cons(t,imports);
486 && (tycon(t).what == DATATYPE
487 || tycon(t).what == NEWTYPE))
488 imports = dupOnto(tycon(t).defn,imports);
492 map2Accum(checkImportEntity,imports,m,priv,impList);
497 static Void local checkImportList(importSpec) /*Import a module unqualified*/
499 Module m = fst(importSpec);
500 Cell impList = snd(importSpec);
502 List imports = NIL; /* entities we want to import */
503 List hidden = NIL; /* entities we want to hide */
505 if (moduleThisScript(m)) {
506 ERRMSG(0) "Module \"%s\" recursively imports itself",
507 textToStr(module(m).text)
510 if (isPair(impList) && HIDDEN == fst(impList)) {
511 /* Somewhat inefficient - but obviously correct:
512 * imports = importsOf("module Foo") `setDifference` hidden;
514 hidden = resolveImportList(m, snd(impList),FALSE);
515 imports = resolveImportList(m, DOTDOT,FALSE);
516 } else if (isPair(impList) && STAR == fst(impList)) {
517 /* Somewhat inefficient - but obviously correct:
518 * imports = importsOf("module Foo") `setDifference` hidden;
520 imports = resolveImportList(m, snd(impList),TRUE);
522 imports = resolveImportList(m, impList,FALSE);
525 for(; nonNull(imports); imports=tl(imports)) {
526 Cell e = hd(imports);
527 if (!cellIsMember(e,hidden))
530 /* ToDo: hang onto the imports list for processing export list entries
531 * of the form "module Foo"
535 static Void local importEntity(source,e)
539 case NAME : importName(source,e);
542 case TYCON : importTycon(source,e);
544 case CLASS : importClass(source,e);
546 default: internal("importEntity");
550 static Void local importName(source,n)
553 Name clash = addName(n);
554 if (nonNull(clash) && clash!=n) {
555 ERRMSG(0) "Entity \"%s\" imported from module \"%s\" already defined in module \"%s\"",
556 textToStr(name(n).text),
557 textToStr(module(source).text),
558 textToStr(module(name(clash).mod).text)
563 static Void local importTycon(source,tc)
566 Tycon clash=addTycon(tc);
567 if (nonNull(clash) && clash!=tc) {
568 ERRMSG(0) "Tycon \"%s\" imported from \"%s\" already defined in module \"%s\"",
569 textToStr(tycon(tc).text),
570 textToStr(module(source).text),
571 textToStr(module(tycon(clash).mod).text)
574 if (nonNull(findClass(tycon(tc).text))) {
575 ERRMSG(0) "Import of type constructor \"%s\" clashes with class in module \"%s\"",
576 textToStr(tycon(tc).text),
577 textToStr(module(tycon(tc).mod).text)
582 static Void local importClass(source,c)
585 Class clash=addClass(c);
586 if (nonNull(clash) && clash!=c) {
587 ERRMSG(0) "Class \"%s\" imported from \"%s\" already defined in module \"%s\"",
588 textToStr(cclass(c).text),
589 textToStr(module(source).text),
590 textToStr(module(cclass(clash).mod).text)
593 if (nonNull(findTycon(cclass(c).text))) {
594 ERRMSG(0) "Import of class \"%s\" clashes with type constructor in module \"%s\"",
595 textToStr(cclass(c).text),
596 textToStr(module(source).text)
601 static List local checkExportTycon(exports,mt,spec,tc)
606 if (DOTDOT == spec || SYNONYM == tycon(tc).what) {
607 return cons(pair(tc,DOTDOT), exports);
609 return cons(pair(tc,NIL), exports);
613 static List local checkExportClass(exports,mt,spec,cl)
618 if (DOTDOT == spec) {
619 return cons(pair(cl,DOTDOT), exports);
621 return cons(pair(cl,NIL), exports);
625 static List local checkExport(exports,mt,e) /* Process entry in export list*/
631 List origExports = exports;
632 if (nonNull(export=findQualName(e))) {
633 exports=cons(export,exports);
635 if (isQCon(e) && nonNull(export=findQualTycon(e))) {
636 exports = checkExportTycon(exports,mt,NIL,export);
638 if (isQCon(e) && nonNull(export=findQualClass(e))) {
639 /* opaque class export */
640 exports = checkExportClass(exports,mt,NIL,export);
642 if (exports == origExports) {
643 ERRMSG(0) "Unknown entity \"%s\" exported from module \"%s\"",
649 } else if (MODULEENT == fst(e)) {
650 Module m = findModid(snd(e));
651 /* ToDo: shouldn't allow export of module we didn't import */
653 ERRMSG(0) "Unknown module \"%s\" exported from module \"%s\"",
654 textToStr(textOf(snd(e))),
658 if (m == currentModule) {
659 /* Exporting the current module exports local definitions */
661 for(xs=module(m).classes; nonNull(xs); xs=tl(xs)) {
662 if (cclass(hd(xs)).mod==m)
663 exports = checkExportClass(exports,mt,DOTDOT,hd(xs));
665 for(xs=module(m).tycons; nonNull(xs); xs=tl(xs)) {
666 if (tycon(hd(xs)).mod==m)
667 exports = checkExportTycon(exports,mt,DOTDOT,hd(xs));
669 for(xs=module(m).names; nonNull(xs); xs=tl(xs)) {
670 if (name(hd(xs)).mod==m)
671 exports = cons(hd(xs),exports);
674 /* Exporting other modules imports all things imported
675 * unqualified from it.
676 * ToDo: we reexport everything exported by a module -
677 * whether we imported it or not. This gives the wrong
678 * result for "module M(module N) where import N(x)"
680 exports = dupOnto(module(m).exports,exports);
684 Cell ident = fst(e); /* class name or type name */
685 Cell parts = snd(e); /* members or constructors */
687 if (isQCon(ident) && nonNull(nm=findQualTycon(ident))) {
688 switch (tycon(nm).what) {
691 ERRMSG(0) "Explicit constructor list given for type synonym"
692 " \"%s\" in export list of module \"%s\"",
697 return cons(pair(nm,DOTDOT),exports);
699 ERRMSG(0) "Transparent export of restricted type synonym"
700 " \"%s\" in export list of module \"%s\"",
704 return exports; /* Not reached */
708 return cons(pair(nm,DOTDOT),exports);
710 exports = checkSubentities(exports,parts,tycon(nm).defn,
711 "constructor of type",
713 return cons(pair(nm,DOTDOT), exports);
716 internal("checkExport1");
718 } else if (isQCon(ident) && nonNull(nm=findQualClass(ident))) {
719 if (DOTDOT == parts) {
720 return cons(pair(nm,DOTDOT),exports);
722 exports = checkSubentities(exports,parts,cclass(nm).members,
723 "member of class",cclass(nm).text);
724 return cons(pair(nm,DOTDOT), exports);
727 ERRMSG(0) "Explicit export list given for non-class/datatype \"%s\" in export list of module \"%s\"",
733 return exports; /* NOTUSED */
736 static List local checkExports(exports)
738 Module m = lastModule();
739 Text mt = module(m).text;
742 map1Accum(checkExport,es,mt,exports);
745 for(xs=es; nonNull(xs); xs=tl(xs)) {
746 Printf(" %s", textToStr(textOfEntity(hd(xs))));
753 /* --------------------------------------------------------------------------
754 * Static analysis of type declarations:
756 * Type declarations come in two forms:
757 * - data declarations - define new constructed data types
758 * - type declarations - define new type synonyms
760 * A certain amount of work is carried out as the declarations are
761 * read during parsing. In particular, for each type constructor
762 * definition encountered:
763 * - check that there is no previous definition of constructor
764 * - ensure type constructor not previously used as a class name
765 * - make a new entry in the type constructor table
766 * - record line number of declaration
767 * - Build separate lists of newly defined constructors for later use.
768 * ------------------------------------------------------------------------*/
770 Void tyconDefn(line,lhs,rhs,what) /* process new type definition */
771 Int line; /* definition line number */
772 Cell lhs; /* left hand side of definition */
773 Cell rhs; /* right hand side of definition */
774 Cell what; { /* SYNONYM/DATATYPE/etc... */
775 Text t = textOf(getHead(lhs));
777 if (nonNull(findTycon(t))) {
778 ERRMSG(line) "Repeated definition of type constructor \"%s\"",
782 else if (nonNull(findClass(t))) {
783 ERRMSG(line) "\"%s\" used as both class and type constructor",
788 Tycon nw = newTycon(t);
789 tyconDefns = cons(nw,tyconDefns);
790 tycon(nw).line = line;
791 tycon(nw).arity = argCount;
792 tycon(nw).what = what;
793 if (what==RESTRICTSYN) {
794 h98DoesntSupport(line,"restricted type synonyms");
795 typeInDefns = cons(pair(nw,snd(rhs)),typeInDefns);
798 tycon(nw).defn = pair(lhs,rhs);
802 Void setTypeIns(bs) /* set local synonyms for given */
803 List bs; { /* binding group */
804 List cvs = typeInDefns;
805 for (; nonNull(cvs); cvs=tl(cvs)) {
806 Tycon c = fst(hd(cvs));
807 List vs = snd(hd(cvs));
808 for (tycon(c).what = RESTRICTSYN; nonNull(vs); vs=tl(vs)) {
809 if (nonNull(findBinding(textOf(hd(vs)),bs))) {
810 tycon(c).what = SYNONYM;
817 Void clearTypeIns() { /* clear list of local synonyms */
818 for (; nonNull(typeInDefns); typeInDefns=tl(typeInDefns))
819 tycon(fst(hd(typeInDefns))).what = RESTRICTSYN;
822 /* --------------------------------------------------------------------------
823 * Further analysis of Type declarations:
825 * In order to allow the definition of mutually recursive families of
826 * data types, the static analysis of the right hand sides of type
827 * declarations cannot be performed until all of the type declarations
830 * Once parsing is complete, we carry out the following:
832 * - check format of lhs, extracting list of bound vars and ensuring that
833 * there are no repeated variables and no Skolem variables.
834 * - run dependency analysis on rhs to check that only bound type vars
835 * appear in type and that all constructors are defined.
836 * Replace type variables by offsets, constructors by Tycons.
837 * - use list of dependents to sort into strongly connected components.
838 * - ensure that there is not more than one synonym in each group.
839 * - kind-check each group of type definitions.
841 * - check that there are no previous definitions for constructor
842 * functions in data type definitions.
843 * - install synonym expansions and constructor definitions.
844 * ------------------------------------------------------------------------*/
846 static List tcDeps = NIL; /* list of dependent tycons/classes*/
848 static Void local checkTyconDefn(d) /* validate type constructor defn */
850 Cell lhs = fst(tycon(d).defn);
851 Cell rhs = snd(tycon(d).defn);
852 Int line = tycon(d).line;
853 List tyvars = getArgs(lhs);
855 /* check for repeated tyvars on lhs*/
856 for (temp=tyvars; nonNull(temp); temp=tl(temp))
857 if (nonNull(varIsMember(textOf(hd(temp)),tl(temp)))) {
858 ERRMSG(line) "Repeated type variable \"%s\" on left hand side",
859 textToStr(textOf(hd(temp)))
863 tcDeps = NIL; /* find dependents */
864 switch (whatIs(tycon(d).what)) {
866 case SYNONYM : rhs = depTypeExp(line,tyvars,rhs);
867 if (cellIsMember(d,tcDeps)) {
868 ERRMSG(line) "Recursive type synonym \"%s\"",
869 textToStr(tycon(d).text)
875 case NEWTYPE : depConstrs(d,tyvars,rhs);
879 default : internal("checkTyconDefn");
884 tycon(d).kind = tcDeps;
888 static Void local depConstrs(t,tyvars,cd)
889 Tycon t; /* Define constructor functions and*/
890 List tyvars; /* do dependency analysis for data */
891 Cell cd; { /* definitions (w or w/o deriving) */
892 Int line = tycon(t).line;
897 List derivs = snd(cd);
898 List compTypes = NIL;
902 for (i=0; i<tycon(t).arity; ++i) /* build representation for tycon */
903 lhs = ap(lhs,mkOffset(i)); /* applied to full comp. of args */
905 if (isQualType(cs)) { /* allow for possible context */
908 map2Over(depPredExp,line,tyvars,ctxt);
909 h98CheckCtxt(line,"context",TRUE,ctxt,NIL);
912 if (nonNull(cs) && isNull(tl(cs))) /* Single constructor datatype? */
915 for (; nonNull(cs); cs=tl(cs)) { /* For each constructor function: */
917 List sig = dupList(tyvars);
918 List evs = NIL; /* locally quantified vars */
919 List lps = NIL; /* locally bound predicates */
920 List ctxt1 = ctxt; /* constructor function context */
921 List scs = NIL; /* strict components */
922 List fs = NONE; /* selector names */
923 Type type = lhs; /* constructor function type */
924 Int arity = 0; /* arity of constructor function */
925 Int nr2 = 0; /* Number of rank 2 args */
926 Name n; /* name for constructor function */
928 if (whatIs(con)==POLYTYPE) { /* Locally quantified vars */
931 sig = checkQuantVars(line,evs,sig,con);
934 if (isQualType(con)) { /* Local predicates */
937 for (us = typeVarsIn(lps,NIL,NIL,NIL); nonNull(us); us=tl(us))
938 if (!varIsMember(textOf(hd(us)),evs)) {
940 "Variable \"%s\" in constraint is not locally bound",
941 textToStr(textOf(hd(us)))
944 map2Over(depPredExp,line,sig,lps);
949 if (whatIs(con)==LABC) { /* Skeletize constr components */
950 Cell fls = snd(snd(con)); /* get field specifications */
953 for (; nonNull(fls); fls=tl(fls)) { /* for each field spec: */
954 List vs = fst(hd(fls));
955 Type t = snd(hd(fls)); /* - scrutinize type */
956 Bool banged = whatIs(t)==BANG;
957 t = depCompType(line,sig,(banged ? arg(t) : t));
958 while (nonNull(vs)) { /* - add named components */
966 scs = cons(mkInt(arity),scs);
970 scs = rev(scs); /* put strict comps in ascend ord */
972 else { /* Non-labelled constructor */
975 for (; isAp(c); c=fun(c))
977 for (compNo=arity, c=con; isAp(c); c=fun(c)) {
979 if (whatIs(t)==BANG) {
980 scs = cons(mkInt(compNo),scs);
984 arg(c) = depCompType(line,sig,t);
988 if (nonNull(ctxt1)) /* Extract relevant part of context*/
989 ctxt1 = selectCtxt(ctxt1,offsetTyvarsIn(con,NIL));
991 for (i=arity; isAp(con); i--) { /* Calculate type of constructor */
994 fun(con) = typeArrow;
995 if (isPolyOrQualType(cmp)) {
996 if (nonNull(derivs)) {
997 ERRMSG(line) "Cannot derive instances for types" ETHEN
998 ERRTEXT " with polymorphic or qualified components"
1004 if (nonNull(derivs)) /* and build list of components */
1005 compTypes = cons(cmp,compTypes);
1006 type = ap(con,type);
1010 if (nr2>0) { /* Add rank 2 annotation */
1011 type = ap(RANK2,pair(mkInt(nr2-length(lps)),type));
1014 if (nonNull(evs)) { /* Add existential annotation */
1015 if (nonNull(derivs)) {
1016 ERRMSG(line) "Cannot derive instances for types" ETHEN
1017 ERRTEXT " with existentially typed components"
1022 "Cannot use selectors with existentially typed components"
1025 type = ap(EXIST,pair(mkInt(length(evs)),type));
1028 if (nonNull(lps)) { /* Add local preds part to type */
1029 type = ap(CDICTS,pair(lps,type));
1032 if (nonNull(ctxt1)) { /* Add context part to type */
1033 type = ap(QUAL,pair(ctxt1,type));
1036 if (nonNull(sig)) { /* Add quantifiers to type */
1038 for (; nonNull(ts1); ts1=tl(ts1)) {
1041 type = mkPolyType(sig,type);
1044 n = findName(textOf(con)); /* Allocate constructor fun name */
1046 n = newName(textOf(con),NIL);
1047 } else if (name(n).defn!=PREDEFINED) {
1048 duplicateError(line,name(n).mod,name(n).text,
1049 "constructor function");
1051 name(n).arity = arity; /* Save constructor fun details */
1052 name(n).line = line;
1054 name(n).number = cfunNo(conNo++);
1055 name(n).type = type;
1056 if (tycon(t).what==NEWTYPE) {
1059 "A newtype constructor cannot have class constraints"
1064 "A newtype constructor must have exactly one argument"
1069 "Illegal strictess annotation for newtype constructor"
1072 name(n).defn = nameId;
1074 implementCfun(n,scs);
1079 sels = addSels(line,n,fs,sels);
1083 if (nonNull(sels)) {
1085 fst(cd) = appendOnto(fst(cd),sels);
1086 selDefns = cons(sels,selDefns);
1089 if (nonNull(derivs)) { /* Generate derived instances */
1090 map3Proc(checkDerive,t,ctxt,compTypes,derivs);
1094 Int userArity(c) /* Find arity for cfun, ignoring */
1095 Name c; { /* CDICTS parameters */
1096 Int a = name(c).arity;
1097 Type t = name(c).type;
1099 if (isPolyType(t)) {
1102 if ((w=whatIs(t))==QUAL) {
1103 w = whatIs(t=snd(snd(t)));
1106 a -= length(fst(snd(t)));
1112 static List local addSels(line,c,fs,ss) /* Add fields to selector list */
1113 Int line; /* line number of constructor */
1114 Name c; /* corresponding constr function */
1115 List fs; /* list of fields (varids) */
1116 List ss; { /* list of existing selectors */
1118 cfunSfuns = cons(pair(c,fs),cfunSfuns);
1119 for (; nonNull(fs); fs=tl(fs), ++sn) {
1121 Text t = textOf(hd(fs));
1123 if (nonNull(varIsMember(t,tl(fs)))) {
1124 ERRMSG(line) "Repeated field name \"%s\" for constructor \"%s\"",
1125 textToStr(t), textToStr(name(c).text)
1129 while (nonNull(ns) && t!=name(hd(ns)).text) {
1134 name(hd(ns)).defn = cons(pair(c,mkInt(sn)),name(hd(ns)).defn);
1136 Name n = findName(t);
1138 ERRMSG(line) "Repeated definition for selector \"%s\"",
1143 name(n).line = line;
1144 name(n).number = SELNAME;
1145 name(n).defn = singleton(pair(c,mkInt(sn)));
1152 static List local selectCtxt(ctxt,vs) /* calculate subset of context */
1159 for (; nonNull(ctxt); ctxt=tl(ctxt)) {
1160 List us = offsetTyvarsIn(hd(ctxt),NIL);
1161 for (; nonNull(us) && cellIsMember(hd(us),vs); us=tl(us)) {
1164 ps = cons(hd(ctxt),ps);
1171 static Void local checkSynonyms(ts) /* Check for mutually recursive */
1172 List ts; { /* synonyms */
1174 for (; nonNull(ts); ts=tl(ts)) { /* build list of all synonyms */
1176 switch (whatIs(tycon(t).what)) {
1178 case RESTRICTSYN : syns = cons(t,syns);
1182 while (nonNull(syns)) { /* then visit each synonym */
1183 syns = visitSyn(NIL,hd(syns),syns);
1187 static List local visitSyn(path,t,syns) /* visit synonym definition to look*/
1188 List path; /* for cycles */
1191 if (cellIsMember(t,path)) { /* every elt in path depends on t */
1192 ERRMSG(tycon(t).line)
1193 "Type synonyms \"%s\" and \"%s\" are mutually recursive",
1194 textToStr(tycon(t).text), textToStr(tycon(hd(path)).text)
1197 List ds = tycon(t).kind;
1199 for (; nonNull(ds); ds=tl(ds)) {
1200 if (cellIsMember(hd(ds),syns)) {
1201 if (isNull(path1)) {
1202 path1 = cons(t,path);
1204 syns = visitSyn(path1,hd(ds),syns);
1208 tycon(t).defn = fullExpand(tycon(t).defn);
1209 return removeCell(t,syns);
1212 /* --------------------------------------------------------------------------
1213 * Expanding out all type synonyms in a type expression:
1214 * ------------------------------------------------------------------------*/
1216 Type fullExpand(t) /* find full expansion of type exp */
1217 Type t; { /* assuming that all relevant */
1218 Cell h = t; /* synonym defns of lower rank have*/
1219 Int n = 0; /* already been fully expanded */
1221 for (args=NIL; isAp(h); h=fun(h), n++) {
1222 args = cons(fullExpand(arg(h)),args);
1224 t = applyToArgs(h,args);
1225 if (isSynonym(h) && n>=tycon(h).arity) {
1226 if (n==tycon(h).arity) {
1227 t = instantiateSyn(tycon(h).defn,t);
1230 while (--n > tycon(h).arity) {
1233 fun(p) = instantiateSyn(tycon(h).defn,fun(p));
1239 static Type local instantiateSyn(t,env) /* instantiate type according using*/
1240 Type t; /* env to determine appropriate */
1241 Type env; { /* values for OFFSET type vars */
1242 switch (whatIs(t)) {
1243 case AP : return ap(instantiateSyn(fun(t),env),
1244 instantiateSyn(arg(t),env));
1246 case OFFSET : return nthArg(offsetOf(t),env);
1252 /* --------------------------------------------------------------------------
1253 * Static analysis of class declarations:
1255 * Performed in a similar manner to that used for type declarations.
