2 /* --------------------------------------------------------------------------
3 * Static Analysis for Hugs
5 * The Hugs 98 system is Copyright (c) Mark P Jones, Alastair Reid, the
6 * Yale Haskell Group, and the Oregon Graduate Institute of Science and
7 * Technology, 1994-1999, All rights reserved. It is distributed as
8 * free software under the license in the file "License", which is
9 * included in the distribution.
11 * $RCSfile: static.c,v $
13 * $Date: 2000/03/13 11:37:16 $
14 * ------------------------------------------------------------------------*/
21 /* --------------------------------------------------------------------------
22 * local function prototypes:
23 * ------------------------------------------------------------------------*/
25 static Void local kindError ( Int,Constr,Constr,String,Kind,Int );
26 static Void local checkQualImport ( Pair );
27 static Void local checkUnqualImport ( Triple );
29 static Name local lookupName ( Text,List );
30 static List local checkSubentities ( List,List,List,String,Text );
31 static List local checkExportTycon ( List,Text,Cell,Tycon );
32 static List local checkExportClass ( List,Text,Cell,Class );
33 static List local checkExport ( List,Text,Cell );
34 static List local checkImportEntity ( List,Module,Bool,Cell );
35 static List local resolveImportList ( Module,Cell,Bool );
36 static Void local checkImportList ( Pair );
38 static Void local importEntity ( Module,Cell );
39 static Void local importName ( Module,Name );
40 static Void local importTycon ( Module,Tycon );
41 static Void local importClass ( Module,Class );
42 static List local checkExports ( List );
44 static Void local checkTyconDefn ( Tycon );
45 static Void local depConstrs ( Tycon,List,Cell );
46 static List local addSels ( Int,Name,List,List );
47 static List local selectCtxt ( List,List );
48 static Void local checkSynonyms ( List );
49 static List local visitSyn ( List,Tycon,List );
50 static Type local instantiateSyn ( Type,Type );
52 static Void local checkClassDefn ( Class );
53 static Cell local depPredExp ( Int,List,Cell );
54 static Void local checkMems ( Class,List,Cell );
55 static Void local checkMems2 ( Class,Cell );
56 static Void local addMembers ( Class );
57 static Name local newMember ( Int,Int,Cell,Type,Class );
58 static Text local generateText ( String,Class );
60 static List local classBindings ( String,Class,List );
61 static Name local memberName ( Class,Text );
62 static List local numInsert ( Int,Cell,List );
64 static List local maybeAppendVar ( Cell,List );
66 static Type local checkSigType ( Int,String,Cell,Type );
67 static Void local checkOptQuantVars ( Int,List,List );
68 static Type local depTopType ( Int,List,Type );
69 static Type local depCompType ( Int,List,Type );
70 static Type local depTypeExp ( Int,List,Type );
71 static Type local depTypeVar ( Int,List,Text );
72 static List local checkQuantVars ( Int,List,List,Cell );
73 static List local otvars ( Cell,List );
74 static Bool local osubset ( List,List );
75 static Void local kindConstr ( Int,Int,Int,Constr );
76 static Kind local kindAtom ( Int,Constr );
77 static Void local kindPred ( Int,Int,Int,Cell );
78 static Void local kindType ( Int,String,Type );
79 static Void local fixKinds ( Void );
81 static Void local kindTCGroup ( List );
82 static Void local initTCKind ( Cell );
83 static Void local kindTC ( Cell );
84 static Void local genTC ( Cell );
86 static Void local checkInstDefn ( Inst );
87 static Void local insertInst ( Inst );
88 static Bool local instCompare ( Inst,Inst );
89 static Name local newInstImp ( Inst );
90 static Void local kindInst ( Inst,Int );
91 static Void local checkDerive ( Tycon,List,List,Cell );
92 static Void local addDerInst ( Int,Class,List,List,Type,Int );
93 static Void local deriveContexts ( List );
94 static Void local initDerInst ( Inst );
95 static Void local calcInstPreds ( Inst );
96 static Void local maybeAddPred ( Cell,Int,Int,List );
97 static List local calcFunDeps ( List );
98 static Cell local copyAdj ( Cell,Int,Int );
99 static Void local tidyDerInst ( Inst );
100 static List local otvarsZonk ( Cell,List,Int );
102 static Void local addDerivImp ( Inst );
104 static Void local checkDefaultDefns ( Void );
106 static Void local checkForeignImport ( Name );
107 static Void local checkForeignExport ( Name );
109 static Cell local tidyInfix ( Int,Cell );
110 static Pair local attachFixity ( Int,Cell );
111 static Syntax local lookupSyntax ( Text );
113 static Cell local checkPat ( Int,Cell );
114 static Cell local checkMaybeCnkPat ( Int,Cell );
115 static Cell local checkApPat ( Int,Int,Cell );
116 static Void local addToPatVars ( Int,Cell );
117 static Name local conDefined ( Int,Cell );
118 static Void local checkIsCfun ( Int,Name );
119 static Void local checkCfunArgs ( Int,Cell,Int );
120 static Cell local checkPatType ( Int,String,Cell,Type );
121 static Cell local applyBtyvs ( Cell );
122 static Cell local bindPat ( Int,Cell );
123 static Void local bindPats ( Int,List );
125 static List local extractSigdecls ( List );
126 static List local extractFixdecls ( List );
127 static List local extractBindings ( List );
128 static List local getPatVars ( Int,Cell,List );
129 static List local addPatVar ( Int,Cell,List );
130 static List local eqnsToBindings ( List,List,List,List );
131 static Void local notDefined ( Int,List,Cell );
132 static Cell local findBinding ( Text,List );
133 static Cell local getAttr ( List,Cell );
134 static Void local addSigdecl ( List,Cell );
135 static Void local addFixdecl ( List,List,List,List,Triple );
136 static Void local dupFixity ( Int,Text );
137 static Void local missFixity ( Int,Text );
139 static List local dependencyAnal ( List );
140 static List local topDependAnal ( List );
141 static Void local addDepField ( Cell );
142 static Void local remDepField ( List );
143 static Void local remDepField1 ( Cell );
144 static Void local clearScope ( Void );
145 static Void local withinScope ( List );
146 static Void local leaveScope ( Void );
147 static Void local saveSyntax ( Cell,Cell );
149 static Void local depBinding ( Cell );
150 static Void local depDefaults ( Class );
151 static Void local depInsts ( Inst );
152 static Void local depClassBindings ( List );
153 static Void local depAlt ( Cell );
154 static Void local depRhs ( Cell );
155 static Void local depGuard ( Cell );
156 static Cell local depExpr ( Int,Cell );
157 static Void local depPair ( Int,Cell );
158 static Void local depTriple ( Int,Cell );
159 static Void local depComp ( Int,Cell,List );
160 static Void local depCaseAlt ( Int,Cell );
161 static Cell local depVar ( Int,Cell );
162 static Cell local depQVar ( Int,Cell );
163 static Void local depConFlds ( Int,Cell,Bool );
164 static Void local depUpdFlds ( Int,Cell );
165 static List local depFields ( Int,Cell,List,Bool );
167 static Void local depWith ( Int,Cell );
168 static List local depDwFlds ( Int,Cell,List );
171 static Cell local depRecord ( Int,Cell );
174 static List local tcscc ( List,List );
175 static List local bscc ( List );
177 static Void local addRSsigdecls ( Pair );
178 static Void local allNoPrevDef ( Cell );
179 static Void local noPrevDef ( Int,Cell );
180 static Bool local odiff ( List,List );
182 static Void local duplicateErrorAux ( Int,Module,Text,String );
183 #define duplicateError(l,m,t,k) duplicateErrorAux(l,m,t,k)
184 static Void local checkTypeIn ( Pair );
186 /* --------------------------------------------------------------------------
187 * The code in this file is arranged in roughly the following order:
188 * - Kind inference preliminaries
189 * - Module declarations
190 * - Type declarations (data, type, newtype, type in)
191 * - Class declarations
193 * - Instance declarations
194 * - Default declarations
195 * - Primitive definitions
197 * - Infix expressions
198 * - Value definitions
199 * - Top-level static analysis and control
200 * - Haskell 98 compatibility tests
201 * ------------------------------------------------------------------------*/
203 /* --------------------------------------------------------------------------
204 * Kind checking preliminaries:
205 * ------------------------------------------------------------------------*/
207 Bool kindExpert = FALSE; /* TRUE => display kind errors in */
210 static Void local kindError(l,c,in,wh,k,o)
211 Int l; /* line number near constuctor exp */
212 Constr c; /* constructor */
213 Constr in; /* context (if any) */
214 String wh; /* place in which error occurs */
215 Kind k; /* expected kind (k,o) */
216 Int o; { /* inferred kind (typeIs,typeOff) */
219 if (!kindExpert) { /* for those with a fear of kinds */
220 ERRMSG(l) "Illegal type" ETHEN
222 ERRTEXT " \"" ETHEN ERRTYPE(in);
225 ERRTEXT " in %s\n", wh
229 ERRMSG(l) "Kind error in %s", wh ETHEN
231 ERRTEXT "\n*** expression : " ETHEN ERRTYPE(in);
233 ERRTEXT "\n*** constructor : " ETHEN ERRTYPE(c);
234 ERRTEXT "\n*** kind : " ETHEN ERRKIND(copyType(typeIs,typeOff));
235 ERRTEXT "\n*** does not match : " ETHEN ERRKIND(copyType(k,o));
237 ERRTEXT "\n*** because : %s", unifyFails ETHEN
243 #define shouldKind(l,c,in,wh,k,o) if (!kunify(typeIs,typeOff,k,o)) \
244 kindError(l,c,in,wh,k,o)
245 #define checkKind(l,a,m,c,in,wh,k,o) kindConstr(l,a,m,c); \
