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: 1999/11/17 16:57:44 $
14 * ------------------------------------------------------------------------*/
24 /* --------------------------------------------------------------------------
25 * local function prototypes:
26 * ------------------------------------------------------------------------*/
28 static Void local kindError Args((Int,Constr,Constr,String,Kind,Int));
29 static Void local checkQualImport Args((Pair));
30 static Void local checkUnqualImport Args((Triple));
32 static Name local lookupName Args((Text,List));
33 static List local checkSubentities Args((List,List,List,String,Text));
34 static List local checkExportTycon Args((List,Text,Cell,Tycon));
35 static List local checkExportClass Args((List,Text,Cell,Class));
36 static List local checkExport Args((List,Text,Cell));
37 static List local checkImportEntity Args((List,Module,Cell));
38 static List local resolveImportList Args((Module,Cell));
39 static Void local checkImportList Args((Pair));
41 static Void local importEntity Args((Module,Cell));
42 static Void local importName Args((Module,Name));
43 static Void local importTycon Args((Module,Tycon));
44 static Void local importClass Args((Module,Class));
45 static List local checkExports Args((List));
47 static Void local checkTyconDefn Args((Tycon));
48 static Void local depConstrs Args((Tycon,List,Cell));
49 static List local addSels Args((Int,Name,List,List));
50 static List local selectCtxt Args((List,List));
51 static Void local checkSynonyms Args((List));
52 static List local visitSyn Args((List,Tycon,List));
53 static Type local instantiateSyn Args((Type,Type));
55 static Void local checkClassDefn Args((Class));
56 static Cell local depPredExp Args((Int,List,Cell));
57 static Void local checkMems Args((Class,List,Cell));
58 static Void local checkMems2 Args((Class,Cell));
59 static Void local addMembers Args((Class));
60 static Name local newMember Args((Int,Int,Cell,Type,Class));
61 static Name local newDSel Args((Class,Int));
62 static Text local generateText Args((String,Class));
63 static Int local visitClass Args((Class));
65 static List local classBindings Args((String,Class,List));
66 static Name local memberName Args((Class,Text));
67 static List local numInsert Args((Int,Cell,List));
69 static List local maybeAppendVar Args((Cell,List));
71 static Type local checkSigType Args((Int,String,Cell,Type));
72 static Void local checkOptQuantVars Args((Int,List,List));
73 static Type local depTopType Args((Int,List,Type));
74 static Type local depCompType Args((Int,List,Type));
75 static Type local depTypeExp Args((Int,List,Type));
76 static Type local depTypeVar Args((Int,List,Text));
77 static List local checkQuantVars Args((Int,List,List,Cell));
78 static List local otvars Args((Cell,List));
79 static Bool local osubset Args((List,List));
80 static Void local kindConstr Args((Int,Int,Int,Constr));
81 static Kind local kindAtom Args((Int,Constr));
82 static Void local kindPred Args((Int,Int,Int,Cell));
83 static Void local kindType Args((Int,String,Type));
84 static Void local fixKinds Args((Void));
86 static Void local kindTCGroup Args((List));
87 static Void local initTCKind Args((Cell));
88 static Void local kindTC Args((Cell));
89 static Void local genTC Args((Cell));
91 static Void local checkInstDefn Args((Inst));
92 static Void local insertInst Args((Inst));
93 static Bool local instCompare Args((Inst,Inst));
94 static Name local newInstImp Args((Inst));
95 static Void local kindInst Args((Inst,Int));
96 static Void local checkDerive Args((Tycon,List,List,Cell));
97 static Void local addDerInst Args((Int,Class,List,List,Type,Int));
98 static Void local deriveContexts Args((List));
99 static Void local initDerInst Args((Inst));
100 static Void local calcInstPreds Args((Inst));
101 static Void local maybeAddPred Args((Cell,Int,Int,List));
102 static List local calcFunDeps Args((List));
103 static Cell local copyAdj Args((Cell,Int,Int));
104 static Void local tidyDerInst Args((Inst));
105 static List local otvarsZonk Args((Cell,List,Int));
107 static Void local addDerivImp Args((Inst));
109 static Void local checkDefaultDefns Args((Void));
111 static Void local checkForeignImport Args((Name));
112 static Void local checkForeignExport Args((Name));
114 static Cell local tidyInfix Args((Int,Cell));
115 static Pair local attachFixity Args((Int,Cell));
116 static Syntax local lookupSyntax Args((Text));
118 static Cell local checkPat Args((Int,Cell));
119 static Cell local checkMaybeCnkPat Args((Int,Cell));
120 static Cell local checkApPat Args((Int,Int,Cell));
121 static Void local addToPatVars Args((Int,Cell));
122 static Name local conDefined Args((Int,Cell));
123 static Void local checkIsCfun Args((Int,Name));
124 static Void local checkCfunArgs Args((Int,Cell,Int));
125 static Cell local checkPatType Args((Int,String,Cell,Type));
126 static Cell local applyBtyvs Args((Cell));
127 static Cell local bindPat Args((Int,Cell));
128 static Void local bindPats Args((Int,List));
130 static List local extractSigdecls Args((List));
131 static List local extractFixdecls Args((List));
132 static List local extractBindings Args((List));
133 static List local getPatVars Args((Int,Cell,List));
134 static List local addPatVar Args((Int,Cell,List));
135 static List local eqnsToBindings Args((List,List,List,List));
136 static Void local notDefined Args((Int,List,Cell));
137 static Cell local findBinding Args((Text,List));
138 static Cell local getAttr Args((List,Cell));
139 static Void local addSigdecl Args((List,Cell));
140 static Void local addFixdecl Args((List,List,List,List,Triple));
141 static Void local dupFixity Args((Int,Text));
142 static Void local missFixity Args((Int,Text));
144 static List local dependencyAnal Args((List));
145 static List local topDependAnal Args((List));
146 static Void local addDepField Args((Cell));
147 static Void local remDepField Args((List));
148 static Void local remDepField1 Args((Cell));
149 static Void local clearScope Args((Void));
150 static Void local withinScope Args((List));
151 static Void local leaveScope Args((Void));
152 static Void local saveSyntax Args((Cell,Cell));
154 static Void local depBinding Args((Cell));
155 static Void local depDefaults Args((Class));
156 static Void local depInsts Args((Inst));
157 static Void local depClassBindings Args((List));
158 static Void local depAlt Args((Cell));
159 static Void local depRhs Args((Cell));
160 static Void local depGuard Args((Cell));
161 static Cell local depExpr Args((Int,Cell));
162 static Void local depPair Args((Int,Cell));
163 static Void local depTriple Args((Int,Cell));
164 static Void local depComp Args((Int,Cell,List));
165 static Void local depCaseAlt Args((Int,Cell));
166 static Cell local depVar Args((Int,Cell));
167 static Cell local depQVar Args((Int,Cell));
168 static Void local depConFlds Args((Int,Cell,Bool));
169 static Void local depUpdFlds Args((Int,Cell));
170 static List local depFields Args((Int,Cell,List,Bool));
172 static Void local depWith Args((Int,Cell));
173 static List local depDwFlds Args((Int,Cell,List));
176 static Cell local depRecord Args((Int,Cell));
179 static List local tcscc Args((List,List));
180 static List local bscc Args((List));
182 static Void local addRSsigdecls Args((Pair));
183 static Void local allNoPrevDef Args((Cell));
184 static Void local noPrevDef Args((Int,Cell));
185 static Bool local odiff Args((List,List));
187 static Void local duplicateErrorAux Args((Int,Module,Text,String));
188 #define duplicateError(l,m,t,k) duplicateErrorAux(l,m,t,k)
189 static Void local checkTypeIn Args((Pair));
191 /* --------------------------------------------------------------------------
192 * The code in this file is arranged in roughly the following order:
193 * - Kind inference preliminaries
194 * - Module declarations
195 * - Type declarations (data, type, newtype, type in)
196 * - Class declarations
198 * - Instance declarations
199 * - Default declarations
200 * - Primitive definitions
202 * - Infix expressions
203 * - Value definitions
204 * - Top-level static analysis and control
205 * - Haskell 98 compatibility tests
206 * ------------------------------------------------------------------------*/
208 /* --------------------------------------------------------------------------
209 * Kind checking preliminaries:
210 * ------------------------------------------------------------------------*/
212 Bool kindExpert = FALSE; /* TRUE => display kind errors in */
215 static Void local kindError(l,c,in,wh,k,o)
216 Int l; /* line number near constuctor exp */
217 Constr c; /* constructor */
218 Constr in; /* context (if any) */
219 String wh; /* place in which error occurs */
220 Kind k; /* expected kind (k,o) */
221 Int o; { /* inferred kind (typeIs,typeOff) */
224 if (!kindExpert) { /* for those with a fear of kinds */
225 ERRMSG(l) "Illegal type" ETHEN
227 ERRTEXT " \"" ETHEN ERRTYPE(in);
230 ERRTEXT " in %s\n", wh
234 ERRMSG(l) "Kind error in %s", wh ETHEN
236 ERRTEXT "\n*** expression : " ETHEN ERRTYPE(in);
238 ERRTEXT "\n*** constructor : " ETHEN ERRTYPE(c);
239 ERRTEXT "\n*** kind : " ETHEN ERRKIND(copyType(typeIs,typeOff));
240 ERRTEXT "\n*** does not match : " ETHEN ERRKIND(copyType(k,o));
242 ERRTEXT "\n*** because : %s", unifyFails ETHEN
248 #define shouldKind(l,c,in,wh,k,o) if (!kunify(typeIs,typeOff,k,o)) \
249 kindError(l,c,in,wh,k,o)
250 #define checkKind(l,a,m,c,in,wh,k,o) kindConstr(l,a,m,c); \
251 shouldKind(l,c,in,wh,k,o)
252 #define inferKind(k,o) typeIs=k; typeOff=o
254 static List unkindTypes; /* types in need of kind annotation*/
256 Kind extKind; /* Kind of extension, *->row->row */
259 /* --------------------------------------------------------------------------
260 * Static analysis of modules:
261 * ------------------------------------------------------------------------*/
267 Void startModule(nm) /* switch to a new module */
270 if (!isCon(nm)) internal("startModule");
271 if (isNull(m = findModule(textOf(nm))))
272 m = newModule(textOf(nm));
273 else if (!isPreludeScript()) {
274 /* You're allowed to break the rules in the Prelude! */
276 reloadModule = textToStr(textOf(nm));
278 ERRMSG(0) "Module \"%s\" already loaded", textToStr(textOf(nm))
284 Void setExportList(exps) /* Add export list to current module */
286 module(currentModule).exports = exps;
289 Void addQualImport(orig,new) /* Add to qualified import list */
290 Cell orig; /* Original name of module */
291 Cell new; { /* Name module is called within this module (or NIL) */
292 module(currentModule).qualImports =
293 cons(pair(isNull(new)?orig:new,orig),module(currentModule).qualImports);
296 Void addUnqualImport(mod,entities) /* Add to unqualified import list */
297 Cell mod; /* Name of module */
298 List entities; { /* List of entity names */
299 unqualImports = cons(pair(mod,entities),unqualImports);
302 static Void local checkQualImport(i) /* Process qualified import */
304 Module m = findModid(snd(i));
306 ERRMSG(0) "Module \"%s\" not previously loaded",
307 textToStr(textOf(snd(i)))
313 static Void local checkUnqualImport(i) /* Process unqualified import */
315 Module m = findModid(fst(i));
317 ERRMSG(0) "Module \"%s\" not previously loaded",
318 textToStr(textOf(fst(i)))
324 static Name local lookupName(t,nms) /* find text t in list of Names */
326 List nms; { /* :: [Name] */
327 for(; nonNull(nms); nms=tl(nms)) {
328 if (t == name(hd(nms)).text)
334 static List local checkSubentities(imports,named,wanted,description,textParent)
336 List named; /* :: [ Q?(Var|Con)(Id|Op) ] */
337 List wanted; /* :: [Name] */
338 String description; /* "<constructor>|<member> of <type>|<class>" */
340 for(; nonNull(named); named=tl(named)) {
342 /* ToDo: ignores qualifier; doesn't check that entity is in scope */
343 Text t = isPair(snd(x)) ? qtextOf(x) : textOf(x);
344 Name n = lookupName(t,wanted);
346 ERRMSG(0) "Entity \"%s\" is not a %s \"%s\"",
349 textToStr(textParent)
352 imports = cons(n,imports);
357 static List local checkImportEntity(imports,exporter,entity)
358 List imports; /* Accumulated list of things to import */
360 Cell entity; { /* Entry from import list */
361 List oldImports = imports;
362 Text t = isIdent(entity) ? textOf(entity) : textOf(fst(entity));
363 List es = module(exporter).exports;
364 for(; nonNull(es); es=tl(es)) {
365 Cell e = hd(es); /* :: Entity | (Entity, NIL|DOTDOT) */
369 if (tycon(f).text == t) {
370 imports = cons(f,imports);
371 if (!isIdent(entity)) {
372 switch (tycon(f).what) {
375 if (DOTDOT == snd(entity)) {
376 imports=dupOnto(tycon(f).defn,imports);
378 imports=checkSubentities(imports,snd(entity),tycon(f).defn,
379 "constructor of type",t);
383 /* deliberate fall thru */
387 } else if (isClass(f)) {
388 if (cclass(f).text == t) {
389 imports = cons(f,imports);
390 if (!isIdent(entity)) {
391 if (DOTDOT == snd(entity)) {
392 return dupOnto(cclass(f).members,imports);
394 return checkSubentities(imports,snd(entity),cclass(f).members,
395 "member of class",t);
400 internal("checkImportEntity2");
402 } else if (isName(e)) {
403 if (isIdent(entity) && name(e).text == t) {
404 imports = cons(e,imports);
407 internal("checkImportEntity3");
410 if (imports == oldImports) {
411 ERRMSG(0) "Unknown entity \"%s\" imported from module \"%s\"",
413 textToStr(module(exporter ).text)
419 static List local resolveImportList(m,impList)
420 Module m; /* exporting module */
423 if (DOTDOT == impList) {
424 List es = module(m).exports;
425 for(; nonNull(es); es=tl(es)) {
428 imports = cons(e,imports);
431 List subentities = NIL;
432 imports = cons(c,imports);
434 && (tycon(c).what == DATATYPE
435 || tycon(c).what == NEWTYPE))
436 subentities = tycon(c).defn;
438 subentities = cclass(c).members;
439 if (DOTDOT == snd(e)) {
440 imports = dupOnto(subentities,imports);
445 map1Accum(checkImportEntity,imports,m,impList);
450 static Void local checkImportList(importSpec) /*Import a module unqualified*/
452 Module m = fst(importSpec);
453 Cell impList = snd(importSpec);
455 List imports = NIL; /* entities we want to import */
456 List hidden = NIL; /* entities we want to hide */
458 if (moduleThisScript(m)) {
459 ERRMSG(0) "Module \"%s\" recursively imports itself",
460 textToStr(module(m).text)
463 if (isPair(impList) && HIDDEN == fst(impList)) {
464 /* Somewhat inefficient - but obviously correct:
465 * imports = importsOf("module Foo") `setDifference` hidden;
467 hidden = resolveImportList(m, snd(impList));
468 imports = resolveImportList(m, DOTDOT);
470 imports = resolveImportList(m, impList);
472 for(; nonNull(imports); imports=tl(imports)) {
473 Cell e = hd(imports);
474 if (!cellIsMember(e,hidden))
477 /* ToDo: hang onto the imports list for processing export list entries
478 * of the form "module Foo"
482 static Void local importEntity(source,e)
486 case NAME : importName(source,e);
488 case TYCON : importTycon(source,e);
490 case CLASS : importClass(source,e);
492 default: internal("importEntity");
496 static Void local importName(source,n)
499 Name clash = addName(n);
500 if (nonNull(clash) && clash!=n) {
501 ERRMSG(0) "Entity \"%s\" imported from module \"%s\" already defined in module \"%s\"",
502 textToStr(name(n).text),
503 textToStr(module(source).text),
504 textToStr(module(name(clash).mod).text)
509 static Void local importTycon(source,tc)
512 Tycon clash=addTycon(tc);
513 if (nonNull(clash) && clash!=tc) {
514 ERRMSG(0) "Tycon \"%s\" imported from \"%s\" already defined in module \"%s\"",
515 textToStr(tycon(tc).text),
516 textToStr(module(source).text),
517 textToStr(module(tycon(clash).mod).text)
520 if (nonNull(findClass(tycon(tc).text))) {
521 ERRMSG(0) "Import of type constructor \"%s\" clashes with class in module \"%s\"",
522 textToStr(tycon(tc).text),
523 textToStr(module(tycon(tc).mod).text)
528 static Void local importClass(source,c)
531 Class clash=addClass(c);
532 if (nonNull(clash) && clash!=c) {
533 ERRMSG(0) "Class \"%s\" imported from \"%s\" already defined in module \"%s\"",
534 textToStr(cclass(c).text),
535 textToStr(module(source).text),
536 textToStr(module(cclass(clash).mod).text)
539 if (nonNull(findTycon(cclass(c).text))) {
540 ERRMSG(0) "Import of class \"%s\" clashes with type constructor in module \"%s\"",
541 textToStr(cclass(c).text),
542 textToStr(module(source).text)
547 static List local checkExportTycon(exports,mt,spec,tc)
552 if (DOTDOT == spec || SYNONYM == tycon(tc).what) {
553 return cons(pair(tc,DOTDOT), exports);
555 return cons(pair(tc,NIL), exports);
559 static List local checkExportClass(exports,mt,spec,cl)
564 if (DOTDOT == spec) {
565 return cons(pair(cl,DOTDOT), exports);
567 return cons(pair(cl,NIL), exports);
571 static List local checkExport(exports,mt,e) /* Process entry in export list*/
577 List origExports = exports;
578 if (nonNull(export=findQualName(e))) {
579 exports=cons(export,exports);
581 if (isQCon(e) && nonNull(export=findQualTycon(e))) {
582 exports = checkExportTycon(exports,mt,NIL,export);
584 if (isQCon(e) && nonNull(export=findQualClass(e))) {
585 /* opaque class export */
586 exports = checkExportClass(exports,mt,NIL,export);
588 if (exports == origExports) {
589 ERRMSG(0) "Unknown entity \"%s\" exported from module \"%s\"",
595 } else if (MODULEENT == fst(e)) {
596 Module m = findModid(snd(e));
597 /* ToDo: shouldn't allow export of module we didn't import */
599 ERRMSG(0) "Unknown module \"%s\" exported from module \"%s\"",
600 textToStr(textOf(snd(e))),
604 if (m == currentModule) {
605 /* Exporting the current module exports local definitions */
607 for(xs=module(m).classes; nonNull(xs); xs=tl(xs)) {
608 if (cclass(hd(xs)).mod==m)
609 exports = checkExportClass(exports,mt,DOTDOT,hd(xs));
611 for(xs=module(m).tycons; nonNull(xs); xs=tl(xs)) {
612 if (tycon(hd(xs)).mod==m)
613 exports = checkExportTycon(exports,mt,DOTDOT,hd(xs));
615 for(xs=module(m).names; nonNull(xs); xs=tl(xs)) {
616 if (name(hd(xs)).mod==m)
617 exports = cons(hd(xs),exports);
620 /* Exporting other modules imports all things imported
621 * unqualified from it.