1257 * The first part of the static analysis is performed as the declarations
1258 * are read during parsing. The parser ensures that:
1259 * - the class header and all superclass predicates are of the form
1262 * The classDefn() function:
1263 * - ensures that there is no previous definition for class
1264 * - checks that class name has not previously been used as a type constr.
1265 * - make new entry in class table
1266 * - record line number of declaration
1267 * - build list of classes defined in current script for use in later
1268 * stages of static analysis.
1269 * ------------------------------------------------------------------------*/
1271 Void classDefn(line,head,ms,fds) /* process new class definition */
1272 Int line; /* definition line number */
1273 Cell head; /* class header :: ([Supers],Class) */
1274 List ms; /* class definition body */
1275 List fds; { /* functional dependencies */
1276 Text ct = textOf(getHead(snd(head)));
1277 Int arity = argCount;
1279 if (nonNull(findClass(ct))) {
1280 ERRMSG(line) "Repeated definition of class \"%s\"",
1283 } else if (nonNull(findTycon(ct))) {
1284 ERRMSG(line) "\"%s\" used as both class and type constructor",
1288 Class nw = newClass(ct);
1289 cclass(nw).line = line;
1290 cclass(nw).arity = arity;
1291 cclass(nw).head = snd(head);
1292 cclass(nw).supers = fst(head);
1293 cclass(nw).members = ms;
1294 cclass(nw).level = 0;
1295 cclass(nw).fds = fds;
1296 cclass(nw).xfds = NIL;
1297 classDefns = cons(nw,classDefns);
1299 h98DoesntSupport(line,"multiple parameter classes");
1303 /* --------------------------------------------------------------------------
1304 * Further analysis of class declarations:
1306 * Full static analysis of class definitions must be postponed until the
1307 * complete script has been read and all static analysis on type definitions
1308 * has been completed.
1310 * Once this has been achieved, we carry out the following checks on each
1312 * - check that variables in header are distinct
1313 * - replace head by skeleton
1314 * - check superclass declarations, replace by skeletons
1315 * - split body of class into members and declarations
1316 * - make new name entry for each member function
1317 * - record member function number (eventually an offset into dictionary!)
1318 * - no member function has a previous definition ...
1319 * - no member function is mentioned more than once in the list of members
1320 * - each member function type is valid, replace vars by offsets
1321 * - qualify each member function type by class header
1322 * - only bindings for members appear in defaults
1323 * - only function bindings appear in defaults
1324 * - check that extended class hierarchy does not contain any cycles
1325 * ------------------------------------------------------------------------*/
1327 static Void local checkClassDefn(c) /* validate class definition */
1330 Int args = cclass(c).arity - 1;
1331 Cell temp = cclass(c).head;
1335 for (; isAp(temp); temp=fun(temp)) {
1336 if (!isVar(arg(temp))) {
1337 ERRMSG(cclass(c).line) "Type variable required in class head"
1340 if (nonNull(varIsMember(textOf(arg(temp)),tyvars))) {
1341 ERRMSG(cclass(c).line)
1342 "Repeated type variable \"%s\" in class head",
1343 textToStr(textOf(arg(temp)))
1346 tyvars = cons(arg(temp),tyvars);
1349 for (fs=cclass(c).fds; nonNull(fs); fs=tl(fs)) {
1353 /* Check for trivial dependency
1356 ERRMSG(cclass(c).line) "Functional dependency is trivial"
1360 /* Check for duplicated vars on right hand side, and for vars on
1361 * right that also appear on the left:
1363 for (vs=snd(fd); nonNull(vs); vs=tl(vs)) {
1364 if (varIsMember(textOf(hd(vs)),fst(fd))) {
1365 ERRMSG(cclass(c).line)
1366 "Trivial dependency for variable \"%s\"",
1367 textToStr(textOf(hd(vs)))
1370 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1371 ERRMSG(cclass(c).line)
1372 "Repeated variable \"%s\" in functional dependency",
1373 textToStr(textOf(hd(vs)))
1376 hd(vs) = depTypeVar(cclass(c).line,tyvars,textOf(hd(vs)));
1379 /* Check for duplicated vars on left hand side:
1381 for (vs=fst(fd); nonNull(vs); vs=tl(vs)) {
1382 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1383 ERRMSG(cclass(c).line)
1384 "Repeated variable \"%s\" in functional dependency",
1385 textToStr(textOf(hd(vs)))
1388 hd(vs) = depTypeVar(cclass(c).line,tyvars,textOf(hd(vs)));
1392 if (cclass(c).arity==0) {
1395 Int args = cclass(c).arity - 1;
1396 for (temp=cclass(c).head; args>0; temp=fun(temp), args--) {
1397 arg(temp) = mkOffset(args);
1399 arg(temp) = mkOffset(0);
1403 tcDeps = NIL; /* find dependents */
1404 map2Over(depPredExp,cclass(c).line,tyvars,cclass(c).supers);
1405 h98CheckCtxt(cclass(c).line,"class definition",FALSE,cclass(c).supers,NIL);
1406 cclass(c).numSupers = length(cclass(c).supers);
1407 cclass(c).defaults = extractBindings(cclass(c).members); /* defaults*/
1408 ss = extractSigdecls(cclass(c).members);
1409 fs = extractFixdecls(cclass(c).members);
1410 cclass(c).members = pair(ss,fs);
1411 map2Proc(checkMems,c,tyvars,ss);
1413 cclass(c).kinds = tcDeps;
1418 /* --------------------------------------------------------------------------
1419 * Functional dependencies are inherited from superclasses.
1420 * For example, if I've got the following classes:
1422 * class C a b | a -> b
1423 * class C [b] a => D a b
1425 * then C will have the dependency ([a], [b]) as expected, and D will inherit
1426 * the dependency ([b], [a]) from C.
1427 * When doing pairwise improvement, we have to consider not just improving
1428 * when we see a pair of Cs or a pair of Ds in the context, but when we've
1429 * got a C and a D as well. In this case, we only improve when the
1430 * predicate in question matches the type skeleton in the relevant superclass
1431 * constraint. E.g., we improve the pair (C [Int] a, D b Int) (unifying
1432 * a and b), but we don't improve the pair (C Int a, D b Int).
1433 * To implement functional dependency inheritance, we calculate
1434 * the closure of all functional dependencies, and store the result
1435 * in an additional field `xfds' (extended functional dependencies).
1436 * The `xfds' field is a list of functional dependency lists, annotated
1437 * with a list of predicate skeletons constraining when improvement can
1438 * happen against this dependency list. For example, the xfds field
1439 * for C above would be:
1440 * [([C a b], [([a], [b])])]
1441 * and the xfds field for D would be:
1442 * [([C [b] a, D a b], [([b], [a])])]
1443 * Self-improvement (of a C with a C, or a D with a D) is treated as a
1444 * special case of an inherited dependency.
1445 * ------------------------------------------------------------------------*/
1446 static List local inheritFundeps ( Class c, Cell pi, Int o )
1448 Int alpha = newKindedVars(cclass(c).kinds);
1449 List scs = cclass(c).supers;
1452 /* better not fail ;-) */
1453 if (!matchPred(pi,o,cclass(c).head,alpha))
1454 internal("inheritFundeps - predicate failed to match it's own head!");
1455 this = copyPred(pi,o);
1456 for (; nonNull(scs); scs=tl(scs)) {
1457 Class s = getHead(hd(scs));
1459 List sfds = inheritFundeps(s,hd(scs),alpha);
1460 for (; nonNull(sfds); sfds=tl(sfds)) {
1462 xfds = cons(pair(cons(this,fst(h)),snd(h)),xfds);
1466 if (nonNull(cclass(c).fds)) {
1467 List fds = NIL, fs = cclass(c).fds;
1468 for (; nonNull(fs); fs=tl(fs)) {
1469 fds = cons(pair(otvars(this,fst(hd(fs))),
1470 otvars(this,snd(hd(fs)))),fds);
1472 xfds = cons(pair(cons(this,NIL),fds),xfds);
1477 static Void local extendFundeps ( Class c )
1480 emptySubstitution();
1481 alpha = newKindedVars(cclass(c).kinds);
1482 cclass(c).xfds = inheritFundeps(c,cclass(c).head,alpha);
1484 /* we can now check for ambiguity */
1485 map1Proc(checkMems2,c,fst(cclass(c).members));
1489 static Cell local depPredExp(line,tyvars,pred)
1496 for (; isAp(h); args++) {
1497 arg(h) = depTypeExp(line,tyvars,arg(h));
1503 h98DoesntSupport(line,"tag classes");
1504 } else if (args!=1) {
1505 h98DoesntSupport(line,"multiple parameter classes");
1508 if (isQCon(h)) { /* standard class constraint */
1509 Class c = findQualClass(h);
1511 ERRMSG(line) "Undefined class \"%s\"", identToStr(h)
1519 if (args!=cclass(c).arity) {
1520 ERRMSG(line) "Wrong number of arguments for class \"%s\"",
1521 textToStr(cclass(c).text)
1524 if (cellIsMember(c,classDefns) && !cellIsMember(c,tcDeps)) {
1525 tcDeps = cons(c,tcDeps);
1529 else if (isExt(h)) { /* Lacks predicate */
1530 if (args!=1) { /* parser shouldn't let this happen*/
1531 ERRMSG(line) "Wrong number of arguments for lacks predicate"
1538 if (whatIs(h) != IPCELL)
1541 internal("depPredExp");
1546 static Void local checkMems(c,tyvars,m) /* check member function details */
1550 Int line = intOf(fst3(m));
1557 if (isPolyType(t)) {
1563 tyvars = typeVarsIn(t,NIL,xtvs,tyvars);
1564 /* Look for extra type vars. */
1565 checkOptQuantVars(line,xtvs,tyvars);
1567 if (isQualType(t)) { /* Overloaded member signatures? */
1568 map2Over(depPredExp,line,tyvars,fst(snd(t)));
1570 t = ap(QUAL,pair(NIL,t));
1573 fst(snd(t)) = cons(cclass(c).head,fst(snd(t)));/* Add main predicate */
1574 snd(snd(t)) = depTopType(line,tyvars,snd(snd(t)));
1576 for (tvs=tyvars; nonNull(tvs); tvs=tl(tvs)){/* Quantify */
1580 t = mkPolyType(sig,t);
1582 thd3(m) = t; /* Save type */
1583 take(cclass(c).arity,tyvars); /* Delete extra type vars */
1585 if (isAmbiguous(t)) {
1586 ambigError(line,"class declaration",hd(vs),t);
1588 h98CheckType(line,"member type",hd(vs),t);
1591 static Void local checkMems2(c,m) /* check member function details */
1594 Int line = intOf(fst3(m));
1599 static Void local addMembers(c) /* Add definitions of member funs */
1600 Class c; { /* and other parts of class struct.*/
1601 List ms = fst(cclass(c).members);
1602 List fs = snd(cclass(c).members);
1603 List ns = NIL; /* List of names */
1604 Int mno; /* Member function number */
1606 for (mno=0; mno<cclass(c).numSupers; mno++) {
1607 ns = cons(newDSel(c,mno),ns);
1609 cclass(c).dsels = rev(ns); /* Save dictionary selectors */
1611 for (mno=1, ns=NIL; nonNull(ms); ms=tl(ms)) {
1612 Int line = intOf(fst3(hd(ms)));
1613 List vs = rev(snd3(hd(ms)));
1614 Type t = thd3(hd(ms));
1615 for (; nonNull(vs); vs=tl(vs)) {
1616 ns = cons(newMember(line,mno++,hd(vs),t,c),ns);
1619 cclass(c).members = rev(ns); /* Save list of members */
1620 cclass(c).numMembers = length(cclass(c).members);
1622 for (; nonNull(fs); fs=tl(fs)) { /* fixity declarations */
1623 Int line = intOf(fst3(hd(fs)));
1624 List ops = snd3(hd(fs));
1625 Syntax s = intOf(thd3(hd(fs)));
1626 for (; nonNull(ops); ops=tl(ops)) {
1627 Name n = nameIsMember(textOf(hd(ops)),cclass(c).members);
1629 missFixity(line,textOf(hd(ops)));
1630 } else if (name(n).syntax!=NO_SYNTAX) {
1631 dupFixity(line,textOf(hd(ops)));
1637 /* Not actually needed just yet; for the time being, dictionary code will
1638 not be passed through the type checker.
1640 cclass(c).dtycon = addPrimTycon(generateText("Dict.%s",c),
1647 mno = cclass(c).numSupers + cclass(c).numMembers;
1648 /* cclass(c).dcon = addPrimCfun(generateText("Make.%s",c),mno,0,NIL); */
1649 cclass(c).dcon = addPrimCfun(generateText(":D%s",c),mno,0,NIL);
1650 /* implementCfun(cclass(c).dcon,NIL);
1651 Don't manufacture a wrapper fn for dictionary constructors.
1652 Applications of dictionary constructors are always saturated,
1653 and translate.c:stgExpr() special-cases saturated constructor apps.