246 shouldKind(l,c,in,wh,k,o)
247 #define inferKind(k,o) typeIs=k; typeOff=o
249 static List unkindTypes; /* types in need of kind annotation*/
251 Kind extKind; /* Kind of extension, *->row->row */
254 /* --------------------------------------------------------------------------
255 * Static analysis of modules:
256 * ------------------------------------------------------------------------*/
262 Void startModule(nm) /* switch to a new module */
265 if (!isCon(nm)) internal("startModule");
266 if (isNull(m = findModule(textOf(nm))))
267 m = newModule(textOf(nm));
268 else if (!isPreludeScript()) {
269 /* You're allowed to break the rules in the Prelude! */
271 reloadModule = textToStr(textOf(nm));
273 ERRMSG(0) "Module \"%s\" already loaded", textToStr(textOf(nm))
279 Void setExportList(exps) /* Add export list to current module */
281 module(currentModule).exports = exps;
284 Void addQualImport(orig,new) /* Add to qualified import list */
285 Cell orig; /* Original name of module */
286 Cell new; { /* Name module is called within this module (or NIL) */
287 module(currentModule).qualImports =
288 cons(pair(isNull(new)?orig:new,orig),module(currentModule).qualImports);
291 Void addUnqualImport(mod,entities) /* Add to unqualified import list */
292 Cell mod; /* Name of module */
293 List entities; { /* List of entity names */
294 unqualImports = cons(pair(mod,entities),unqualImports);
297 static Void local checkQualImport(i) /* Process qualified import */
299 Module m = findModid(snd(i));
301 ERRMSG(0) "Module \"%s\" not previously loaded",
302 textToStr(textOf(snd(i)))
308 static Void local checkUnqualImport(i) /* Process unqualified import */
310 Module m = findModid(fst(i));
312 ERRMSG(0) "Module \"%s\" not previously loaded",
313 textToStr(textOf(fst(i)))
319 static Name local lookupName(t,nms) /* find text t in list of Names */
321 List nms; { /* :: [Name] */
322 for(; nonNull(nms); nms=tl(nms)) {
323 if (t == name(hd(nms)).text)
329 static List local checkSubentities(imports,named,wanted,description,textParent)
331 List named; /* :: [ Q?(Var|Con)(Id|Op) ] */
332 List wanted; /* :: [Name] */
333 String description; /* "<constructor>|<member> of <type>|<class>" */
335 for(; nonNull(named); named=tl(named)) {
337 /* ToDo: ignores qualifier; doesn't check that entity is in scope */
338 Text t = isPair(snd(x)) ? qtextOf(x) : textOf(x);
339 Name n = lookupName(t,wanted);
341 ERRMSG(0) "Entity \"%s\" is not a %s \"%s\"",
344 textToStr(textParent)
347 imports = cons(n,imports);
352 static List local checkImportEntity(imports,exporter,priv,entity)
353 List imports; /* Accumulated list of things to import */
356 Cell entity; { /* Entry from import list */
357 List oldImports = imports;
358 Text t = isIdent(entity) ? textOf(entity) : textOf(fst(entity));
361 es = module(exporter).names;
362 es = dupOnto(module(exporter).tycons,es);
363 es = dupOnto(module(exporter).classes,es);
365 es = module(exporter).exports;
368 for(; nonNull(es); es=tl(es)) {
369 Cell e = hd(es); /* :: Entity
370 | (Entity, NIL|DOTDOT)
377 if (tycon(f).text == t) {
378 imports = cons(f,imports);
379 if (!isIdent(entity)) {
380 switch (tycon(f).what) {
383 if (DOTDOT == snd(entity)) {
384 imports=dupOnto(tycon(f).defn,imports);
386 imports=checkSubentities(imports,snd(entity),tycon(f).defn,
387 "constructor of type",t);
391 /* deliberate fall thru */
395 } else if (isClass(f)) {
396 if (cclass(f).text == t) {
397 imports = cons(f,imports);
398 if (!isIdent(entity)) {
399 if (DOTDOT == snd(entity)) {
400 return dupOnto(cclass(f).members,imports);
402 return checkSubentities(imports,snd(entity),cclass(f).members,
403 "member of class",t);
408 internal("checkImportEntity2");
410 } else if (isName(e)) {
411 if (isIdent(entity) && name(e).text == t) {
412 imports = cons(e,imports);
414 } else if (isTycon(e) && priv) {
415 if (tycon(e).text == t) {
416 imports = cons(e,imports);
417 return dupOnto(tycon(e).defn,imports);
419 } else if (isClass(e) && priv) {
420 if (cclass(e).text == t) {
421 imports = cons(e,imports);
422 return dupOnto(cclass(e).members,imports);
424 } else if (whatIs(e) == TUPLE && priv) {
427 internal("checkImportEntity3");
430 if (imports == oldImports) {
431 ERRMSG(0) "Unknown entity \"%s\" imported from module \"%s\"",
433 textToStr(module(exporter ).text)
439 static List local resolveImportList(m,impList,priv)
440 Module m; /* exporting module */
444 if (DOTDOT == impList) {
445 List es = module(m).exports;
446 for(; nonNull(es); es=tl(es)) {
449 imports = cons(e,imports);
452 List subentities = NIL;
453 imports = cons(c,imports);
455 && (tycon(c).what == DATATYPE
456 || tycon(c).what == NEWTYPE))
457 subentities = tycon(c).defn;
459 subentities = cclass(c).members;
460 if (DOTDOT == snd(e)) {
461 imports = dupOnto(subentities,imports);
466 map2Accum(checkImportEntity,imports,m,priv,impList);
471 static Void local checkImportList(importSpec) /*Import a module unqualified*/
473 Module m = fst(importSpec);
474 Cell impList = snd(importSpec);
476 List imports = NIL; /* entities we want to import */
477 List hidden = NIL; /* entities we want to hide */
479 if (moduleThisScript(m)) {
480 ERRMSG(0) "Module \"%s\" recursively imports itself",
481 textToStr(module(m).text)
484 if (isPair(impList) && HIDDEN == fst(impList)) {
485 /* Somewhat inefficient - but obviously correct:
486 * imports = importsOf("module Foo") `setDifference` hidden;
488 hidden = resolveImportList(m, snd(impList),FALSE);
489 imports = resolveImportList(m, DOTDOT,FALSE);
490 } else if (isPair(impList) && STAR == fst(impList)) {
492 imports = resolveImportList(m, DOTDOT, FALSE);
493 privileged = resolveImportList(m, snd(impList),TRUE);
494 imports = dupOnto(privileged,imports);
496 imports = resolveImportList(m, impList,FALSE);
499 for(; nonNull(imports); imports=tl(imports)) {
500 Cell e = hd(imports);
501 if (!cellIsMember(e,hidden))
504 /* ToDo: hang onto the imports list for processing export list entries
505 * of the form "module Foo"
509 static Void local importEntity(source,e)
513 case NAME : importName(source,e);
516 case TYCON : importTycon(source,e);
518 case CLASS : importClass(source,e);
520 default: internal("importEntity");
524 static Void local importName(source,n)
527 Name clash = addName(n);
528 if (nonNull(clash) && clash!=n) {
529 ERRMSG(0) "Entity \"%s\" imported from module \"%s\" already defined in module \"%s\"",
530 textToStr(name(n).text),
531 textToStr(module(source).text),
532 textToStr(module(name(clash).mod).text)
537 static Void local importTycon(source,tc)
540 Tycon clash=addTycon(tc);
541 if (nonNull(clash) && clash!=tc) {
542 ERRMSG(0) "Tycon \"%s\" imported from \"%s\" already defined in module \"%s\"",
543 textToStr(tycon(tc).text),
544 textToStr(module(source).text),
545 textToStr(module(tycon(clash).mod).text)
548 if (nonNull(findClass(tycon(tc).text))) {
549 ERRMSG(0) "Import of type constructor \"%s\" clashes with class in module \"%s\"",
550 textToStr(tycon(tc).text),
551 textToStr(module(tycon(tc).mod).text)
556 static Void local importClass(source,c)
559 Class clash=addClass(c);
560 if (nonNull(clash) && clash!=c) {
561 ERRMSG(0) "Class \"%s\" imported from \"%s\" already defined in module \"%s\"",
562 textToStr(cclass(c).text),
563 textToStr(module(source).text),
564 textToStr(module(cclass(clash).mod).text)
567 if (nonNull(findTycon(cclass(c).text))) {
568 ERRMSG(0) "Import of class \"%s\" clashes with type constructor in module \"%s\"",
569 textToStr(cclass(c).text),
570 textToStr(module(source).text)
575 static List local checkExportTycon(exports,mt,spec,tc)
580 if (DOTDOT == spec || SYNONYM == tycon(tc).what) {
581 return cons(pair(tc,DOTDOT), exports);
583 return cons(pair(tc,NIL), exports);
587 static List local checkExportClass(exports,mt,spec,cl)
592 if (DOTDOT == spec) {
593 return cons(pair(cl,DOTDOT), exports);
595 return cons(pair(cl,NIL), exports);
599 static List local checkExport(exports,mt,e) /* Process entry in export list*/
605 List origExports = exports;
606 if (nonNull(export=findQualName(e))) {
607 exports=cons(export,exports);
609 if (isQCon(e) && nonNull(export=findQualTycon(e))) {
610 exports = checkExportTycon(exports,mt,NIL,export);
612 if (isQCon(e) && nonNull(export=findQualClass(e))) {
613 /* opaque class export */
614 exports = checkExportClass(exports,mt,NIL,export);
616 if (exports == origExports) {
617 ERRMSG(0) "Unknown entity \"%s\" exported from module \"%s\"",
623 } else if (MODULEENT == fst(e)) {
624 Module m = findModid(snd(e));
625 /* ToDo: shouldn't allow export of module we didn't import */
627 ERRMSG(0) "Unknown module \"%s\" exported from module \"%s\"",
628 textToStr(textOf(snd(e))),
632 if (m == currentModule) {
633 /* Exporting the current module exports local definitions */
635 for(xs=module(m).classes; nonNull(xs); xs=tl(xs)) {
636 if (cclass(hd(xs)).mod==m)
637 exports = checkExportClass(exports,mt,DOTDOT,hd(xs));
639 for(xs=module(m).tycons; nonNull(xs); xs=tl(xs)) {
640 if (tycon(hd(xs)).mod==m)
641 exports = checkExportTycon(exports,mt,DOTDOT,hd(xs));
643 for(xs=module(m).names; nonNull(xs); xs=tl(xs)) {
644 if (name(hd(xs)).mod==m)
645 exports = cons(hd(xs),exports);
648 /* Exporting other modules imports all things imported
649 * unqualified from it.