622 * ToDo: we reexport everything exported by a module -
623 * whether we imported it or not. This gives the wrong
624 * result for "module M(module N) where import N(x)"
626 exports = dupOnto(module(m).exports,exports);
630 Cell ident = fst(e); /* class name or type name */
631 Cell parts = snd(e); /* members or constructors */
633 if (isQCon(ident) && nonNull(nm=findQualTycon(ident))) {
634 switch (tycon(nm).what) {
637 ERRMSG(0) "Explicit constructor list given for type synonym"
638 " \"%s\" in export list of module \"%s\"",
643 return cons(pair(nm,DOTDOT),exports);
645 ERRMSG(0) "Transparent export of restricted type synonym"
646 " \"%s\" in export list of module \"%s\"",
650 return exports; /* Not reached */
654 return cons(pair(nm,DOTDOT),exports);
656 exports = checkSubentities(exports,parts,tycon(nm).defn,
657 "constructor of type",
659 return cons(pair(nm,DOTDOT), exports);
662 internal("checkExport1");
664 } else if (isQCon(ident) && nonNull(nm=findQualClass(ident))) {
665 if (DOTDOT == parts) {
666 return cons(pair(nm,DOTDOT),exports);
668 exports = checkSubentities(exports,parts,cclass(nm).members,
669 "member of class",cclass(nm).text);
670 return cons(pair(nm,DOTDOT), exports);
673 ERRMSG(0) "Explicit export list given for non-class/datatype \"%s\" in export list of module \"%s\"",
679 return exports; /* NOTUSED */
682 static List local checkExports(exports)
684 Module m = lastModule();
685 Text mt = module(m).text;
688 map1Accum(checkExport,es,mt,exports);
691 for(xs=es; nonNull(xs); xs=tl(xs)) {
692 Printf(" %s", textToStr(textOfEntity(hd(xs))));
699 /* --------------------------------------------------------------------------
700 * Static analysis of type declarations:
702 * Type declarations come in two forms:
703 * - data declarations - define new constructed data types
704 * - type declarations - define new type synonyms
706 * A certain amount of work is carried out as the declarations are
707 * read during parsing. In particular, for each type constructor
708 * definition encountered:
709 * - check that there is no previous definition of constructor
710 * - ensure type constructor not previously used as a class name
711 * - make a new entry in the type constructor table
712 * - record line number of declaration
713 * - Build separate lists of newly defined constructors for later use.
714 * ------------------------------------------------------------------------*/
716 Void tyconDefn(line,lhs,rhs,what) /* process new type definition */
717 Int line; /* definition line number */
718 Cell lhs; /* left hand side of definition */
719 Cell rhs; /* right hand side of definition */
720 Cell what; { /* SYNONYM/DATATYPE/etc... */
721 Text t = textOf(getHead(lhs));
723 if (nonNull(findTycon(t))) {
724 ERRMSG(line) "Repeated definition of type constructor \"%s\"",
728 else if (nonNull(findClass(t))) {
729 ERRMSG(line) "\"%s\" used as both class and type constructor",
734 Tycon nw = newTycon(t);
735 tyconDefns = cons(nw,tyconDefns);
736 tycon(nw).line = line;
737 tycon(nw).arity = argCount;
738 tycon(nw).what = what;
739 if (what==RESTRICTSYN) {
740 h98DoesntSupport(line,"restricted type synonyms");
741 typeInDefns = cons(pair(nw,snd(rhs)),typeInDefns);
744 tycon(nw).defn = pair(lhs,rhs);
748 Void setTypeIns(bs) /* set local synonyms for given */
749 List bs; { /* binding group */
750 List cvs = typeInDefns;
751 for (; nonNull(cvs); cvs=tl(cvs)) {
752 Tycon c = fst(hd(cvs));
753 List vs = snd(hd(cvs));
754 for (tycon(c).what = RESTRICTSYN; nonNull(vs); vs=tl(vs)) {
755 if (nonNull(findBinding(textOf(hd(vs)),bs))) {
756 tycon(c).what = SYNONYM;
763 Void clearTypeIns() { /* clear list of local synonyms */
764 for (; nonNull(typeInDefns); typeInDefns=tl(typeInDefns))
765 tycon(fst(hd(typeInDefns))).what = RESTRICTSYN;
768 /* --------------------------------------------------------------------------
769 * Further analysis of Type declarations:
771 * In order to allow the definition of mutually recursive families of
772 * data types, the static analysis of the right hand sides of type
773 * declarations cannot be performed until all of the type declarations
776 * Once parsing is complete, we carry out the following:
778 * - check format of lhs, extracting list of bound vars and ensuring that
779 * there are no repeated variables and no Skolem variables.
780 * - run dependency analysis on rhs to check that only bound type vars
781 * appear in type and that all constructors are defined.
782 * Replace type variables by offsets, constructors by Tycons.
783 * - use list of dependents to sort into strongly connected components.
784 * - ensure that there is not more than one synonym in each group.
785 * - kind-check each group of type definitions.
787 * - check that there are no previous definitions for constructor
788 * functions in data type definitions.
789 * - install synonym expansions and constructor definitions.
790 * ------------------------------------------------------------------------*/
792 static List tcDeps = NIL; /* list of dependent tycons/classes*/
794 static Void local checkTyconDefn(d) /* validate type constructor defn */
796 Cell lhs = fst(tycon(d).defn);
797 Cell rhs = snd(tycon(d).defn);
798 Int line = tycon(d).line;
799 List tyvars = getArgs(lhs);
801 /* check for repeated tyvars on lhs*/
802 for (temp=tyvars; nonNull(temp); temp=tl(temp))
803 if (nonNull(varIsMember(textOf(hd(temp)),tl(temp)))) {
804 ERRMSG(line) "Repeated type variable \"%s\" on left hand side",
805 textToStr(textOf(hd(temp)))
809 tcDeps = NIL; /* find dependents */
810 switch (whatIs(tycon(d).what)) {
812 case SYNONYM : rhs = depTypeExp(line,tyvars,rhs);
813 if (cellIsMember(d,tcDeps)) {
814 ERRMSG(line) "Recursive type synonym \"%s\"",
815 textToStr(tycon(d).text)
821 case NEWTYPE : depConstrs(d,tyvars,rhs);
825 default : internal("checkTyconDefn");
830 tycon(d).kind = tcDeps;
834 static Void local depConstrs(t,tyvars,cd)
835 Tycon t; /* Define constructor functions and*/
836 List tyvars; /* do dependency analysis for data */
837 Cell cd; { /* definitions (w or w/o deriving) */
838 Int line = tycon(t).line;
843 List derivs = snd(cd);
844 List compTypes = NIL;
848 for (i=0; i<tycon(t).arity; ++i) /* build representation for tycon */
849 lhs = ap(lhs,mkOffset(i)); /* applied to full comp. of args */
851 if (isQualType(cs)) { /* allow for possible context */
854 map2Over(depPredExp,line,tyvars,ctxt);
855 h98CheckCtxt(line,"context",TRUE,ctxt,NIL);
858 if (nonNull(cs) && isNull(tl(cs))) /* Single constructor datatype? */
861 for (; nonNull(cs); cs=tl(cs)) { /* For each constructor function: */
863 List sig = dupList(tyvars);
864 List evs = NIL; /* locally quantified vars */
865 List lps = NIL; /* locally bound predicates */
866 List ctxt1 = ctxt; /* constructor function context */
867 List scs = NIL; /* strict components */
868 List fs = NONE; /* selector names */
869 Type type = lhs; /* constructor function type */
870 Int arity = 0; /* arity of constructor function */
871 Int nr2 = 0; /* Number of rank 2 args */
872 Name n; /* name for constructor function */
874 if (whatIs(con)==POLYTYPE) { /* Locally quantified vars */
877 sig = checkQuantVars(line,evs,sig,con);
880 if (isQualType(con)) { /* Local predicates */
883 for (us = typeVarsIn(lps,NIL,NIL,NIL); nonNull(us); us=tl(us))
884 if (!varIsMember(textOf(hd(us)),evs)) {
886 "Variable \"%s\" in constraint is not locally bound",
887 textToStr(textOf(hd(us)))
890 map2Over(depPredExp,line,sig,lps);
895 if (whatIs(con)==LABC) { /* Skeletize constr components */
896 Cell fls = snd(snd(con)); /* get field specifications */
899 for (; nonNull(fls); fls=tl(fls)) { /* for each field spec: */
900 List vs = fst(hd(fls));
901 Type t = snd(hd(fls)); /* - scrutinize type */
902 Bool banged = whatIs(t)==BANG;
903 t = depCompType(line,sig,(banged ? arg(t) : t));
904 while (nonNull(vs)) { /* - add named components */
912 scs = cons(mkInt(arity),scs);
916 scs = rev(scs); /* put strict comps in ascend ord */
918 else { /* Non-labelled constructor */
921 for (; isAp(c); c=fun(c))
923 for (compNo=arity, c=con; isAp(c); c=fun(c)) {
925 if (whatIs(t)==BANG) {
926 scs = cons(mkInt(compNo),scs);
930 arg(c) = depCompType(line,sig,t);
934 if (nonNull(ctxt1)) /* Extract relevant part of context*/
935 ctxt1 = selectCtxt(ctxt1,offsetTyvarsIn(con,NIL));
937 for (i=arity; isAp(con); i--) { /* Calculate type of constructor */
940 fun(con) = typeArrow;
941 if (isPolyOrQualType(cmp)) {
942 if (nonNull(derivs)) {
943 ERRMSG(line) "Cannot derive instances for types" ETHEN
944 ERRTEXT " with polymorphic or qualified components"
950 if (nonNull(derivs)) /* and build list of components */
951 compTypes = cons(cmp,compTypes);
956 if (nr2>0) { /* Add rank 2 annotation */
957 type = ap(RANK2,pair(mkInt(nr2-length(lps)),type));
960 if (nonNull(evs)) { /* Add existential annotation */
961 if (nonNull(derivs)) {
962 ERRMSG(line) "Cannot derive instances for types" ETHEN
963 ERRTEXT " with existentially typed components"
968 "Cannot use selectors with existentially typed components"
971 type = ap(EXIST,pair(mkInt(length(evs)),type));
974 if (nonNull(lps)) { /* Add local preds part to type */
975 type = ap(CDICTS,pair(lps,type));
978 if (nonNull(ctxt1)) { /* Add context part to type */
979 type = ap(QUAL,pair(ctxt1,type));
982 if (nonNull(sig)) { /* Add quantifiers to type */
984 for (; nonNull(ts1); ts1=tl(ts1)) {
987 type = mkPolyType(sig,type);
990 n = findName(textOf(con)); /* Allocate constructor fun name */
992 n = newName(textOf(con),NIL);
993 } else if (name(n).defn!=PREDEFINED) {
994 duplicateError(line,name(n).mod,name(n).text,
995 "constructor function");
997 name(n).arity = arity; /* Save constructor fun details */
1000 name(n).number = cfunNo(conNo++);
1001 name(n).type = type;
1002 if (tycon(t).what==NEWTYPE) {
1005 "A newtype constructor cannot have class constraints"
1010 "A newtype constructor must have exactly one argument"
1015 "Illegal strictess annotation for newtype constructor"
1018 name(n).defn = nameId;
1020 implementCfun(n,scs);
1025 sels = addSels(line,n,fs,sels);
1029 if (nonNull(sels)) {
1031 fst(cd) = appendOnto(fst(cd),sels);
1032 selDefns = cons(sels,selDefns);
1035 if (nonNull(derivs)) { /* Generate derived instances */
1036 map3Proc(checkDerive,t,ctxt,compTypes,derivs);
1040 Int userArity(c) /* Find arity for cfun, ignoring */
1041 Name c; { /* CDICTS parameters */
1042 Int a = name(c).arity;
1043 Type t = name(c).type;
1045 if (isPolyType(t)) {
1048 if ((w=whatIs(t))==QUAL) {
1049 w = whatIs(t=snd(snd(t)));
1052 a -= length(fst(snd(t)));
1058 static List local addSels(line,c,fs,ss) /* Add fields to selector list */
1059 Int line; /* line number of constructor */
1060 Name c; /* corresponding constr function */
1061 List fs; /* list of fields (varids) */
1062 List ss; { /* list of existing selectors */
1064 cfunSfuns = cons(pair(c,fs),cfunSfuns);
1065 for (; nonNull(fs); fs=tl(fs), ++sn) {
1067 Text t = textOf(hd(fs));
1069 if (nonNull(varIsMember(t,tl(fs)))) {
1070 ERRMSG(line) "Repeated field name \"%s\" for constructor \"%s\"",
1071 textToStr(t), textToStr(name(c).text)
1075 while (nonNull(ns) && t!=name(hd(ns)).text) {
1080 name(hd(ns)).defn = cons(pair(c,mkInt(sn)),name(hd(ns)).defn);
1082 Name n = findName(t);
1084 ERRMSG(line) "Repeated definition for selector \"%s\"",
1089 name(n).line = line;
1090 name(n).number = SELNAME;
1091 name(n).defn = singleton(pair(c,mkInt(sn)));
1098 static List local selectCtxt(ctxt,vs) /* calculate subset of context */
1105 for (; nonNull(ctxt); ctxt=tl(ctxt)) {
1106 List us = offsetTyvarsIn(hd(ctxt),NIL);
1107 for (; nonNull(us) && cellIsMember(hd(us),vs); us=tl(us)) {
1110 ps = cons(hd(ctxt),ps);
1117 static Void local checkSynonyms(ts) /* Check for mutually recursive */
1118 List ts; { /* synonyms */
1120 for (; nonNull(ts); ts=tl(ts)) { /* build list of all synonyms */
1122 switch (whatIs(tycon(t).what)) {
1124 case RESTRICTSYN : syns = cons(t,syns);
1128 while (nonNull(syns)) { /* then visit each synonym */
1129 syns = visitSyn(NIL,hd(syns),syns);
1133 static List local visitSyn(path,t,syns) /* visit synonym definition to look*/
1134 List path; /* for cycles */
1137 if (cellIsMember(t,path)) { /* every elt in path depends on t */
1138 ERRMSG(tycon(t).line)
1139 "Type synonyms \"%s\" and \"%s\" are mutually recursive",
1140 textToStr(tycon(t).text), textToStr(tycon(hd(path)).text)
1143 List ds = tycon(t).kind;
1145 for (; nonNull(ds); ds=tl(ds)) {
1146 if (cellIsMember(hd(ds),syns)) {
1147 if (isNull(path1)) {
1148 path1 = cons(t,path);
1150 syns = visitSyn(path1,hd(ds),syns);
1154 tycon(t).defn = fullExpand(tycon(t).defn);
1155 return removeCell(t,syns);
1158 /* --------------------------------------------------------------------------
1159 * Expanding out all type synonyms in a type expression:
1160 * ------------------------------------------------------------------------*/
1162 Type fullExpand(t) /* find full expansion of type exp */
1163 Type t; { /* assuming that all relevant */
1164 Cell h = t; /* synonym defns of lower rank have*/
1165 Int n = 0; /* already been fully expanded */
1167 for (args=NIL; isAp(h); h=fun(h), n++) {
1168 args = cons(fullExpand(arg(h)),args);
1170 t = applyToArgs(h,args);
1171 if (isSynonym(h) && n>=tycon(h).arity) {
1172 if (n==tycon(h).arity) {
1173 t = instantiateSyn(tycon(h).defn,t);
1176 while (--n > tycon(h).arity) {
1179 fun(p) = instantiateSyn(tycon(h).defn,fun(p));
1185 static Type local instantiateSyn(t,env) /* instantiate type according using*/
1186 Type t; /* env to determine appropriate */
1187 Type env; { /* values for OFFSET type vars */
1188 switch (whatIs(t)) {
1189 case AP : return ap(instantiateSyn(fun(t),env),
1190 instantiateSyn(arg(t),env));
1192 case OFFSET : return nthArg(offsetOf(t),env);
1198 /* --------------------------------------------------------------------------
1199 * Static analysis of class declarations:
1201 * Performed in a similar manner to that used for type declarations.
1203 * The first part of the static analysis is performed as the declarations
1204 * are read during parsing. The parser ensures that:
1205 * - the class header and all superclass predicates are of the form
1208 * The classDefn() function:
1209 * - ensures that there is no previous definition for class
1210 * - checks that class name has not previously been used as a type constr.
1211 * - make new entry in class table
1212 * - record line number of declaration
1213 * - build list of classes defined in current script for use in later
1214 * stages of static analysis.
1215 * ------------------------------------------------------------------------*/
1217 Void classDefn(line,head,ms,fds) /* process new class definition */
1218 Int line; /* definition line number */
1219 Cell head; /* class header :: ([Supers],Class) */
1220 List ms; /* class definition body */
1221 List fds; { /* functional dependencies */
1222 Text ct = textOf(getHead(snd(head)));
1223 Int arity = argCount;
1225 if (nonNull(findClass(ct))) {
1226 ERRMSG(line) "Repeated definition of class \"%s\"",
1229 } else if (nonNull(findTycon(ct))) {
1230 ERRMSG(line) "\"%s\" used as both class and type constructor",
1234 Class nw = newClass(ct);
1235 cclass(nw).line = line;
1236 cclass(nw).arity = arity;
1237 cclass(nw).head = snd(head);
1238 cclass(nw).supers = fst(head);
1239 cclass(nw).members = ms;
1240 cclass(nw).level = 0;
1241 cclass(nw).fds = fds;
1242 cclass(nw).xfds = NIL;
1243 classDefns = cons(nw,classDefns);
1245 h98DoesntSupport(line,"multiple parameter classes");
1249 /* --------------------------------------------------------------------------
1250 * Further analysis of class declarations:
1252 * Full static analysis of class definitions must be postponed until the
1253 * complete script has been read and all static analysis on type definitions
1254 * has been completed.
1256 * Once this has been achieved, we carry out the following checks on each
1258 * - check that variables in header are distinct
1259 * - replace head by skeleton
1260 * - check superclass declarations, replace by skeletons
1261 * - split body of class into members and declarations
1262 * - make new name entry for each member function
1263 * - record member function number (eventually an offset into dictionary!)
1264 * - no member function has a previous definition ...