1656 if (mno==1) { /* Single entry dicts use newtype */
1657 name(cclass(c).dcon).defn = nameId;
1658 if (nonNull(cclass(c).members)) {
1659 name(hd(cclass(c).members)).number = mfunNo(0);
1662 cclass(c).defaults = classBindings("class",c,cclass(c).defaults);
1665 static Name local newMember(l,no,v,t,parent)
1666 Int l; /* Make definition for member fn */
1671 Name m = findName(textOf(v));
1674 m = newName(textOf(v),parent);
1675 } else if (name(m).defn!=PREDEFINED) {
1676 ERRMSG(l) "Repeated definition for member function \"%s\"",
1677 textToStr(name(m).text)
1683 name(m).number = mfunNo(no);
1688 Name newDSel(c,no) /* Make definition for dict selectr*/
1694 /* sprintf(buf,"sc%d.%s",no,"%s"); */
1695 sprintf(buf,"$p%d%s",no+1,"%s");
1696 s = newName(generateText(buf,c),c);
1697 name(s).line = cclass(c).line;
1699 name(s).number = DFUNNAME;
1705 static Text local generateText(sk,c) /* We need to generate names for */
1706 String sk; /* certain objects corresponding */
1707 Class c; { /* to each class. */
1708 String cname = textToStr(cclass(c).text);
1709 char buffer[MAX_GEN+1];
1711 if ((strlen(sk)+strlen(cname))>=MAX_GEN) {
1712 ERRMSG(0) "Please use a shorter name for class \"%s\"", cname
1715 sprintf(buffer,sk,cname);
1716 return findText(buffer);
1719 Int visitClass(c) /* visit class defn to check that */
1720 Class c; { /* class hierarchy is acyclic */
1722 if (isExt(c)) { /* special case for lacks preds */
1726 if (cclass(c).level < 0) { /* already visiting this class? */
1727 ERRMSG(cclass(c).line) "Class hierarchy for \"%s\" is not acyclic",
1728 textToStr(cclass(c).text)
1730 } else if (cclass(c).level == 0) { /* visiting class for first time */
1731 List scs = cclass(c).supers;
1733 cclass(c).level = (-1);
1734 for (; nonNull(scs); scs=tl(scs)) {
1735 Int l = visitClass(getHead(hd(scs)));
1738 cclass(c).level = 1+lev; /* level = 1 + max level of supers */
1740 return cclass(c).level;
1743 /* --------------------------------------------------------------------------
1744 * Process class and instance declaration binding groups:
1745 * ------------------------------------------------------------------------*/
1747 static List local classBindings(where,c,bs)
1748 String where; /* Check validity of bindings bs */
1749 Class c; /* for class c (or an inst of c) */
1750 List bs; { /* sort into approp. member order */
1753 for (; nonNull(bs); bs=tl(bs)) {
1755 Cell body = snd(snd(b));
1758 if (!isVar(fst(b))) { /* Only allow function bindings */
1759 ERRMSG(rhsLine(snd(body)))
1760 "Pattern binding illegal in %s declaration", where
1764 if (isNull(mnm=memberName(c,textOf(fst(b))))) {
1765 ERRMSG(rhsLine(snd(hd(body))))
1766 "No member \"%s\" in class \"%s\"",
1767 textToStr(textOf(fst(b))), textToStr(cclass(c).text)
1771 nbs = numInsert(mfunOf(mnm)-1,b,nbs);
1776 static Name local memberName(c,t) /* return name of member function */
1777 Class c; /* with name t in class c */
1778 Text t; { /* return NIL if not a member */
1779 List ms = cclass(c).members;
1780 for (; nonNull(ms); ms=tl(ms)) {
1781 if (t==name(hd(ms)).text) {
1788 static List local numInsert(n,x,xs) /* insert x at nth position in xs, */
1789 Int n; /* filling gaps with NIL */
1792 List start = isNull(xs) ? cons(NIL,NIL) : xs;
1794 for (xs=start; 0<n--; xs=tl(xs)) {
1795 if (isNull(tl(xs))) {
1796 tl(xs) = cons(NIL,NIL);
1803 /* --------------------------------------------------------------------------
1804 * Calculate set of variables appearing in a given type expression (possibly
1805 * qualified) as a list of distinct values. The order in which variables
1806 * appear in the list is the same as the order in which those variables
1807 * occur in the type expression when read from left to right.
1808 * ------------------------------------------------------------------------*/
1810 List local typeVarsIn(ty,us,ws,vs) /*Calculate list of type variables*/
1811 Cell ty; /* used in type expression, reading*/
1812 List us; /* from left to right ignoring any */
1813 List ws; /* listed in us. */
1814 List vs; { /* ws = explicitly quantified vars */
1815 if (isNull(ty)) return vs;
1816 switch (whatIs(ty)) {
1817 case DICTAP : return typeVarsIn(snd(snd(ty)),us,ws,vs);
1818 case UNBOXEDTUP: return typeVarsIn(snd(ty),us,ws,vs);
1820 case AP : return typeVarsIn(snd(ty),us,ws,
1821 typeVarsIn(fst(ty),us,ws,vs));
1824 case VAROPCELL : if ((nonNull(findBtyvs(textOf(ty)))
1825 && !varIsMember(textOf(ty),ws))
1826 || varIsMember(textOf(ty),us)) {
1829 return maybeAppendVar(ty,vs);
1832 case POLYTYPE : return typeVarsIn(monotypeOf(ty),polySigOf(ty),ws,vs);
1834 case QUAL : { vs = typeVarsIn(fst(snd(ty)),us,ws,vs);
1835 return typeVarsIn(snd(snd(ty)),us,ws,vs);
1838 case BANG : return typeVarsIn(snd(ty),us,ws,vs);
1840 case LABC : { List fs = snd(snd(ty));
1841 for (; nonNull(fs); fs=tl(fs)) {
1842 vs = typeVarsIn(snd(hd(fs)),us,ws,vs);
1849 case QUALIDENT: return vs;
1851 default: fprintf(stderr, " bad tag = %d\n", whatIs(ty));internal("typeVarsIn");
1856 static List local maybeAppendVar(v,vs) /* append variable to list if not */
1857 Cell v; /* already included */
1863 while (nonNull(c)) {
1864 if (textOf(hd(c))==t) {
1872 tl(p) = cons(v,NIL);
1880 /* --------------------------------------------------------------------------
1881 * Static analysis for type expressions is required to:
1882 * - ensure that each type constructor or class used has been defined.
1883 * - replace type variables by offsets, constructor names by Tycons.
1884 * - ensure that the type is well-kinded.
1885 * ------------------------------------------------------------------------*/
1887 static Type local checkSigType(line,where,e,type)
1888 Int line; /* Check validity of type expr in */
1889 String where; /* explicit type signature */
1896 if (isPolyType(type)) {
1897 xtvs = fst(snd(type));
1898 type = monotypeOf(type);
1900 tvs = typeVarsIn(type,NIL,xtvs,NIL);
1902 checkOptQuantVars(line,xtvs,tvs);
1904 if (isQualType(type)) {
1905 map2Over(depPredExp,line,tvs,fst(snd(type)));
1906 snd(snd(type)) = depTopType(line,tvs,snd(snd(type)));
1908 if (isAmbiguous(type)) {
1909 ambigError(line,where,e,type);
1912 type = depTopType(line,tvs,type);
1916 if (length(tvs)>=NUM_OFFSETS) {
1917 ERRMSG(line) "Too many type variables in %s\n", where
1921 for (; nonNull(ts); ts=tl(ts)) {
1924 type = mkPolyType(tvs,type);
1929 kindType(line,"type expression",type);
1933 h98CheckType(line,where,e,type);
1937 static Void local checkOptQuantVars(line,xtvs,tvs)
1939 List xtvs; /* Explicitly quantified vars */
1940 List tvs; { /* Implicitly quantified vars */
1941 if (nonNull(xtvs)) {
1943 for (; nonNull(vs); vs=tl(vs)) {
1944 if (!varIsMember(textOf(hd(vs)),xtvs)) {
1945 ERRMSG(line) "Quantifier does not mention type variable \"%s\"",
1946 textToStr(textOf(hd(vs)))
1950 for (vs=xtvs; nonNull(vs); vs=tl(vs)) {
1951 if (!varIsMember(textOf(hd(vs)),tvs)) {
1952 ERRMSG(line) "Quantified type variable \"%s\" is not used",
1953 textToStr(textOf(hd(vs)))
1956 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1957 ERRMSG(line) "Quantified type variable \"%s\" is repeated",
1958 textToStr(textOf(hd(vs)))
1965 static Type local depTopType(l,tvs,t) /* Check top-level of type sig */
1973 for (; getHead(t1)==typeArrow && argCount==2; ++i) {
1974 arg(fun(t1)) = depCompType(l,tvs,arg(fun(t1)));
1975 if (isPolyOrQualType(arg(fun(t1)))) {
1981 if (nonNull(prev)) {
1982 arg(prev) = depTypeExp(l,tvs,t1);
1984 t = depTypeExp(l,tvs,t1);
1987 t = ap(RANK2,pair(mkInt(nr2),t));
1992 static Type local depCompType(l,tvs,t) /* Check component type for constr */
1996 Int ntvs = length(tvs);
1998 if (isPolyType(t)) {
1999 List vs = fst(snd(t));
2001 tvs = checkQuantVars(l,vs,tvs,t);
2002 nfr = replicate(length(vs),NIL);
2004 if (isQualType(t)) {
2005 map2Over(depPredExp,l,tvs,fst(snd(t)));
2006 snd(snd(t)) = depTypeExp(l,tvs,snd(snd(t)));
2007 if (isAmbiguous(t)) {
2008 ambigError(l,"type component",NIL,t);
2011 t = depTypeExp(l,tvs,t);
2017 return mkPolyType(nfr,t);
2020 static Type local depTypeExp(line,tyvars,type)
2024 switch (whatIs(type)) {
2025 case AP : fst(type) = depTypeExp(line,tyvars,fst(type));
2026 snd(type) = depTypeExp(line,tyvars,snd(type));
2029 case VARIDCELL : return depTypeVar(line,tyvars,textOf(type));
2031 case QUALIDENT : if (isQVar(type)) {
2032 ERRMSG(line) "Qualified type variables not allowed"
2035 /* deliberate fall through */
2036 case CONIDCELL : { Tycon tc = findQualTycon(type);
2039 "Undefined type constructor \"%s\"",
2043 if (cellIsMember(tc,tyconDefns) &&
2044 !cellIsMember(tc,tcDeps)) {
2045 tcDeps = cons(tc,tcDeps);
2051 case EXT : h98DoesntSupport(line,"extensible records");
2056 default : internal("depTypeExp");
2061 static Type local depTypeVar(line,tyvars,tv)
2068 for (; nonNull(tyvars); offset++) {
2069 if (tv==textOf(hd(tyvars))) {
2072 tyvars = tl(tyvars);
2075 Cell vt = findBtyvs(tv);
2079 ERRMSG(line) "Undefined type variable \"%s\"", textToStr(tv)
2082 return mkOffset(found);
2085 static List local checkQuantVars(line,vs,tvs,body)
2087 List vs; /* variables to quantify over */
2088 List tvs; /* variables already in scope */
2089 Cell body; { /* type/constr for scope of vars */
2091 List bvs = typeVarsIn(body,NIL,NIL,NIL);
2093 for (; nonNull(us); us=tl(us)) {
2094 Text u = textOf(hd(us));
2095 if (varIsMember(u,tl(us))) {
2096 ERRMSG(line) "Duplicated quantified variable %s",
2101 if (varIsMember(u,tvs)) {
2102 ERRMSG(line) "Local quantifier for %s hides an outer use",
2107 if (!varIsMember(u,bvs)) {
2108 ERRMSG(line) "Locally quantified variable %s is not used",
2113 tvs = appendOnto(tvs,vs);
2118 /* --------------------------------------------------------------------------
2119 * Check for ambiguous types:
2120 * A type Preds => type is ambiguous if not (TV(P) `subset` TV(type))
2121 * ------------------------------------------------------------------------*/
2123 List offsetTyvarsIn(t,vs) /* add list of offset tyvars in t */
2124 Type t; /* to list vs */
2126 switch (whatIs(t)) {
2127 case AP : return offsetTyvarsIn(fun(t),
2128 offsetTyvarsIn(arg(t),vs));
2130 case OFFSET : if (cellIsMember(t,vs))
2135 case QUAL : return offsetTyvarsIn(snd(t),vs);
2137 case POLYTYPE : return offsetTyvarsIn(monotypeOf(t),vs);
2138 /* slightly inaccurate, but won't matter here */
2141 case RANK2 : return offsetTyvarsIn(snd(snd(t)),vs);
2143 default : return vs;
2147 List zonkTyvarsIn(t,vs)
2150 switch (whatIs(t)) {
2151 case AP : return zonkTyvarsIn(fun(t),
2152 zonkTyvarsIn(arg(t),vs));
2154 case INTCELL : if (cellIsMember(t,vs))
2159 /* this case will lead to a type error --
2160 much better than reporting an internal error ;-) */
2161 /* case OFFSET : internal("zonkTyvarsIn"); */
2163 default : return vs;
2167 static List local otvars(pi,os) /* os is a list of offsets that */
2168 Cell pi; /* refer to the arguments of pi; */
2169 List os; { /* find list of offsets in those */
2170 List us = NIL; /* positions */
2171 for (; nonNull(os); os=tl(os)) {
2172 us = offsetTyvarsIn(nthArg(offsetOf(hd(os)),pi),us);
2177 static List local otvarsZonk(pi,os,o) /* same as above, but zonks */
2181 for (; nonNull(os); os=tl(os)) {
2182 Type t = zonkType(nthArg(offsetOf(hd(os)),pi),o);
2183 us = zonkTyvarsIn(t,us);
2188 static Bool local odiff(us,vs)
2190 while (nonNull(us) && cellIsMember(hd(us),vs)) {
2196 static Bool local osubset(us,vs) /* Determine whether us is subset */
2197 List us, vs; { /* of vs */
2198 while (nonNull(us) && cellIsMember(hd(us),vs)) {
2204 List oclose(fds,vs) /* Compute closure of vs wrt to fds*/
2207 Bool changed = TRUE;
2211 while (nonNull(fds)) {
2213 List next = tl(fds);
2214 if (osubset(fst(fd),vs)) { /* Test if fd applies */
2216 for (; nonNull(os); os=tl(os)) {
2217 if (!cellIsMember(hd(os),vs)) {
2218 vs = cons(hd(os),vs);
2222 } else { /* Didn't apply this time, so keep */
2233 Bool isAmbiguous(type) /* Determine whether type is */
2234 Type type; { /* ambiguous */
2235 if (isPolyType(type)) {
2236 type = monotypeOf(type);
2238 if (isQualType(type)) { /* only qualified types can be */
2239 List ps = fst(snd(type)); /* ambiguous */
2240 List tvps = offsetTyvarsIn(ps,NIL);
2241 List tvts = offsetTyvarsIn(snd(snd(type)),NIL);
2242 List fds = calcFunDeps(ps);
2244 tvts = oclose(fds,tvts); /* Close tvts under fds */
2245 return !osubset(tvps,tvts);
2250 List calcFunDeps(ps)
2253 for (; nonNull(ps); ps=tl(ps)) {/* Calc functional dependencies */
2255 Cell c = getHead(pi);
2257 List xfs = cclass(c).xfds;
2258 for (; nonNull(xfs); xfs=tl(xfs)) {
2259 List fs = snd(hd(xfs));
2260 for (; nonNull(fs); fs=tl(fs)) {
2261 fds = cons(pair(otvars(pi,fst(hd(fs))),
2262 otvars(pi,snd(hd(fs)))),fds);
2268 fds = cons(pair(NIL,offsetTyvarsIn(arg(pi),NIL)),fds);
2275 List calcFunDepsPreds(ps)
2278 for (; nonNull(ps); ps=tl(ps)) {/* Calc functional dependencies */
2280 Cell pi = fst3(pi3);
2281 Cell c = getHead(pi);
2282 Int o = intOf(snd3(pi3));
2284 List xfs = cclass(c).xfds;
2285 for (; nonNull(xfs); xfs=tl(xfs)) {
2286 List fs = snd(hd(xfs));
2287 for (; nonNull(fs); fs=tl(fs)) {
2288 fds = cons(pair(otvarsZonk(pi,fst(hd(fs)),o),
2289 otvarsZonk(pi,snd(hd(fs)),o)),fds);
2295 fds = cons(pair(NIL,zonkTyvarsIn(arg(pi),NIL)),fds);
2302 Void ambigError(line,where,e,type) /* produce error message for */
2303 Int line; /* ambiguity */
2307 ERRMSG(line) "Ambiguous type signature in %s", where ETHEN
2308 ERRTEXT "\n*** ambiguous type : " ETHEN ERRTYPE(type);
2310 ERRTEXT "\n*** assigned to : " ETHEN ERREXPR(e);
2316 /* --------------------------------------------------------------------------
2317 * Kind inference for simple types:
2318 * ------------------------------------------------------------------------*/
2320 static Void local kindConstr(line,alpha,m,c)
2321 Int line; /* Determine kind of constructor */
2325 Cell h = getHead(c);
2329 Printf("kindConstr: alpha=%d, m=%d, c=",alpha,m);
2330 printType(stdout,c);
2334 switch (whatIs(h)) {
2335 case POLYTYPE : if (n!=0) {
2336 internal("kindConstr1");
2338 static String pt = "polymorphic type";
2339 Type t = dropRank1(c,alpha,m);
2340 Kinds ks = polySigOf(t);
2343 for (; isAp(ks); ks=tl(ks)) {
2346 beta = newKindvars(m1);
2347 unkindTypes = cons(pair(mkInt(beta),t),unkindTypes);
2348 checkKind(line,beta,m1,monotypeOf(t),NIL,pt,STAR,0);
2353 case QUAL : if (n!=0) {
2354 internal("kindConstr2");
2356 map3Proc(kindPred,line,alpha,m,fst(snd(c)));
2357 kindConstr(line,alpha,m,snd(snd(c)));
2361 case RANK2 : kindConstr(line,alpha,m,snd(snd(c)));
2365 case EXT : if (n!=2) {
2367 "Illegal use of row in " ETHEN ERRTYPE(c);
2374 case TYCON : if (isSynonym(h) && n<tycon(h).arity) {
2376 "Not enough arguments for type synonym \"%s\"",
2377 textToStr(tycon(h).text)
2383 if (n==0) { /* trivial case, no arguments */
2384 typeIs = kindAtom(alpha,c);
2385 } else { /* non-trivial application */
2386 static String app = "constructor application";
2396 typeIs = kindAtom(alpha,h); /* h :: v1 -> ... -> vn -> w */
2397 shouldKind(line,h,c,app,k,beta);
2399 for (i=n; i>0; --i) { /* ci :: vi for each 1 <- 1..n */
2400 checkKind(line,alpha,m,arg(a),c,app,aVar,beta+i-1);
2403 tyvarType(beta+n); /* inferred kind is w */
2407 static Kind local kindAtom(alpha,c) /* Find kind of atomic constructor */
2410 switch (whatIs(c)) {
2411 case TUPLE : return simpleKind(tupleOf(c)); /*(,)::* -> * -> * */