650 * ToDo: we reexport everything exported by a module -
651 * whether we imported it or not. This gives the wrong
652 * result for "module M(module N) where import N(x)"
654 exports = dupOnto(module(m).exports,exports);
658 Cell ident = fst(e); /* class name or type name */
659 Cell parts = snd(e); /* members or constructors */
661 if (isQCon(ident) && nonNull(nm=findQualTycon(ident))) {
662 switch (tycon(nm).what) {
665 ERRMSG(0) "Explicit constructor list given for type synonym"
666 " \"%s\" in export list of module \"%s\"",
671 return cons(pair(nm,DOTDOT),exports);
673 ERRMSG(0) "Transparent export of restricted type synonym"
674 " \"%s\" in export list of module \"%s\"",
678 return exports; /* Not reached */
682 return cons(pair(nm,DOTDOT),exports);
684 exports = checkSubentities(exports,parts,tycon(nm).defn,
685 "constructor of type",
687 return cons(pair(nm,DOTDOT), exports);
690 internal("checkExport1");
692 } else if (isQCon(ident) && nonNull(nm=findQualClass(ident))) {
693 if (DOTDOT == parts) {
694 return cons(pair(nm,DOTDOT),exports);
696 exports = checkSubentities(exports,parts,cclass(nm).members,
697 "member of class",cclass(nm).text);
698 return cons(pair(nm,DOTDOT), exports);
701 ERRMSG(0) "Explicit export list given for non-class/datatype \"%s\" in export list of module \"%s\"",
707 return exports; /* NOTUSED */
710 static List local checkExports(exports)
712 Module m = lastModule();
713 Text mt = module(m).text;
716 map1Accum(checkExport,es,mt,exports);
719 for(xs=es; nonNull(xs); xs=tl(xs)) {
720 Printf(" %s", textToStr(textOfEntity(hd(xs))));
727 /* --------------------------------------------------------------------------
728 * Static analysis of type declarations:
730 * Type declarations come in two forms:
731 * - data declarations - define new constructed data types
732 * - type declarations - define new type synonyms
734 * A certain amount of work is carried out as the declarations are
735 * read during parsing. In particular, for each type constructor
736 * definition encountered:
737 * - check that there is no previous definition of constructor
738 * - ensure type constructor not previously used as a class name
739 * - make a new entry in the type constructor table
740 * - record line number of declaration
741 * - Build separate lists of newly defined constructors for later use.
742 * ------------------------------------------------------------------------*/
744 Void tyconDefn(line,lhs,rhs,what) /* process new type definition */
745 Int line; /* definition line number */
746 Cell lhs; /* left hand side of definition */
747 Cell rhs; /* right hand side of definition */
748 Cell what; { /* SYNONYM/DATATYPE/etc... */
749 Text t = textOf(getHead(lhs));
751 if (nonNull(findTycon(t))) {
752 ERRMSG(line) "Repeated definition of type constructor \"%s\"",
756 else if (nonNull(findClass(t))) {
757 ERRMSG(line) "\"%s\" used as both class and type constructor",
762 Tycon nw = newTycon(t);
763 tyconDefns = cons(nw,tyconDefns);
764 tycon(nw).line = line;
765 tycon(nw).arity = argCount;
766 tycon(nw).what = what;
767 if (what==RESTRICTSYN) {
768 h98DoesntSupport(line,"restricted type synonyms");
769 typeInDefns = cons(pair(nw,snd(rhs)),typeInDefns);
772 tycon(nw).defn = pair(lhs,rhs);
776 Void setTypeIns(bs) /* set local synonyms for given */
777 List bs; { /* binding group */
778 List cvs = typeInDefns;
779 for (; nonNull(cvs); cvs=tl(cvs)) {
780 Tycon c = fst(hd(cvs));
781 List vs = snd(hd(cvs));
782 for (tycon(c).what = RESTRICTSYN; nonNull(vs); vs=tl(vs)) {
783 if (nonNull(findBinding(textOf(hd(vs)),bs))) {
784 tycon(c).what = SYNONYM;
791 Void clearTypeIns() { /* clear list of local synonyms */
792 for (; nonNull(typeInDefns); typeInDefns=tl(typeInDefns))
793 tycon(fst(hd(typeInDefns))).what = RESTRICTSYN;
796 /* --------------------------------------------------------------------------
797 * Further analysis of Type declarations:
799 * In order to allow the definition of mutually recursive families of
800 * data types, the static analysis of the right hand sides of type
801 * declarations cannot be performed until all of the type declarations
804 * Once parsing is complete, we carry out the following:
806 * - check format of lhs, extracting list of bound vars and ensuring that
807 * there are no repeated variables and no Skolem variables.
808 * - run dependency analysis on rhs to check that only bound type vars
809 * appear in type and that all constructors are defined.
810 * Replace type variables by offsets, constructors by Tycons.
811 * - use list of dependents to sort into strongly connected components.
812 * - ensure that there is not more than one synonym in each group.
813 * - kind-check each group of type definitions.
815 * - check that there are no previous definitions for constructor
816 * functions in data type definitions.
817 * - install synonym expansions and constructor definitions.