1265 * - no member function is mentioned more than once in the list of members
1266 * - each member function type is valid, replace vars by offsets
1267 * - qualify each member function type by class header
1268 * - only bindings for members appear in defaults
1269 * - only function bindings appear in defaults
1270 * - check that extended class hierarchy does not contain any cycles
1271 * ------------------------------------------------------------------------*/
1273 static Void local checkClassDefn(c) /* validate class definition */
1276 Int args = cclass(c).arity - 1;
1277 Cell temp = cclass(c).head;
1281 for (; isAp(temp); temp=fun(temp)) {
1282 if (!isVar(arg(temp))) {
1283 ERRMSG(cclass(c).line) "Type variable required in class head"
1286 if (nonNull(varIsMember(textOf(arg(temp)),tyvars))) {
1287 ERRMSG(cclass(c).line)
1288 "Repeated type variable \"%s\" in class head",
1289 textToStr(textOf(arg(temp)))
1292 tyvars = cons(arg(temp),tyvars);
1295 for (fs=cclass(c).fds; nonNull(fs); fs=tl(fs)) {
1299 /* Check for trivial dependency
1302 ERRMSG(cclass(c).line) "Functional dependency is trivial"
1306 /* Check for duplicated vars on right hand side, and for vars on
1307 * right that also appear on the left:
1309 for (vs=snd(fd); nonNull(vs); vs=tl(vs)) {
1310 if (varIsMember(textOf(hd(vs)),fst(fd))) {
1311 ERRMSG(cclass(c).line)
1312 "Trivial dependency for variable \"%s\"",
1313 textToStr(textOf(hd(vs)))
1316 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1317 ERRMSG(cclass(c).line)
1318 "Repeated variable \"%s\" in functional dependency",
1319 textToStr(textOf(hd(vs)))
1322 hd(vs) = depTypeVar(cclass(c).line,tyvars,textOf(hd(vs)));
1325 /* Check for duplicated vars on left hand side:
1327 for (vs=fst(fd); nonNull(vs); vs=tl(vs)) {
1328 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1329 ERRMSG(cclass(c).line)
1330 "Repeated variable \"%s\" in functional dependency",
1331 textToStr(textOf(hd(vs)))
1334 hd(vs) = depTypeVar(cclass(c).line,tyvars,textOf(hd(vs)));
1338 if (cclass(c).arity==0) {
1341 Int args = cclass(c).arity - 1;
1342 for (temp=cclass(c).head; args>0; temp=fun(temp), args--) {
1343 arg(temp) = mkOffset(args);
1345 arg(temp) = mkOffset(0);
1349 tcDeps = NIL; /* find dependents */
1350 map2Over(depPredExp,cclass(c).line,tyvars,cclass(c).supers);
1351 h98CheckCtxt(cclass(c).line,"class definition",FALSE,cclass(c).supers,NIL);
1352 cclass(c).numSupers = length(cclass(c).supers);
1353 cclass(c).defaults = extractBindings(cclass(c).members); /* defaults*/
1354 ss = extractSigdecls(cclass(c).members);
1355 fs = extractFixdecls(cclass(c).members);
1356 cclass(c).members = pair(ss,fs);
1357 map2Proc(checkMems,c,tyvars,ss);
1359 cclass(c).kinds = tcDeps;
1364 /* --------------------------------------------------------------------------
1365 * Functional dependencies are inherited from superclasses.
1366 * For example, if I've got the following classes:
1368 * class C a b | a -> b
1369 * class C [b] a => D a b
1371 * then C will have the dependency ([a], [b]) as expected, and D will inherit
1372 * the dependency ([b], [a]) from C.
1373 * When doing pairwise improvement, we have to consider not just improving
1374 * when we see a pair of Cs or a pair of Ds in the context, but when we've
1375 * got a C and a D as well. In this case, we only improve when the
1376 * predicate in question matches the type skeleton in the relevant superclass
1377 * constraint. E.g., we improve the pair (C [Int] a, D b Int) (unifying
1378 * a and b), but we don't improve the pair (C Int a, D b Int).
1379 * To implement functional dependency inheritance, we calculate
1380 * the closure of all functional dependencies, and store the result
1381 * in an additional field `xfds' (extended functional dependencies).
1382 * The `xfds' field is a list of functional dependency lists, annotated
1383 * with a list of predicate skeletons constraining when improvement can
1384 * happen against this dependency list. For example, the xfds field
1385 * for C above would be:
1386 * [([C a b], [([a], [b])])]
1387 * and the xfds field for D would be:
1388 * [([C [b] a, D a b], [([b], [a])])]
1389 * Self-improvement (of a C with a C, or a D with a D) is treated as a
1390 * special case of an inherited dependency.
1391 * ------------------------------------------------------------------------*/
1392 static List local inheritFundeps(c,pi,o)
1396 Int alpha = newKindedVars(cclass(c).kinds);
1397 List scs = cclass(c).supers;
1400 /* better not fail ;-) */
1401 if (!matchPred(pi,o,cclass(c).head,alpha))
1402 internal("inheritFundeps - predicate failed to match it's own head!");
1403 this = copyPred(pi,o);
1404 for (; nonNull(scs); scs=tl(scs)) {
1405 Class s = getHead(hd(scs));
1407 List sfds = inheritFundeps(s,hd(scs),alpha);
1408 for (; nonNull(sfds); sfds=tl(sfds)) {
1410 xfds = cons(pair(cons(this,fst(h)),snd(h)),xfds);
1414 if (nonNull(cclass(c).fds)) {
1415 List fds = NIL, fs = cclass(c).fds;
1416 for (; nonNull(fs); fs=tl(fs)) {
1417 fds = cons(pair(otvars(this,fst(hd(fs))),
1418 otvars(this,snd(hd(fs)))),fds);
1420 xfds = cons(pair(cons(this,NIL),fds),xfds);
1425 static Void local extendFundeps(c)
1428 emptySubstitution();
1429 alpha = newKindedVars(cclass(c).kinds);
1430 cclass(c).xfds = inheritFundeps(c,cclass(c).head,alpha);
1432 /* we can now check for ambiguity */
1433 map1Proc(checkMems2,c,fst(cclass(c).members));
1437 static Cell local depPredExp(line,tyvars,pred)
1444 for (; isAp(h); args++) {
1445 arg(h) = depTypeExp(line,tyvars,arg(h));
1451 h98DoesntSupport(line,"tag classes");
1452 } else if (args!=1) {
1453 h98DoesntSupport(line,"multiple parameter classes");
1456 if (isQCon(h)) { /* standard class constraint */
1457 Class c = findQualClass(h);
1459 ERRMSG(line) "Undefined class \"%s\"", identToStr(h)
1467 if (args!=cclass(c).arity) {
1468 ERRMSG(line) "Wrong number of arguments for class \"%s\"",
1469 textToStr(cclass(c).text)
1472 if (cellIsMember(c,classDefns) && !cellIsMember(c,tcDeps)) {
1473 tcDeps = cons(c,tcDeps);
1477 else if (isExt(h)) { /* Lacks predicate */
1478 if (args!=1) { /* parser shouldn't let this happen*/
1479 ERRMSG(line) "Wrong number of arguments for lacks predicate"
1486 if (whatIs(h) != IPCELL)
1489 internal("depPredExp");
1494 static Void local checkMems(c,tyvars,m) /* check member function details */
1498 Int line = intOf(fst3(m));
1505 if (isPolyType(t)) {
1511 tyvars = typeVarsIn(t,NIL,xtvs,tyvars);
1512 /* Look for extra type vars. */
1513 checkOptQuantVars(line,xtvs,tyvars);
1515 if (isQualType(t)) { /* Overloaded member signatures? */
1516 map2Over(depPredExp,line,tyvars,fst(snd(t)));
1518 t = ap(QUAL,pair(NIL,t));
1521 fst(snd(t)) = cons(cclass(c).head,fst(snd(t)));/* Add main predicate */
1522 snd(snd(t)) = depTopType(line,tyvars,snd(snd(t)));
1524 for (tvs=tyvars; nonNull(tvs); tvs=tl(tvs)){/* Quantify */
1528 t = mkPolyType(sig,t);
1530 thd3(m) = t; /* Save type */
1531 take(cclass(c).arity,tyvars); /* Delete extra type vars */
1533 if (isAmbiguous(t)) {
1534 ambigError(line,"class declaration",hd(vs),t);
1536 h98CheckType(line,"member type",hd(vs),t);
1539 static Void local checkMems2(c,m) /* check member function details */
1542 Int line = intOf(fst3(m));
1547 static Void local addMembers(c) /* Add definitions of member funs */
1548 Class c; { /* and other parts of class struct.*/
1549 List ms = fst(cclass(c).members);
1550 List fs = snd(cclass(c).members);
1551 List ns = NIL; /* List of names */
1552 Int mno; /* Member function number */
1554 for (mno=0; mno<cclass(c).numSupers; mno++) {
1555 ns = cons(newDSel(c,mno),ns);
1557 cclass(c).dsels = rev(ns); /* Save dictionary selectors */
1559 for (mno=1, ns=NIL; nonNull(ms); ms=tl(ms)) {
1560 Int line = intOf(fst3(hd(ms)));
1561 List vs = rev(snd3(hd(ms)));
1562 Type t = thd3(hd(ms));
1563 for (; nonNull(vs); vs=tl(vs)) {
1564 ns = cons(newMember(line,mno++,hd(vs),t,c),ns);
1567 cclass(c).members = rev(ns); /* Save list of members */
1568 cclass(c).numMembers = length(cclass(c).members);
1570 for (; nonNull(fs); fs=tl(fs)) { /* fixity declarations */
1571 Int line = intOf(fst3(hd(fs)));
1572 List ops = snd3(hd(fs));
1573 Syntax s = intOf(thd3(hd(fs)));
1574 for (; nonNull(ops); ops=tl(ops)) {
1575 Name n = nameIsMember(textOf(hd(ops)),cclass(c).members);
1577 missFixity(line,textOf(hd(ops)));
1578 } else if (name(n).syntax!=NO_SYNTAX) {
1579 dupFixity(line,textOf(hd(ops)));
1585 /* Not actually needed just yet; for the time being, dictionary code will
1586 not be passed through the type checker.
1588 cclass(c).dtycon = addPrimTycon(generateText("Dict.%s",c),
1595 mno = cclass(c).numSupers + cclass(c).numMembers;
1596 cclass(c).dcon = addPrimCfun(generateText("Make.%s",c),mno,0,NIL);
1597 implementCfun(cclass(c).dcon,NIL); /* ADR addition */
1599 if (mno==1) { /* Single entry dicts use newtype */
1600 name(cclass(c).dcon).defn = nameId;
1601 if (nonNull(cclass(c).members)) {
1602 name(hd(cclass(c).members)).number = mfunNo(0);
1605 cclass(c).defaults = classBindings("class",c,cclass(c).defaults);
1608 static Name local newMember(l,no,v,t,parent)
1609 Int l; /* Make definition for member fn */
1614 Name m = findName(textOf(v));
1617 m = newName(textOf(v),parent);
1618 } else if (name(m).defn!=PREDEFINED) {
1619 ERRMSG(l) "Repeated definition for member function \"%s\"",
1620 textToStr(name(m).text)
1626 name(m).number = mfunNo(no);
1631 static Name local newDSel(c,no) /* Make definition for dict selectr*/
1637 sprintf(buf,"sc%d.%s",no,"%s");
1638 s = newName(generateText(buf,c),c);
1639 name(s).line = cclass(c).line;
1641 name(s).number = DFUNNAME;
1647 static Text local generateText(sk,c) /* We need to generate names for */
1648 String sk; /* certain objects corresponding */
1649 Class c; { /* to each class. */
1650 String cname = textToStr(cclass(c).text);
1651 char buffer[MAX_GEN+1];
1653 if ((strlen(sk)+strlen(cname))>=MAX_GEN) {
1654 ERRMSG(0) "Please use a shorter name for class \"%s\"", cname
1657 sprintf(buffer,sk,cname);
1658 return findText(buffer);
1661 static Int local visitClass(c) /* visit class defn to check that */
1662 Class c; { /* class hierarchy is acyclic */
1664 if (isExt(c)) { /* special case for lacks preds */
1668 if (cclass(c).level < 0) { /* already visiting this class? */
1669 ERRMSG(cclass(c).line) "Class hierarchy for \"%s\" is not acyclic",
1670 textToStr(cclass(c).text)
1672 } else if (cclass(c).level == 0) { /* visiting class for first time */
1673 List scs = cclass(c).supers;
1675 cclass(c).level = (-1);
1676 for (; nonNull(scs); scs=tl(scs)) {
1677 Int l = visitClass(getHead(hd(scs)));
1680 cclass(c).level = 1+lev; /* level = 1 + max level of supers */
1682 return cclass(c).level;
1685 /* --------------------------------------------------------------------------
1686 * Process class and instance declaration binding groups:
1687 * ------------------------------------------------------------------------*/
1689 static List local classBindings(where,c,bs)
1690 String where; /* Check validity of bindings bs */
1691 Class c; /* for class c (or an inst of c) */
1692 List bs; { /* sort into approp. member order */
1695 for (; nonNull(bs); bs=tl(bs)) {
1697 Cell body = snd(snd(b));
1700 if (!isVar(fst(b))) { /* Only allow function bindings */
1701 ERRMSG(rhsLine(snd(body)))
1702 "Pattern binding illegal in %s declaration", where
1706 if (isNull(mnm=memberName(c,textOf(fst(b))))) {
1707 ERRMSG(rhsLine(snd(hd(body))))
1708 "No member \"%s\" in class \"%s\"",
1709 textToStr(textOf(fst(b))), textToStr(cclass(c).text)
1713 nbs = numInsert(mfunOf(mnm)-1,b,nbs);
1718 static Name local memberName(c,t) /* return name of member function */
1719 Class c; /* with name t in class c */
1720 Text t; { /* return NIL if not a member */
1721 List ms = cclass(c).members;
1722 for (; nonNull(ms); ms=tl(ms)) {
1723 if (t==name(hd(ms)).text) {
1730 static List local numInsert(n,x,xs) /* insert x at nth position in xs, */
1731 Int n; /* filling gaps with NIL */
1734 List start = isNull(xs) ? cons(NIL,NIL) : xs;
1736 for (xs=start; 0<n--; xs=tl(xs)) {
1737 if (isNull(tl(xs))) {
1738 tl(xs) = cons(NIL,NIL);
1745 /* --------------------------------------------------------------------------
1746 * Calculate set of variables appearing in a given type expression (possibly
1747 * qualified) as a list of distinct values. The order in which variables
1748 * appear in the list is the same as the order in which those variables
1749 * occur in the type expression when read from left to right.
1750 * ------------------------------------------------------------------------*/
1752 List local typeVarsIn(ty,us,ws,vs) /*Calculate list of type variables*/
1753 Cell ty; /* used in type expression, reading*/
1754 List us; /* from left to right ignoring any */
1755 List ws; /* listed in us. */
1756 List vs; { /* ws = explicitly quantified vars */
1757 switch (whatIs(ty)) {
1758 case AP : return typeVarsIn(snd(ty),us,ws,
1759 typeVarsIn(fst(ty),us,ws,vs));
1762 case VAROPCELL : if ((nonNull(findBtyvs(textOf(ty)))
1763 && !varIsMember(textOf(ty),ws))
1764 || varIsMember(textOf(ty),us)) {
1767 return maybeAppendVar(ty,vs);
1770 case POLYTYPE : return typeVarsIn(monotypeOf(ty),polySigOf(ty),ws,vs);
1772 case QUAL : { vs = typeVarsIn(fst(snd(ty)),us,ws,vs);
1773 return typeVarsIn(snd(snd(ty)),us,ws,vs);
1776 case BANG : return typeVarsIn(snd(ty),us,ws,vs);
1778 case LABC : { List fs = snd(snd(ty));
1779 for (; nonNull(fs); fs=tl(fs)) {
1780 vs = typeVarsIn(snd(hd(fs)),us,ws,vs);
1788 static List local maybeAppendVar(v,vs) /* append variable to list if not */
1789 Cell v; /* already included */
1795 while (nonNull(c)) {
1796 if (textOf(hd(c))==t) {
1804 tl(p) = cons(v,NIL);
1812 /* --------------------------------------------------------------------------
1813 * Static analysis for type expressions is required to:
1814 * - ensure that each type constructor or class used has been defined.
1815 * - replace type variables by offsets, constructor names by Tycons.
1816 * - ensure that the type is well-kinded.