2412 case OFFSET : return mkInt(alpha+offsetOf(c));
2413 case TYCON : return tycon(c).kind;
2414 case INTCELL : return c;
2416 case VAROPCELL : { Cell vt = findBtyvs(textOf(c));
2422 case EXT : return extKind;
2426 Printf("kindAtom(%d,whatIs(%d)) on ",alpha,whatIs(c));
2427 printType(stdout,c);
2430 internal("kindAtom");
2431 return STAR;/* not reached */
2434 static Void local kindPred(l,alpha,m,pi)/* Check kinds of arguments in pred*/
2440 if (isAp(pi) && isExt(fun(pi))) {
2441 static String lackspred = "lacks predicate";
2442 checkKind(l,alpha,m,arg(pi),NIL,lackspred,ROW,0);
2447 if (isAp(pi) && whatIs(fun(pi)) == IPCELL) {
2448 static String ippred = "iparam predicate";
2449 checkKind(l,alpha,m,arg(pi),NIL,ippred,STAR,0);
2453 { static String predicate = "class constraint";
2454 Class c = getHead(pi);
2455 List as = getArgs(pi);
2456 Kinds ks = cclass(c).kinds;
2458 while (nonNull(ks)) {
2459 checkKind(l,alpha,m,hd(as),NIL,predicate,hd(ks),0);
2466 static Void local kindType(line,wh,type)/* check that (poss qualified) type*/
2467 Int line; /* is well-kinded */
2470 checkKind(line,0,0,type,NIL,wh,STAR,0);
2473 static Void local fixKinds() { /* add kind annotations to types */
2474 for (; nonNull(unkindTypes); unkindTypes=tl(unkindTypes)) {
2475 Pair pr = hd(unkindTypes);
2476 Int beta = intOf(fst(pr));
2477 Cell qts = polySigOf(snd(pr));
2479 if (isNull(hd(qts))) {
2480 hd(qts) = copyKindvar(beta++);
2482 internal("fixKinds");
2484 if (nonNull(tl(qts))) {
2492 Printf("Type expression: ");
2493 printType(stdout,snd(pr));
2495 printKind(stdout,polySigOf(snd(pr)));
2501 /* --------------------------------------------------------------------------
2502 * Kind checking of groups of type constructors and classes:
2503 * ------------------------------------------------------------------------*/
2505 static Void local kindTCGroup(tcs) /* find kinds for mutually rec. gp */
2506 List tcs; { /* of tycons and classes */
2507 emptySubstitution();
2509 mapProc(initTCKind,tcs);
2510 mapProc(kindTC,tcs);
2513 emptySubstitution();
2516 static Void local initTCKind(c) /* build initial kind/arity for c */
2518 if (isTycon(c)) { /* Initial kind of tycon is: */
2519 Int beta = newKindvars(1); /* v1 -> ... -> vn -> vn+1 */
2520 varKind(tycon(c).arity); /* where n is the arity of c. */
2521 bindTv(beta,typeIs,typeOff); /* For data definitions, vn+1 == * */
2522 switch (whatIs(tycon(c).what)) {
2524 case DATATYPE : bindTv(typeOff+tycon(c).arity,STAR,0);
2526 tycon(c).kind = mkInt(beta);
2528 Int n = cclass(c).arity;
2529 Int beta = newKindvars(n);
2530 cclass(c).kinds = NIL;
2533 cclass(c).kinds = pair(mkInt(beta+n),cclass(c).kinds);
2538 static Void local kindTC(c) /* check each part of a tycon/class*/
2539 Cell c; { /* is well-kinded */
2541 static String cfun = "constructor function";
2542 static String tsyn = "synonym definition";
2543 Int line = tycon(c).line;
2544 Int beta = tyvar(intOf(tycon(c).kind))->offs;
2545 Int m = tycon(c).arity;
2546 switch (whatIs(tycon(c).what)) {
2548 case DATATYPE : { List cs = tycon(c).defn;
2549 if (isQualType(cs)) {
2550 map3Proc(kindPred,line,beta,m,
2552 tycon(c).defn = cs = snd(snd(cs));
2554 for (; hasCfun(cs); cs=tl(cs)) {
2555 kindType(line,cfun,name(hd(cs)).type);
2560 default : checkKind(line,beta,m,tycon(c).defn,NIL,
2564 else { /* scan type exprs in class defn to*/
2565 List ms = fst(cclass(c).members);
2566 Int m = cclass(c).arity; /* determine the class signature */
2567 Int beta = newKindvars(m);
2568 kindPred(cclass(c).line,beta,m,cclass(c).head);
2569 map3Proc(kindPred,cclass(c).line,beta,m,cclass(c).supers);
2570 for (; nonNull(ms); ms=tl(ms)) {
2571 Int line = intOf(fst3(hd(ms)));
2572 Type type = thd3(hd(ms));
2573 kindType(line,"member function type signature",type);
2578 static Void local genTC(c) /* generalise kind inferred for */
2579 Cell c; { /* given tycon/class */
2581 tycon(c).kind = copyKindvar(intOf(tycon(c).kind));
2583 Printf("%s :: ",textToStr(tycon(c).text));
2584 printKind(stdout,tycon(c).kind);
2588 Kinds ks = cclass(c).kinds;
2589 for (; nonNull(ks); ks=tl(ks)) {
2590 hd(ks) = copyKindvar(intOf(hd(ks)));
2593 Printf("%s :: ",textToStr(cclass(c).text));
2594 printKinds(stdout,cclass(c).kinds);
2600 /* --------------------------------------------------------------------------
2601 * Static analysis of instance declarations:
2603 * The first part of the static analysis is performed as the declarations
2604 * are read during parsing:
2605 * - make new entry in instance table
2606 * - record line number of declaration
2607 * - build list of instances defined in current script for use in later
2608 * stages of static analysis.
2609 * ------------------------------------------------------------------------*/
2611 Void instDefn(line,head,ms) /* process new instance definition */
2612 Int line; /* definition line number */
2613 Cell head; /* inst header :: (context,Class) */
2614 List ms; { /* instance members */
2615 Inst nw = newInst();
2616 inst(nw).line = line;
2617 inst(nw).specifics = fst(head);
2618 inst(nw).head = snd(head);
2619 inst(nw).implements = ms;
2620 instDefns = cons(nw,instDefns);
2623 /* --------------------------------------------------------------------------
2624 * Further static analysis of instance declarations:
2626 * Makes the following checks:
2627 * - Class part of header has form C (T a1 ... an) where C is a known
2628 * class, and T is a known datatype constructor (or restricted synonym),
2629 * and there is no previous C-T instance, and (T a1 ... an) has a kind
2630 * appropriate for the class C.
2631 * - Each element of context is a valid class expression, with type vars
2632 * drawn from a1, ..., an.
2633 * - All bindings are function bindings
2634 * - All bindings define member functions for class C
2635 * - Arrange bindings into appropriate order for member list
2636 * - No top level type signature declarations
2637 * ------------------------------------------------------------------------*/
2639 Bool allowOverlap = FALSE; /* TRUE => allow overlapping insts */
2640 Name nameListMonad = NIL; /* builder function for List Monad */
2642 static Void local checkInstDefn(in) /* Validate instance declaration */
2644 Int line = inst(in).line;
2645 List tyvars = typeVarsIn(inst(in).head,NIL,NIL,NIL);
2646 List tvps = NIL, tvts = NIL;
2649 if (haskell98) { /* Check for `simple' type */
2651 Cell t = arg(inst(in).head);
2652 for (; isAp(t); t=fun(t)) {
2653 if (!isVar(arg(t))) {
2655 "syntax error in instance head (variable expected)"
2658 if (varIsMember(textOf(arg(t)),tvs)) {
2659 ERRMSG(line) "repeated type variable \"%s\" in instance head",
2660 textToStr(textOf(arg(t)))
2663 tvs = cons(arg(t),tvs);
2667 "syntax error in instance head (constructor expected)"
2672 /* add in the tyvars from the `specifics' so that we don't
2673 prematurely complain about undefined tyvars */
2674 tyvars = typeVarsIn(inst(in).specifics,NIL,NIL,tyvars);
2675 inst(in).head = depPredExp(line,tyvars,inst(in).head);
2678 Type h = getHead(arg(inst(in).head));
2680 ERRMSG(line) "Cannot use type synonym in instance head"
2685 map2Over(depPredExp,line,tyvars,inst(in).specifics);
2687 /* OK, now we start over, and test for ambiguity */
2688 tvts = offsetTyvarsIn(inst(in).head,NIL);
2689 tvps = offsetTyvarsIn(inst(in).specifics,NIL);
2690 fds = calcFunDeps(inst(in).specifics);
2691 tvts = oclose(fds,tvts);
2692 tvts = odiff(tvps,tvts);
2693 if (!isNull(tvts)) {
2694 ERRMSG(line) "Undefined type variable \"%s\"",
2695 textToStr(textOf(nth(offsetOf(hd(tvts)),tyvars)))
2699 h98CheckCtxt(line,"instance definition",FALSE,inst(in).specifics,NIL);
2700 inst(in).numSpecifics = length(inst(in).specifics);
2701 inst(in).c = getHead(inst(in).head);
2702 if (!isClass(inst(in).c)) {
2703 ERRMSG(line) "Illegal predicate in instance declaration"
2707 if (nonNull(cclass(inst(in).c).fds)) {
2708 List fds = cclass(inst(in).c).fds;
2709 for (; nonNull(fds); fds=tl(fds)) {
2710 List as = otvars(inst(in).head, fst(hd(fds)));
2711 List bs = otvars(inst(in).head, snd(hd(fds)));
2712 List fs = calcFunDeps(inst(in).specifics);
2714 if (!osubset(bs,as)) {
2715 ERRMSG(inst(in).line)
2716 "Instance is more general than a dependency allows"
2718 ERRTEXT "\n*** Instance : "
2719 ETHEN ERRPRED(inst(in).head);
2720 ERRTEXT "\n*** For class : "
2721 ETHEN ERRPRED(cclass(inst(in).c).head);
2722 ERRTEXT "\n*** Under dependency : "
2723 ETHEN ERRFD(hd(fds));
2730 kindInst(in,length(tyvars));
2733 if (nonNull(extractSigdecls(inst(in).implements))) {
2735 "Type signature declarations not permitted in instance declaration"
2738 if (nonNull(extractFixdecls(inst(in).implements))) {
2740 "Fixity declarations not permitted in instance declaration"
2743 inst(in).implements = classBindings("instance",
2745 extractBindings(inst(in).implements));
2746 inst(in).builder = newInstImp(in);
2747 if (!preludeLoaded && isNull(nameListMonad) && isAp(inst(in).head)
2748 && fun(inst(in).head)==classMonad && arg(inst(in).head)==typeList) {
2749 nameListMonad = inst(in).builder;
2753 static Void local insertInst(in) /* Insert instance into class */
2755 Class c = inst(in).c;
2756 List ins = cclass(c).instances;
2759 if (nonNull(cclass(c).fds)) { /* Check for conflicts with fds */
2760 List ins1 = cclass(c).instances;
2761 for (; nonNull(ins1); ins1=tl(ins1)) {
2762 List fds = cclass(c).fds;
2763 substitution(RESET);
2764 for (; nonNull(fds); fds=tl(fds)) {
2765 Int alpha = newKindedVars(inst(in).kinds);
2766 Int beta = newKindedVars(inst(hd(ins1)).kinds);
2767 List as = fst(hd(fds));
2769 for (; same && nonNull(as); as=tl(as)) {
2770 Int n = offsetOf(hd(as));
2771 same &= unify(nthArg(n,inst(in).head),alpha,
2772 nthArg(n,inst(hd(ins1)).head),beta);
2774 if (isNull(as) && same) {
2775 for (as=snd(hd(fds)); same && nonNull(as); as=tl(as)) {
2776 Int n = offsetOf(hd(as));
2777 same &= sameType(nthArg(n,inst(in).head),alpha,
2778 nthArg(n,inst(hd(ins1)).head),beta);
2781 ERRMSG(inst(in).line)
2782 "Instances are not consistent with dependencies"
2784 ERRTEXT "\n*** This instance : "
2785 ETHEN ERRPRED(inst(in).head);
2786 ERRTEXT "\n*** Conflicts with : "
2787 ETHEN ERRPRED(inst(hd(ins)).head);
2788 ERRTEXT "\n*** For class : "
2789 ETHEN ERRPRED(cclass(c).head);
2790 ERRTEXT "\n*** Under dependency : "
2791 ETHEN ERRFD(hd(fds));
2801 substitution(RESET);
2802 while (nonNull(ins)) { /* Look for overlap w/ other insts */
2803 Int alpha = newKindedVars(inst(in).kinds);
2804 Int beta = newKindedVars(inst(hd(ins)).kinds);
2805 if (unifyPred(inst(in).head,alpha,inst(hd(ins)).head,beta)) {
2806 Cell pi = copyPred(inst(in).head,alpha);
2807 if (allowOverlap && !haskell98) {
2808 Bool bef = instCompare(in,hd(ins));
2809 Bool aft = instCompare(hd(ins),in);
2810 if (bef && !aft) { /* in comes strictly before hd(ins)*/
2813 if (aft && !bef) { /* in comes strictly after hd(ins) */
2820 if (multiInstRes && nonNull(inst(in).specifics)) {
2824 ERRMSG(inst(in).line) "Overlapping instances for class \"%s\"",
2825 textToStr(cclass(c).text)
2827 ERRTEXT "\n*** This instance : " ETHEN ERRPRED(inst(in).head);
2828 ERRTEXT "\n*** Overlaps with : " ETHEN
2829 ERRPRED(inst(hd(ins)).head);
2830 ERRTEXT "\n*** Common instance : " ETHEN
2838 prev = ins; /* No overlap detected, so move on */
2839 ins = tl(ins); /* to next instance */
2841 substitution(RESET);
2843 if (nonNull(prev)) { /* Insert instance at this point */
2844 tl(prev) = cons(in,ins);
2846 cclass(c).instances = cons(in,ins);
2850 static Bool local instCompare(ia,ib) /* See if ia is an instance of ib */
2852 Int alpha = newKindedVars(inst(ia).kinds);
2853 Int beta = newKindedVars(inst(ib).kinds);
2854 return matchPred(inst(ia).head,alpha,inst(ib).head,beta);
2857 static Name local newInstImp(in) /* Make definition for inst builder*/
2859 Name b = newName(inventText(),in);
2860 name(b).line = inst(in).line;
2861 name(b).arity = inst(in).numSpecifics;
2862 name(b).number = DFUNNAME;
2866 /* --------------------------------------------------------------------------
2867 * Kind checking of instance declaration headers:
2868 * ------------------------------------------------------------------------*/
2870 static Void local kindInst(in,freedom) /* check predicates in instance */
2875 emptySubstitution();
2876 beta = newKindvars(freedom);
2877 kindPred(inst(in).line,beta,freedom,inst(in).head);
2878 if (whatIs(inst(in).specifics)!=DERIVE) {
2879 map3Proc(kindPred,inst(in).line,beta,freedom,inst(in).specifics);
2881 for (inst(in).kinds = NIL; 0<freedom--; ) {
2882 inst(in).kinds = cons(copyKindvar(beta+freedom),inst(in).kinds);
2885 Printf("instance ");
2886 printPred(stdout,inst(in).head);
2888 printKinds(stdout,inst(in).kinds);
2891 emptySubstitution();
2894 /* --------------------------------------------------------------------------
2895 * Process derived instance requests:
2896 * ------------------------------------------------------------------------*/
2898 static List derivedInsts; /* list of derived instances */
2900 static Void local checkDerive(t,p,ts,ct)/* verify derived instance request */
2901 Tycon t; /* for tycon t, with explicit */
2902 List p; /* context p, component types ts */
2903 List ts; /* and named class ct */
2905 Int line = tycon(t).line;
2906 Class c = findQualClass(ct);
2908 ERRMSG(line) "Unknown class \"%s\" in derived instance",
2912 addDerInst(line,c,p,dupList(ts),t,tycon(t).arity);
2915 static Void local addDerInst(line,c,p,cts,t,a) /* Add a derived instance */
2922 Cell head = t; /* Build instance head */
2926 head = ap(head,mkOffset(i));
2932 inst(in).line = line;
2933 inst(in).head = head;
2934 inst(in).specifics = ap(DERIVE,pair(dupList(p),cts));
2935 inst(in).implements = NIL;
2936 inst(in).kinds = mkInt(a);
2937 derivedInsts = cons(in,derivedInsts);
2940 Void addTupInst(c,n) /* Request derived instance of c */
2941 Class c; /* for mkTuple(n) constructor */
2946 cts = cons(mkOffset(m),cts);
2949 addDerInst(0,c,NIL,cts,mkTuple(n),n);
2953 Inst addRecShowInst(c,e) /* Generate instance for ShowRecRow*/
2954 Class c; /* c *must* be ShowRecRow */
2956 Inst in = newInst();
2958 inst(in).head = ap(c,ap2(e,aVar,bVar));
2959 inst(in).kinds = extKind;
2960 inst(in).specifics = cons(ap(classShow,aVar),
2962 cons(ap(c,bVar),NIL)));
2963 inst(in).numSpecifics = 3;
2964 inst(in).builder = implementRecShw(extText(e),in);
2965 cclass(c).instances = appendOnto(cclass(c).instances,singleton(in));
2969 Inst addRecEqInst(c,e) /* Generate instance for EqRecRow */
2970 Class c; /* c *must* be EqRecRow */
2972 Inst in = newInst();
2974 inst(in).head = ap(c,ap2(e,aVar,bVar));
2975 inst(in).kinds = extKind;
2976 inst(in).specifics = cons(ap(classEq,aVar),
2978 cons(ap(c,bVar),NIL)));
2979 inst(in).numSpecifics = 3;
2980 inst(in).builder = implementRecEq(extText(e),in);
2981 cclass(c).instances = appendOnto(cclass(c).instances,singleton(in));
2986 /* --------------------------------------------------------------------------
2987 * Calculation of contexts for derived instances:
2989 * Allowing arbitrary types to appear in contexts makes it rather harder
2990 * to decide what the context for a derived instance should be. For
2993 * data T a = MkT [a] deriving Show,
2995 * we could have either of the following:
2997 * instance (Show [a]) => Show (T a) where ...