818 * ------------------------------------------------------------------------*/
820 static List tcDeps = NIL; /* list of dependent tycons/classes*/
822 static Void local checkTyconDefn(d) /* validate type constructor defn */
824 Cell lhs = fst(tycon(d).defn);
825 Cell rhs = snd(tycon(d).defn);
826 Int line = tycon(d).line;
827 List tyvars = getArgs(lhs);
829 /* check for repeated tyvars on lhs*/
830 for (temp=tyvars; nonNull(temp); temp=tl(temp))
831 if (nonNull(varIsMember(textOf(hd(temp)),tl(temp)))) {
832 ERRMSG(line) "Repeated type variable \"%s\" on left hand side",
833 textToStr(textOf(hd(temp)))
837 tcDeps = NIL; /* find dependents */
838 switch (whatIs(tycon(d).what)) {
840 case SYNONYM : rhs = depTypeExp(line,tyvars,rhs);
841 if (cellIsMember(d,tcDeps)) {
842 ERRMSG(line) "Recursive type synonym \"%s\"",
843 textToStr(tycon(d).text)
849 case NEWTYPE : depConstrs(d,tyvars,rhs);
853 default : internal("checkTyconDefn");
858 tycon(d).kind = tcDeps;
862 static Void local depConstrs(t,tyvars,cd)
863 Tycon t; /* Define constructor functions and*/
864 List tyvars; /* do dependency analysis for data */
865 Cell cd; { /* definitions (w or w/o deriving) */
866 Int line = tycon(t).line;
871 List derivs = snd(cd);
872 List compTypes = NIL;
876 for (i=0; i<tycon(t).arity; ++i) /* build representation for tycon */
877 lhs = ap(lhs,mkOffset(i)); /* applied to full comp. of args */
879 if (isQualType(cs)) { /* allow for possible context */
882 map2Over(depPredExp,line,tyvars,ctxt);
883 h98CheckCtxt(line,"context",TRUE,ctxt,NIL);
886 if (nonNull(cs) && isNull(tl(cs))) /* Single constructor datatype? */
889 for (; nonNull(cs); cs=tl(cs)) { /* For each constructor function: */
891 List sig = dupList(tyvars);
892 List evs = NIL; /* locally quantified vars */
893 List lps = NIL; /* locally bound predicates */
894 List ctxt1 = ctxt; /* constructor function context */
895 List scs = NIL; /* strict components */
896 List fs = NONE; /* selector names */
897 Type type = lhs; /* constructor function type */
898 Int arity = 0; /* arity of constructor function */
899 Int nr2 = 0; /* Number of rank 2 args */
900 Name n; /* name for constructor function */
902 if (whatIs(con)==POLYTYPE) { /* Locally quantified vars */
905 sig = checkQuantVars(line,evs,sig,con);
908 if (isQualType(con)) { /* Local predicates */
911 for (us = typeVarsIn(lps,NIL,NIL,NIL); nonNull(us); us=tl(us))
912 if (!varIsMember(textOf(hd(us)),evs)) {
914 "Variable \"%s\" in constraint is not locally bound",
915 textToStr(textOf(hd(us)))
918 map2Over(depPredExp,line,sig,lps);
923 if (whatIs(con)==LABC) { /* Skeletize constr components */
924 Cell fls = snd(snd(con)); /* get field specifications */
927 for (; nonNull(fls); fls=tl(fls)) { /* for each field spec: */
928 List vs = fst(hd(fls));
929 Type t = snd(hd(fls)); /* - scrutinize type */
930 Bool banged = whatIs(t)==BANG;
931 t = depCompType(line,sig,(banged ? arg(t) : t));
932 while (nonNull(vs)) { /* - add named components */
940 scs = cons(mkInt(arity),scs);
944 scs = rev(scs); /* put strict comps in ascend ord */
946 else { /* Non-labelled constructor */
949 for (; isAp(c); c=fun(c))
951 for (compNo=arity, c=con; isAp(c); c=fun(c)) {
953 if (whatIs(t)==BANG) {
954 scs = cons(mkInt(compNo),scs);
958 arg(c) = depCompType(line,sig,t);
962 if (nonNull(ctxt1)) /* Extract relevant part of context*/
963 ctxt1 = selectCtxt(ctxt1,offsetTyvarsIn(con,NIL));
965 for (i=arity; isAp(con); i--) { /* Calculate type of constructor */
968 fun(con) = typeArrow;
969 if (isPolyOrQualType(cmp)) {
970 if (nonNull(derivs)) {
971 ERRMSG(line) "Cannot derive instances for types" ETHEN
972 ERRTEXT " with polymorphic or qualified components"
978 if (nonNull(derivs)) /* and build list of components */
979 compTypes = cons(cmp,compTypes);
984 if (nr2>0) { /* Add rank 2 annotation */
985 type = ap(RANK2,pair(mkInt(nr2-length(lps)),type));
988 if (nonNull(evs)) { /* Add existential annotation */
989 if (nonNull(derivs)) {
990 ERRMSG(line) "Cannot derive instances for types" ETHEN
991 ERRTEXT " with existentially typed components"
996 "Cannot use selectors with existentially typed components"
999 type = ap(EXIST,pair(mkInt(length(evs)),type));
1002 if (nonNull(lps)) { /* Add local preds part to type */
1003 type = ap(CDICTS,pair(lps,type));
1006 if (nonNull(ctxt1)) { /* Add context part to type */
1007 type = ap(QUAL,pair(ctxt1,type));
1010 if (nonNull(sig)) { /* Add quantifiers to type */
1012 for (; nonNull(ts1); ts1=tl(ts1)) {
1015 type = mkPolyType(sig,type);
1018 n = findName(textOf(con)); /* Allocate constructor fun name */
1020 n = newName(textOf(con),NIL);
1021 } else if (name(n).defn!=PREDEFINED) {
1022 duplicateError(line,name(n).mod,name(n).text,
1023 "constructor function");
1025 name(n).arity = arity; /* Save constructor fun details */
1026 name(n).line = line;
1028 name(n).number = cfunNo(conNo++);
1029 name(n).type = type;
1030 if (tycon(t).what==NEWTYPE) {
1033 "A newtype constructor cannot have class constraints"
1038 "A newtype constructor must have exactly one argument"
1043 "Illegal strictess annotation for newtype constructor"
1046 name(n).defn = nameId;
1048 implementCfun(n,scs);
1053 sels = addSels(line,n,fs,sels);
1057 if (nonNull(sels)) {
1059 fst(cd) = appendOnto(fst(cd),sels);
1060 selDefns = cons(sels,selDefns);
1063 if (nonNull(derivs)) { /* Generate derived instances */
1064 map3Proc(checkDerive,t,ctxt,compTypes,derivs);
1068 Int userArity(c) /* Find arity for cfun, ignoring */
1069 Name c; { /* CDICTS parameters */
1070 Int a = name(c).arity;
1071 Type t = name(c).type;
1073 if (isPolyType(t)) {
1076 if ((w=whatIs(t))==QUAL) {
1077 w = whatIs(t=snd(snd(t)));
1080 a -= length(fst(snd(t)));
1086 static List local addSels(line,c,fs,ss) /* Add fields to selector list */
1087 Int line; /* line number of constructor */
1088 Name c; /* corresponding constr function */
1089 List fs; /* list of fields (varids) */
1090 List ss; { /* list of existing selectors */
1092 cfunSfuns = cons(pair(c,fs),cfunSfuns);
1093 for (; nonNull(fs); fs=tl(fs), ++sn) {
1095 Text t = textOf(hd(fs));
1097 if (nonNull(varIsMember(t,tl(fs)))) {
1098 ERRMSG(line) "Repeated field name \"%s\" for constructor \"%s\"",
1099 textToStr(t), textToStr(name(c).text)
1103 while (nonNull(ns) && t!=name(hd(ns)).text) {
1108 name(hd(ns)).defn = cons(pair(c,mkInt(sn)),name(hd(ns)).defn);
1110 Name n = findName(t);
1112 ERRMSG(line) "Repeated definition for selector \"%s\"",
1117 name(n).line = line;
1118 name(n).number = SELNAME;
1119 name(n).defn = singleton(pair(c,mkInt(sn)));
1126 static List local selectCtxt(ctxt,vs) /* calculate subset of context */
1133 for (; nonNull(ctxt); ctxt=tl(ctxt)) {
1134 List us = offsetTyvarsIn(hd(ctxt),NIL);
1135 for (; nonNull(us) && cellIsMember(hd(us),vs); us=tl(us)) {
1138 ps = cons(hd(ctxt),ps);
1145 static Void local checkSynonyms(ts) /* Check for mutually recursive */
1146 List ts; { /* synonyms */
1148 for (; nonNull(ts); ts=tl(ts)) { /* build list of all synonyms */
1150 switch (whatIs(tycon(t).what)) {
1152 case RESTRICTSYN : syns = cons(t,syns);
1156 while (nonNull(syns)) { /* then visit each synonym */
1157 syns = visitSyn(NIL,hd(syns),syns);
1161 static List local visitSyn(path,t,syns) /* visit synonym definition to look*/
1162 List path; /* for cycles */
1165 if (cellIsMember(t,path)) { /* every elt in path depends on t */
1166 ERRMSG(tycon(t).line)
1167 "Type synonyms \"%s\" and \"%s\" are mutually recursive",
1168 textToStr(tycon(t).text), textToStr(tycon(hd(path)).text)
1171 List ds = tycon(t).kind;
1173 for (; nonNull(ds); ds=tl(ds)) {
1174 if (cellIsMember(hd(ds),syns)) {
1175 if (isNull(path1)) {
1176 path1 = cons(t,path);
1178 syns = visitSyn(path1,hd(ds),syns);
1182 tycon(t).defn = fullExpand(tycon(t).defn);
1183 return removeCell(t,syns);
1186 /* --------------------------------------------------------------------------
1187 * Expanding out all type synonyms in a type expression:
1188 * ------------------------------------------------------------------------*/
1190 Type fullExpand(t) /* find full expansion of type exp */
1191 Type t; { /* assuming that all relevant */
1192 Cell h = t; /* synonym defns of lower rank have*/
1193 Int n = 0; /* already been fully expanded */
1195 for (args=NIL; isAp(h); h=fun(h), n++) {
1196 args = cons(fullExpand(arg(h)),args);
1198 t = applyToArgs(h,args);
1199 if (isSynonym(h) && n>=tycon(h).arity) {
1200 if (n==tycon(h).arity) {
1201 t = instantiateSyn(tycon(h).defn,t);
1204 while (--n > tycon(h).arity) {
1207 fun(p) = instantiateSyn(tycon(h).defn,fun(p));
1213 static Type local instantiateSyn(t,env) /* instantiate type according using*/
1214 Type t; /* env to determine appropriate */
1215 Type env; { /* values for OFFSET type vars */
1216 switch (whatIs(t)) {
1217 case AP : return ap(instantiateSyn(fun(t),env),
1218 instantiateSyn(arg(t),env));
1220 case OFFSET : return nthArg(offsetOf(t),env);
1226 /* --------------------------------------------------------------------------
1227 * Static analysis of class declarations:
1229 * Performed in a similar manner to that used for type declarations.