1817 * ------------------------------------------------------------------------*/
1819 static Type local checkSigType(line,where,e,type)
1820 Int line; /* Check validity of type expr in */
1821 String where; /* explicit type signature */
1828 if (isPolyType(type)) {
1829 xtvs = fst(snd(type));
1830 type = monotypeOf(type);
1832 tvs = typeVarsIn(type,NIL,xtvs,NIL);
1834 checkOptQuantVars(line,xtvs,tvs);
1836 if (isQualType(type)) {
1837 map2Over(depPredExp,line,tvs,fst(snd(type)));
1838 snd(snd(type)) = depTopType(line,tvs,snd(snd(type)));
1840 if (isAmbiguous(type)) {
1841 ambigError(line,where,e,type);
1844 type = depTopType(line,tvs,type);
1848 if (length(tvs)>=NUM_OFFSETS) {
1849 ERRMSG(line) "Too many type variables in %s\n", where
1853 for (; nonNull(ts); ts=tl(ts)) {
1856 type = mkPolyType(tvs,type);
1861 kindType(line,"type expression",type);
1865 h98CheckType(line,where,e,type);
1869 static Void local checkOptQuantVars(line,xtvs,tvs)
1871 List xtvs; /* Explicitly quantified vars */
1872 List tvs; { /* Implicitly quantified vars */
1873 if (nonNull(xtvs)) {
1875 for (; nonNull(vs); vs=tl(vs)) {
1876 if (!varIsMember(textOf(hd(vs)),xtvs)) {
1877 ERRMSG(line) "Quantifier does not mention type variable \"%s\"",
1878 textToStr(textOf(hd(vs)))
1882 for (vs=xtvs; nonNull(vs); vs=tl(vs)) {
1883 if (!varIsMember(textOf(hd(vs)),tvs)) {
1884 ERRMSG(line) "Quantified type variable \"%s\" is not used",
1885 textToStr(textOf(hd(vs)))
1888 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1889 ERRMSG(line) "Quantified type variable \"%s\" is repeated",
1890 textToStr(textOf(hd(vs)))
1897 static Type local depTopType(l,tvs,t) /* Check top-level of type sig */
1905 for (; getHead(t1)==typeArrow && argCount==2; ++i) {
1906 arg(fun(t1)) = depCompType(l,tvs,arg(fun(t1)));
1907 if (isPolyOrQualType(arg(fun(t1)))) {
1913 if (nonNull(prev)) {
1914 arg(prev) = depTypeExp(l,tvs,t1);
1916 t = depTypeExp(l,tvs,t1);
1919 t = ap(RANK2,pair(mkInt(nr2),t));
1924 static Type local depCompType(l,tvs,t) /* Check component type for constr */
1928 Int ntvs = length(tvs);
1930 if (isPolyType(t)) {
1931 List vs = fst(snd(t));
1933 tvs = checkQuantVars(l,vs,tvs,t);
1934 nfr = replicate(length(vs),NIL);
1936 if (isQualType(t)) {
1937 map2Over(depPredExp,l,tvs,fst(snd(t)));
1938 snd(snd(t)) = depTypeExp(l,tvs,snd(snd(t)));
1939 if (isAmbiguous(t)) {
1940 ambigError(l,"type component",NIL,t);
1943 t = depTypeExp(l,tvs,t);
1949 return mkPolyType(nfr,t);
1952 static Type local depTypeExp(line,tyvars,type)
1956 switch (whatIs(type)) {
1957 case AP : fst(type) = depTypeExp(line,tyvars,fst(type));
1958 snd(type) = depTypeExp(line,tyvars,snd(type));
1961 case VARIDCELL : return depTypeVar(line,tyvars,textOf(type));
1963 case QUALIDENT : if (isQVar(type)) {
1964 ERRMSG(line) "Qualified type variables not allowed"
1967 /* deliberate fall through */
1968 case CONIDCELL : { Tycon tc = findQualTycon(type);
1971 "Undefined type constructor \"%s\"",
1975 if (cellIsMember(tc,tyconDefns) &&
1976 !cellIsMember(tc,tcDeps)) {
1977 tcDeps = cons(tc,tcDeps);
1983 case EXT : h98DoesntSupport(line,"extensible records");
1988 default : internal("depTypeExp");
1993 static Type local depTypeVar(line,tyvars,tv)
2000 for (; nonNull(tyvars); offset++) {
2001 if (tv==textOf(hd(tyvars))) {
2004 tyvars = tl(tyvars);
2007 Cell vt = findBtyvs(tv);
2011 ERRMSG(line) "Undefined type variable \"%s\"", textToStr(tv)
2014 return mkOffset(found);
2017 static List local checkQuantVars(line,vs,tvs,body)
2019 List vs; /* variables to quantify over */
2020 List tvs; /* variables already in scope */
2021 Cell body; { /* type/constr for scope of vars */
2023 List bvs = typeVarsIn(body,NIL,NIL,NIL);
2025 for (; nonNull(us); us=tl(us)) {
2026 Text u = textOf(hd(us));
2027 if (varIsMember(u,tl(us))) {
2028 ERRMSG(line) "Duplicated quantified variable %s",
2033 if (varIsMember(u,tvs)) {
2034 ERRMSG(line) "Local quantifier for %s hides an outer use",
2039 if (!varIsMember(u,bvs)) {
2040 ERRMSG(line) "Locally quantified variable %s is not used",
2045 tvs = appendOnto(tvs,vs);
2050 /* --------------------------------------------------------------------------
2051 * Check for ambiguous types:
2052 * A type Preds => type is ambiguous if not (TV(P) `subset` TV(type))
2053 * ------------------------------------------------------------------------*/
2055 List offsetTyvarsIn(t,vs) /* add list of offset tyvars in t */
2056 Type t; /* to list vs */
2058 switch (whatIs(t)) {
2059 case AP : return offsetTyvarsIn(fun(t),
2060 offsetTyvarsIn(arg(t),vs));
2062 case OFFSET : if (cellIsMember(t,vs))
2067 case QUAL : return offsetTyvarsIn(snd(t),vs);
2069 case POLYTYPE : return offsetTyvarsIn(monotypeOf(t),vs);
2070 /* slightly inaccurate, but won't matter here */
2073 case RANK2 : return offsetTyvarsIn(snd(snd(t)),vs);
2075 default : return vs;
2079 List zonkTyvarsIn(t,vs)
2082 switch (whatIs(t)) {
2083 case AP : return zonkTyvarsIn(fun(t),
2084 zonkTyvarsIn(arg(t),vs));
2086 case INTCELL : if (cellIsMember(t,vs))
2091 /* this case will lead to a type error --
2092 much better than reporting an internal error ;-) */
2093 /* case OFFSET : internal("zonkTyvarsIn"); */
2095 default : return vs;
2099 static List local otvars(pi,os) /* os is a list of offsets that */
2100 Cell pi; /* refer to the arguments of pi; */
2101 List os; { /* find list of offsets in those */
2102 List us = NIL; /* positions */
2103 for (; nonNull(os); os=tl(os)) {
2104 us = offsetTyvarsIn(nthArg(offsetOf(hd(os)),pi),us);
2109 static List local otvarsZonk(pi,os,o) /* same as above, but zonks */
2113 for (; nonNull(os); os=tl(os)) {
2114 Type t = zonkType(nthArg(offsetOf(hd(os)),pi),o);
2115 us = zonkTyvarsIn(t,us);
2120 static Bool local odiff(us,vs)
2122 while (nonNull(us) && cellIsMember(hd(us),vs)) {
2128 static Bool local osubset(us,vs) /* Determine whether us is subset */
2129 List us, vs; { /* of vs */
2130 while (nonNull(us) && cellIsMember(hd(us),vs)) {
2136 List oclose(fds,vs) /* Compute closure of vs wrt to fds*/
2139 Bool changed = TRUE;
2143 while (nonNull(fds)) {
2145 List next = tl(fds);
2146 if (osubset(fst(fd),vs)) { /* Test if fd applies */
2148 for (; nonNull(os); os=tl(os)) {
2149 if (!cellIsMember(hd(os),vs)) {
2150 vs = cons(hd(os),vs);
2154 } else { /* Didn't apply this time, so keep */
2165 Bool isAmbiguous(type) /* Determine whether type is */
2166 Type type; { /* ambiguous */
2167 if (isPolyType(type)) {
2168 type = monotypeOf(type);
2170 if (isQualType(type)) { /* only qualified types can be */
2171 List ps = fst(snd(type)); /* ambiguous */
2172 List tvps = offsetTyvarsIn(ps,NIL);
2173 List tvts = offsetTyvarsIn(snd(snd(type)),NIL);
2174 List fds = calcFunDeps(ps);
2176 tvts = oclose(fds,tvts); /* Close tvts under fds */
2177 return !osubset(tvps,tvts);
2182 List calcFunDeps(ps)
2185 for (; nonNull(ps); ps=tl(ps)) {/* Calc functional dependencies */
2187 Cell c = getHead(pi);
2189 List xfs = cclass(c).xfds;
2190 for (; nonNull(xfs); xfs=tl(xfs)) {
2191 List fs = snd(hd(xfs));
2192 for (; nonNull(fs); fs=tl(fs)) {
2193 fds = cons(pair(otvars(pi,fst(hd(fs))),
2194 otvars(pi,snd(hd(fs)))),fds);
2200 fds = cons(pair(NIL,offsetTyvarsIn(arg(pi),NIL)),fds);
2207 List calcFunDepsPreds(ps)
2210 for (; nonNull(ps); ps=tl(ps)) {/* Calc functional dependencies */
2212 Cell pi = fst3(pi3);
2213 Cell c = getHead(pi);
2214 Int o = intOf(snd3(pi3));
2216 List xfs = cclass(c).xfds;
2217 for (; nonNull(xfs); xfs=tl(xfs)) {
2218 List fs = snd(hd(xfs));
2219 for (; nonNull(fs); fs=tl(fs)) {
2220 fds = cons(pair(otvarsZonk(pi,fst(hd(fs)),o),
2221 otvarsZonk(pi,snd(hd(fs)),o)),fds);
2227 fds = cons(pair(NIL,zonkTyvarsIn(arg(pi),NIL)),fds);
2234 Void ambigError(line,where,e,type) /* produce error message for */
2235 Int line; /* ambiguity */
2239 ERRMSG(line) "Ambiguous type signature in %s", where ETHEN
2240 ERRTEXT "\n*** ambiguous type : " ETHEN ERRTYPE(type);
2242 ERRTEXT "\n*** assigned to : " ETHEN ERREXPR(e);
2248 /* --------------------------------------------------------------------------
2249 * Kind inference for simple types:
2250 * ------------------------------------------------------------------------*/
2252 static Void local kindConstr(line,alpha,m,c)
2253 Int line; /* Determine kind of constructor */
2257 Cell h = getHead(c);
2261 Printf("kindConstr: alpha=%d, m=%d, c=",alpha,m);
2262 printType(stdout,c);
2266 switch (whatIs(h)) {
2267 case POLYTYPE : if (n!=0) {
2268 internal("kindConstr1");
2270 static String pt = "polymorphic type";
2271 Type t = dropRank1(c,alpha,m);
2272 Kinds ks = polySigOf(t);
2275 for (; isAp(ks); ks=tl(ks)) {
2278 beta = newKindvars(m1);
2279 unkindTypes = cons(pair(mkInt(beta),t),unkindTypes);
2280 checkKind(line,beta,m1,monotypeOf(t),NIL,pt,STAR,0);
2285 case QUAL : if (n!=0) {
2286 internal("kindConstr2");
2288 map3Proc(kindPred,line,alpha,m,fst(snd(c)));
2289 kindConstr(line,alpha,m,snd(snd(c)));
2293 case RANK2 : kindConstr(line,alpha,m,snd(snd(c)));
2297 case EXT : if (n!=2) {
2299 "Illegal use of row in " ETHEN ERRTYPE(c);
2306 case TYCON : if (isSynonym(h) && n<tycon(h).arity) {
2308 "Not enough arguments for type synonym \"%s\"",
2309 textToStr(tycon(h).text)
2315 if (n==0) { /* trivial case, no arguments */
2316 typeIs = kindAtom(alpha,c);
2317 } else { /* non-trivial application */
2318 static String app = "constructor application";
2328 typeIs = kindAtom(alpha,h); /* h :: v1 -> ... -> vn -> w */
2329 shouldKind(line,h,c,app,k,beta);
2331 for (i=n; i>0; --i) { /* ci :: vi for each 1 <- 1..n */
2332 checkKind(line,alpha,m,arg(a),c,app,aVar,beta+i-1);
2335 tyvarType(beta+n); /* inferred kind is w */
2339 static Kind local kindAtom(alpha,c) /* Find kind of atomic constructor */
2342 switch (whatIs(c)) {
2343 case TUPLE : return simpleKind(tupleOf(c)); /*(,)::* -> * -> * */
2344 case OFFSET : return mkInt(alpha+offsetOf(c));
2345 case TYCON : return tycon(c).kind;
2346 case INTCELL : return c;
2348 case VAROPCELL : { Cell vt = findBtyvs(textOf(c));
2354 case EXT : return extKind;
2358 Printf("kindAtom(%d,whatIs(%d)) on ",alpha,whatIs(c));
2359 printType(stdout,c);
2362 internal("kindAtom");
2363 return STAR;/* not reached */
2366 static Void local kindPred(l,alpha,m,pi)/* Check kinds of arguments in pred*/
2372 if (isAp(pi) && isExt(fun(pi))) {
2373 static String lackspred = "lacks predicate";
2374 checkKind(l,alpha,m,arg(pi),NIL,lackspred,ROW,0);
2379 if (isAp(pi) && whatIs(fun(pi)) == IPCELL) {
2380 static String ippred = "iparam predicate";
2381 checkKind(l,alpha,m,arg(pi),NIL,ippred,STAR,0);
2385 { static String predicate = "class constraint";
2386 Class c = getHead(pi);
2387 List as = getArgs(pi);
2388 Kinds ks = cclass(c).kinds;
2390 while (nonNull(ks)) {
2391 checkKind(l,alpha,m,hd(as),NIL,predicate,hd(ks),0);
2398 static Void local kindType(line,wh,type)/* check that (poss qualified) type*/
2399 Int line; /* is well-kinded */
2402 checkKind(line,0,0,type,NIL,wh,STAR,0);
2405 static Void local fixKinds() { /* add kind annotations to types */
2406 for (; nonNull(unkindTypes); unkindTypes=tl(unkindTypes)) {
2407 Pair pr = hd(unkindTypes);
2408 Int beta = intOf(fst(pr));
2409 Cell qts = polySigOf(snd(pr));
2411 if (isNull(hd(qts))) {
2412 hd(qts) = copyKindvar(beta++);
2414 internal("fixKinds");
2416 if (nonNull(tl(qts))) {
2424 Printf("Type expression: ");
2425 printType(stdout,snd(pr));
2427 printKind(stdout,polySigOf(snd(pr)));
2433 /* --------------------------------------------------------------------------
2434 * Kind checking of groups of type constructors and classes:
2435 * ------------------------------------------------------------------------*/
2437 static Void local kindTCGroup(tcs) /* find kinds for mutually rec. gp */
2438 List tcs; { /* of tycons and classes */
2439 emptySubstitution();
2441 mapProc(initTCKind,tcs);
2442 mapProc(kindTC,tcs);
2445 emptySubstitution();
2448 static Void local initTCKind(c) /* build initial kind/arity for c */
2450 if (isTycon(c)) { /* Initial kind of tycon is: */
2451 Int beta = newKindvars(1); /* v1 -> ... -> vn -> vn+1 */
2452 varKind(tycon(c).arity); /* where n is the arity of c. */
2453 bindTv(beta,typeIs,typeOff); /* For data definitions, vn+1 == * */
2454 switch (whatIs(tycon(c).what)) {
2456 case DATATYPE : bindTv(typeOff+tycon(c).arity,STAR,0);
2458 tycon(c).kind = mkInt(beta);
2460 Int n = cclass(c).arity;
2461 Int beta = newKindvars(n);
2462 cclass(c).kinds = NIL;
2465 cclass(c).kinds = pair(mkInt(beta+n),cclass(c).kinds);
2470 static Void local kindTC(c) /* check each part of a tycon/class*/
2471 Cell c; { /* is well-kinded */
2473 static String cfun = "constructor function";
2474 static String tsyn = "synonym definition";
2475 Int line = tycon(c).line;
2476 Int beta = tyvar(intOf(tycon(c).kind))->offs;
2477 Int m = tycon(c).arity;
2478 switch (whatIs(tycon(c).what)) {
2480 case DATATYPE : { List cs = tycon(c).defn;
2481 if (isQualType(cs)) {
2482 map3Proc(kindPred,line,beta,m,
2484 tycon(c).defn = cs = snd(snd(cs));
2486 for (; hasCfun(cs); cs=tl(cs)) {
2487 kindType(line,cfun,name(hd(cs)).type);
2492 default : checkKind(line,beta,m,tycon(c).defn,NIL,
2496 else { /* scan type exprs in class defn to*/
2497 List ms = fst(cclass(c).members);
2498 Int m = cclass(c).arity; /* determine the class signature */
2499 Int beta = newKindvars(m);
2500 kindPred(cclass(c).line,beta,m,cclass(c).head);
2501 map3Proc(kindPred,cclass(c).line,beta,m,cclass(c).supers);
2502 for (; nonNull(ms); ms=tl(ms)) {
2503 Int line = intOf(fst3(hd(ms)));
2504 Type type = thd3(hd(ms));
2505 kindType(line,"member function type signature",type);
2510 static Void local genTC(c) /* generalise kind inferred for */
2511 Cell c; { /* given tycon/class */
2513 tycon(c).kind = copyKindvar(intOf(tycon(c).kind));
2515 Printf("%s :: ",textToStr(tycon(c).text));
2516 printKind(stdout,tycon(c).kind);
2520 Kinds ks = cclass(c).kinds;
2521 for (; nonNull(ks); ks=tl(ks)) {
2522 hd(ks) = copyKindvar(intOf(hd(ks)));
2525 Printf("%s :: ",textToStr(cclass(c).text));
2526 printKinds(stdout,cclass(c).kinds);
2532 /* --------------------------------------------------------------------------
2533 * Static analysis of instance declarations:
2535 * The first part of the static analysis is performed as the declarations
2536 * are read during parsing:
2537 * - make new entry in instance table
2538 * - record line number of declaration
2539 * - build list of instances defined in current script for use in later
2540 * stages of static analysis.
2541 * ------------------------------------------------------------------------*/
2543 Void instDefn(line,head,ms) /* process new instance definition */
2544 Int line; /* definition line number */
2545 Cell head; /* inst header :: (context,Class) */
2546 List ms; { /* instance members */
2547 Inst nw = newInst();
2548 inst(nw).line = line;
2549 inst(nw).specifics = fst(head);
2550 inst(nw).head = snd(head);
2551 inst(nw).implements = ms;
2552 instDefns = cons(nw,instDefns);
2555 /* --------------------------------------------------------------------------
2556 * Further static analysis of instance declarations:
2558 * Makes the following checks:
2559 * - Class part of header has form C (T a1 ... an) where C is a known
2560 * class, and T is a known datatype constructor (or restricted synonym),
2561 * and there is no previous C-T instance, and (T a1 ... an) has a kind
2562 * appropriate for the class C.
2563 * - Each element of context is a valid class expression, with type vars
2564 * drawn from a1, ..., an.