2998 * instance (Show a) => Show (T a) where ...
3000 * (assuming, of course, that instance (Show a) => Show [a]). For now, we
3001 * choose to reduce contexts in the hope of detecting errors at an earlier
3002 * stage---in contrast with value definitions, there is no way for a user
3003 * to provide something analogous to a `type signature' by which they might
3004 * be able to control this behaviour themselves. We eliminate tautological
3005 * predicates, but only allow predicates to appear in the final result if
3006 * they have at least one argument with a variable at its head.
3008 * In general, we have to deal with mutually recursive instance declarations.
3009 * We find a solution in the obvious way by iterating to find a fixed point.
3010 * Of course, without restrictions on the form of instance declarations, we
3011 * cannot be sure that this will always terminate!
3013 * For each instance we maintain a pair of the form DERIVE (ctxt,ps).
3014 * Ctxt is a list giving the parts of the context that have been produced
3015 * so far in the form of predicate skeletons. During the calculation of
3016 * derived instances, we attach a dummy NIL value to the end of the list
3017 * which acts as a kind of `variable': other parts of the system maintain
3018 * pointers to this variable, and use it to detect when the context has
3019 * been extended with new elements. Meanwhile, ps is a list containing
3020 * predicates (pi,o) together with (delayed) substitutions of the form
3021 * (o,xs) where o is an offset and xs is one of the context variables
3022 * described above, which may have been partially instantiated.
3023 * ------------------------------------------------------------------------*/
3025 static Bool instsChanged;
3027 static Void local deriveContexts(is) /* Calc contexts for derived insts */
3029 emptySubstitution();
3030 mapProc(initDerInst,is); /* Prepare derived instances */
3032 do { /* Main calculation of contexts */
3033 instsChanged = FALSE;
3034 mapProc(calcInstPreds,is);
3035 } while (instsChanged);
3037 mapProc(tidyDerInst,is); /* Tidy up results */
3040 static Void local initDerInst(in) /* Prepare instance for calculation*/
3041 Inst in; { /* of derived instance context */
3042 Cell spcs = inst(in).specifics;
3043 Int beta = newKindedVars(inst(in).kinds);
3044 if (whatIs(spcs)!=DERIVE) {
3045 internal("initDerInst");
3047 fst(snd(spcs)) = appendOnto(fst(snd(spcs)),singleton(NIL));
3048 for (spcs=snd(snd(spcs)); nonNull(spcs); spcs=tl(spcs)) {
3049 hd(spcs) = ap2(inst(in).c,hd(spcs),mkInt(beta));
3051 inst(in).numSpecifics = beta;
3053 #ifdef DEBUG_DERIVING
3054 Printf("initDerInst: ");
3055 printPred(stdout,inst(in).head);
3057 printContext(stdout,snd(snd(inst(in).specifics)));
3062 static Void local calcInstPreds(in) /* Calculate next approximation */
3063 Inst in; { /* of the context for a derived */
3064 List retain = NIL; /* instance */
3065 List ps = snd(snd(inst(in).specifics));
3066 List spcs = fst(snd(inst(in).specifics));
3067 Int beta = inst(in).numSpecifics;
3069 Int factor = 1+length(ps);
3071 #ifdef DEBUG_DERIVING
3072 Printf("calcInstPreds: ");
3073 printPred(stdout,inst(in).head);
3077 while (nonNull(ps)) {
3080 if (its++ >= factor*cutoff) {
3081 Cell bpi = inst(in).head;
3082 ERRMSG(inst(in).line) "\n*** Cannot derive " ETHEN ERRPRED(bpi);
3083 ERRTEXT " after %d iterations.", its-1 ETHEN
3085 "\n*** This may indicate that the problem is undecidable. However,\n"
3087 "*** you may still try to increase the cutoff limit using the -c\n"
3089 "*** option and then try again. (The current setting is -c%d)\n",
3093 if (isInt(fst(p))) { /* Delayed substitution? */
3095 for (; nonNull(hd(qs)); qs=tl(qs)) {
3096 ps = cons(pair(hd(qs),fst(p)),ps);
3098 retain = cons(pair(fst(p),qs),retain);
3101 else if (isExt(fun(fst(p)))) { /* Lacks predicate */
3102 Text l = extText(fun(fst(p)));
3103 Type t = arg(fst(p));
3104 Int o = intOf(snd(p));
3109 h = getDerefHead(t,o);
3110 while (isExt(h) && argCount==2 && l!=extText(h)) {
3113 h = getDerefHead(t,o);
3115 if (argCount==0 && isOffset(h)) {
3116 maybeAddPred(ap(fun(fun(p)),h),o,beta,spcs);
3117 } else if (argCount!=0 || h!=typeNoRow) {
3118 Cell bpi = inst(in).head;
3119 Cell pi = copyPred(fun(p),intOf(snd(p)));
3120 ERRMSG(inst(in).line) "Cannot derive " ETHEN ERRPRED(bpi);
3121 ERRTEXT " because predicate " ETHEN ERRPRED(pi);
3122 ERRTEXT " does not hold\n"
3127 else { /* Class predicate */
3129 Int o = intOf(snd(p));
3130 Inst in1 = findInstFor(pi,o);
3132 List qs = inst(in1).specifics;
3133 Int off = mkInt(typeOff);
3134 if (whatIs(qs)==DERIVE) { /* Still being derived */
3135 for (qs=fst(snd(qs)); nonNull(hd(qs)); qs=tl(qs)) {
3136 ps = cons(pair(hd(qs),off),ps);
3138 retain = cons(pair(off,qs),retain);
3139 } else { /* Previously def'd inst */
3140 for (; nonNull(qs); qs=tl(qs)) {
3141 ps = cons(pair(hd(qs),off),ps);
3144 } else { /* No matching instance */
3146 while (isAp(qi) && isOffset(getDerefHead(arg(qi),o))) {
3150 Cell bpi = inst(in).head;
3151 pi = copyPred(pi,o);
3152 ERRMSG(inst(in).line) "An instance of " ETHEN ERRPRED(pi);
3153 ERRTEXT " is required to derive " ETHEN ERRPRED(bpi);
3157 maybeAddPred(pi,o,beta,spcs);
3162 snd(snd(inst(in).specifics)) = retain;
3165 static Void local maybeAddPred(pi,o,beta,ps)
3166 Cell pi; /* Add predicate pi to the list ps,*/
3167 Int o; /* setting the instsChanged flag if*/
3168 Int beta; /* pi is not already a member and */
3169 List ps; { /* using beta to adjust vars */
3170 Cell c = getHead(pi);
3171 for (; nonNull(ps); ps=tl(ps)) {
3172 if (isNull(hd(ps))) { /* reached the `dummy' end of list?*/
3173 hd(ps) = copyAdj(pi,o,beta);
3174 tl(ps) = pair(NIL,NIL);
3175 instsChanged = TRUE;
3177 } else if (c==getHead(hd(ps)) && samePred(pi,o,hd(ps),beta)) {
3183 static Cell local copyAdj(c,o,beta) /* Copy (c,o), replacing vars with */
3184 Cell c; /* offsets relative to beta. */
3187 switch (whatIs(c)) {
3188 case AP : { Cell l = copyAdj(fst(c),o,beta);
3189 Cell r = copyAdj(snd(c),o,beta);
3193 case OFFSET : { Int vn = o+offsetOf(c);
3194 Tyvar *tyv = tyvar(vn);
3196 return copyAdj(tyv->bound,tyv->offs,beta);
3199 if (vn<0 || vn>=NUM_OFFSETS) {
3200 internal("copyAdj");
3202 return mkOffset(vn);
3208 static Void local tidyDerInst(in) /* Tidy up results of derived inst */
3209 Inst in; { /* calculations */
3210 Int o = inst(in).numSpecifics;
3211 List ps = tl(rev(fst(snd(inst(in).specifics))));
3213 copyPred(inst(in).head,o);
3214 inst(in).specifics = simpleContext(ps,o);
3215 h98CheckCtxt(inst(in).line,"derived instance",FALSE,inst(in).specifics,in);
3216 inst(in).numSpecifics = length(inst(in).specifics);
3218 #ifdef DEBUG_DERIVING
3219 Printf("Derived instance: ");
3220 printContext(stdout,inst(in).specifics);
3222 printPred(stdout,inst(in).head);
3227 /* --------------------------------------------------------------------------
3228 * Generate code for derived instances:
3229 * ------------------------------------------------------------------------*/
3231 static Void local addDerivImp(in)
3234 Type t = getHead(arg(inst(in).head));
3235 Class c = inst(in).c;
3238 } else if (c==classOrd) {
3240 } else if (c==classEnum) {
3241 imp = deriveEnum(t);
3242 } else if (c==classIx) {
3244 } else if (c==classShow) {
3245 imp = deriveShow(t);
3246 } else if (c==classRead) {
3247 imp = deriveRead(t);
3248 } else if (c==classBounded) {
3249 imp = deriveBounded(t);
3251 ERRMSG(inst(in).line) "Cannot derive instances of class \"%s\"",
3252 textToStr(cclass(inst(in).c).text)
3256 kindInst(in,intOf(inst(in).kinds));
3258 inst(in).builder = newInstImp(in);
3259 inst(in).implements = classBindings("derived instance",
3265 /* --------------------------------------------------------------------------
3266 * Default definitions; only one default definition is permitted in a
3267 * given script file. If no default is supplied, then a standard system
3268 * default will be used where necessary.
3269 * ------------------------------------------------------------------------*/
3271 Void defaultDefn(line,defs) /* Handle default types definition */
3274 if (defaultLine!=0) {
3275 ERRMSG(line) "Multiple default declarations are not permitted in" ETHEN
3276 ERRTEXT "a single script file.\n"
3279 defaultDefns = defs;
3283 static Void local checkDefaultDefns() { /* check that default types are */
3284 List ds = NIL; /* well-kinded instances of Num */
3286 if (defaultLine!=0) {
3287 map2Over(depTypeExp,defaultLine,NIL,defaultDefns);
3288 emptySubstitution();
3290 map2Proc(kindType,defaultLine,"default type",defaultDefns);
3292 emptySubstitution();
3293 mapOver(fullExpand,defaultDefns);
3295 defaultDefns = stdDefaults;
3298 if (isNull(classNum)) {
3299 classNum = findClass(findText("Num"));
3302 for (ds=defaultDefns; nonNull(ds); ds=tl(ds)) {
3303 if (isNull(provePred(NIL,NIL,ap(classNum,hd(ds))))) {
3305 "Default types must be instances of the Num class"
3312 /* --------------------------------------------------------------------------
3313 * Foreign import declarations are Hugs' equivalent of GHC's ccall mechanism.
3314 * They are used to "import" C functions into a module.
3315 * They are usually not written by hand but, rather, generated automatically
3316 * by GreenCard, IDL compilers or whatever. We support foreign import
3317 * (static) and foreign import dynamic. In the latter case, extName==NIL.
3319 * Foreign export declarations generate C wrappers for Hugs functions.
3320 * Hugs only provides "foreign export dynamic" because it's not obvious
3321 * what "foreign export static" would mean in an interactive setting.
3322 * ------------------------------------------------------------------------*/
3324 Void foreignImport(line,callconv,extName,intName,type)
3325 /* Handle foreign imports */
3331 Text t = textOf(intName);
3332 Name n = findName(t);
3333 Int l = intOf(line);
3337 } else if (name(n).defn!=PREDEFINED) {
3338 ERRMSG(l) "Redeclaration of foreign \"%s\"", textToStr(t)
3342 name(n).defn = extName;
3343 name(n).type = type;
3344 name(n).callconv = callconv;
3345 foreignImports = cons(n,foreignImports);
3348 static Void local checkForeignImport(p) /* Check foreign import */
3350 emptySubstitution();
3351 name(p).type = checkSigType(name(p).line,
3352 "foreign import declaration",
3355 /* We don't expand synonyms here because we don't want the IO
3356 * part to be expanded.
3357 * name(p).type = fullExpand(name(p).type);
3359 implementForeignImport(p);
3362 Void foreignExport(line,callconv,extName,intName,type)
3363 /* Handle foreign exports */
3369 Text t = textOf(intName);
3370 Name n = findName(t);
3371 Int l = intOf(line);
3375 } else if (name(n).defn!=PREDEFINED) {
3376 ERRMSG(l) "Redeclaration of foreign \"%s\"", textToStr(t)
3380 name(n).defn = NIL; /* nothing to say */
3381 name(n).type = type;
3382 name(n).callconv = callconv;
3383 foreignExports = cons(n,foreignExports);
3386 static Void local checkForeignExport(p) /* Check foreign export */
3388 emptySubstitution();
3389 name(p).type = checkSigType(name(p).line,
3390 "foreign export declaration",
3393 implementForeignExport(p);
3398 /* --------------------------------------------------------------------------
3399 * Static analysis of patterns:
3401 * Patterns are parsed as ordinary (atomic) expressions. Static analysis
3402 * makes the following checks:
3403 * - Patterns are well formed (according to pattern syntax), including the
3404 * special case of (n+k) patterns.
3405 * - All constructor functions have been defined and are used with the
3406 * correct number of arguments.
3407 * - No variable name is used more than once in a pattern.
3409 * The list of pattern variables occuring in each pattern is accumulated in
3410 * a global list `patVars', which must be initialised to NIL at appropriate
3411 * points before using these routines to check for valid patterns. This
3412 * mechanism enables the pattern checking routine to be mapped over a list
3413 * of patterns, ensuring that no variable occurs more than once in the
3414 * complete pattern list (as is required on the lhs of a function defn).