1231 * The first part of the static analysis is performed as the declarations
1232 * are read during parsing. The parser ensures that:
1233 * - the class header and all superclass predicates are of the form
1236 * The classDefn() function:
1237 * - ensures that there is no previous definition for class
1238 * - checks that class name has not previously been used as a type constr.
1239 * - make new entry in class table
1240 * - record line number of declaration
1241 * - build list of classes defined in current script for use in later
1242 * stages of static analysis.
1243 * ------------------------------------------------------------------------*/
1245 Void classDefn(line,head,ms,fds) /* process new class definition */
1246 Int line; /* definition line number */
1247 Cell head; /* class header :: ([Supers],Class) */
1248 List ms; /* class definition body */
1249 List fds; { /* functional dependencies */
1250 Text ct = textOf(getHead(snd(head)));
1251 Int arity = argCount;
1253 if (nonNull(findClass(ct))) {
1254 ERRMSG(line) "Repeated definition of class \"%s\"",
1257 } else if (nonNull(findTycon(ct))) {
1258 ERRMSG(line) "\"%s\" used as both class and type constructor",
1262 Class nw = newClass(ct);
1263 cclass(nw).line = line;
1264 cclass(nw).arity = arity;
1265 cclass(nw).head = snd(head);
1266 cclass(nw).supers = fst(head);
1267 cclass(nw).members = ms;
1268 cclass(nw).level = 0;
1269 cclass(nw).fds = fds;
1270 cclass(nw).xfds = NIL;
1271 classDefns = cons(nw,classDefns);
1273 h98DoesntSupport(line,"multiple parameter classes");
1277 /* --------------------------------------------------------------------------
1278 * Further analysis of class declarations:
1280 * Full static analysis of class definitions must be postponed until the
1281 * complete script has been read and all static analysis on type definitions
1282 * has been completed.
1284 * Once this has been achieved, we carry out the following checks on each
1286 * - check that variables in header are distinct
1287 * - replace head by skeleton
1288 * - check superclass declarations, replace by skeletons
1289 * - split body of class into members and declarations
1290 * - make new name entry for each member function
1291 * - record member function number (eventually an offset into dictionary!)
1292 * - no member function has a previous definition ...
1293 * - no member function is mentioned more than once in the list of members
1294 * - each member function type is valid, replace vars by offsets
1295 * - qualify each member function type by class header
1296 * - only bindings for members appear in defaults
1297 * - only function bindings appear in defaults
1298 * - check that extended class hierarchy does not contain any cycles
1299 * ------------------------------------------------------------------------*/
1301 static Void local checkClassDefn(c) /* validate class definition */
1304 Int args = cclass(c).arity - 1;
1305 Cell temp = cclass(c).head;
1309 for (; isAp(temp); temp=fun(temp)) {
1310 if (!isVar(arg(temp))) {
1311 ERRMSG(cclass(c).line) "Type variable required in class head"
1314 if (nonNull(varIsMember(textOf(arg(temp)),tyvars))) {
1315 ERRMSG(cclass(c).line)
1316 "Repeated type variable \"%s\" in class head",
1317 textToStr(textOf(arg(temp)))
1320 tyvars = cons(arg(temp),tyvars);
1323 for (fs=cclass(c).fds; nonNull(fs); fs=tl(fs)) {
1327 /* Check for trivial dependency
1330 ERRMSG(cclass(c).line) "Functional dependency is trivial"
1334 /* Check for duplicated vars on right hand side, and for vars on
1335 * right that also appear on the left:
1337 for (vs=snd(fd); nonNull(vs); vs=tl(vs)) {
1338 if (varIsMember(textOf(hd(vs)),fst(fd))) {
1339 ERRMSG(cclass(c).line)
1340 "Trivial dependency for variable \"%s\"",
1341 textToStr(textOf(hd(vs)))
1344 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1345 ERRMSG(cclass(c).line)
1346 "Repeated variable \"%s\" in functional dependency",
1347 textToStr(textOf(hd(vs)))
1350 hd(vs) = depTypeVar(cclass(c).line,tyvars,textOf(hd(vs)));
1353 /* Check for duplicated vars on left hand side:
1355 for (vs=fst(fd); nonNull(vs); vs=tl(vs)) {
1356 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1357 ERRMSG(cclass(c).line)
1358 "Repeated variable \"%s\" in functional dependency",
1359 textToStr(textOf(hd(vs)))
1362 hd(vs) = depTypeVar(cclass(c).line,tyvars,textOf(hd(vs)));
1366 if (cclass(c).arity==0) {
1369 Int args = cclass(c).arity - 1;
1370 for (temp=cclass(c).head; args>0; temp=fun(temp), args--) {
1371 arg(temp) = mkOffset(args);
1373 arg(temp) = mkOffset(0);
1377 tcDeps = NIL; /* find dependents */
1378 map2Over(depPredExp,cclass(c).line,tyvars,cclass(c).supers);
1379 h98CheckCtxt(cclass(c).line,"class definition",FALSE,cclass(c).supers,NIL);
1380 cclass(c).numSupers = length(cclass(c).supers);
1381 cclass(c).defaults = extractBindings(cclass(c).members); /* defaults*/
1382 ss = extractSigdecls(cclass(c).members);
1383 fs = extractFixdecls(cclass(c).members);
1384 cclass(c).members = pair(ss,fs);
1385 map2Proc(checkMems,c,tyvars,ss);
1387 cclass(c).kinds = tcDeps;
1392 /* --------------------------------------------------------------------------
1393 * Functional dependencies are inherited from superclasses.
1394 * For example, if I've got the following classes:
1396 * class C a b | a -> b
1397 * class C [b] a => D a b
1399 * then C will have the dependency ([a], [b]) as expected, and D will inherit
1400 * the dependency ([b], [a]) from C.
1401 * When doing pairwise improvement, we have to consider not just improving
1402 * when we see a pair of Cs or a pair of Ds in the context, but when we've
1403 * got a C and a D as well. In this case, we only improve when the
1404 * predicate in question matches the type skeleton in the relevant superclass
1405 * constraint. E.g., we improve the pair (C [Int] a, D b Int) (unifying
1406 * a and b), but we don't improve the pair (C Int a, D b Int).
1407 * To implement functional dependency inheritance, we calculate
1408 * the closure of all functional dependencies, and store the result
1409 * in an additional field `xfds' (extended functional dependencies).
1410 * The `xfds' field is a list of functional dependency lists, annotated
1411 * with a list of predicate skeletons constraining when improvement can
1412 * happen against this dependency list. For example, the xfds field
1413 * for C above would be:
1414 * [([C a b], [([a], [b])])]
1415 * and the xfds field for D would be:
1416 * [([C [b] a, D a b], [([b], [a])])]
1417 * Self-improvement (of a C with a C, or a D with a D) is treated as a
1418 * special case of an inherited dependency.