2565 * - All bindings are function bindings
2566 * - All bindings define member functions for class C
2567 * - Arrange bindings into appropriate order for member list
2568 * - No top level type signature declarations
2569 * ------------------------------------------------------------------------*/
2571 Bool allowOverlap = FALSE; /* TRUE => allow overlapping insts */
2572 Name nameListMonad = NIL; /* builder function for List Monad */
2574 static Void local checkInstDefn(in) /* Validate instance declaration */
2576 Int line = inst(in).line;
2577 List tyvars = typeVarsIn(inst(in).head,NIL,NIL,NIL);
2578 List tvps = NIL, tvts = NIL;
2581 if (haskell98) { /* Check for `simple' type */
2583 Cell t = arg(inst(in).head);
2584 for (; isAp(t); t=fun(t)) {
2585 if (!isVar(arg(t))) {
2587 "syntax error in instance head (variable expected)"
2590 if (varIsMember(textOf(arg(t)),tvs)) {
2591 ERRMSG(line) "repeated type variable \"%s\" in instance head",
2592 textToStr(textOf(arg(t)))
2595 tvs = cons(arg(t),tvs);
2599 "syntax error in instance head (constructor expected)"
2604 /* add in the tyvars from the `specifics' so that we don't
2605 prematurely complain about undefined tyvars */
2606 tyvars = typeVarsIn(inst(in).specifics,NIL,NIL,tyvars);
2607 inst(in).head = depPredExp(line,tyvars,inst(in).head);
2610 Type h = getHead(arg(inst(in).head));
2612 ERRMSG(line) "Cannot use type synonym in instance head"
2617 map2Over(depPredExp,line,tyvars,inst(in).specifics);
2619 /* OK, now we start over, and test for ambiguity */
2620 tvts = offsetTyvarsIn(inst(in).head,NIL);
2621 tvps = offsetTyvarsIn(inst(in).specifics,NIL);
2622 fds = calcFunDeps(inst(in).specifics);
2623 tvts = oclose(fds,tvts);
2624 tvts = odiff(tvps,tvts);
2625 if (!isNull(tvts)) {
2626 ERRMSG(line) "Undefined type variable \"%s\"",
2627 textToStr(textOf(nth(offsetOf(hd(tvts)),tyvars)))
2631 h98CheckCtxt(line,"instance definition",FALSE,inst(in).specifics,NIL);
2632 inst(in).numSpecifics = length(inst(in).specifics);
2633 inst(in).c = getHead(inst(in).head);
2634 if (!isClass(inst(in).c)) {
2635 ERRMSG(line) "Illegal predicate in instance declaration"
2639 if (nonNull(cclass(inst(in).c).fds)) {
2640 List fds = cclass(inst(in).c).fds;
2641 for (; nonNull(fds); fds=tl(fds)) {
2642 List as = otvars(inst(in).head, fst(hd(fds)));
2643 List bs = otvars(inst(in).head, snd(hd(fds)));
2644 List fs = calcFunDeps(inst(in).specifics);
2646 if (!osubset(bs,as)) {
2647 ERRMSG(inst(in).line)
2648 "Instance is more general than a dependency allows"
2650 ERRTEXT "\n*** Instance : "
2651 ETHEN ERRPRED(inst(in).head);
2652 ERRTEXT "\n*** For class : "
2653 ETHEN ERRPRED(cclass(inst(in).c).head);
2654 ERRTEXT "\n*** Under dependency : "
2655 ETHEN ERRFD(hd(fds));
2662 kindInst(in,length(tyvars));
2665 if (nonNull(extractSigdecls(inst(in).implements))) {
2667 "Type signature declarations not permitted in instance declaration"
2670 if (nonNull(extractFixdecls(inst(in).implements))) {
2672 "Fixity declarations not permitted in instance declaration"
2675 inst(in).implements = classBindings("instance",
2677 extractBindings(inst(in).implements));
2678 inst(in).builder = newInstImp(in);
2679 if (!preludeLoaded && isNull(nameListMonad) && isAp(inst(in).head)
2680 && fun(inst(in).head)==classMonad && arg(inst(in).head)==typeList) {
2681 nameListMonad = inst(in).builder;
2685 static Void local insertInst(in) /* Insert instance into class */
2687 Class c = inst(in).c;
2688 List ins = cclass(c).instances;
2691 if (nonNull(cclass(c).fds)) { /* Check for conflicts with fds */
2692 List ins1 = cclass(c).instances;
2693 for (; nonNull(ins1); ins1=tl(ins1)) {
2694 List fds = cclass(c).fds;
2695 substitution(RESET);
2696 for (; nonNull(fds); fds=tl(fds)) {
2697 Int alpha = newKindedVars(inst(in).kinds);
2698 Int beta = newKindedVars(inst(hd(ins1)).kinds);
2699 List as = fst(hd(fds));
2701 for (; same && nonNull(as); as=tl(as)) {
2702 Int n = offsetOf(hd(as));
2703 same &= unify(nthArg(n,inst(in).head),alpha,
2704 nthArg(n,inst(hd(ins1)).head),beta);
2706 if (isNull(as) && same) {
2707 for (as=snd(hd(fds)); same && nonNull(as); as=tl(as)) {
2708 Int n = offsetOf(hd(as));
2709 same &= sameType(nthArg(n,inst(in).head),alpha,
2710 nthArg(n,inst(hd(ins1)).head),beta);
2713 ERRMSG(inst(in).line)
2714 "Instances are not consistent with dependencies"
2716 ERRTEXT "\n*** This instance : "
2717 ETHEN ERRPRED(inst(in).head);
2718 ERRTEXT "\n*** Conflicts with : "
2719 ETHEN ERRPRED(inst(hd(ins)).head);
2720 ERRTEXT "\n*** For class : "
2721 ETHEN ERRPRED(cclass(c).head);
2722 ERRTEXT "\n*** Under dependency : "
2723 ETHEN ERRFD(hd(fds));
2733 substitution(RESET);
2734 while (nonNull(ins)) { /* Look for overlap w/ other insts */
2735 Int alpha = newKindedVars(inst(in).kinds);
2736 Int beta = newKindedVars(inst(hd(ins)).kinds);
2737 if (unifyPred(inst(in).head,alpha,inst(hd(ins)).head,beta)) {
2738 Cell pi = copyPred(inst(in).head,alpha);
2739 if (allowOverlap && !haskell98) {
2740 Bool bef = instCompare(in,hd(ins));
2741 Bool aft = instCompare(hd(ins),in);
2742 if (bef && !aft) { /* in comes strictly before hd(ins)*/
2745 if (aft && !bef) { /* in comes strictly after hd(ins) */
2752 if (multiInstRes && nonNull(inst(in).specifics)) {
2756 ERRMSG(inst(in).line) "Overlapping instances for class \"%s\"",
2757 textToStr(cclass(c).text)
2759 ERRTEXT "\n*** This instance : " ETHEN ERRPRED(inst(in).head);
2760 ERRTEXT "\n*** Overlaps with : " ETHEN
2761 ERRPRED(inst(hd(ins)).head);
2762 ERRTEXT "\n*** Common instance : " ETHEN
2770 prev = ins; /* No overlap detected, so move on */
2771 ins = tl(ins); /* to next instance */
2773 substitution(RESET);
2775 if (nonNull(prev)) { /* Insert instance at this point */
2776 tl(prev) = cons(in,ins);
2778 cclass(c).instances = cons(in,ins);
2782 static Bool local instCompare(ia,ib) /* See if ia is an instance of ib */
2784 Int alpha = newKindedVars(inst(ia).kinds);
2785 Int beta = newKindedVars(inst(ib).kinds);
2786 return matchPred(inst(ia).head,alpha,inst(ib).head,beta);
2789 static Name local newInstImp(in) /* Make definition for inst builder*/
2791 Name b = newName(inventText(),in);
2792 name(b).line = inst(in).line;
2793 name(b).arity = inst(in).numSpecifics;
2794 name(b).number = DFUNNAME;
2798 /* --------------------------------------------------------------------------
2799 * Kind checking of instance declaration headers:
2800 * ------------------------------------------------------------------------*/
2802 static Void local kindInst(in,freedom) /* check predicates in instance */
2807 emptySubstitution();
2808 beta = newKindvars(freedom);
2809 kindPred(inst(in).line,beta,freedom,inst(in).head);
2810 if (whatIs(inst(in).specifics)!=DERIVE) {
2811 map3Proc(kindPred,inst(in).line,beta,freedom,inst(in).specifics);
2813 for (inst(in).kinds = NIL; 0<freedom--; ) {
2814 inst(in).kinds = cons(copyKindvar(beta+freedom),inst(in).kinds);
2817 Printf("instance ");
2818 printPred(stdout,inst(in).head);
2820 printKinds(stdout,inst(in).kinds);
2823 emptySubstitution();
2826 /* --------------------------------------------------------------------------
2827 * Process derived instance requests:
2828 * ------------------------------------------------------------------------*/
2830 static List derivedInsts; /* list of derived instances */
2832 static Void local checkDerive(t,p,ts,ct)/* verify derived instance request */
2833 Tycon t; /* for tycon t, with explicit */
2834 List p; /* context p, component types ts */
2835 List ts; /* and named class ct */
2837 Int line = tycon(t).line;
2838 Class c = findQualClass(ct);
2840 ERRMSG(line) "Unknown class \"%s\" in derived instance",
2844 addDerInst(line,c,p,dupList(ts),t,tycon(t).arity);
2847 static Void local addDerInst(line,c,p,cts,t,a) /* Add a derived instance */
2854 Cell head = t; /* Build instance head */
2858 head = ap(head,mkOffset(i));
2864 inst(in).line = line;
2865 inst(in).head = head;
2866 inst(in).specifics = ap(DERIVE,pair(dupList(p),cts));
2867 inst(in).implements = NIL;
2868 inst(in).kinds = mkInt(a);
2869 derivedInsts = cons(in,derivedInsts);
2872 Void addTupInst(c,n) /* Request derived instance of c */
2873 Class c; /* for mkTuple(n) constructor */
2878 cts = cons(mkOffset(m),cts);
2881 addDerInst(0,c,NIL,cts,mkTuple(n),n);
2885 Inst addRecShowInst(c,e) /* Generate instance for ShowRecRow*/
2886 Class c; /* c *must* be ShowRecRow */
2888 Inst in = newInst();
2890 inst(in).head = ap(c,ap2(e,aVar,bVar));
2891 inst(in).kinds = extKind;
2892 inst(in).specifics = cons(ap(classShow,aVar),
2894 cons(ap(c,bVar),NIL)));
2895 inst(in).numSpecifics = 3;
2896 inst(in).builder = implementRecShw(extText(e),in);
2897 cclass(c).instances = appendOnto(cclass(c).instances,singleton(in));
2901 Inst addRecEqInst(c,e) /* Generate instance for EqRecRow */
2902 Class c; /* c *must* be EqRecRow */
2904 Inst in = newInst();
2906 inst(in).head = ap(c,ap2(e,aVar,bVar));
2907 inst(in).kinds = extKind;
2908 inst(in).specifics = cons(ap(classEq,aVar),
2910 cons(ap(c,bVar),NIL)));
2911 inst(in).numSpecifics = 3;
2912 inst(in).builder = implementRecEq(extText(e),in);
2913 cclass(c).instances = appendOnto(cclass(c).instances,singleton(in));
2918 /* --------------------------------------------------------------------------
2919 * Calculation of contexts for derived instances:
2921 * Allowing arbitrary types to appear in contexts makes it rather harder
2922 * to decide what the context for a derived instance should be. For
2925 * data T a = MkT [a] deriving Show,
2927 * we could have either of the following:
2929 * instance (Show [a]) => Show (T a) where ...
2930 * instance (Show a) => Show (T a) where ...
2932 * (assuming, of course, that instance (Show a) => Show [a]). For now, we
2933 * choose to reduce contexts in the hope of detecting errors at an earlier
2934 * stage---in contrast with value definitions, there is no way for a user
2935 * to provide something analogous to a `type signature' by which they might
2936 * be able to control this behaviour themselves. We eliminate tautological
2937 * predicates, but only allow predicates to appear in the final result if
2938 * they have at least one argument with a variable at its head.
2940 * In general, we have to deal with mutually recursive instance declarations.
2941 * We find a solution in the obvious way by iterating to find a fixed point.
2942 * Of course, without restrictions on the form of instance declarations, we
2943 * cannot be sure that this will always terminate!
2945 * For each instance we maintain a pair of the form DERIVE (ctxt,ps).
2946 * Ctxt is a list giving the parts of the context that have been produced
2947 * so far in the form of predicate skeletons. During the calculation of
2948 * derived instances, we attach a dummy NIL value to the end of the list
2949 * which acts as a kind of `variable': other parts of the system maintain
2950 * pointers to this variable, and use it to detect when the context has
2951 * been extended with new elements. Meanwhile, ps is a list containing
2952 * predicates (pi,o) together with (delayed) substitutions of the form
2953 * (o,xs) where o is an offset and xs is one of the context variables
2954 * described above, which may have been partially instantiated.
2955 * ------------------------------------------------------------------------*/
2957 static Bool instsChanged;
2959 static Void local deriveContexts(is) /* Calc contexts for derived insts */
2961 emptySubstitution();
2962 mapProc(initDerInst,is); /* Prepare derived instances */
2964 do { /* Main calculation of contexts */
2965 instsChanged = FALSE;
2966 mapProc(calcInstPreds,is);
2967 } while (instsChanged);
2969 mapProc(tidyDerInst,is); /* Tidy up results */
2972 static Void local initDerInst(in) /* Prepare instance for calculation*/
2973 Inst in; { /* of derived instance context */
2974 Cell spcs = inst(in).specifics;
2975 Int beta = newKindedVars(inst(in).kinds);
2976 if (whatIs(spcs)!=DERIVE) {
2977 internal("initDerInst");
2979 fst(snd(spcs)) = appendOnto(fst(snd(spcs)),singleton(NIL));
2980 for (spcs=snd(snd(spcs)); nonNull(spcs); spcs=tl(spcs)) {
2981 hd(spcs) = ap2(inst(in).c,hd(spcs),mkInt(beta));
2983 inst(in).numSpecifics = beta;
2985 #ifdef DEBUG_DERIVING
2986 Printf("initDerInst: ");
2987 printPred(stdout,inst(in).head);
2989 printContext(stdout,snd(snd(inst(in).specifics)));
2994 static Void local calcInstPreds(in) /* Calculate next approximation */
2995 Inst in; { /* of the context for a derived */
2996 List retain = NIL; /* instance */
2997 List ps = snd(snd(inst(in).specifics));
2998 List spcs = fst(snd(inst(in).specifics));
2999 Int beta = inst(in).numSpecifics;
3001 Int factor = 1+length(ps);
3003 #ifdef DEBUG_DERIVING
3004 Printf("calcInstPreds: ");
3005 printPred(stdout,inst(in).head);
3009 while (nonNull(ps)) {
3012 if (its++ >= factor*cutoff) {
3013 Cell bpi = inst(in).head;
3014 Cell pi = copyPred(fun(p),intOf(snd(p)));
3015 ERRMSG(inst(in).line) "\n*** Cannot derive " ETHEN ERRPRED(bpi);
3016 ERRTEXT " after %d iterations.", its-1 ETHEN
3018 "\n*** This may indicate that the problem is undecidable. However,\n"
3020 "*** you may still try to increase the cutoff limit using the -c\n"
3022 "*** option and then try again. (The current setting is -c%d)\n",
3026 if (isInt(fst(p))) { /* Delayed substitution? */
3028 for (; nonNull(hd(qs)); qs=tl(qs)) {
3029 ps = cons(pair(hd(qs),fst(p)),ps);
3031 retain = cons(pair(fst(p),qs),retain);
3034 else if (isExt(fun(fst(p)))) { /* Lacks predicate */
3035 Text l = extText(fun(fst(p)));
3036 Type t = arg(fst(p));
3037 Int o = intOf(snd(p));
3042 h = getDerefHead(t,o);
3043 while (isExt(h) && argCount==2 && l!=extText(h)) {
3046 h = getDerefHead(t,o);
3048 if (argCount==0 && isOffset(h)) {
3049 maybeAddPred(ap(fun(fun(p)),h),o,beta,spcs);
3050 } else if (argCount!=0 || h!=typeNoRow) {
3051 Cell bpi = inst(in).head;
3052 Cell pi = copyPred(fun(p),intOf(snd(p)));
3053 ERRMSG(inst(in).line) "Cannot derive " ETHEN ERRPRED(bpi);
3054 ERRTEXT " because predicate " ETHEN ERRPRED(pi);
3055 ERRTEXT " does not hold\n"
3060 else { /* Class predicate */
3062 Int o = intOf(snd(p));
3063 Inst in1 = findInstFor(pi,o);
3065 List qs = inst(in1).specifics;
3066 Int off = mkInt(typeOff);
3067 if (whatIs(qs)==DERIVE) { /* Still being derived */
3068 for (qs=fst(snd(qs)); nonNull(hd(qs)); qs=tl(qs)) {
3069 ps = cons(pair(hd(qs),off),ps);
3071 retain = cons(pair(off,qs),retain);
3072 } else { /* Previously def'd inst */
3073 for (; nonNull(qs); qs=tl(qs)) {
3074 ps = cons(pair(hd(qs),off),ps);
3077 } else { /* No matching instance */
3079 while (isAp(qi) && isOffset(getDerefHead(arg(qi),o))) {
3083 Cell bpi = inst(in).head;
3084 pi = copyPred(pi,o);
3085 ERRMSG(inst(in).line) "An instance of " ETHEN ERRPRED(pi);
3086 ERRTEXT " is required to derive " ETHEN ERRPRED(bpi);
3090 maybeAddPred(pi,o,beta,spcs);
3095 snd(snd(inst(in).specifics)) = retain;
3098 static Void local maybeAddPred(pi,o,beta,ps)
3099 Cell pi; /* Add predicate pi to the list ps,*/
3100 Int o; /* setting the instsChanged flag if*/
3101 Int beta; /* pi is not already a member and */
3102 List ps; { /* using beta to adjust vars */
3103 Cell c = getHead(pi);
3104 for (; nonNull(ps); ps=tl(ps)) {
3105 if (isNull(hd(ps))) { /* reached the `dummy' end of list?*/
3106 hd(ps) = copyAdj(pi,o,beta);
3107 tl(ps) = pair(NIL,NIL);
3108 instsChanged = TRUE;
3110 } else if (c==getHead(hd(ps)) && samePred(pi,o,hd(ps),beta)) {
3116 static Cell local copyAdj(c,o,beta) /* Copy (c,o), replacing vars with */
3117 Cell c; /* offsets relative to beta. */
3120 switch (whatIs(c)) {
3121 case AP : { Cell l = copyAdj(fst(c),o,beta);
3122 Cell r = copyAdj(snd(c),o,beta);
3126 case OFFSET : { Int vn = o+offsetOf(c);
3127 Tyvar *tyv = tyvar(vn);
3129 return copyAdj(tyv->bound,tyv->offs,beta);
3132 if (vn<0 || vn>=NUM_OFFSETS) {
3133 internal("copyAdj");
3135 return mkOffset(vn);
3141 static Void local tidyDerInst(in) /* Tidy up results of derived inst */
3142 Inst in; { /* calculations */
3143 Int o = inst(in).numSpecifics;
3144 List ps = tl(rev(fst(snd(inst(in).specifics))));
3146 copyPred(inst(in).head,o);
3147 inst(in).specifics = simpleContext(ps,o);
3148 h98CheckCtxt(inst(in).line,"derived instance",FALSE,inst(in).specifics,in);
3149 inst(in).numSpecifics = length(inst(in).specifics);
3151 #ifdef DEBUG_DERIVING
3152 Printf("Derived instance: ");
3153 printContext(stdout,inst(in).specifics);
3155 printPred(stdout,inst(in).head);
3160 /* --------------------------------------------------------------------------
3161 * Generate code for derived instances:
3162 * ------------------------------------------------------------------------*/
3164 static Void local addDerivImp(in)
3167 Type t = getHead(arg(inst(in).head));
3168 Class c = inst(in).c;
3171 } else if (c==classOrd) {
3173 } else if (c==classEnum) {
3174 imp = deriveEnum(t);
3175 } else if (c==classIx) {
3177 } else if (c==classShow) {
3178 imp = deriveShow(t);
3179 } else if (c==classRead) {
3180 imp = deriveRead(t);
3181 } else if (c==classBounded) {
3182 imp = deriveBounded(t);
3184 ERRMSG(inst(in).line) "Cannot derive instances of class \"%s\"",
3185 textToStr(cclass(inst(in).c).text)
3189 kindInst(in,intOf(inst(in).kinds));
3191 inst(in).builder = newInstImp(in);
3192 inst(in).implements = classBindings("derived instance",
3198 /* --------------------------------------------------------------------------
3199 * Default definitions; only one default definition is permitted in a
3200 * given script file. If no default is supplied, then a standard system
3201 * default will be used where necessary.
3202 * ------------------------------------------------------------------------*/
3204 Void defaultDefn(line,defs) /* Handle default types definition */
3207 if (defaultLine!=0) {
3208 ERRMSG(line) "Multiple default declarations are not permitted in" ETHEN
3209 ERRTEXT "a single script file.\n"
3212 defaultDefns = defs;
3216 static Void local checkDefaultDefns() { /* check that default types are */
3217 List ds = NIL; /* well-kinded instances of Num */
3219 if (defaultLine!=0) {
3220 map2Over(depTypeExp,defaultLine,NIL,defaultDefns);
3221 emptySubstitution();
3223 map2Proc(kindType,defaultLine,"default type",defaultDefns);
3225 emptySubstitution();
3226 mapOver(fullExpand,defaultDefns);
3228 defaultDefns = stdDefaults;
3231 if (isNull(classNum)) {
3232 classNum = findClass(findText("Num"));
3235 for (ds=defaultDefns; nonNull(ds); ds=tl(ds)) {
3236 if (isNull(provePred(NIL,NIL,ap(classNum,hd(ds))))) {
3238 "Default types must be instances of the Num class"
3245 /* --------------------------------------------------------------------------
3246 * Foreign import declarations are Hugs' equivalent of GHC's ccall mechanism.