3415 * ------------------------------------------------------------------------*/
3417 static List patVars; /* List of vars bound in pattern */
3419 static Cell local checkPat(line,p) /* Check valid pattern syntax */
3422 switch (whatIs(p)) {
3424 case VAROPCELL : addToPatVars(line,p);
3427 case INFIX : return checkPat(line,tidyInfix(line,snd(p)));
3429 case AP : return checkMaybeCnkPat(line,p);
3434 case CONOPCELL : return checkApPat(line,0,p);
3439 case FLOATCELL : break;
3440 case INTCELL : break;
3442 case ASPAT : addToPatVars(line,fst(snd(p)));
3443 snd(snd(p)) = checkPat(line,snd(snd(p)));
3446 case LAZYPAT : snd(p) = checkPat(line,snd(p));
3449 case FINLIST : map1Over(checkPat,line,snd(p));
3452 case CONFLDS : depConFlds(line,p,TRUE);
3455 case ESIGN : snd(snd(p)) = checkPatType(line,
3459 fst(snd(p)) = checkPat(line,fst(snd(p)));
3462 default : ERRMSG(line) "Illegal pattern syntax"
3468 static Cell local checkMaybeCnkPat(l,p)/* Check applicative pattern with */
3469 Int l; /* the possibility of n+k pattern */
3472 Cell h = getHead(p);
3474 if (argCount==2 && isVar(h) && textOf(h)==textPlus) { /* n+k */
3475 Cell v = arg(fun(p));
3476 if (!isInt(arg(p))) {
3477 ERRMSG(l) "Second argument in (n+k) pattern must be an integer"
3480 if (intOf(arg(p))<=0) {
3481 ERRMSG(l) "Integer k in (n+k) pattern must be > 0"
3484 fst(fun(p)) = ADDPAT;
3485 intValOf(fun(p)) = intOf(arg(p));
3486 arg(p) = checkPat(l,v);
3490 return checkApPat(l,0,p);
3493 static Cell local checkApPat(line,args,p)
3494 Int line; /* check validity of application */
3495 Int args; /* of constructor to arguments */
3497 switch (whatIs(p)) {
3498 case AP : fun(p) = checkApPat(line,args+1,fun(p));
3499 arg(p) = checkPat(line,arg(p));
3502 case TUPLE : if (tupleOf(p)!=args) {
3503 ERRMSG(line) "Illegal tuple pattern"
3509 case EXT : h98DoesntSupport(line,"extensible records");
3511 ERRMSG(line) "Illegal record pattern"
3517 case QUALIDENT : if (!isQCon(p)) {
3519 "Illegal use of qualified variable in pattern"
3522 /* deliberate fall through */
3524 case CONOPCELL : p = conDefined(line,p);
3525 checkCfunArgs(line,p,args);
3528 case NAME : checkIsCfun(line,p);
3529 checkCfunArgs(line,p,args);
3532 default : ERRMSG(line) "Illegal pattern syntax"
3538 static Void local addToPatVars(line,v) /* Add variable v to list of vars */
3539 Int line; /* in current pattern, checking */
3540 Cell v; { /* for repeated variables. */
3545 for (; nonNull(n); p=n, n=tl(n)) {
3546 if (textOf(hd(n))==t) {
3547 ERRMSG(line) "Repeated variable \"%s\" in pattern",
3554 patVars = cons(v,NIL);
3556 tl(p) = cons(v,NIL);
3560 static Name local conDefined(line,nm) /* check that nm is the name of a */
3561 Int line; /* previously defined constructor */
3562 Cell nm; { /* function. */
3563 Name n = findQualName(nm);
3565 ERRMSG(line) "Undefined constructor function \"%s\"", identToStr(nm)
3568 checkIsCfun(line,n);
3572 static Void local checkIsCfun(line,c) /* Check that c is a constructor fn */
3576 ERRMSG(line) "\"%s\" is not a constructor function",
3577 textToStr(name(c).text)
3582 static Void local checkCfunArgs(line,c,args)
3583 Int line; /* Check constructor applied with */
3584 Cell c; /* correct number of arguments */
3586 Int a = userArity(c);
3589 "Constructor \"%s\" must have exactly %d argument%s in pattern",
3590 textToStr(name(c).text), a, ((a==1)?"":"s")
3595 static Cell local checkPatType(l,wh,e,t)/* Check type appearing in pattern */
3600 List tvs = typeVarsIn(t,NIL,NIL,NIL);
3601 h98DoesntSupport(l,"pattern type annotations");
3602 for (; nonNull(tvs); tvs=tl(tvs)) {
3603 Int beta = newKindvars(1);
3604 hd(btyvars) = cons(pair(hd(tvs),mkInt(beta)), hd(btyvars));
3606 t = checkSigType(l,"pattern type",e,t);
3607 if (isPolyOrQualType(t) || whatIs(t)==RANK2) {
3608 ERRMSG(l) "Illegal syntax in %s type annotation", wh
3614 static Cell local applyBtyvs(pat) /* Record bound type vars in pat */
3616 List bts = hd(btyvars);
3619 pat = ap(BIGLAM,pair(bts,pat));
3620 for (; nonNull(bts); bts=tl(bts)) {
3621 snd(hd(bts)) = copyKindvar(intOf(snd(hd(bts))));
3627 /* --------------------------------------------------------------------------
3628 * Maintaining lists of bound variables and local definitions, for
3629 * dependency and scope analysis.
3630 * ------------------------------------------------------------------------*/
3632 static List bounds; /* list of lists of bound vars */
3633 static List bindings; /* list of lists of binds in scope */
3634 static List depends; /* list of lists of dependents */
3636 /* bounds :: [[Var]] -- var equality used on Vars */
3637 /* bindings :: [[([Var],?)]] -- var equality used on Vars */
3638 /* depends :: [[Var]] -- pointer equality used on Vars */
3640 #define saveBvars() hd(bounds) /* list of bvars in current scope */
3641 #define restoreBvars(bs) hd(bounds)=bs /* restore list of bound variables */
3643 static Cell local bindPat(line,p) /* add new bound vars for pattern */
3647 p = checkPat(line,p);
3648 hd(bounds) = revOnto(patVars,hd(bounds));
3652 static Void local bindPats(line,ps) /* add new bound vars for patterns */
3656 map1Over(checkPat,line,ps);
3657 hd(bounds) = revOnto(patVars,hd(bounds));
3660 /* --------------------------------------------------------------------------
3661 * Before processing value and type signature declarations, all data and
3662 * type definitions have been processed so that:
3663 * - all valid type constructors (with their arities) are known.
3664 * - all valid constructor functions (with their arities and types) are
3667 * The result of parsing a list of value declarations is a list of Eqns:
3668 * Eqn ::= (SIGDECL,(Line,[Var],type))
3669 * | (FIXDECL,(Line,[Op],SyntaxInt))
3671 * The ordering of the equations in this list is the reverse of the original
3672 * ordering in the script parsed. This is a consequence of the structure of
3673 * the parser ... but also turns out to be most convenient for the static
3676 * As the first stage of the static analysis of value declarations, each
3677 * list of Eqns is converted to a list of Bindings. As part of this
3679 * - The ordering of the list of Bindings produced is the same as in the
3681 * - When a variable (function) is defined over a number of lines, all
3682 * of the definitions should appear together and each should give the
3683 * same arity to the variable being defined.
3684 * - No variable can have more than one definition.
3685 * - For pattern bindings:
3686 * - Each lhs is a valid pattern/function lhs, all constructor functions
3687 * have been defined and are used with the correct number of arguments.
3688 * - Each lhs contains no repeated pattern variables.
3689 * - Each equation defines at least one variable (e.g. True = False is
3691 * - Types appearing in type signatures are well formed:
3692 * - Type constructors used are defined and used with correct number
3694 * - type variables are replaced by offsets, type constructor names
3696 * - Every variable named in a type signature declaration is defined by
3697 * one or more equations elsewhere in the script.
3698 * - No variable has more than one type declaration.
3699 * - Similar properties for fixity declarations.
3701 * ------------------------------------------------------------------------*/
3703 #define bindingAttr(b) fst(snd(b)) /* type(s)/fixity(ies) for binding */
3704 #define fbindAlts(b) snd(snd(b)) /* alternatives for function binding*/
3706 static List local extractSigdecls(es) /* Extract the SIGDECLS from list */
3707 List es; { /* of equations */
3708 List sigdecls = NIL; /* :: [(Line,[Var],Type)] */
3710 for(; nonNull(es); es=tl(es)) {
3711 if (fst(hd(es))==SIGDECL) { /* type-declaration? */
3712 Pair sig = snd(hd(es));
3713 Int line = intOf(fst3(sig));
3714 List vs = snd3(sig);
3715 for(; nonNull(vs); vs=tl(vs)) {
3716 if (isQualIdent(hd(vs))) {
3717 ERRMSG(line) "Type signature for qualified variable \"%s\" is not allowed",
3722 sigdecls = cons(sig,sigdecls); /* discard SIGDECL tag*/
3728 static List local extractFixdecls(es) /* Extract the FIXDECLS from list */
3729 List es; { /* of equations */
3730 List fixdecls = NIL; /* :: [(Line,SyntaxInt,[Op])] */
3732 for(; nonNull(es); es=tl(es)) {
3733 if (fst(hd(es))==FIXDECL) { /* fixity declaration?*/
3734 fixdecls = cons(snd(hd(es)),fixdecls); /* discard FIXDECL tag*/
3740 static List local extractBindings(ds) /* extract untyped bindings from */
3741 List ds; { /* given list of equations */
3742 Cell lastVar = NIL; /* = var def'd in last eqn (if any)*/
3743 Int lastArity = 0; /* = number of args in last defn */
3744 List bs = NIL; /* :: [Binding] */
3746 for(; nonNull(ds); ds=tl(ds)) {
3748 if (fst(d)==FUNBIND) { /* Function bindings */
3749 Cell rhs = snd(snd(d));
3750 Int line = rhsLine(rhs);
3751 Cell lhs = fst(snd(d));
3752 Cell v = getHead(lhs);
3753 Cell newAlt = pair(getArgs(lhs),rhs);
3755 internal("FUNBIND");
3757 if (nonNull(lastVar) && textOf(v)==textOf(lastVar)) {
3758 if (argCount!=lastArity) {
3759 ERRMSG(line) "Equations give different arities for \"%s\"",
3760 textToStr(textOf(v))
3763 fbindAlts(hd(bs)) = cons(newAlt,fbindAlts(hd(bs)));
3767 lastArity = argCount;
3768 notDefined(line,bs,v);
3769 bs = cons(pair(v,pair(NIL,singleton(newAlt))),bs);
3772 } else if (fst(d)==PATBIND) { /* Pattern bindings */
3773 Cell rhs = snd(snd(d));
3774 Int line = rhsLine(rhs);
3775 Cell pat = fst(snd(d));
3776 while (whatIs(pat)==ESIGN) {/* Move type annotations to rhs */
3777 Cell p = fst(snd(pat));
3778 fst(snd(pat)) = rhs;
3779 snd(snd(d)) = rhs = pat;
3780 fst(snd(d)) = pat = p;
3783 if (isVar(pat)) { /* Convert simple pattern bind to */
3784 notDefined(line,bs,pat);/* a function binding */
3785 bs = cons(pair(pat,pair(NIL,singleton(pair(NIL,rhs)))),bs);
3787 List vs = getPatVars(line,pat,NIL);
3789 ERRMSG(line) "No variables defined in lhs pattern"
3792 map2Proc(notDefined,line,bs,vs);
3793 bs = cons(pair(vs,pair(NIL,snd(d))),bs);
3801 static List local getPatVars(line,p,vs) /* Find list of variables bound in */
3802 Int line; /* pattern p */
3805 switch (whatIs(p)) {
3807 vs = getPatVars(line,arg(p),vs);
3810 return vs; /* Ignore head of application */
3812 case CONFLDS : { List pfs = snd(snd(p));
3813 for (; nonNull(pfs); pfs=tl(pfs)) {
3814 if (isVar(hd(pfs))) {
3815 vs = addPatVar(line,hd(pfs),vs);
3817 vs = getPatVars(line,snd(hd(pfs)),vs);
3823 case FINLIST : { List ps = snd(p);
3824 for (; nonNull(ps); ps=tl(ps)) {
3825 vs = getPatVars(line,hd(ps),vs);
3830 case ESIGN : return getPatVars(line,fst(snd(p)),vs);
3835 case INFIX : return getPatVars(line,snd(p),vs);
3837 case ASPAT : return addPatVar(line,fst(snd(p)),
3838 getPatVars(line,snd(snd(p)),vs));
3841 case VAROPCELL : return addPatVar(line,p,vs);
3851 case WILDCARD : return vs;
3853 default : internal("getPatVars");
3858 static List local addPatVar(line,v,vs) /* Add var to list of previously */
3859 Int line; /* encountered variables */
3862 if (varIsMember(textOf(v),vs)) {
3863 ERRMSG(line) "Repeated use of variable \"%s\" in pattern binding",
3864 textToStr(textOf(v))
3870 static List local eqnsToBindings(es,ts,cs,ps)
3871 List es; /* Convert list of equations to */
3872 List ts; /* list of typed bindings */
3875 List bs = extractBindings(es);
3876 map1Proc(addSigdecl,bs,extractSigdecls(es));
3877 map4Proc(addFixdecl,bs,ts,cs,ps,extractFixdecls(es));
3881 static Void local notDefined(line,bs,v)/* check if name already defined in */
3882 Int line; /* list of bindings */
3885 if (nonNull(findBinding(textOf(v),bs))) {
3886 ERRMSG(line) "\"%s\" multiply defined", textToStr(textOf(v))
3891 static Cell local findBinding(t,bs) /* look for binding for variable t */
3892 Text t; /* in list of bindings bs */
3894 for (; nonNull(bs); bs=tl(bs)) {
3895 if (isVar(fst(hd(bs)))) { /* function-binding? */
3896 if (textOf(fst(hd(bs)))==t) {
3899 } else if (nonNull(varIsMember(t,fst(hd(bs))))){/* pattern-binding?*/
3906 static Cell local getAttr(bs,v) /* Locate type/fixity attribute */
3907 List bs; /* for variable v in bindings bs */
3910 Cell b = findBinding(t,bs);
3912 if (isNull(b)) { /* No binding */
3914 } else if (isVar(fst(b))) { /* func binding? */
3915 if (isNull(bindingAttr(b))) {
3916 bindingAttr(b) = pair(NIL,NIL);
3918 return bindingAttr(b);
3919 } else { /* pat binding? */
3921 List as = bindingAttr(b);
3924 bindingAttr(b) = as = replicate(length(vs),NIL);
3927 while (nonNull(vs) && t!=textOf(hd(vs))) {
3933 internal("getAttr");
3934 } else if (isNull(hd(as))) {
3935 hd(as) = pair(NIL,NIL);
3941 static Void local addSigdecl(bs,sigdecl)/* add type information to bindings*/
3942 List bs; /* :: [Binding] */
3943 Cell sigdecl; { /* :: (Line,[Var],Type) */
3944 Int l = intOf(fst3(sigdecl));
3945 List vs = snd3(sigdecl);
3946 Type type = checkSigType(l,"type declaration",hd(vs),thd3(sigdecl));
3948 for (; nonNull(vs); vs=tl(vs)) {
3950 Pair attr = getAttr(bs,v);
3952 ERRMSG(l) "Missing binding for variable \"%s\" in type signature",
3953 textToStr(textOf(v))
3955 } else if (nonNull(fst(attr))) {
3956 ERRMSG(l) "Repeated type signature for \"%s\"",
3957 textToStr(textOf(v))
3964 static Void local addFixdecl(bs,ts,cs,ps,fixdecl)
3970 Int line = intOf(fst3(fixdecl));
3971 List ops = snd3(fixdecl);
3972 Cell sy = thd3(fixdecl);
3974 for (; nonNull(ops); ops=tl(ops)) {
3976 Text t = textOf(op);
3977 Cell attr = getAttr(bs,op);
3978 if (nonNull(attr)) { /* Found name in binding? */
3979 if (nonNull(snd(attr))) {
3983 } else { /* Look in tycons, classes, prims */
3988 for (; isNull(n) && nonNull(ts1); ts1=tl(ts1)) { /* tycons */
3990 if (tycon(tc).what==DATATYPE || tycon(tc).what==NEWTYPE) {
3991 n = nameIsMember(t,tycon(tc).defn);
3994 for (; isNull(n) && nonNull(cs1); cs1=tl(cs1)) { /* classes */
3995 n = nameIsMember(t,cclass(hd(cs1)).members);
3997 for (; isNull(n) && nonNull(ps1); ps1=tl(ps1)) { /* prims */
3998 n = nameIsMember(t,hd(ps1));
4003 } else if (name(n).syntax!=NO_SYNTAX) {
4006 name(n).syntax = intOf(sy);
4011 static Void local dupFixity(line,t) /* Report repeated fixity decl */
4015 "Repeated fixity declaration for operator \"%s\"", textToStr(t)
4019 static Void local missFixity(line,t) /* Report missing op for fixity */
4023 "Cannot find binding for operator \"%s\" in fixity declaration",
4028 /* --------------------------------------------------------------------------
4029 * Dealing with infix operators:
4031 * Expressions involving infix operators or unary minus are parsed as
4032 * elements of the following type:
4034 * data InfixExp = Only Exp | Neg InfixExp | Infix InfixExp Op Exp
4036 * (The algorithms here do not assume that negation can be applied only once,
4037 * i.e., that - - x is a syntax error, as required by the Haskell report.
4038 * Instead, that restriction is captured by the grammar itself, given above.)
4040 * There are rules of precedence and grouping, expressed by two functions:
4042 * prec :: Op -> Int; assoc :: Op -> Assoc (Assoc = {L, N, R})
4044 * InfixExp values are rearranged accordingly when a complete expression
4045 * has been read using a simple shift-reduce parser whose result may be taken
4046 * to be a value of the following type:
4048 * data Exp = Atom Int | Negate Exp | Apply Op Exp Exp | Error String
4050 * The machine on which this parser is based can be defined as follows:
4052 * tidy :: InfixExp -> [(Op,Exp)] -> Exp
4053 * tidy (Only a) [] = a
4054 * tidy (Only a) ((o,b):ss) = tidy (Only (Apply o a b)) ss
4055 * tidy (Infix a o b) [] = tidy a [(o,b)]
4056 * tidy (Infix a o b) ((p,c):ss)
4057 * | shift o p = tidy a ((o,b):(p,c):ss)
4058 * | red o p = tidy (Infix a o (Apply p b c)) ss
4059 * | ambig o p = Error "ambiguous use of operators"
4060 * tidy (Neg e) [] = tidy (tidyNeg e) []
4061 * tidy (Neg e) ((o,b):ss)
4062 * | nshift o = tidy (Neg (underNeg o b e)) ss
4063 * | nred o = tidy (tidyNeg e) ((o,b):ss)
4064 * | nambig o = Error "illegal use of negation"
4066 * At each stage, the parser can either shift, reduce, accept, or error.
4067 * The transitions when dealing with juxtaposed operators o and p are
4068 * determined by the following rules:
4070 * shift o p = (prec o > prec p)
4071 * || (prec o == prec p && assoc o == L && assoc p == L)
4073 * red o p = (prec o < prec p)
4074 * || (prec o == prec p && assoc o == R && assoc p == R)
4076 * ambig o p = (prec o == prec p)
4077 * && (assoc o == N || assoc p == N || assoc o /= assoc p)
4079 * The transitions when dealing with juxtaposed unary minus and infix
4080 * operators are as follows. The precedence of unary minus (infixl 6) is
4081 * hardwired in to these definitions, as it is to the definitions of the
4082 * Haskell grammar in the official report.