1419 * ------------------------------------------------------------------------*/
1420 static List local inheritFundeps ( Class c, Cell pi, Int o )
1422 Int alpha = newKindedVars(cclass(c).kinds);
1423 List scs = cclass(c).supers;
1426 /* better not fail ;-) */
1427 if (!matchPred(pi,o,cclass(c).head,alpha))
1428 internal("inheritFundeps - predicate failed to match it's own head!");
1429 this = copyPred(pi,o);
1430 for (; nonNull(scs); scs=tl(scs)) {
1431 Class s = getHead(hd(scs));
1433 List sfds = inheritFundeps(s,hd(scs),alpha);
1434 for (; nonNull(sfds); sfds=tl(sfds)) {
1436 xfds = cons(pair(cons(this,fst(h)),snd(h)),xfds);
1440 if (nonNull(cclass(c).fds)) {
1441 List fds = NIL, fs = cclass(c).fds;
1442 for (; nonNull(fs); fs=tl(fs)) {
1443 fds = cons(pair(otvars(this,fst(hd(fs))),
1444 otvars(this,snd(hd(fs)))),fds);
1446 xfds = cons(pair(cons(this,NIL),fds),xfds);
1451 static Void local extendFundeps ( Class c )
1454 emptySubstitution();
1455 alpha = newKindedVars(cclass(c).kinds);
1456 cclass(c).xfds = inheritFundeps(c,cclass(c).head,alpha);
1458 /* we can now check for ambiguity */
1459 map1Proc(checkMems2,c,fst(cclass(c).members));
1463 static Cell local depPredExp(line,tyvars,pred)
1470 for (; isAp(h); args++) {
1471 arg(h) = depTypeExp(line,tyvars,arg(h));
1477 h98DoesntSupport(line,"tag classes");
1478 } else if (args!=1) {
1479 h98DoesntSupport(line,"multiple parameter classes");
1482 if (isQCon(h)) { /* standard class constraint */
1483 Class c = findQualClass(h);
1485 ERRMSG(line) "Undefined class \"%s\"", identToStr(h)
1493 if (args!=cclass(c).arity) {
1494 ERRMSG(line) "Wrong number of arguments for class \"%s\"",
1495 textToStr(cclass(c).text)
1498 if (cellIsMember(c,classDefns) && !cellIsMember(c,tcDeps)) {
1499 tcDeps = cons(c,tcDeps);
1503 else if (isExt(h)) { /* Lacks predicate */
1504 if (args!=1) { /* parser shouldn't let this happen*/
1505 ERRMSG(line) "Wrong number of arguments for lacks predicate"
1512 if (whatIs(h) != IPCELL)
1515 internal("depPredExp");
1520 static Void local checkMems(c,tyvars,m) /* check member function details */
1524 Int line = intOf(fst3(m));
1531 if (isPolyType(t)) {
1537 tyvars = typeVarsIn(t,NIL,xtvs,tyvars);
1538 /* Look for extra type vars. */
1539 checkOptQuantVars(line,xtvs,tyvars);
1541 if (isQualType(t)) { /* Overloaded member signatures? */
1542 map2Over(depPredExp,line,tyvars,fst(snd(t)));
1544 t = ap(QUAL,pair(NIL,t));
1547 fst(snd(t)) = cons(cclass(c).head,fst(snd(t)));/* Add main predicate */
1548 snd(snd(t)) = depTopType(line,tyvars,snd(snd(t)));
1550 for (tvs=tyvars; nonNull(tvs); tvs=tl(tvs)){/* Quantify */
1554 t = mkPolyType(sig,t);
1556 thd3(m) = t; /* Save type */
1557 take(cclass(c).arity,tyvars); /* Delete extra type vars */
1559 if (isAmbiguous(t)) {
1560 ambigError(line,"class declaration",hd(vs),t);
1562 h98CheckType(line,"member type",hd(vs),t);
1565 static Void local checkMems2(c,m) /* check member function details */
1568 Int line = intOf(fst3(m));
1573 static Void local addMembers(c) /* Add definitions of member funs */
1574 Class c; { /* and other parts of class struct.*/
1575 List ms = fst(cclass(c).members);
1576 List fs = snd(cclass(c).members);
1577 List ns = NIL; /* List of names */
1578 Int mno; /* Member function number */
1580 for (mno=0; mno<cclass(c).numSupers; mno++) {
1581 ns = cons(newDSel(c,mno),ns);
1583 cclass(c).dsels = rev(ns); /* Save dictionary selectors */
1585 for (mno=1, ns=NIL; nonNull(ms); ms=tl(ms)) {
1586 Int line = intOf(fst3(hd(ms)));
1587 List vs = rev(snd3(hd(ms)));
1588 Type t = thd3(hd(ms));
1589 for (; nonNull(vs); vs=tl(vs)) {
1590 ns = cons(newMember(line,mno++,hd(vs),t,c),ns);
1593 cclass(c).members = rev(ns); /* Save list of members */
1594 cclass(c).numMembers = length(cclass(c).members);
1596 for (; nonNull(fs); fs=tl(fs)) { /* fixity declarations */
1597 Int line = intOf(fst3(hd(fs)));
1598 List ops = snd3(hd(fs));
1599 Syntax s = intOf(thd3(hd(fs)));
1600 for (; nonNull(ops); ops=tl(ops)) {
1601 Name n = nameIsMember(textOf(hd(ops)),cclass(c).members);
1603 missFixity(line,textOf(hd(ops)));
1604 } else if (name(n).syntax!=NO_SYNTAX) {
1605 dupFixity(line,textOf(hd(ops)));
1611 /* Not actually needed just yet; for the time being, dictionary code will
1612 not be passed through the type checker.
1614 cclass(c).dtycon = addPrimTycon(generateText("Dict.%s",c),
1621 mno = cclass(c).numSupers + cclass(c).numMembers;
1622 /* cclass(c).dcon = addPrimCfun(generateText("Make.%s",c),mno,0,NIL); */
1623 cclass(c).dcon = addPrimCfun(generateText(":D%s",c),mno,0,NIL);
1624 /* implementCfun(cclass(c).dcon,NIL);
1625 Don't manufacture a wrapper fn for dictionary constructors.
1626 Applications of dictionary constructors are always saturated,
1627 and translate.c:stgExpr() special-cases saturated constructor apps.
1630 if (mno==1) { /* Single entry dicts use newtype */
1631 name(cclass(c).dcon).defn = nameId;
1632 if (nonNull(cclass(c).members)) {
1633 name(hd(cclass(c).members)).number = mfunNo(0);
1636 cclass(c).defaults = classBindings("class",c,cclass(c).defaults);
1639 static Name local newMember(l,no,v,t,parent)
1640 Int l; /* Make definition for member fn */
1645 Name m = findName(textOf(v));
1648 m = newName(textOf(v),parent);
1649 } else if (name(m).defn!=PREDEFINED) {
1650 ERRMSG(l) "Repeated definition for member function \"%s\"",
1651 textToStr(name(m).text)
1657 name(m).number = mfunNo(no);
1662 Name newDSel(c,no) /* Make definition for dict selectr*/
1668 /* sprintf(buf,"sc%d.%s",no,"%s"); */
1669 sprintf(buf,"$p%d%s",no+1,"%s");
1670 s = newName(generateText(buf,c),c);
1671 name(s).line = cclass(c).line;
1673 name(s).number = DFUNNAME;
1679 static Text local generateText(sk,c) /* We need to generate names for */
1680 String sk; /* certain objects corresponding */
1681 Class c; { /* to each class. */
1682 String cname = textToStr(cclass(c).text);
1683 char buffer[MAX_GEN+1];
1685 if ((strlen(sk)+strlen(cname))>=MAX_GEN) {
1686 ERRMSG(0) "Please use a shorter name for class \"%s\"", cname
1689 sprintf(buffer,sk,cname);
1690 return findText(buffer);
1693 Int visitClass(c) /* visit class defn to check that */
1694 Class c; { /* class hierarchy is acyclic */
1696 if (isExt(c)) { /* special case for lacks preds */
1700 if (cclass(c).level < 0) { /* already visiting this class? */
1701 ERRMSG(cclass(c).line) "Class hierarchy for \"%s\" is not acyclic",
1702 textToStr(cclass(c).text)
1704 } else if (cclass(c).level == 0) { /* visiting class for first time */
1705 List scs = cclass(c).supers;
1707 cclass(c).level = (-1);
1708 for (; nonNull(scs); scs=tl(scs)) {
1709 Int l = visitClass(getHead(hd(scs)));
1712 cclass(c).level = 1+lev; /* level = 1 + max level of supers */
1714 return cclass(c).level;
1717 /* --------------------------------------------------------------------------
1718 * Process class and instance declaration binding groups:
1719 * ------------------------------------------------------------------------*/
1721 static List local classBindings(where,c,bs)
1722 String where; /* Check validity of bindings bs */
1723 Class c; /* for class c (or an inst of c) */
1724 List bs; { /* sort into approp. member order */
1727 for (; nonNull(bs); bs=tl(bs)) {
1729 Cell body = snd(snd(b));
1732 if (!isVar(fst(b))) { /* Only allow function bindings */
1733 ERRMSG(rhsLine(snd(body)))
1734 "Pattern binding illegal in %s declaration", where
1738 if (isNull(mnm=memberName(c,textOf(fst(b))))) {
1739 ERRMSG(rhsLine(snd(hd(body))))
1740 "No member \"%s\" in class \"%s\"",
1741 textToStr(textOf(fst(b))), textToStr(cclass(c).text)
1745 nbs = numInsert(mfunOf(mnm)-1,b,nbs);
1750 static Name local memberName(c,t) /* return name of member function */
1751 Class c; /* with name t in class c */
1752 Text t; { /* return NIL if not a member */
1753 List ms = cclass(c).members;
1754 for (; nonNull(ms); ms=tl(ms)) {
1755 if (t==name(hd(ms)).text) {
1762 static List local numInsert(n,x,xs) /* insert x at nth position in xs, */
1763 Int n; /* filling gaps with NIL */
1766 List start = isNull(xs) ? cons(NIL,NIL) : xs;
1768 for (xs=start; 0<n--; xs=tl(xs)) {
1769 if (isNull(tl(xs))) {
1770 tl(xs) = cons(NIL,NIL);
1777 /* --------------------------------------------------------------------------
1778 * Calculate set of variables appearing in a given type expression (possibly
1779 * qualified) as a list of distinct values. The order in which variables
1780 * appear in the list is the same as the order in which those variables
1781 * occur in the type expression when read from left to right.