3247 * They are used to "import" C functions into a module.
3248 * They are usually not written by hand but, rather, generated automatically
3249 * by GreenCard, IDL compilers or whatever.
3251 * Foreign export declarations generate C wrappers for Hugs functions.
3252 * Hugs only provides "foreign export dynamic" because it's not obvious
3253 * what "foreign export static" would mean in an interactive setting.
3254 * ------------------------------------------------------------------------*/
3256 Void foreignImport(line,callconv,extName,intName,type)
3257 /* Handle foreign imports */
3263 Text t = textOf(intName);
3264 Name n = findName(t);
3265 Int l = intOf(line);
3269 } else if (name(n).defn!=PREDEFINED) {
3270 ERRMSG(l) "Redeclaration of foreign \"%s\"", textToStr(t)
3274 name(n).defn = extName;
3275 name(n).type = type;
3276 name(n).callconv = callconv;
3277 foreignImports = cons(n,foreignImports);
3280 static Void local checkForeignImport(p) /* Check foreign import */
3282 emptySubstitution();
3283 name(p).type = checkSigType(name(p).line,
3284 "foreign import declaration",
3287 /* We don't expand synonyms here because we don't want the IO
3288 * part to be expanded.
3289 * name(p).type = fullExpand(name(p).type);
3291 implementForeignImport(p);
3294 Void foreignExport(line,callconv,extName,intName,type)
3295 /* Handle foreign exports */
3301 Text t = textOf(intName);
3302 Name n = findName(t);
3303 Int l = intOf(line);
3307 } else if (name(n).defn!=PREDEFINED) {
3308 ERRMSG(l) "Redeclaration of foreign \"%s\"", textToStr(t)
3312 name(n).defn = NIL; /* nothing to say */
3313 name(n).type = type;
3314 name(n).callconv = callconv;
3315 foreignExports = cons(n,foreignExports);
3318 static Void local checkForeignExport(p) /* Check foreign export */
3320 emptySubstitution();
3321 name(p).type = checkSigType(name(p).line,
3322 "foreign export declaration",
3325 implementForeignExport(p);
3330 /* --------------------------------------------------------------------------
3331 * Static analysis of patterns:
3333 * Patterns are parsed as ordinary (atomic) expressions. Static analysis
3334 * makes the following checks:
3335 * - Patterns are well formed (according to pattern syntax), including the
3336 * special case of (n+k) patterns.
3337 * - All constructor functions have been defined and are used with the
3338 * correct number of arguments.
3339 * - No variable name is used more than once in a pattern.
3341 * The list of pattern variables occuring in each pattern is accumulated in
3342 * a global list `patVars', which must be initialised to NIL at appropriate
3343 * points before using these routines to check for valid patterns. This
3344 * mechanism enables the pattern checking routine to be mapped over a list
3345 * of patterns, ensuring that no variable occurs more than once in the
3346 * complete pattern list (as is required on the lhs of a function defn).
3347 * ------------------------------------------------------------------------*/
3349 static List patVars; /* List of vars bound in pattern */
3351 static Cell local checkPat(line,p) /* Check valid pattern syntax */
3354 switch (whatIs(p)) {
3356 case VAROPCELL : addToPatVars(line,p);
3359 case INFIX : return checkPat(line,tidyInfix(line,snd(p)));
3361 case AP : return checkMaybeCnkPat(line,p);
3366 case CONOPCELL : return checkApPat(line,0,p);
3371 case FLOATCELL : break;
3372 case INTCELL : break;
3374 case ASPAT : addToPatVars(line,fst(snd(p)));
3375 snd(snd(p)) = checkPat(line,snd(snd(p)));
3378 case LAZYPAT : snd(p) = checkPat(line,snd(p));
3381 case FINLIST : map1Over(checkPat,line,snd(p));
3384 case CONFLDS : depConFlds(line,p,TRUE);
3387 case ESIGN : snd(snd(p)) = checkPatType(line,
3391 fst(snd(p)) = checkPat(line,fst(snd(p)));
3394 default : ERRMSG(line) "Illegal pattern syntax"
3400 static Cell local checkMaybeCnkPat(l,p)/* Check applicative pattern with */
3401 Int l; /* the possibility of n+k pattern */
3404 Cell h = getHead(p);
3406 if (argCount==2 && isVar(h) && textOf(h)==textPlus) { /* n+k */
3407 Cell v = arg(fun(p));
3408 if (!isInt(arg(p))) {
3409 ERRMSG(l) "Second argument in (n+k) pattern must be an integer"
3412 if (intOf(arg(p))<=0) {
3413 ERRMSG(l) "Integer k in (n+k) pattern must be > 0"
3416 fst(fun(p)) = ADDPAT;
3417 intValOf(fun(p)) = intOf(arg(p));
3418 arg(p) = checkPat(l,v);
3422 return checkApPat(l,0,p);
3425 static Cell local checkApPat(line,args,p)
3426 Int line; /* check validity of application */
3427 Int args; /* of constructor to arguments */
3429 switch (whatIs(p)) {
3430 case AP : fun(p) = checkApPat(line,args+1,fun(p));
3431 arg(p) = checkPat(line,arg(p));
3434 case TUPLE : if (tupleOf(p)!=args) {
3435 ERRMSG(line) "Illegal tuple pattern"
3441 case EXT : h98DoesntSupport(line,"extensible records");
3443 ERRMSG(line) "Illegal record pattern"
3449 case QUALIDENT : if (!isQCon(p)) {
3451 "Illegal use of qualified variable in pattern"
3454 /* deliberate fall through */
3456 case CONOPCELL : p = conDefined(line,p);
3457 checkCfunArgs(line,p,args);
3460 case NAME : checkIsCfun(line,p);
3461 checkCfunArgs(line,p,args);
3464 default : ERRMSG(line) "Illegal pattern syntax"
3470 static Void local addToPatVars(line,v) /* Add variable v to list of vars */
3471 Int line; /* in current pattern, checking */
3472 Cell v; { /* for repeated variables. */
3477 for (; nonNull(n); p=n, n=tl(n)) {
3478 if (textOf(hd(n))==t) {
3479 ERRMSG(line) "Repeated variable \"%s\" in pattern",
3486 patVars = cons(v,NIL);
3488 tl(p) = cons(v,NIL);
3492 static Name local conDefined(line,nm) /* check that nm is the name of a */
3493 Int line; /* previously defined constructor */
3494 Cell nm; { /* function. */
3495 Name n = findQualName(nm);
3497 ERRMSG(line) "Undefined constructor function \"%s\"", identToStr(nm)
3500 checkIsCfun(line,n);
3504 static Void local checkIsCfun(line,c) /* Check that c is a constructor fn */
3508 ERRMSG(line) "\"%s\" is not a constructor function",
3509 textToStr(name(c).text)
3514 static Void local checkCfunArgs(line,c,args)
3515 Int line; /* Check constructor applied with */
3516 Cell c; /* correct number of arguments */
3518 Int a = userArity(c);
3521 "Constructor \"%s\" must have exactly %d argument%s in pattern",
3522 textToStr(name(c).text), a, ((a==1)?"":"s")
3527 static Cell local checkPatType(l,wh,e,t)/* Check type appearing in pattern */
3532 List tvs = typeVarsIn(t,NIL,NIL,NIL);
3533 h98DoesntSupport(l,"pattern type annotations");
3534 for (; nonNull(tvs); tvs=tl(tvs)) {
3535 Int beta = newKindvars(1);
3536 hd(btyvars) = cons(pair(hd(tvs),mkInt(beta)), hd(btyvars));
3538 t = checkSigType(l,"pattern type",e,t);
3539 if (isPolyOrQualType(t) || whatIs(t)==RANK2) {
3540 ERRMSG(l) "Illegal syntax in %s type annotation", wh
3546 static Cell local applyBtyvs(pat) /* Record bound type vars in pat */
3548 List bts = hd(btyvars);
3551 pat = ap(BIGLAM,pair(bts,pat));
3552 for (; nonNull(bts); bts=tl(bts)) {
3553 snd(hd(bts)) = copyKindvar(intOf(snd(hd(bts))));
3559 /* --------------------------------------------------------------------------
3560 * Maintaining lists of bound variables and local definitions, for
3561 * dependency and scope analysis.
3562 * ------------------------------------------------------------------------*/
3564 static List bounds; /* list of lists of bound vars */
3565 static List bindings; /* list of lists of binds in scope */
3566 static List depends; /* list of lists of dependents */
3568 /* bounds :: [[Var]] -- var equality used on Vars */
3569 /* bindings :: [[([Var],?)]] -- var equality used on Vars */
3570 /* depends :: [[Var]] -- pointer equality used on Vars */
3572 #define saveBvars() hd(bounds) /* list of bvars in current scope */
3573 #define restoreBvars(bs) hd(bounds)=bs /* restore list of bound variables */
3575 static Cell local bindPat(line,p) /* add new bound vars for pattern */
3579 p = checkPat(line,p);
3580 hd(bounds) = revOnto(patVars,hd(bounds));
3584 static Void local bindPats(line,ps) /* add new bound vars for patterns */
3588 map1Over(checkPat,line,ps);
3589 hd(bounds) = revOnto(patVars,hd(bounds));
3592 /* --------------------------------------------------------------------------
3593 * Before processing value and type signature declarations, all data and
3594 * type definitions have been processed so that:
3595 * - all valid type constructors (with their arities) are known.
3596 * - all valid constructor functions (with their arities and types) are
3599 * The result of parsing a list of value declarations is a list of Eqns:
3600 * Eqn ::= (SIGDECL,(Line,[Var],type))
3601 * | (FIXDECL,(Line,[Op],SyntaxInt))
3603 * The ordering of the equations in this list is the reverse of the original
3604 * ordering in the script parsed. This is a consequence of the structure of
3605 * the parser ... but also turns out to be most convenient for the static
3608 * As the first stage of the static analysis of value declarations, each
3609 * list of Eqns is converted to a list of Bindings. As part of this
3611 * - The ordering of the list of Bindings produced is the same as in the
3613 * - When a variable (function) is defined over a number of lines, all
3614 * of the definitions should appear together and each should give the
3615 * same arity to the variable being defined.
3616 * - No variable can have more than one definition.
3617 * - For pattern bindings:
3618 * - Each lhs is a valid pattern/function lhs, all constructor functions
3619 * have been defined and are used with the correct number of arguments.
3620 * - Each lhs contains no repeated pattern variables.
3621 * - Each equation defines at least one variable (e.g. True = False is
3623 * - Types appearing in type signatures are well formed:
3624 * - Type constructors used are defined and used with correct number
3626 * - type variables are replaced by offsets, type constructor names
3628 * - Every variable named in a type signature declaration is defined by
3629 * one or more equations elsewhere in the script.
3630 * - No variable has more than one type declaration.
3631 * - Similar properties for fixity declarations.
3633 * ------------------------------------------------------------------------*/
3635 #define bindingAttr(b) fst(snd(b)) /* type(s)/fixity(ies) for binding */
3636 #define fbindAlts(b) snd(snd(b)) /* alternatives for function binding*/
3638 static List local extractSigdecls(es) /* Extract the SIGDECLS from list */
3639 List es; { /* of equations */
3640 List sigdecls = NIL; /* :: [(Line,[Var],Type)] */
3642 for(; nonNull(es); es=tl(es)) {
3643 if (fst(hd(es))==SIGDECL) { /* type-declaration? */
3644 Pair sig = snd(hd(es));
3645 Int line = intOf(fst3(sig));
3646 List vs = snd3(sig);
3647 for(; nonNull(vs); vs=tl(vs)) {
3648 if (isQualIdent(hd(vs))) {
3649 ERRMSG(line) "Type signature for qualified variable \"%s\" is not allowed",
3654 sigdecls = cons(sig,sigdecls); /* discard SIGDECL tag*/
3660 static List local extractFixdecls(es) /* Extract the FIXDECLS from list */
3661 List es; { /* of equations */
3662 List fixdecls = NIL; /* :: [(Line,SyntaxInt,[Op])] */
3664 for(; nonNull(es); es=tl(es)) {
3665 if (fst(hd(es))==FIXDECL) { /* fixity declaration?*/
3666 fixdecls = cons(snd(hd(es)),fixdecls); /* discard FIXDECL tag*/
3672 static List local extractBindings(ds) /* extract untyped bindings from */
3673 List ds; { /* given list of equations */
3674 Cell lastVar = NIL; /* = var def'd in last eqn (if any)*/
3675 Int lastArity = 0; /* = number of args in last defn */
3676 List bs = NIL; /* :: [Binding] */
3678 for(; nonNull(ds); ds=tl(ds)) {
3680 if (fst(d)==FUNBIND) { /* Function bindings */
3681 Cell rhs = snd(snd(d));
3682 Int line = rhsLine(rhs);
3683 Cell lhs = fst(snd(d));
3684 Cell v = getHead(lhs);
3685 Cell newAlt = pair(getArgs(lhs),rhs);
3687 internal("FUNBIND");
3689 if (nonNull(lastVar) && textOf(v)==textOf(lastVar)) {
3690 if (argCount!=lastArity) {
3691 ERRMSG(line) "Equations give different arities for \"%s\"",
3692 textToStr(textOf(v))
3695 fbindAlts(hd(bs)) = cons(newAlt,fbindAlts(hd(bs)));
3699 lastArity = argCount;
3700 notDefined(line,bs,v);
3701 bs = cons(pair(v,pair(NIL,singleton(newAlt))),bs);
3704 } else if (fst(d)==PATBIND) { /* Pattern bindings */
3705 Cell rhs = snd(snd(d));
3706 Int line = rhsLine(rhs);
3707 Cell pat = fst(snd(d));
3708 while (whatIs(pat)==ESIGN) {/* Move type annotations to rhs */
3709 Cell p = fst(snd(pat));
3710 fst(snd(pat)) = rhs;
3711 snd(snd(d)) = rhs = pat;
3712 fst(snd(d)) = pat = p;
3715 if (isVar(pat)) { /* Convert simple pattern bind to */
3716 notDefined(line,bs,pat);/* a function binding */
3717 bs = cons(pair(pat,pair(NIL,singleton(pair(NIL,rhs)))),bs);
3719 List vs = getPatVars(line,pat,NIL);
3721 ERRMSG(line) "No variables defined in lhs pattern"
3724 map2Proc(notDefined,line,bs,vs);
3725 bs = cons(pair(vs,pair(NIL,snd(d))),bs);
3733 static List local getPatVars(line,p,vs) /* Find list of variables bound in */
3734 Int line; /* pattern p */
3737 switch (whatIs(p)) {
3739 vs = getPatVars(line,arg(p),vs);
3742 return vs; /* Ignore head of application */
3744 case CONFLDS : { List pfs = snd(snd(p));
3745 for (; nonNull(pfs); pfs=tl(pfs)) {
3746 if (isVar(hd(pfs))) {
3747 vs = addPatVar(line,hd(pfs),vs);
3749 vs = getPatVars(line,snd(hd(pfs)),vs);
3755 case FINLIST : { List ps = snd(p);
3756 for (; nonNull(ps); ps=tl(ps)) {
3757 vs = getPatVars(line,hd(ps),vs);
3762 case ESIGN : return getPatVars(line,fst(snd(p)),vs);
3767 case INFIX : return getPatVars(line,snd(p),vs);
3769 case ASPAT : return addPatVar(line,fst(snd(p)),
3770 getPatVars(line,snd(snd(p)),vs));
3773 case VAROPCELL : return addPatVar(line,p,vs);
3783 case WILDCARD : return vs;
3785 default : internal("getPatVars");
3790 static List local addPatVar(line,v,vs) /* Add var to list of previously */
3791 Int line; /* encountered variables */
3794 if (varIsMember(textOf(v),vs)) {
3795 ERRMSG(line) "Repeated use of variable \"%s\" in pattern binding",
3796 textToStr(textOf(v))
3802 static List local eqnsToBindings(es,ts,cs,ps)
3803 List es; /* Convert list of equations to */
3804 List ts; /* list of typed bindings */
3807 List bs = extractBindings(es);
3808 map1Proc(addSigdecl,bs,extractSigdecls(es));
3809 map4Proc(addFixdecl,bs,ts,cs,ps,extractFixdecls(es));
3813 static Void local notDefined(line,bs,v)/* check if name already defined in */
3814 Int line; /* list of bindings */
3817 if (nonNull(findBinding(textOf(v),bs))) {
3818 ERRMSG(line) "\"%s\" multiply defined", textToStr(textOf(v))
3823 static Cell local findBinding(t,bs) /* look for binding for variable t */
3824 Text t; /* in list of bindings bs */
3826 for (; nonNull(bs); bs=tl(bs)) {
3827 if (isVar(fst(hd(bs)))) { /* function-binding? */
3828 if (textOf(fst(hd(bs)))==t) {
3831 } else if (nonNull(varIsMember(t,fst(hd(bs))))){/* pattern-binding?*/
3838 static Cell local getAttr(bs,v) /* Locate type/fixity attribute */
3839 List bs; /* for variable v in bindings bs */
3842 Cell b = findBinding(t,bs);
3844 if (isNull(b)) { /* No binding */
3846 } else if (isVar(fst(b))) { /* func binding? */
3847 if (isNull(bindingAttr(b))) {
3848 bindingAttr(b) = pair(NIL,NIL);
3850 return bindingAttr(b);
3851 } else { /* pat binding? */
3853 List as = bindingAttr(b);
3856 bindingAttr(b) = as = replicate(length(vs),NIL);
3859 while (nonNull(vs) && t!=textOf(hd(vs))) {
3865 internal("getAttr");
3866 } else if (isNull(hd(as))) {
3867 hd(as) = pair(NIL,NIL);
3873 static Void local addSigdecl(bs,sigdecl)/* add type information to bindings*/
3874 List bs; /* :: [Binding] */
3875 Cell sigdecl; { /* :: (Line,[Var],Type) */
3876 Int l = intOf(fst3(sigdecl));
3877 List vs = snd3(sigdecl);
3878 Type type = checkSigType(l,"type declaration",hd(vs),thd3(sigdecl));
3880 for (; nonNull(vs); vs=tl(vs)) {
3882 Pair attr = getAttr(bs,v);
3884 ERRMSG(l) "Missing binding for variable \"%s\" in type signature",
3885 textToStr(textOf(v))
3887 } else if (nonNull(fst(attr))) {
3888 ERRMSG(l) "Repeated type signature for \"%s\"",
3889 textToStr(textOf(v))
3896 static Void local addFixdecl(bs,ts,cs,ps,fixdecl)
3902 Int line = intOf(fst3(fixdecl));
3903 List ops = snd3(fixdecl);
3904 Cell sy = thd3(fixdecl);
3906 for (; nonNull(ops); ops=tl(ops)) {
3908 Text t = textOf(op);
3909 Cell attr = getAttr(bs,op);
3910 if (nonNull(attr)) { /* Found name in binding? */
3911 if (nonNull(snd(attr))) {
3915 } else { /* Look in tycons, classes, prims */
3920 for (; isNull(n) && nonNull(ts1); ts1=tl(ts1)) { /* tycons */
3922 if (tycon(tc).what==DATATYPE || tycon(tc).what==NEWTYPE) {
3923 n = nameIsMember(t,tycon(tc).defn);
3926 for (; isNull(n) && nonNull(cs1); cs1=tl(cs1)) { /* classes */
3927 n = nameIsMember(t,cclass(hd(cs1)).members);
3929 for (; isNull(n) && nonNull(ps1); ps1=tl(ps1)) { /* prims */
3930 n = nameIsMember(t,hd(ps1));
3935 } else if (name(n).syntax!=NO_SYNTAX) {
3938 name(n).syntax = intOf(sy);
3943 static Void local dupFixity(line,t) /* Report repeated fixity decl */
3947 "Repeated fixity declaration for operator \"%s\"", textToStr(t)
3951 static Void local missFixity(line,t) /* Report missing op for fixity */
3955 "Cannot find binding for operator \"%s\" in fixity declaration",
3960 /* --------------------------------------------------------------------------
3961 * Dealing with infix operators:
3963 * Expressions involving infix operators or unary minus are parsed as
3964 * elements of the following type:
3966 * data InfixExp = Only Exp | Neg InfixExp | Infix InfixExp Op Exp
3968 * (The algorithms here do not assume that negation can be applied only once,
3969 * i.e., that - - x is a syntax error, as required by the Haskell report.