4084 * nshift o = (prec o > 6)
4085 * nred o = (prec o < 6) || (prec o == 6 && assoc o == L)
4086 * nambig o = prec o == 6 && (assoc o == R || assoc o == N)
4088 * An InfixExp of the form (Neg e) means negate the last thing in
4089 * the InfixExp e; we can force this negation using:
4091 * tidyNeg :: OpExp -> OpExp
4092 * tidyNeg (Only e) = Only (Negate e)
4093 * tidyNeg (Infix a o b) = Infix a o (Negate b)
4094 * tidyNeg (Neg e) = tidyNeg (tidyNeg e)
4096 * On the other hand, if we want to sneak application of an infix operator
4097 * under a negation, then we use:
4099 * underNeg :: Op -> Exp -> OpExp -> OpExp
4100 * underNeg o b (Only e) = Only (Apply o e b)
4101 * underNeg o b (Neg e) = Neg (underNeg o b e)
4102 * underNeg o b (Infix e p f) = Infix e p (Apply o f b)
4104 * As a concession to efficiency, we lower the number of calls to syntaxOf
4105 * by keeping track of the values of sye, sys throughout the process. The
4106 * value APPLIC is used to indicate that the syntax value is unknown.
4107 * ------------------------------------------------------------------------*/
4109 static Cell local tidyInfix(line,e) /* Convert infixExp to Exp */
4111 Cell e; { /* :: OpExp */
4112 Cell s = NIL; /* :: [(Op,Exp)] */
4113 Syntax sye = APPLIC; /* Syntax of op in e (init unknown)*/
4114 Syntax sys = APPLIC; /* Syntax of op in s (init unknown)*/
4117 while (fst(d)!=ONLY) { /* Attach fixities to operators */
4121 fun(fun(d)) = attachFixity(line,fun(fun(d)));
4127 switch (whatIs(e)) {
4128 case ONLY : e = snd(e);
4129 while (nonNull(s)) {
4130 Cell next = arg(fun(s));
4132 fun(fun(s)) = snd(fun(fun(s)));
4138 case NEG : if (nonNull(s)) {
4139 if (sys==APPLIC) { /* calculate sys */
4140 sys = intOf(fst(fun(fun(s))));
4143 if (precOf(sys)==UMINUS_PREC && /* nambig */
4144 assocOf(sys)!=UMINUS_ASSOC) {
4146 "Ambiguous use of unary minus with \""
4147 ETHEN ERREXPR(snd(fun(fun(s))));
4152 if (precOf(sys)>UMINUS_PREC) { /* nshift */
4156 while (whatIs(e1)==NEG)
4158 arg(fun(t)) = arg(e1);
4159 fun(fun(t)) = snd(fun(fun(t)));
4166 /* Intentional fall-thru for nreduce and isNull(s) */
4168 { Cell prev = e; /* e := tidyNeg e */
4169 Cell temp = arg(prev);
4171 for (; whatIs(temp)==NEG; nneg++) {
4172 fun(prev) = nameNegate;
4176 if (isInt(arg(temp))) { /* special cases */
4177 if (nneg&1) /* for literals */
4178 arg(temp) = mkInt(-intOf(arg(temp)));
4180 else if (isFloat(arg(temp))) {
4182 arg(temp) = floatNegate(arg(temp));
4183 //mkFloat(-floatOf(arg(temp)));
4186 fun(prev) = nameNegate;
4187 arg(prev) = arg(temp);
4194 default : if (isNull(s)) {/* Move operation onto empty stack */
4195 Cell next = arg(fun(e));
4202 else { /* deal with pair of operators */
4204 if (sye==APPLIC) { /* calculate sys and sye */
4205 sye = intOf(fst(fun(fun(e))));
4208 sys = intOf(fst(fun(fun(s))));
4211 if (precOf(sye)==precOf(sys) && /* ambig */
4212 (assocOf(sye)!=assocOf(sys) ||
4213 assocOf(sye)==NON_ASS)) {
4214 ERRMSG(line) "Ambiguous use of operator \""
4215 ETHEN ERREXPR(snd(fun(fun(e))));
4216 ERRTEXT "\" with \""
4217 ETHEN ERREXPR(snd(fun(fun(s))));
4222 if (precOf(sye)>precOf(sys) || /* shift */
4223 (precOf(sye)==precOf(sys) &&
4224 assocOf(sye)==LEFT_ASS &&
4225 assocOf(sys)==LEFT_ASS)) {
4226 Cell next = arg(fun(e));
4234 Cell next = arg(fun(s));
4235 arg(fun(s)) = arg(e);
4236 fun(fun(s)) = snd(fun(fun(s)));
4247 static Pair local attachFixity(line,op) /* Attach fixity to operator in an */
4248 Int line; /* infix expression */
4250 Syntax sy = DEF_OPSYNTAX;
4252 switch (whatIs(op)) {
4254 case VARIDCELL : if ((sy=lookupSyntax(textOf(op)))==NO_SYNTAX) {
4255 Name n = findName(textOf(op));
4257 ERRMSG(line) "Undefined variable \"%s\"",
4258 textToStr(textOf(op))
4267 case CONIDCELL : sy = syntaxOf(op = conDefined(line,op));
4270 case QUALIDENT : { Name n = findQualName(op);
4276 "Undefined qualified variable \"%s\"",
4286 return pair(mkInt(sy),op); /* Pair fixity with (possibly) */
4287 /* translated operator */
4290 static Syntax local lookupSyntax(t) /* Try to find fixity for var in */
4291 Text t; { /* enclosing bindings */
4292 List bounds1 = bounds;
4293 List bindings1 = bindings;
4295 while (nonNull(bindings1)) {
4296 if (nonNull(varIsMember(t,hd(bounds1)))) {
4297 return DEF_OPSYNTAX;
4299 Cell b = findBinding(t,hd(bindings1));
4301 Cell a = fst(snd(b));
4302 if (isVar(fst(b))) { /* Function binding */
4303 if (nonNull(a) && nonNull(snd(a))) {
4304 return intOf(snd(a));
4306 } else { /* Pattern binding */
4308 while (nonNull(vs) && nonNull(a)) {
4309 if (t==textOf(hd(vs))) {
4310 if (nonNull(hd(a)) && isInt(snd(hd(a)))) {
4311 return intOf(snd(hd(a)));
4319 return DEF_OPSYNTAX;
4322 bounds1 = tl(bounds1);
4323 bindings1 = tl(bindings1);
4328 /* --------------------------------------------------------------------------
4329 * To facilitate dependency analysis, lists of bindings are temporarily
4330 * augmented with an additional field, which is used in two ways:
4331 * - to build the `adjacency lists' for the dependency graph. Represented by
4332 * a list of pointers to other bindings in the same list of bindings.
4333 * - to hold strictly positive integer values (depth first search numbers) of
4334 * elements `on the stack' during the strongly connected components search
4335 * algorithm, or a special value mkInt(0), once the binding has been added
4336 * to a particular strongly connected component.
4338 * Using this extra field, the type of each list of declarations during
4339 * dependency analysis is [Binding'] where:
4341 * Binding' ::= (Var, (Attr, (Dep, [Alt]))) -- function binding
4342 * | ([Var], ([Attr], (Dep, (Pat,Rhs)))) -- pattern binding
4344 * ------------------------------------------------------------------------*/
4346 #define depVal(d) (fst(snd(snd(d)))) /* Access to dependency information*/
4348 static List local dependencyAnal(bs) /* Separate lists of bindings into */
4349 List bs; { /* mutually recursive groups in */
4350 /* order of dependency */
4351 mapProc(addDepField,bs); /* add extra field for dependents */
4352 mapProc(depBinding,bs); /* find dependents of each binding */
4353 bs = bscc(bs); /* sort to strongly connected comps*/
4354 mapProc(remDepField,bs); /* remove dependency info field */
4358 static List local topDependAnal(bs) /* Like dependencyAnal(), but at */
4359 List bs; { /* top level, reporting on progress*/
4363 setGoal("Dependency analysis",(Target)(length(bs)));
4365 mapProc(addDepField,bs); /* add extra field for dependents */
4366 for (xs=bs; nonNull(xs); xs=tl(xs)) {
4367 emptySubstitution();
4369 soFar((Target)(i++));
4371 bs = bscc(bs); /* sort to strongly connected comps */
4372 mapProc(remDepField,bs); /* remove dependency info field */
4377 static Void local addDepField(b) /* add extra field to binding to */
4378 Cell b; { /* hold list of dependents */
4379 snd(snd(b)) = pair(NIL,snd(snd(b)));
4382 static Void local remDepField(bs) /* remove dependency field from */
4383 List bs; { /* list of bindings */
4384 mapProc(remDepField1,bs);
4387 static Void local remDepField1(b) /* remove dependency field from */
4388 Cell b; { /* single binding */
4389 snd(snd(b)) = snd(snd(snd(b)));
4392 static Void local clearScope() { /* initialise dependency scoping */
4398 static Void local withinScope(bs) /* Enter scope of bindings bs */
4400 bounds = cons(NIL,bounds);
4401 bindings = cons(bs,bindings);
4402 depends = cons(NIL,depends);
4405 static Void local leaveScope() { /* Leave scope of last withinScope */
4406 List bs = hd(bindings); /* Remove fixity info from binds */
4407 Bool toplevel = isNull(tl(bindings));
4408 for (; nonNull(bs); bs=tl(bs)) {
4410 if (isVar(fst(b))) { /* Variable binding */
4411 Cell a = fst(snd(b));
4414 saveSyntax(fst(b),snd(a));
4416 fst(snd(b)) = fst(a);
4418 } else { /* Pattern binding */
4420 List as = fst(snd(b));
4421 while (nonNull(vs) && nonNull(as)) {
4422 if (isPair(hd(as))) {
4424 saveSyntax(hd(vs),snd(hd(as)));
4426 hd(as) = fst(hd(as));
4433 bounds = tl(bounds);
4434 bindings = tl(bindings);
4435 depends = tl(depends);
4438 static Void local saveSyntax(v,sy) /* Save syntax of top-level var */
4439 Cell v; /* in corresponding Name */
4441 Name n = findName(textOf(v));
4442 if (isNull(n) || name(n).syntax!=NO_SYNTAX) {
4443 internal("saveSyntax");
4446 name(n).syntax = intOf(sy);
4450 /* --------------------------------------------------------------------------
4451 * As a side effect of the dependency analysis we also make the following
4453 * - Each lhs is a valid pattern/function lhs, all constructor functions
4454 * have been defined and are used with the correct number of arguments.
4455 * - No lhs contains repeated pattern variables.
4456 * - Expressions used on the rhs of an eqn should be well formed. This
4458 * - Checking for valid patterns (including repeated vars) in lambda,
4459 * case, and list comprehension expressions.
4460 * - Recursively checking local lists of equations.
4461 * - No free (i.e. unbound) variables are used in the declaration list.
4462 * ------------------------------------------------------------------------*/
4464 static Void local depBinding(b) /* find dependents of binding */
4466 Cell defpart = snd(snd(snd(b))); /* definition part of binding */
4470 if (isVar(fst(b))) { /* function-binding? */
4471 mapProc(depAlt,defpart);
4472 if (isNull(fst(snd(b)))) { /* Save dep info if no type sig */
4473 fst(snd(b)) = pair(ap(IMPDEPS,hd(depends)),NIL);
4474 } else if (isNull(fst(fst(snd(b))))) {
4475 fst(fst(snd(b))) = ap(IMPDEPS,hd(depends));
4477 } else { /* pattern-binding? */
4478 Int line = rhsLine(snd(defpart));
4481 fst(defpart) = checkPat(line,fst(defpart));
4482 depRhs(snd(defpart));
4484 if (nonNull(hd(btyvars))) {
4486 "Sorry, no type variables are allowed in pattern binding type annotations"
4490 fst(defpart) = applyBtyvs(fst(defpart));
4492 depVal(b) = hd(depends);
4495 static Void local depDefaults(c) /* dependency analysis on defaults */
4496 Class c; { /* from class definition */
4497 depClassBindings(cclass(c).defaults);
4500 static Void local depInsts(in) /* dependency analysis on instance */
4501 Inst in; { /* bindings */
4502 depClassBindings(inst(in).implements);
4505 static Void local depClassBindings(bs) /* dependency analysis on list of */
4506 List bs; { /* bindings, possibly containing */
4507 for (; nonNull(bs); bs=tl(bs)) { /* NIL bindings ... */
4508 if (nonNull(hd(bs))) { /* No need to add extra field for */
4509 mapProc(depAlt,snd(hd(bs)));/* dependency information... */
4514 static Void local depAlt(a) /* Find dependents of alternative */
4516 List obvs = saveBvars(); /* Save list of bound variables */
4518 bindPats(rhsLine(snd(a)),fst(a)); /* add new bound vars for patterns */
4519 depRhs(snd(a)); /* find dependents of rhs */
4520 fst(a) = applyBtyvs(fst(a));
4521 restoreBvars(obvs); /* restore original list of bvars */
4524 static Void local depRhs(r) /* Find dependents of rhs */
4526 switch (whatIs(r)) {
4527 case GUARDED : mapProc(depGuard,snd(r));
4530 case LETREC : fst(snd(r)) = eqnsToBindings(fst(snd(r)),NIL,NIL,NIL);
4531 withinScope(fst(snd(r)));
4532 fst(snd(r)) = dependencyAnal(fst(snd(r)));
4533 hd(depends) = fst(snd(r));
4534 depRhs(snd(snd(r)));
4538 case RSIGN : snd(snd(r)) = checkPatType(rhsLine(fst(snd(r))),
4540 rhsExpr(fst(snd(r))),
4542 depRhs(fst(snd(r)));
4545 default : snd(r) = depExpr(intOf(fst(r)),snd(r));
4550 static Void local depGuard(g) /* find dependents of single guarded*/
4551 Cell g; { /* expression */
4552 depPair(intOf(fst(g)),snd(g));
4555 static Cell local depExpr(line,e) /* find dependents of expression */
4558 // Printf( "\n\n"); print(e,100); Printf("\n");
4559 //printExp(stdout,e);
4560 switch (whatIs(e)) {
4563 case VAROPCELL : return depVar(line,e);
4566 case CONOPCELL : return conDefined(line,e);
4568 case QUALIDENT : if (isQVar(e)) {
4569 return depQVar(line,e);
4570 } else { /* QConOrConOp */
4571 return conDefined(line,e);
4574 case INFIX : return depExpr(line,tidyInfix(line,snd(e)));
4577 case RECSEL : break;
4579 case AP : if (isAp(e) && isAp(fun(e)) && isExt(fun(fun(e)))) {
4580 return depRecord(line,e);
4586 arg(a) = depExpr(line,arg(a));
4589 fun(a) = depExpr(line,fun(a));
4593 case AP : depPair(line,e);
4607 case INTCELL : break;
4609 case COND : depTriple(line,snd(e));
4612 case FINLIST : map1Over(depExpr,line,snd(e));
4615 case LETREC : fst(snd(e)) = eqnsToBindings(fst(snd(e)),NIL,NIL,NIL);
4616 withinScope(fst(snd(e)));
4617 fst(snd(e)) = dependencyAnal(fst(snd(e)));
4618 hd(depends) = fst(snd(e));
4619 snd(snd(e)) = depExpr(line,snd(snd(e)));
4623 case LAMBDA : depAlt(snd(e));
4626 case DOCOMP : /* fall-thru */
4627 case COMP : depComp(line,snd(e),snd(snd(e)));
4630 case ESIGN : fst(snd(e)) = depExpr(line,fst(snd(e)));
4631 snd(snd(e)) = checkSigType(line,
4637 case CASE : fst(snd(e)) = depExpr(line,fst(snd(e)));
4638 map1Proc(depCaseAlt,line,snd(snd(e)));
4641 case CONFLDS : depConFlds(line,e,FALSE);
4644 case UPDFLDS : depUpdFlds(line,e);
4648 case WITHEXP : depWith(line,e);
4652 case ASPAT : ERRMSG(line) "Illegal `@' in expression"
4655 case LAZYPAT : ERRMSG(line) "Illegal `~' in expression"
4658 case WILDCARD : ERRMSG(line) "Illegal `_' in expression"
4662 case EXT : ERRMSG(line) "Illegal application of record"
4666 default : internal("depExpr");
4671 static Void local depPair(line,e) /* find dependents of pair of exprs*/
4674 fst(e) = depExpr(line,fst(e));
4675 snd(e) = depExpr(line,snd(e));
4678 static Void local depTriple(line,e) /* find dependents of triple exprs */
4681 fst3(e) = depExpr(line,fst3(e));
4682 snd3(e) = depExpr(line,snd3(e));
4683 thd3(e) = depExpr(line,thd3(e));
4686 static Void local depComp(l,e,qs) /* find dependents of comprehension*/
4691 fst(e) = depExpr(l,fst(e));
4695 switch (whatIs(q)) {
4696 case FROMQUAL : { List obvs = saveBvars();
4697 snd(snd(q)) = depExpr(l,snd(snd(q)));
4699 fst(snd(q)) = bindPat(l,fst(snd(q)));
4701 fst(snd(q)) = applyBtyvs(fst(snd(q)));
4706 case QWHERE : snd(q) = eqnsToBindings(snd(q),NIL,NIL,NIL);
4707 withinScope(snd(q));
4708 snd(q) = dependencyAnal(snd(q));
4709 hd(depends) = snd(q);
4714 case DOQUAL : /* fall-thru */
4715 case BOOLQUAL : snd(q) = depExpr(l,snd(q));
4722 static Void local depCaseAlt(line,a) /* Find dependents of case altern. */
4725 List obvs = saveBvars(); /* Save list of bound variables */
4727 fst(a) = bindPat(line,fst(a)); /* Add new bound vars for pats */
4728 depRhs(snd(a)); /* Find dependents of rhs */
4729 fst(a) = applyBtyvs(fst(a));
4730 restoreBvars(obvs); /* Restore original list of bvars */
4733 static Cell local depVar(line,e) /* Register occurrence of variable */
4736 List bounds1 = bounds;
4737 List bindings1 = bindings;
4738 List depends1 = depends;
4742 while (nonNull(bindings1)) {
4743 n = varIsMember(t,hd(bounds1)); /* look for t in bound variables */
4747 n = findBinding(t,hd(bindings1)); /* look for t in var bindings */
4749 if (!cellIsMember(n,hd(depends1))) {
4750 hd(depends1) = cons(n,hd(depends1));
4752 return (isVar(fst(n)) ? fst(n) : e);
4755 bounds1 = tl(bounds1);
4756 bindings1 = tl(bindings1);
4757 depends1 = tl(depends1);
4760 if (isNull(n=findName(t))) { /* check global definitions */
4761 ERRMSG(line) "Undefined variable \"%s\"", textToStr(t)
4765 if (!moduleThisScript(name(n).mod)) {
4768 /* Later phases of the system cannot cope if we resolve references
4769 * to unprocessed objects too early. This is the main reason that
4770 * we cannot cope with recursive modules at the moment.