1782 * ------------------------------------------------------------------------*/
1784 List local typeVarsIn(ty,us,ws,vs) /*Calculate list of type variables*/
1785 Cell ty; /* used in type expression, reading*/
1786 List us; /* from left to right ignoring any */
1787 List ws; /* listed in us. */
1788 List vs; { /* ws = explicitly quantified vars */
1789 if (isNull(ty)) return vs;
1790 switch (whatIs(ty)) {
1791 case DICTAP : return typeVarsIn(snd(snd(ty)),us,ws,vs);
1792 case UNBOXEDTUP: return typeVarsIn(snd(ty),us,ws,vs);
1794 case AP : return typeVarsIn(snd(ty),us,ws,
1795 typeVarsIn(fst(ty),us,ws,vs));
1798 case VAROPCELL : if ((nonNull(findBtyvs(textOf(ty)))
1799 && !varIsMember(textOf(ty),ws))
1800 || varIsMember(textOf(ty),us)) {
1803 return maybeAppendVar(ty,vs);
1806 case POLYTYPE : return typeVarsIn(monotypeOf(ty),polySigOf(ty),ws,vs);
1808 case QUAL : { vs = typeVarsIn(fst(snd(ty)),us,ws,vs);
1809 return typeVarsIn(snd(snd(ty)),us,ws,vs);
1812 case BANG : return typeVarsIn(snd(ty),us,ws,vs);
1814 case LABC : { List fs = snd(snd(ty));
1815 for (; nonNull(fs); fs=tl(fs)) {
1816 vs = typeVarsIn(snd(hd(fs)),us,ws,vs);
1823 case QUALIDENT: return vs;
1825 default: fprintf(stderr, " bad tag = %d\n", whatIs(ty));internal("typeVarsIn");
1830 static List local maybeAppendVar(v,vs) /* append variable to list if not */
1831 Cell v; /* already included */
1837 while (nonNull(c)) {
1838 if (textOf(hd(c))==t) {
1846 tl(p) = cons(v,NIL);
1854 /* --------------------------------------------------------------------------
1855 * Static analysis for type expressions is required to:
1856 * - ensure that each type constructor or class used has been defined.
1857 * - replace type variables by offsets, constructor names by Tycons.
1858 * - ensure that the type is well-kinded.
1859 * ------------------------------------------------------------------------*/
1861 static Type local checkSigType(line,where,e,type)
1862 Int line; /* Check validity of type expr in */
1863 String where; /* explicit type signature */
1870 if (isPolyType(type)) {
1871 xtvs = fst(snd(type));
1872 type = monotypeOf(type);
1874 tvs = typeVarsIn(type,NIL,xtvs,NIL);
1876 checkOptQuantVars(line,xtvs,tvs);
1878 if (isQualType(type)) {
1879 map2Over(depPredExp,line,tvs,fst(snd(type)));
1880 snd(snd(type)) = depTopType(line,tvs,snd(snd(type)));
1882 if (isAmbiguous(type)) {
1883 ambigError(line,where,e,type);
1886 type = depTopType(line,tvs,type);
1890 if (length(tvs)>=NUM_OFFSETS) {
1891 ERRMSG(line) "Too many type variables in %s\n", where
1895 for (; nonNull(ts); ts=tl(ts)) {
1898 type = mkPolyType(tvs,type);
1903 kindType(line,"type expression",type);
1907 h98CheckType(line,where,e,type);
1911 static Void local checkOptQuantVars(line,xtvs,tvs)
1913 List xtvs; /* Explicitly quantified vars */
1914 List tvs; { /* Implicitly quantified vars */
1915 if (nonNull(xtvs)) {
1917 for (; nonNull(vs); vs=tl(vs)) {
1918 if (!varIsMember(textOf(hd(vs)),xtvs)) {
1919 ERRMSG(line) "Quantifier does not mention type variable \"%s\"",
1920 textToStr(textOf(hd(vs)))
1924 for (vs=xtvs; nonNull(vs); vs=tl(vs)) {
1925 if (!varIsMember(textOf(hd(vs)),tvs)) {
1926 ERRMSG(line) "Quantified type variable \"%s\" is not used",
1927 textToStr(textOf(hd(vs)))
1930 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1931 ERRMSG(line) "Quantified type variable \"%s\" is repeated",
1932 textToStr(textOf(hd(vs)))
1939 static Type local depTopType(l,tvs,t) /* Check top-level of type sig */
1947 for (; getHead(t1)==typeArrow && argCount==2; ++i) {
1948 arg(fun(t1)) = depCompType(l,tvs,arg(fun(t1)));
1949 if (isPolyOrQualType(arg(fun(t1)))) {
1955 if (nonNull(prev)) {
1956 arg(prev) = depTypeExp(l,tvs,t1);
1958 t = depTypeExp(l,tvs,t1);
1961 t = ap(RANK2,pair(mkInt(nr2),t));
1966 static Type local depCompType(l,tvs,t) /* Check component type for constr */
1970 Int ntvs = length(tvs);
1972 if (isPolyType(t)) {
1973 List vs = fst(snd(t));
1975 tvs = checkQuantVars(l,vs,tvs,t);
1976 nfr = replicate(length(vs),NIL);
1978 if (isQualType(t)) {
1979 map2Over(depPredExp,l,tvs,fst(snd(t)));
1980 snd(snd(t)) = depTypeExp(l,tvs,snd(snd(t)));
1981 if (isAmbiguous(t)) {
1982 ambigError(l,"type component",NIL,t);
1985 t = depTypeExp(l,tvs,t);
1991 return mkPolyType(nfr,t);
1994 static Type local depTypeExp(line,tyvars,type)
1998 switch (whatIs(type)) {
1999 case AP : fst(type) = depTypeExp(line,tyvars,fst(type));
2000 snd(type) = depTypeExp(line,tyvars,snd(type));
2003 case VARIDCELL : return depTypeVar(line,tyvars,textOf(type));
2005 case QUALIDENT : if (isQVar(type)) {
2006 ERRMSG(line) "Qualified type variables not allowed"
2009 /* deliberate fall through */
2010 case CONIDCELL : { Tycon tc = findQualTycon(type);
2013 "Undefined type constructor \"%s\"",
2017 if (cellIsMember(tc,tyconDefns) &&
2018 !cellIsMember(tc,tcDeps)) {
2019 tcDeps = cons(tc,tcDeps);
2025 case EXT : h98DoesntSupport(line,"extensible records");
2030 default : internal("depTypeExp");
2035 static Type local depTypeVar(line,tyvars,tv)
2042 for (; nonNull(tyvars); offset++) {
2043 if (tv==textOf(hd(tyvars))) {
2046 tyvars = tl(tyvars);
2049 Cell vt = findBtyvs(tv);
2053 ERRMSG(line) "Undefined type variable \"%s\"", textToStr(tv)
2056 return mkOffset(found);
2059 static List local checkQuantVars(line,vs,tvs,body)
2061 List vs; /* variables to quantify over */
2062 List tvs; /* variables already in scope */
2063 Cell body; { /* type/constr for scope of vars */
2065 List bvs = typeVarsIn(body,NIL,NIL,NIL);
2067 for (; nonNull(us); us=tl(us)) {
2068 Text u = textOf(hd(us));
2069 if (varIsMember(u,tl(us))) {
2070 ERRMSG(line) "Duplicated quantified variable %s",
2075 if (varIsMember(u,tvs)) {
2076 ERRMSG(line) "Local quantifier for %s hides an outer use",
2081 if (!varIsMember(u,bvs)) {
2082 ERRMSG(line) "Locally quantified variable %s is not used",
2087 tvs = appendOnto(tvs,vs);
2092 /* --------------------------------------------------------------------------
2093 * Check for ambiguous types:
2094 * A type Preds => type is ambiguous if not (TV(P) `subset` TV(type))
2095 * ------------------------------------------------------------------------*/
2097 List offsetTyvarsIn(t,vs) /* add list of offset tyvars in t */
2098 Type t; /* to list vs */
2100 switch (whatIs(t)) {
2101 case AP : return offsetTyvarsIn(fun(t),
2102 offsetTyvarsIn(arg(t),vs));
2104 case OFFSET : if (cellIsMember(t,vs))
2109 case QUAL : return offsetTyvarsIn(snd(t),vs);
2111 case POLYTYPE : return offsetTyvarsIn(monotypeOf(t),vs);
2112 /* slightly inaccurate, but won't matter here */
2115 case RANK2 : return offsetTyvarsIn(snd(snd(t)),vs);
2117 default : return vs;
2121 List zonkTyvarsIn(t,vs)
2124 switch (whatIs(t)) {
2125 case AP : return zonkTyvarsIn(fun(t),
2126 zonkTyvarsIn(arg(t),vs));
2128 case INTCELL : if (cellIsMember(t,vs))