3970 * Instead, that restriction is captured by the grammar itself, given above.)
3972 * There are rules of precedence and grouping, expressed by two functions:
3974 * prec :: Op -> Int; assoc :: Op -> Assoc (Assoc = {L, N, R})
3976 * InfixExp values are rearranged accordingly when a complete expression
3977 * has been read using a simple shift-reduce parser whose result may be taken
3978 * to be a value of the following type:
3980 * data Exp = Atom Int | Negate Exp | Apply Op Exp Exp | Error String
3982 * The machine on which this parser is based can be defined as follows:
3984 * tidy :: InfixExp -> [(Op,Exp)] -> Exp
3985 * tidy (Only a) [] = a
3986 * tidy (Only a) ((o,b):ss) = tidy (Only (Apply o a b)) ss
3987 * tidy (Infix a o b) [] = tidy a [(o,b)]
3988 * tidy (Infix a o b) ((p,c):ss)
3989 * | shift o p = tidy a ((o,b):(p,c):ss)
3990 * | red o p = tidy (Infix a o (Apply p b c)) ss
3991 * | ambig o p = Error "ambiguous use of operators"
3992 * tidy (Neg e) [] = tidy (tidyNeg e) []
3993 * tidy (Neg e) ((o,b):ss)
3994 * | nshift o = tidy (Neg (underNeg o b e)) ss
3995 * | nred o = tidy (tidyNeg e) ((o,b):ss)
3996 * | nambig o = Error "illegal use of negation"
3998 * At each stage, the parser can either shift, reduce, accept, or error.
3999 * The transitions when dealing with juxtaposed operators o and p are
4000 * determined by the following rules:
4002 * shift o p = (prec o > prec p)
4003 * || (prec o == prec p && assoc o == L && assoc p == L)
4005 * red o p = (prec o < prec p)
4006 * || (prec o == prec p && assoc o == R && assoc p == R)
4008 * ambig o p = (prec o == prec p)
4009 * && (assoc o == N || assoc p == N || assoc o /= assoc p)
4011 * The transitions when dealing with juxtaposed unary minus and infix
4012 * operators are as follows. The precedence of unary minus (infixl 6) is
4013 * hardwired in to these definitions, as it is to the definitions of the
4014 * Haskell grammar in the official report.
4016 * nshift o = (prec o > 6)
4017 * nred o = (prec o < 6) || (prec o == 6 && assoc o == L)
4018 * nambig o = prec o == 6 && (assoc o == R || assoc o == N)
4020 * An InfixExp of the form (Neg e) means negate the last thing in
4021 * the InfixExp e; we can force this negation using:
4023 * tidyNeg :: OpExp -> OpExp
4024 * tidyNeg (Only e) = Only (Negate e)
4025 * tidyNeg (Infix a o b) = Infix a o (Negate b)
4026 * tidyNeg (Neg e) = tidyNeg (tidyNeg e)
4028 * On the other hand, if we want to sneak application of an infix operator
4029 * under a negation, then we use:
4031 * underNeg :: Op -> Exp -> OpExp -> OpExp
4032 * underNeg o b (Only e) = Only (Apply o e b)
4033 * underNeg o b (Neg e) = Neg (underNeg o b e)
4034 * underNeg o b (Infix e p f) = Infix e p (Apply o f b)
4036 * As a concession to efficiency, we lower the number of calls to syntaxOf
4037 * by keeping track of the values of sye, sys throughout the process. The
4038 * value APPLIC is used to indicate that the syntax value is unknown.
4039 * ------------------------------------------------------------------------*/
4041 static Cell local tidyInfix(line,e) /* Convert infixExp to Exp */
4043 Cell e; { /* :: OpExp */
4044 Cell s = NIL; /* :: [(Op,Exp)] */
4045 Syntax sye = APPLIC; /* Syntax of op in e (init unknown)*/
4046 Syntax sys = APPLIC; /* Syntax of op in s (init unknown)*/
4049 while (fst(d)!=ONLY) { /* Attach fixities to operators */
4053 fun(fun(d)) = attachFixity(line,fun(fun(d)));
4059 switch (whatIs(e)) {
4060 case ONLY : e = snd(e);
4061 while (nonNull(s)) {
4062 Cell next = arg(fun(s));
4064 fun(fun(s)) = snd(fun(fun(s)));
4070 case NEG : if (nonNull(s)) {
4071 if (sys==APPLIC) { /* calculate sys */
4072 sys = intOf(fst(fun(fun(s))));
4075 if (precOf(sys)==UMINUS_PREC && /* nambig */
4076 assocOf(sys)!=UMINUS_ASSOC) {
4078 "Ambiguous use of unary minus with \""
4079 ETHEN ERREXPR(snd(fun(fun(s))));
4084 if (precOf(sys)>UMINUS_PREC) { /* nshift */
4088 while (whatIs(e1)==NEG)
4090 arg(fun(t)) = arg(e1);
4091 fun(fun(t)) = snd(fun(fun(t)));
4098 /* Intentional fall-thru for nreduce and isNull(s) */
4100 { Cell prev = e; /* e := tidyNeg e */
4101 Cell temp = arg(prev);
4103 for (; whatIs(temp)==NEG; nneg++) {
4104 fun(prev) = nameNegate;
4108 if (isInt(arg(temp))) { /* special cases */
4109 if (nneg&1) /* for literals */
4110 arg(temp) = mkInt(-intOf(arg(temp)));
4112 else if (isFloat(arg(temp))) {
4114 arg(temp) = floatNegate(arg(temp));
4115 //mkFloat(-floatOf(arg(temp)));
4118 fun(prev) = nameNegate;
4119 arg(prev) = arg(temp);
4126 default : if (isNull(s)) {/* Move operation onto empty stack */
4127 Cell next = arg(fun(e));
4134 else { /* deal with pair of operators */
4136 if (sye==APPLIC) { /* calculate sys and sye */
4137 sye = intOf(fst(fun(fun(e))));
4140 sys = intOf(fst(fun(fun(s))));
4143 if (precOf(sye)==precOf(sys) && /* ambig */
4144 (assocOf(sye)!=assocOf(sys) ||
4145 assocOf(sye)==NON_ASS)) {
4146 ERRMSG(line) "Ambiguous use of operator \""
4147 ETHEN ERREXPR(snd(fun(fun(e))));
4148 ERRTEXT "\" with \""
4149 ETHEN ERREXPR(snd(fun(fun(s))));
4154 if (precOf(sye)>precOf(sys) || /* shift */
4155 (precOf(sye)==precOf(sys) &&
4156 assocOf(sye)==LEFT_ASS &&
4157 assocOf(sys)==LEFT_ASS)) {
4158 Cell next = arg(fun(e));
4166 Cell next = arg(fun(s));
4167 arg(fun(s)) = arg(e);
4168 fun(fun(s)) = snd(fun(fun(s)));
4179 static Pair local attachFixity(line,op) /* Attach fixity to operator in an */
4180 Int line; /* infix expression */
4182 Syntax sy = DEF_OPSYNTAX;
4184 switch (whatIs(op)) {
4186 case VARIDCELL : if ((sy=lookupSyntax(textOf(op)))==NO_SYNTAX) {
4187 Name n = findName(textOf(op));
4189 ERRMSG(line) "Undefined variable \"%s\"",
4190 textToStr(textOf(op))
4199 case CONIDCELL : sy = syntaxOf(op = conDefined(line,op));
4202 case QUALIDENT : { Name n = findQualName(op);
4208 "Undefined qualified variable \"%s\"",
4218 return pair(mkInt(sy),op); /* Pair fixity with (possibly) */
4219 /* translated operator */
4222 static Syntax local lookupSyntax(t) /* Try to find fixity for var in */
4223 Text t; { /* enclosing bindings */
4224 List bounds1 = bounds;
4225 List bindings1 = bindings;
4227 while (nonNull(bindings1)) {
4228 if (nonNull(varIsMember(t,hd(bounds1)))) {
4229 return DEF_OPSYNTAX;
4231 Cell b = findBinding(t,hd(bindings1));
4233 Cell a = fst(snd(b));
4234 if (isVar(fst(b))) { /* Function binding */
4235 if (nonNull(a) && nonNull(snd(a))) {
4236 return intOf(snd(a));
4238 } else { /* Pattern binding */
4240 while (nonNull(vs) && nonNull(a)) {
4241 if (t==textOf(hd(vs))) {
4242 if (nonNull(hd(a)) && isInt(snd(hd(a)))) {
4243 return intOf(snd(hd(a)));
4251 return DEF_OPSYNTAX;
4254 bounds1 = tl(bounds1);
4255 bindings1 = tl(bindings1);
4260 /* --------------------------------------------------------------------------
4261 * To facilitate dependency analysis, lists of bindings are temporarily
4262 * augmented with an additional field, which is used in two ways:
4263 * - to build the `adjacency lists' for the dependency graph. Represented by
4264 * a list of pointers to other bindings in the same list of bindings.
4265 * - to hold strictly positive integer values (depth first search numbers) of
4266 * elements `on the stack' during the strongly connected components search
4267 * algorithm, or a special value mkInt(0), once the binding has been added
4268 * to a particular strongly connected component.
4270 * Using this extra field, the type of each list of declarations during
4271 * dependency analysis is [Binding'] where:
4273 * Binding' ::= (Var, (Attr, (Dep, [Alt]))) -- function binding
4274 * | ([Var], ([Attr], (Dep, (Pat,Rhs)))) -- pattern binding
4276 * ------------------------------------------------------------------------*/
4278 #define depVal(d) (fst(snd(snd(d)))) /* Access to dependency information*/
4280 static List local dependencyAnal(bs) /* Separate lists of bindings into */
4281 List bs; { /* mutually recursive groups in */
4282 /* order of dependency */
4283 mapProc(addDepField,bs); /* add extra field for dependents */
4284 mapProc(depBinding,bs); /* find dependents of each binding */
4285 bs = bscc(bs); /* sort to strongly connected comps*/
4286 mapProc(remDepField,bs); /* remove dependency info field */
4290 static List local topDependAnal(bs) /* Like dependencyAnal(), but at */
4291 List bs; { /* top level, reporting on progress*/
4295 setGoal("Dependency analysis",(Target)(length(bs)));
4297 mapProc(addDepField,bs); /* add extra field for dependents */
4298 for (xs=bs; nonNull(xs); xs=tl(xs)) {
4299 emptySubstitution();
4301 soFar((Target)(i++));
4303 bs = bscc(bs); /* sort to strongly connected comps */
4304 mapProc(remDepField,bs); /* remove dependency info field */
4309 static Void local addDepField(b) /* add extra field to binding to */
4310 Cell b; { /* hold list of dependents */
4311 snd(snd(b)) = pair(NIL,snd(snd(b)));
4314 static Void local remDepField(bs) /* remove dependency field from */
4315 List bs; { /* list of bindings */
4316 mapProc(remDepField1,bs);
4319 static Void local remDepField1(b) /* remove dependency field from */
4320 Cell b; { /* single binding */
4321 snd(snd(b)) = snd(snd(snd(b)));
4324 static Void local clearScope() { /* initialise dependency scoping */
4330 static Void local withinScope(bs) /* Enter scope of bindings bs */
4332 bounds = cons(NIL,bounds);
4333 bindings = cons(bs,bindings);
4334 depends = cons(NIL,depends);
4337 static Void local leaveScope() { /* Leave scope of last withinScope */
4338 List bs = hd(bindings); /* Remove fixity info from binds */
4339 Bool toplevel = isNull(tl(bindings));
4340 for (; nonNull(bs); bs=tl(bs)) {
4342 if (isVar(fst(b))) { /* Variable binding */
4343 Cell a = fst(snd(b));
4346 saveSyntax(fst(b),snd(a));
4348 fst(snd(b)) = fst(a);
4350 } else { /* Pattern binding */
4352 List as = fst(snd(b));
4353 while (nonNull(vs) && nonNull(as)) {
4354 if (isPair(hd(as))) {
4356 saveSyntax(hd(vs),snd(hd(as)));
4358 hd(as) = fst(hd(as));
4365 bounds = tl(bounds);
4366 bindings = tl(bindings);
4367 depends = tl(depends);
4370 static Void local saveSyntax(v,sy) /* Save syntax of top-level var */
4371 Cell v; /* in corresponding Name */
4373 Name n = findName(textOf(v));
4374 if (isNull(n) || name(n).syntax!=NO_SYNTAX) {
4375 internal("saveSyntax");
4378 name(n).syntax = intOf(sy);
4382 /* --------------------------------------------------------------------------
4383 * As a side effect of the dependency analysis we also make the following
4385 * - Each lhs is a valid pattern/function lhs, all constructor functions
4386 * have been defined and are used with the correct number of arguments.
4387 * - No lhs contains repeated pattern variables.
4388 * - Expressions used on the rhs of an eqn should be well formed. This
4390 * - Checking for valid patterns (including repeated vars) in lambda,
4391 * case, and list comprehension expressions.
4392 * - Recursively checking local lists of equations.
4393 * - No free (i.e. unbound) variables are used in the declaration list.
4394 * ------------------------------------------------------------------------*/
4396 static Void local depBinding(b) /* find dependents of binding */
4398 Cell defpart = snd(snd(snd(b))); /* definition part of binding */
4402 if (isVar(fst(b))) { /* function-binding? */
4403 mapProc(depAlt,defpart);
4404 if (isNull(fst(snd(b)))) { /* Save dep info if no type sig */
4405 fst(snd(b)) = pair(ap(IMPDEPS,hd(depends)),NIL);
4406 } else if (isNull(fst(fst(snd(b))))) {
4407 fst(fst(snd(b))) = ap(IMPDEPS,hd(depends));
4409 } else { /* pattern-binding? */
4410 Int line = rhsLine(snd(defpart));
4413 fst(defpart) = checkPat(line,fst(defpart));
4414 depRhs(snd(defpart));
4416 if (nonNull(hd(btyvars))) {
4418 "Sorry, no type variables are allowed in pattern binding type annotations"
4422 fst(defpart) = applyBtyvs(fst(defpart));
4424 depVal(b) = hd(depends);
4427 static Void local depDefaults(c) /* dependency analysis on defaults */
4428 Class c; { /* from class definition */
4429 depClassBindings(cclass(c).defaults);
4432 static Void local depInsts(in) /* dependency analysis on instance */
4433 Inst in; { /* bindings */
4434 depClassBindings(inst(in).implements);
4437 static Void local depClassBindings(bs) /* dependency analysis on list of */
4438 List bs; { /* bindings, possibly containing */
4439 for (; nonNull(bs); bs=tl(bs)) { /* NIL bindings ... */
4440 if (nonNull(hd(bs))) { /* No need to add extra field for */
4441 mapProc(depAlt,snd(hd(bs)));/* dependency information... */
4446 static Void local depAlt(a) /* Find dependents of alternative */
4448 List obvs = saveBvars(); /* Save list of bound variables */
4450 bindPats(rhsLine(snd(a)),fst(a)); /* add new bound vars for patterns */
4451 depRhs(snd(a)); /* find dependents of rhs */
4452 fst(a) = applyBtyvs(fst(a));
4453 restoreBvars(obvs); /* restore original list of bvars */
4456 static Void local depRhs(r) /* Find dependents of rhs */
4458 switch (whatIs(r)) {
4459 case GUARDED : mapProc(depGuard,snd(r));
4462 case LETREC : fst(snd(r)) = eqnsToBindings(fst(snd(r)),NIL,NIL,NIL);
4463 withinScope(fst(snd(r)));
4464 fst(snd(r)) = dependencyAnal(fst(snd(r)));
4465 hd(depends) = fst(snd(r));
4466 depRhs(snd(snd(r)));
4470 case RSIGN : snd(snd(r)) = checkPatType(rhsLine(fst(snd(r))),
4472 rhsExpr(fst(snd(r))),
4474 depRhs(fst(snd(r)));
4477 default : snd(r) = depExpr(intOf(fst(r)),snd(r));
4482 static Void local depGuard(g) /* find dependents of single guarded*/
4483 Cell g; { /* expression */
4484 depPair(intOf(fst(g)),snd(g));
4487 static Cell local depExpr(line,e) /* find dependents of expression */
4490 // Printf( "\n\n"); print(e,100); Printf("\n");
4491 //printExp(stdout,e);
4492 switch (whatIs(e)) {
4495 case VAROPCELL : return depVar(line,e);
4498 case CONOPCELL : return conDefined(line,e);
4500 case QUALIDENT : if (isQVar(e)) {
4501 return depQVar(line,e);
4502 } else { /* QConOrConOp */
4503 return conDefined(line,e);
4506 case INFIX : return depExpr(line,tidyInfix(line,snd(e)));
4509 case RECSEL : break;
4511 case AP : if (isAp(e) && isAp(fun(e)) && isExt(fun(fun(e)))) {
4512 return depRecord(line,e);
4518 arg(a) = depExpr(line,arg(a));
4521 fun(a) = depExpr(line,fun(a));
4525 case AP : depPair(line,e);
4539 case INTCELL : break;
4541 case COND : depTriple(line,snd(e));
4544 case FINLIST : map1Over(depExpr,line,snd(e));
4547 case LETREC : fst(snd(e)) = eqnsToBindings(fst(snd(e)),NIL,NIL,NIL);
4548 withinScope(fst(snd(e)));
4549 fst(snd(e)) = dependencyAnal(fst(snd(e)));
4550 hd(depends) = fst(snd(e));
4551 snd(snd(e)) = depExpr(line,snd(snd(e)));
4555 case LAMBDA : depAlt(snd(e));
4558 case DOCOMP : /* fall-thru */
4559 case COMP : depComp(line,snd(e),snd(snd(e)));
4562 case ESIGN : fst(snd(e)) = depExpr(line,fst(snd(e)));
4563 snd(snd(e)) = checkSigType(line,
4569 case CASE : fst(snd(e)) = depExpr(line,fst(snd(e)));
4570 map1Proc(depCaseAlt,line,snd(snd(e)));
4573 case CONFLDS : depConFlds(line,e,FALSE);
4576 case UPDFLDS : depUpdFlds(line,e);
4580 case WITHEXP : depWith(line,e);
4584 case ASPAT : ERRMSG(line) "Illegal `@' in expression"
4587 case LAZYPAT : ERRMSG(line) "Illegal `~' in expression"
4590 case WILDCARD : ERRMSG(line) "Illegal `_' in expression"
4594 case EXT : ERRMSG(line) "Illegal application of record"
4598 default : internal("depExpr");
4603 static Void local depPair(line,e) /* find dependents of pair of exprs*/
4606 fst(e) = depExpr(line,fst(e));
4607 snd(e) = depExpr(line,snd(e));
4610 static Void local depTriple(line,e) /* find dependents of triple exprs */
4613 fst3(e) = depExpr(line,fst3(e));
4614 snd3(e) = depExpr(line,snd3(e));
4615 thd3(e) = depExpr(line,thd3(e));
4618 static Void local depComp(l,e,qs) /* find dependents of comprehension*/
4623 fst(e) = depExpr(l,fst(e));
4627 switch (whatIs(q)) {
4628 case FROMQUAL : { List obvs = saveBvars();
4629 snd(snd(q)) = depExpr(l,snd(snd(q)));
4631 fst(snd(q)) = bindPat(l,fst(snd(q)));
4633 fst(snd(q)) = applyBtyvs(fst(snd(q)));
4638 case QWHERE : snd(q) = eqnsToBindings(snd(q),NIL,NIL,NIL);
4639 withinScope(snd(q));
4640 snd(q) = dependencyAnal(snd(q));
4641 hd(depends) = snd(q);
4646 case DOQUAL : /* fall-thru */
4647 case BOOLQUAL : snd(q) = depExpr(l,snd(q));
4654 static Void local depCaseAlt(line,a) /* Find dependents of case altern. */
4657 List obvs = saveBvars(); /* Save list of bound variables */
4659 fst(a) = bindPat(line,fst(a)); /* Add new bound vars for pats */
4660 depRhs(snd(a)); /* Find dependents of rhs */
4661 fst(a) = applyBtyvs(fst(a));
4662 restoreBvars(obvs); /* Restore original list of bvars */
4665 static Cell local depVar(line,e) /* Register occurrence of variable */
4668 List bounds1 = bounds;
4669 List bindings1 = bindings;
4670 List depends1 = depends;
4674 while (nonNull(bindings1)) {
4675 n = varIsMember(t,hd(bounds1)); /* look for t in bound variables */
4679 n = findBinding(t,hd(bindings1)); /* look for t in var bindings */
4681 if (!cellIsMember(n,hd(depends1))) {
4682 hd(depends1) = cons(n,hd(depends1));
4684 return (isVar(fst(n)) ? fst(n) : e);
4687 bounds1 = tl(bounds1);
4688 bindings1 = tl(bindings1);
4689 depends1 = tl(depends1);
4692 if (isNull(n=findName(t))) { /* check global definitions */
4693 ERRMSG(line) "Undefined variable \"%s\"", textToStr(t)
4697 if (!moduleThisScript(name(n).mod)) {
4700 /* Later phases of the system cannot cope if we resolve references
4701 * to unprocessed objects too early. This is the main reason that
4702 * we cannot cope with recursive modules at the moment.