4775 static Cell local depQVar(line,e)/* register occurrence of qualified variable */
4778 Name n = findQualName(e);
4779 if (isNull(n)) { /* check global definitions */
4780 ERRMSG(line) "Undefined qualified variable \"%s\"", identToStr(e)
4783 if (name(n).mod != currentModule) {
4786 if (fst(e) == VARIDCELL) {
4787 e = mkVar(qtextOf(e));
4789 e = mkVarop(qtextOf(e));
4791 return depVar(line,e);
4794 static Void local depConFlds(line,e,isP)/* check construction using fields */
4798 Name c = conDefined(line,fst(snd(e)));
4799 if (isNull(snd(snd(e))) ||
4800 nonNull(cellIsMember(c,depFields(line,e,snd(snd(e)),isP)))) {
4803 ERRMSG(line) "Constructor \"%s\" does not have selected fields in ",
4804 textToStr(name(c).text)
4809 if (!isP && isPair(name(c).defn)) { /* Check that banged fields defined*/
4810 List scs = fst(name(c).defn); /* List of strict components */
4811 Type t = name(c).type;
4812 Int a = userArity(c);
4813 List fs = snd(snd(e));
4815 if (isPolyType(t)) { /* Find tycon that c belongs to */
4818 if (isQualType(t)) {
4821 if (whatIs(t)==CDICTS) {
4830 for (ss=tycon(t).defn; hasCfun(ss); ss=tl(ss)) {
4832 /* Now we know the tycon t that c belongs to, and the corresponding
4833 * list of selectors for that type, ss. Now we have to check that
4834 * each of the fields identified by scs appears in fs, using ss to
4835 * cross reference, and convert integers to selector names.
4837 for (; nonNull(scs); scs=tl(scs)) {
4838 Int i = intOf(hd(scs));
4840 for (; nonNull(ss1); ss1=tl(ss1)) {
4841 List cns = name(hd(ss1)).defn;
4842 for (; nonNull(cns); cns=tl(cns)) {
4843 if (fst(hd(cns))==c) {
4847 if (nonNull(cns) && intOf(snd(hd(cns)))==i) {
4852 internal("depConFlds");
4856 for (; nonNull(fs1) && s!=fst(hd(fs1)); fs1=tl(fs1)) {
4859 ERRMSG(line) "Construction does not define strict field"
4861 ERRTEXT "\nExpression : " ETHEN ERREXPR(e);
4862 ERRTEXT "\nField : " ETHEN ERREXPR(s);
4871 static Void local depUpdFlds(line,e) /* check update using fields */
4874 if (isNull(thd3(snd(e)))) {
4875 ERRMSG(line) "Empty field list in update"
4878 fst3(snd(e)) = depExpr(line,fst3(snd(e)));
4879 snd3(snd(e)) = depFields(line,e,thd3(snd(e)),FALSE);
4882 static List local depFields(l,e,fs,isP) /* check field binding list */
4890 for (; nonNull(fs); fs=tl(fs)) { /* for each field binding */
4894 if (isVar(fb)) { /* expand var to var = var */
4895 h98DoesntSupport(l,"missing field bindings");
4896 fb = hd(fs) = pair(fb,fb);
4899 s = findQualName(fst(fb)); /* check for selector */
4900 if (nonNull(s) && isSfun(s)) {
4903 ERRMSG(l) "\"%s\" is not a selector function/field name",
4904 textToStr(textOf(fst(fb)))
4908 if (isNull(ss)) { /* for first named selector */
4909 List scs = name(s).defn; /* calculate list of constructors */
4910 for (; nonNull(scs); scs=tl(scs)) {
4911 cs = cons(fst(hd(scs)),cs);
4913 ss = singleton(s); /* initialize selector list */
4914 } else { /* for subsequent selectors */
4915 List ds = cs; /* intersect constructor lists */
4916 for (cs=NIL; nonNull(ds); ) {
4917 List scs = name(s).defn;
4918 while (nonNull(scs) && fst(hd(scs))!=hd(ds)) {
4931 if (cellIsMember(s,ss)) { /* check for repeated uses */
4932 ERRMSG(l) "Repeated field name \"%s\" in field list",
4933 textToStr(name(s).text)
4939 if (isNull(cs)) { /* Are there any matching constrs? */
4940 ERRMSG(l) "No constructor has all of the fields specified in "
4946 snd(fb) = (isP ? checkPat(l,snd(fb)) : depExpr(l,snd(fb)));
4952 static Void local depWith(line,e) /* check with using fields */
4955 fst(snd(e)) = depExpr(line,fst(snd(e)));
4956 snd(snd(e)) = depDwFlds(line,e,snd(snd(e)));
4959 static List local depDwFlds(l,e,fs)/* check field binding list */
4965 for (; nonNull(c); c=tl(c)) { /* for each field binding */
4966 snd(hd(c)) = depExpr(l,snd(hd(c)));
4973 static Cell local depRecord(line,e) /* find dependents of record and */
4974 Int line; /* sort fields into approp. order */
4975 Cell e; { /* to make construction and update */
4976 List exts = NIL; /* more efficient. */
4979 h98DoesntSupport(line,"extensible records");
4980 do { /* build up list of extensions */
4981 Text t = extText(fun(fun(r)));
4982 String s = textToStr(t);
4985 while (nonNull(nx) && strcmp(textToStr(extText(fun(fun(nx)))),s)>0) {
4989 if (nonNull(nx) && t==extText(fun(fun(nx)))) {
4990 ERRMSG(line) "Repeated label \"%s\" in record ", s
4996 exts = cons(fun(r),exts);
4998 tl(prev) = cons(fun(r),nx);
5000 extField(r) = depExpr(line,extField(r));
5002 } while (isAp(r) && isAp(fun(r)) && isExt(fun(fun(r))));
5003 r = depExpr(line,r);
5004 return revOnto(exts,r);
5009 /* --------------------------------------------------------------------------
5010 * Several parts of this program require an algorithm for sorting a list
5011 * of values (with some added dependency information) into a list of strongly
5012 * connected components in which each value appears before its dependents.
5014 * Each of these algorithms is obtained by parameterising a standard
5015 * algorithm in "scc.c" as shown below.
5016 * ------------------------------------------------------------------------*/
5018 #define SCC2 tcscc /* make scc algorithm for Tycons */
5019 #define LOWLINK tclowlink
5020 #define DEPENDS(c) (isTycon(c) ? tycon(c).kind : cclass(c).kinds)
5021 #define SETDEPENDS(c,v) if(isTycon(c)) tycon(c).kind=v; else cclass(c).kinds=v
5028 #define SCC bscc /* make scc algorithm for Bindings */
5029 #define LOWLINK blowlink
5030 #define DEPENDS(t) depVal(t)
5031 #define SETDEPENDS(c,v) depVal(c)=v
5038 /* --------------------------------------------------------------------------
5039 * Main static analysis:
5040 * ------------------------------------------------------------------------*/
5042 Void checkExp() { /* Top level static check on Expr */
5043 staticAnalysis(RESET);
5044 clearScope(); /* Analyse expression in the scope */
5045 withinScope(NIL); /* of no local bindings */
5046 inputExpr = depExpr(0,inputExpr);
5048 staticAnalysis(RESET);
5051 #if EXPLAIN_INSTANCE_RESOLUTION
5052 Void checkContext(void) { /* Top level static check on Expr */
5055 staticAnalysis(RESET);
5056 clearScope(); /* Analyse expression in the scope */
5057 withinScope(NIL); /* of no local bindings */
5059 for (vs = NIL; nonNull(qs); qs=tl(qs)) {
5060 vs = typeVarsIn(hd(qs),NIL,NIL,vs);
5062 map2Proc(depPredExp,0,vs,inputContext);
5064 staticAnalysis(RESET);
5068 Void checkDefns() { /* Top level static analysis */
5069 Module thisModule = lastModule();
5070 staticAnalysis(RESET);
5072 setCurrModule(thisModule);
5074 /* Resolve module references */
5075 mapProc(checkQualImport, module(thisModule).qualImports);
5076 mapProc(checkUnqualImport,unqualImports);
5077 /* Add "import Prelude" if there`s no explicit import */
5078 if (thisModule!=modulePrelude
5079 && isNull(cellAssoc(modulePrelude,unqualImports))
5080 && isNull(cellRevAssoc(modulePrelude,module(thisModule).qualImports))) {
5081 unqualImports = cons(pair(modulePrelude,DOTDOT),unqualImports);
5083 /* Every module (including the Prelude) implicitly contains
5084 * "import qualified Prelude"
5086 module(thisModule).qualImports=cons(pair(mkCon(textPrelude),modulePrelude),
5087 module(thisModule).qualImports);
5089 mapProc(checkImportList, unqualImports);
5091 /* Note: there's a lot of side-effecting going on here, so
5092 don't monkey about with the order of operations here unless
5093 you know what you are doing */
5094 if (!combined) linkPreludeTC(); /* Get prelude tycons and classes */
5096 mapProc(checkTyconDefn,tyconDefns); /* validate tycon definitions */
5097 checkSynonyms(tyconDefns); /* check synonym definitions */
5098 mapProc(checkClassDefn,classDefns); /* process class definitions */
5099 mapProc(kindTCGroup,tcscc(tyconDefns,classDefns)); /* attach kinds */
5100 mapProc(visitClass,classDefns); /* check class hierarchy */
5101 mapProc(extendFundeps,classDefns); /* finish class definitions */
5102 /* (convenient if we do this after */
5103 /* calling `visitClass' so that we */
5104 /* know the class hierarchy is */
5107 mapProc(addMembers,classDefns); /* add definitions for member funs */
5109 if (!combined) linkPreludeCM(); /* Get prelude cfuns and mfuns */
5111 instDefns = rev(instDefns); /* process instance definitions */
5112 mapProc(checkInstDefn,instDefns);
5114 setCurrModule(thisModule);
5115 mapProc(addRSsigdecls,typeInDefns); /* add sigdecls for RESTRICTSYN */
5116 valDefns = eqnsToBindings(valDefns,tyconDefns,classDefns,/*primDefns*/NIL);
5117 mapProc(allNoPrevDef,valDefns); /* check against previous defns */
5118 mapProc(addDerivImp,derivedInsts); /* Add impls for derived instances */
5119 deriveContexts(derivedInsts); /* Calculate derived inst contexts */
5120 instDefns = appendOnto(instDefns,derivedInsts);
5121 checkDefaultDefns(); /* validate default definitions */
5123 mapProc(allNoPrevDef,valDefns); /* check against previous defns */
5125 if (!combined) linkPrimitiveNames(); /* link primitive names */
5127 mapProc(checkForeignImport,foreignImports); /* check foreign imports */
5128 mapProc(checkForeignExport,foreignExports); /* check foreign exports */
5129 foreignImports = NIL;
5130 foreignExports = NIL;
5132 /* Every top-level name has now been created - so we can build the */
5133 /* export list. Note that this has to happen before dependency */
5134 /* analysis so that references to Prelude.foo will be resolved */
5135 /* when compiling the prelude. */
5136 module(thisModule).exports = checkExports(module(thisModule).exports);
5138 mapProc(checkTypeIn,typeInDefns); /* check restricted synonym defns */
5141 withinScope(valDefns);
5142 valDefns = topDependAnal(valDefns); /* top level dependency ordering */
5143 mapProc(depDefaults,classDefns); /* dep. analysis on class defaults */
5144 mapProc(depInsts,instDefns); /* dep. analysis on inst defns */
5147 /* ToDo: evalDefaults should match current evaluation module */
5148 evalDefaults = defaultDefns; /* Set defaults for evaluator */
5150 staticAnalysis(RESET);
5156 static Void local addRSsigdecls(pr) /* add sigdecls from TYPE ... IN ..*/
5158 List vs = snd(pr); /* get list of variables */
5159 for (; nonNull(vs); vs=tl(vs)) {
5160 if (fst(hd(vs))==SIGDECL) { /* find a sigdecl */
5161 valDefns = cons(hd(vs),valDefns); /* add to valDefns */
5162 hd(vs) = hd(snd3(snd(hd(vs)))); /* and replace with var */
5167 static Void local allNoPrevDef(b) /* ensure no previous bindings for*/
5168 Cell b; { /* variables in new binding */
5169 if (isVar(fst(b))) {
5170 noPrevDef(rhsLine(snd(hd(snd(snd(b))))),fst(b));
5172 Int line = rhsLine(snd(snd(snd(b))));
5173 map1Proc(noPrevDef,line,fst(b));
5177 static Void local noPrevDef(line,v) /* ensure no previous binding for */
5178 Int line; /* new variable */
5180 Name n = findName(textOf(v));
5183 n = newName(textOf(v),NIL);
5184 name(n).defn = PREDEFINED;
5185 } else if (name(n).defn!=PREDEFINED) {
5186 duplicateError(line,name(n).mod,name(n).text,"variable");
5188 name(n).line = line;
5191 static Void local duplicateErrorAux(line,mod,t,kind)/* report duplicate defn */
5196 if (mod == currentModule) {
5197 ERRMSG(line) "Repeated definition for %s \"%s\"", kind,
5201 ERRMSG(line) "Definition of %s \"%s\" clashes with import", kind,
5207 static Void local checkTypeIn(cvs) /* Check that vars in restricted */
5208 Pair cvs; { /* synonym are defined */
5212 for (; nonNull(vs); vs=tl(vs)) {
5213 if (isNull(findName(textOf(hd(vs))))) {
5214 ERRMSG(tycon(c).line)
5215 "No top level binding of \"%s\" for restricted synonym \"%s\"",
5216 textToStr(textOf(hd(vs))), textToStr(tycon(c).text)
5222 /* --------------------------------------------------------------------------
5223 * Haskell 98 compatibility tests:
5224 * ------------------------------------------------------------------------*/
5226 Bool h98Pred(allowArgs,pi) /* Check syntax of Hask98 predicate*/
5229 return isClass(getHead(pi)) && argCount==1 &&
5230 isOffset(getHead(arg(pi))) && (argCount==0 || allowArgs);
5233 Cell h98Context(allowArgs,ps) /* Check syntax of Hask98 context */
5236 for (; nonNull(ps); ps=tl(ps)) {
5237 if (!h98Pred(allowArgs,hd(ps))) {
5244 Void h98CheckCtxt(line,wh,allowArgs,ps,in)
5245 Int line; /* Report illegal context/predicate*/
5251 Cell pi = h98Context(allowArgs,ps);
5253 ERRMSG(line) "Illegal Haskell 98 class constraint in %s",wh ETHEN
5255 ERRTEXT "\n*** Instance : " ETHEN ERRPRED(inst(in).head);
5257 ERRTEXT "\n*** Constraint : " ETHEN ERRPRED(pi);
5258 if (nonNull(ps) && nonNull(tl(ps))) {
5259 ERRTEXT "\n*** Context : " ETHEN ERRCONTEXT(ps);
5267 Void h98CheckType(line,wh,e,t) /* Check for Haskell 98 type */
5276 if (isQualType(t)) {
5277 Cell pi = h98Context(TRUE,fst(snd(t)));
5279 ERRMSG(line) "Illegal Haskell 98 class constraint in %s",wh
5281 ERRTEXT "\n*** Expression : " ETHEN ERREXPR(e);
5282 ERRTEXT "\n*** Type : " ETHEN ERRTYPE(ty);
5290 Void h98DoesntSupport(line,wh) /* Report feature missing in H98 */
5294 ERRMSG(line) "Haskell 98 does not support %s", wh
5299 /* --------------------------------------------------------------------------
5300 * Static Analysis control:
5301 * ------------------------------------------------------------------------*/
5303 Void staticAnalysis(what)
5306 case RESET : cfunSfuns = NIL;
5319 case MARK : mark(daSccs);
5334 case POSTPREL: break;
5336 case PREPREL : staticAnalysis(RESET);
5338 extKind = pair(STAR,pair(ROW,ROW));
5343 /*-------------------------------------------------------------------------*/