4707 static Cell local depQVar(line,e)/* register occurrence of qualified variable */
4710 Name n = findQualName(e);
4711 if (isNull(n)) { /* check global definitions */
4712 ERRMSG(line) "Undefined qualified variable \"%s\"", identToStr(e)
4715 if (name(n).mod != currentModule) {
4718 if (fst(e) == VARIDCELL) {
4719 e = mkVar(qtextOf(e));
4721 e = mkVarop(qtextOf(e));
4723 return depVar(line,e);
4726 static Void local depConFlds(line,e,isP)/* check construction using fields */
4730 Name c = conDefined(line,fst(snd(e)));
4731 if (isNull(snd(snd(e))) ||
4732 nonNull(cellIsMember(c,depFields(line,e,snd(snd(e)),isP)))) {
4735 ERRMSG(line) "Constructor \"%s\" does not have selected fields in ",
4736 textToStr(name(c).text)
4741 if (!isP && isPair(name(c).defn)) { /* Check that banged fields defined*/
4742 List scs = fst(name(c).defn); /* List of strict components */
4743 Type t = name(c).type;
4744 Int a = userArity(c);
4745 List fs = snd(snd(e));
4747 if (isPolyType(t)) { /* Find tycon that c belongs to */
4750 if (isQualType(t)) {
4753 if (whatIs(t)==CDICTS) {
4762 for (ss=tycon(t).defn; hasCfun(ss); ss=tl(ss)) {
4764 /* Now we know the tycon t that c belongs to, and the corresponding
4765 * list of selectors for that type, ss. Now we have to check that
4766 * each of the fields identified by scs appears in fs, using ss to
4767 * cross reference, and convert integers to selector names.
4769 for (; nonNull(scs); scs=tl(scs)) {
4770 Int i = intOf(hd(scs));
4772 for (; nonNull(ss1); ss1=tl(ss1)) {
4773 List cns = name(hd(ss1)).defn;
4774 for (; nonNull(cns); cns=tl(cns)) {
4775 if (fst(hd(cns))==c) {
4779 if (nonNull(cns) && intOf(snd(hd(cns)))==i) {
4784 internal("depConFlds");
4788 for (; nonNull(fs1) && s!=fst(hd(fs1)); fs1=tl(fs1)) {
4791 ERRMSG(line) "Construction does not define strict field"
4793 ERRTEXT "\nExpression : " ETHEN ERREXPR(e);
4794 ERRTEXT "\nField : " ETHEN ERREXPR(s);
4803 static Void local depUpdFlds(line,e) /* check update using fields */
4806 if (isNull(thd3(snd(e)))) {
4807 ERRMSG(line) "Empty field list in update"
4810 fst3(snd(e)) = depExpr(line,fst3(snd(e)));
4811 snd3(snd(e)) = depFields(line,e,thd3(snd(e)),FALSE);
4814 static List local depFields(l,e,fs,isP) /* check field binding list */
4822 for (; nonNull(fs); fs=tl(fs)) { /* for each field binding */
4826 if (isVar(fb)) { /* expand var to var = var */
4827 h98DoesntSupport(l,"missing field bindings");
4828 fb = hd(fs) = pair(fb,fb);
4831 s = findQualName(fst(fb)); /* check for selector */
4832 if (nonNull(s) && isSfun(s)) {
4835 ERRMSG(l) "\"%s\" is not a selector function/field name",
4836 textToStr(textOf(fst(fb)))
4840 if (isNull(ss)) { /* for first named selector */
4841 List scs = name(s).defn; /* calculate list of constructors */
4842 for (; nonNull(scs); scs=tl(scs)) {
4843 cs = cons(fst(hd(scs)),cs);
4845 ss = singleton(s); /* initialize selector list */
4846 } else { /* for subsequent selectors */
4847 List ds = cs; /* intersect constructor lists */
4848 for (cs=NIL; nonNull(ds); ) {
4849 List scs = name(s).defn;
4850 while (nonNull(scs) && fst(hd(scs))!=hd(ds)) {
4863 if (cellIsMember(s,ss)) { /* check for repeated uses */
4864 ERRMSG(l) "Repeated field name \"%s\" in field list",
4865 textToStr(name(s).text)
4871 if (isNull(cs)) { /* Are there any matching constrs? */
4872 ERRMSG(l) "No constructor has all of the fields specified in "
4878 snd(fb) = (isP ? checkPat(l,snd(fb)) : depExpr(l,snd(fb)));
4884 static Void local depWith(line,e) /* check with using fields */
4887 fst(snd(e)) = depExpr(line,fst(snd(e)));
4888 snd(snd(e)) = depDwFlds(line,e,snd(snd(e)));
4891 static List local depDwFlds(l,e,fs)/* check field binding list */
4897 for (; nonNull(c); c=tl(c)) { /* for each field binding */
4898 snd(hd(c)) = depExpr(l,snd(hd(c)));
4905 static Cell local depRecord(line,e) /* find dependents of record and */
4906 Int line; /* sort fields into approp. order */
4907 Cell e; { /* to make construction and update */
4908 List exts = NIL; /* more efficient. */
4911 h98DoesntSupport(line,"extensible records");
4912 do { /* build up list of extensions */
4913 Text t = extText(fun(fun(r)));
4914 String s = textToStr(t);
4917 while (nonNull(nx) && strcmp(textToStr(extText(fun(fun(nx)))),s)>0) {
4921 if (nonNull(nx) && t==extText(fun(fun(nx)))) {
4922 ERRMSG(line) "Repeated label \"%s\" in record ", s
4928 exts = cons(fun(r),exts);
4930 tl(prev) = cons(fun(r),nx);
4932 extField(r) = depExpr(line,extField(r));
4934 } while (isAp(r) && isAp(fun(r)) && isExt(fun(fun(r))));
4935 r = depExpr(line,r);
4936 return revOnto(exts,r);
4941 /* --------------------------------------------------------------------------
4942 * Several parts of this program require an algorithm for sorting a list
4943 * of values (with some added dependency information) into a list of strongly
4944 * connected components in which each value appears before its dependents.
4946 * Each of these algorithms is obtained by parameterising a standard
4947 * algorithm in "scc.c" as shown below.
4948 * ------------------------------------------------------------------------*/
4950 #define SCC2 tcscc /* make scc algorithm for Tycons */
4951 #define LOWLINK tclowlink
4952 #define DEPENDS(c) (isTycon(c) ? tycon(c).kind : cclass(c).kinds)
4953 #define SETDEPENDS(c,v) if(isTycon(c)) tycon(c).kind=v; else cclass(c).kinds=v
4960 #define SCC bscc /* make scc algorithm for Bindings */
4961 #define LOWLINK blowlink
4962 #define DEPENDS(t) depVal(t)
4963 #define SETDEPENDS(c,v) depVal(c)=v
4970 /* --------------------------------------------------------------------------
4971 * Main static analysis:
4972 * ------------------------------------------------------------------------*/
4974 Void checkExp() { /* Top level static check on Expr */
4975 staticAnalysis(RESET);
4976 clearScope(); /* Analyse expression in the scope */
4977 withinScope(NIL); /* of no local bindings */
4978 inputExpr = depExpr(0,inputExpr);
4980 staticAnalysis(RESET);
4983 #if EXPLAIN_INSTANCE_RESOLUTION
4984 Void checkContext(void) { /* Top level static check on Expr */
4987 staticAnalysis(RESET);
4988 clearScope(); /* Analyse expression in the scope */
4989 withinScope(NIL); /* of no local bindings */
4991 for (vs = NIL; nonNull(qs); qs=tl(qs)) {
4992 vs = typeVarsIn(hd(qs),NIL,NIL,vs);
4994 map2Proc(depPredExp,0,vs,inputContext);
4996 staticAnalysis(RESET);
5000 Void checkDefns() { /* Top level static analysis */
5001 Module thisModule = lastModule();
5002 staticAnalysis(RESET);
5004 setCurrModule(thisModule);
5006 /* Resolve module references */
5007 mapProc(checkQualImport, module(thisModule).qualImports);
5008 mapProc(checkUnqualImport,unqualImports);
5009 /* Add "import Prelude" if there`s no explicit import */
5010 if (thisModule!=modulePrelude
5011 && isNull(cellAssoc(modulePrelude,unqualImports))
5012 && isNull(cellRevAssoc(modulePrelude,module(thisModule).qualImports))) {
5013 unqualImports = cons(pair(modulePrelude,DOTDOT),unqualImports);
5015 /* Every module (including the Prelude) implicitly contains
5016 * "import qualified Prelude"
5018 module(thisModule).qualImports=cons(pair(mkCon(textPrelude),modulePrelude),
5019 module(thisModule).qualImports);
5021 mapProc(checkImportList, unqualImports);
5023 linkPreludeTC(); /* Get prelude tycons and classes */
5024 mapProc(checkTyconDefn,tyconDefns); /* validate tycon definitions */
5025 checkSynonyms(tyconDefns); /* check synonym definitions */
5026 mapProc(checkClassDefn,classDefns); /* process class definitions */
5027 mapProc(kindTCGroup,tcscc(tyconDefns,classDefns)); /* attach kinds */
5028 mapProc(extendFundeps,classDefns); /* finish class definitions */
5029 mapProc(addMembers,classDefns); /* add definitions for member funs */
5030 mapProc(visitClass,classDefns); /* check class hierarchy */
5031 linkPreludeCM(); /* Get prelude cfuns and mfuns */
5033 instDefns = rev(instDefns); /* process instance definitions */
5034 mapProc(checkInstDefn,instDefns);
5036 setCurrModule(thisModule);
5037 mapProc(addRSsigdecls,typeInDefns); /* add sigdecls for RESTRICTSYN */
5038 valDefns = eqnsToBindings(valDefns,tyconDefns,classDefns,/*primDefns*/NIL);
5039 mapProc(allNoPrevDef,valDefns); /* check against previous defns */
5040 mapProc(addDerivImp,derivedInsts); /* Add impls for derived instances */
5041 deriveContexts(derivedInsts); /* Calculate derived inst contexts */
5042 instDefns = appendOnto(instDefns,derivedInsts);
5043 checkDefaultDefns(); /* validate default definitions */
5045 mapProc(allNoPrevDef,valDefns); /* check against previous defns */
5049 mapProc(checkForeignImport,foreignImports); /* check foreign imports */
5050 mapProc(checkForeignExport,foreignExports); /* check foreign exports */
5051 foreignImports = NIL;
5052 foreignExports = NIL;
5054 /* Every top-level name has now been created - so we can build the */
5055 /* export list. Note that this has to happen before dependency */
5056 /* analysis so that references to Prelude.foo will be resolved */
5057 /* when compiling the prelude. */
5058 module(thisModule).exports = checkExports(module(thisModule).exports);
5060 mapProc(checkTypeIn,typeInDefns); /* check restricted synonym defns */
5063 withinScope(valDefns);
5064 valDefns = topDependAnal(valDefns); /* top level dependency ordering */
5065 mapProc(depDefaults,classDefns); /* dep. analysis on class defaults */
5066 mapProc(depInsts,instDefns); /* dep. analysis on inst defns */
5069 /* ToDo: evalDefaults should match current evaluation module */
5070 evalDefaults = defaultDefns; /* Set defaults for evaluator */
5072 staticAnalysis(RESET);
5078 static Void local addRSsigdecls(pr) /* add sigdecls from TYPE ... IN ..*/
5080 List vs = snd(pr); /* get list of variables */
5081 for (; nonNull(vs); vs=tl(vs)) {
5082 if (fst(hd(vs))==SIGDECL) { /* find a sigdecl */
5083 valDefns = cons(hd(vs),valDefns); /* add to valDefns */
5084 hd(vs) = hd(snd3(snd(hd(vs)))); /* and replace with var */
5089 static Void local allNoPrevDef(b) /* ensure no previous bindings for*/
5090 Cell b; { /* variables in new binding */
5091 if (isVar(fst(b))) {
5092 noPrevDef(rhsLine(snd(hd(snd(snd(b))))),fst(b));
5094 Int line = rhsLine(snd(snd(snd(b))));
5095 map1Proc(noPrevDef,line,fst(b));
5099 static Void local noPrevDef(line,v) /* ensure no previous binding for */
5100 Int line; /* new variable */
5102 Name n = findName(textOf(v));
5105 n = newName(textOf(v),NIL);
5106 name(n).defn = PREDEFINED;
5107 } else if (name(n).defn!=PREDEFINED) {
5108 duplicateError(line,name(n).mod,name(n).text,"variable");
5110 name(n).line = line;
5113 static Void local duplicateErrorAux(line,mod,t,kind)/* report duplicate defn */
5118 if (mod == currentModule) {
5119 ERRMSG(line) "Repeated definition for %s \"%s\"", kind,
5123 ERRMSG(line) "Definition of %s \"%s\" clashes with import", kind,
5129 static Void local checkTypeIn(cvs) /* Check that vars in restricted */
5130 Pair cvs; { /* synonym are defined */
5134 for (; nonNull(vs); vs=tl(vs)) {
5135 if (isNull(findName(textOf(hd(vs))))) {
5136 ERRMSG(tycon(c).line)
5137 "No top level binding of \"%s\" for restricted synonym \"%s\"",
5138 textToStr(textOf(hd(vs))), textToStr(tycon(c).text)
5144 /* --------------------------------------------------------------------------
5145 * Haskell 98 compatibility tests:
5146 * ------------------------------------------------------------------------*/
5148 Bool h98Pred(allowArgs,pi) /* Check syntax of Hask98 predicate*/
5151 return isClass(getHead(pi)) && argCount==1 &&
5152 isOffset(getHead(arg(pi))) && (argCount==0 || allowArgs);
5155 Cell h98Context(allowArgs,ps) /* Check syntax of Hask98 context */
5158 for (; nonNull(ps); ps=tl(ps)) {
5159 if (!h98Pred(allowArgs,hd(ps))) {
5166 Void h98CheckCtxt(line,wh,allowArgs,ps,in)
5167 Int line; /* Report illegal context/predicate*/
5173 Cell pi = h98Context(allowArgs,ps);
5175 ERRMSG(line) "Illegal Haskell 98 class constraint in %s",wh ETHEN
5177 ERRTEXT "\n*** Instance : " ETHEN ERRPRED(inst(in).head);
5179 ERRTEXT "\n*** Constraint : " ETHEN ERRPRED(pi);
5180 if (nonNull(ps) && nonNull(tl(ps))) {
5181 ERRTEXT "\n*** Context : " ETHEN ERRCONTEXT(ps);
5189 Void h98CheckType(line,wh,e,t) /* Check for Haskell 98 type */
5198 if (isQualType(t)) {
5199 Cell pi = h98Context(TRUE,fst(snd(t)));
5201 ERRMSG(line) "Illegal Haskell 98 class constraint in %s",wh
5203 ERRTEXT "\n*** Expression : " ETHEN ERREXPR(e);
5204 ERRTEXT "\n*** Type : " ETHEN ERRTYPE(ty);
5212 Void h98DoesntSupport(line,wh) /* Report feature missing in H98 */
5216 ERRMSG(line) "Haskell 98 does not support %s", wh
5221 /* --------------------------------------------------------------------------
5222 * Static Analysis control:
5223 * ------------------------------------------------------------------------*/
5225 Void staticAnalysis(what)
5228 case RESET : cfunSfuns = NIL;
5241 case MARK : mark(daSccs);
5256 case INSTALL : staticAnalysis(RESET);
5258 extKind = pair(STAR,pair(ROW,ROW));
5264 /*-------------------------------------------------------------------------*/