2133 /* this case will lead to a type error --
2134 much better than reporting an internal error ;-) */
2135 /* case OFFSET : internal("zonkTyvarsIn"); */
2137 default : return vs;
2141 static List local otvars(pi,os) /* os is a list of offsets that */
2142 Cell pi; /* refer to the arguments of pi; */
2143 List os; { /* find list of offsets in those */
2144 List us = NIL; /* positions */
2145 for (; nonNull(os); os=tl(os)) {
2146 us = offsetTyvarsIn(nthArg(offsetOf(hd(os)),pi),us);
2151 static List local otvarsZonk(pi,os,o) /* same as above, but zonks */
2155 for (; nonNull(os); os=tl(os)) {
2156 Type t = zonkType(nthArg(offsetOf(hd(os)),pi),o);
2157 us = zonkTyvarsIn(t,us);
2162 static Bool local odiff(us,vs)
2164 while (nonNull(us) && cellIsMember(hd(us),vs)) {
2170 static Bool local osubset(us,vs) /* Determine whether us is subset */
2171 List us, vs; { /* of vs */
2172 while (nonNull(us) && cellIsMember(hd(us),vs)) {
2178 List oclose(fds,vs) /* Compute closure of vs wrt to fds*/
2181 Bool changed = TRUE;
2185 while (nonNull(fds)) {
2187 List next = tl(fds);
2188 if (osubset(fst(fd),vs)) { /* Test if fd applies */
2190 for (; nonNull(os); os=tl(os)) {
2191 if (!cellIsMember(hd(os),vs)) {
2192 vs = cons(hd(os),vs);
2196 } else { /* Didn't apply this time, so keep */
2207 Bool isAmbiguous(type) /* Determine whether type is */
2208 Type type; { /* ambiguous */
2209 if (isPolyType(type)) {
2210 type = monotypeOf(type);
2212 if (isQualType(type)) { /* only qualified types can be */
2213 List ps = fst(snd(type)); /* ambiguous */
2214 List tvps = offsetTyvarsIn(ps,NIL);
2215 List tvts = offsetTyvarsIn(snd(snd(type)),NIL);
2216 List fds = calcFunDeps(ps);
2218 tvts = oclose(fds,tvts); /* Close tvts under fds */
2219 return !osubset(tvps,tvts);
2224 List calcFunDeps(ps)
2227 for (; nonNull(ps); ps=tl(ps)) {/* Calc functional dependencies */
2229 Cell c = getHead(pi);
2231 List xfs = cclass(c).xfds;
2232 for (; nonNull(xfs); xfs=tl(xfs)) {
2233 List fs = snd(hd(xfs));
2234 for (; nonNull(fs); fs=tl(fs)) {
2235 fds = cons(pair(otvars(pi,fst(hd(fs))),
2236 otvars(pi,snd(hd(fs)))),fds);
2242 fds = cons(pair(NIL,offsetTyvarsIn(arg(pi),NIL)),fds);
2249 List calcFunDepsPreds(ps)
2252 for (; nonNull(ps); ps=tl(ps)) {/* Calc functional dependencies */
2254 Cell pi = fst3(pi3);
2255 Cell c = getHead(pi);
2256 Int o = intOf(snd3(pi3));
2258 List xfs = cclass(c).xfds;
2259 for (; nonNull(xfs); xfs=tl(xfs)) {
2260 List fs = snd(hd(xfs));
2261 for (; nonNull(fs); fs=tl(fs)) {
2262 fds = cons(pair(otvarsZonk(pi,fst(hd(fs)),o),
2263 otvarsZonk(pi,snd(hd(fs)),o)),fds);
2269 fds = cons(pair(NIL,zonkTyvarsIn(arg(pi),NIL)),fds);
2276 Void ambigError(line,where,e,type) /* produce error message for */
2277 Int line; /* ambiguity */
2281 ERRMSG(line) "Ambiguous type signature in %s", where ETHEN
2282 ERRTEXT "\n*** ambiguous type : " ETHEN ERRTYPE(type);
2284 ERRTEXT "\n*** assigned to : " ETHEN ERREXPR(e);
2290 /* --------------------------------------------------------------------------
2291 * Kind inference for simple types:
2292 * ------------------------------------------------------------------------*/
2294 static Void local kindConstr(line,alpha,m,c)
2295 Int line; /* Determine kind of constructor */
2299 Cell h = getHead(c);
2303 Printf("kindConstr: alpha=%d, m=%d, c=",alpha,m);
2304 printType(stdout,c);
2308 switch (whatIs(h)) {
2309 case POLYTYPE : if (n!=0) {
2310 internal("kindConstr1");
2312 static String pt = "polymorphic type";
2313 Type t = dropRank1(c,alpha,m);
2314 Kinds ks = polySigOf(t);
2317 for (; isAp(ks); ks=tl(ks)) {
2320 beta = newKindvars(m1);
2321 unkindTypes = cons(pair(mkInt(beta),t),unkindTypes);
2322 checkKind(line,beta,m1,monotypeOf(t),NIL,pt,STAR,0);
2327 case QUAL : if (n!=0) {
2328 internal("kindConstr2");
2330 map3Proc(kindPred,line,alpha,m,fst(snd(c)));
2331 kindConstr(line,alpha,m,snd(snd(c)));
2335 case RANK2 : kindConstr(line,alpha,m,snd(snd(c)));
2339 case EXT : if (n!=2) {
2341 "Illegal use of row in " ETHEN ERRTYPE(c);
2348 case TYCON : if (isSynonym(h) && n<tycon(h).arity) {
2350 "Not enough arguments for type synonym \"%s\"",
2351 textToStr(tycon(h).text)
2357 if (n==0) { /* trivial case, no arguments */
2358 typeIs = kindAtom(alpha,c);
2359 } else { /* non-trivial application */
2360 static String app = "constructor application";
2370 typeIs = kindAtom(alpha,h); /* h :: v1 -> ... -> vn -> w */
2371 shouldKind(line,h,c,app,k,beta);
2373 for (i=n; i>0; --i) { /* ci :: vi for each 1 <- 1..n */
2374 checkKind(line,alpha,m,arg(a),c,app,aVar,beta+i-1);
2377 tyvarType(beta+n); /* inferred kind is w */
2381 static Kind local kindAtom(alpha,c) /* Find kind of atomic constructor */
2384 switch (whatIs(c)) {
2385 case TUPLE : return simpleKind(tupleOf(c)); /*(,)::* -> * -> * */
2386 case OFFSET : return mkInt(alpha+offsetOf(c));
2387 case TYCON : return tycon(c).kind;
2388 case INTCELL : return c;
2390 case VAROPCELL : { Cell vt = findBtyvs(textOf(c));
2396 case EXT : return extKind;
2400 Printf("kindAtom(%d,whatIs(%d)) on ",alpha,whatIs(c));
2401 printType(stdout,c);
2404 internal("kindAtom");
2405 return STAR;/* not reached */
2408 static Void local kindPred(l,alpha,m,pi)/* Check kinds of arguments in pred*/
2414 if (isAp(pi) && isExt(fun(pi))) {
2415 static String lackspred = "lacks predicate";
2416 checkKind(l,alpha,m,arg(pi),NIL,lackspred,ROW,0);
2421 if (isAp(pi) && whatIs(fun(pi)) == IPCELL) {
2422 static String ippred = "iparam predicate";
2423 checkKind(l,alpha,m,arg(pi),NIL,ippred,STAR,0);
2427 { static String predicate = "class constraint";
2428 Class c = getHead(pi);
2429 List as = getArgs(pi);
2430 Kinds ks = cclass(c).kinds;
2432 while (nonNull(ks)) {
2433 checkKind(l,alpha,m,hd(as),NIL,predicate,hd(ks),0);
2440 static Void local kindType(line,wh,type)/* check that (poss qualified) type*/
2441 Int line; /* is well-kinded */
2444 checkKind(line,0,0,type,NIL,wh,STAR,0);
2447 static Void local fixKinds() { /* add kind annotations to types */
2448 for (; nonNull(unkindTypes); unkindTypes=tl(unkindTypes)) {
2449 Pair pr = hd(unkindTypes);
2450 Int beta = intOf(fst(pr));
2451 Cell qts = polySigOf(snd(pr));
2453 if (isNull(hd(qts))) {
2454 hd(qts) = copyKindvar(beta++);
2456 internal("fixKinds");
2458 if (nonNull(tl(qts))) {
2466 Printf("Type expression: ");
2467 printType(stdout,snd(pr));
2469 printKind(stdout,polySigOf(snd(pr)));
2475 /* --------------------------------------------------------------------------
2476 * Kind checking of groups of type constructors and classes:
2477 * ------------------------------------------------------------------------*/
2479 static Void local kindTCGroup(tcs) /* find kinds for mutually rec. gp */
2480 List tcs; { /* of tycons and classes */
2481 emptySubstitution();
2483 mapProc(initTCKind,tcs);
2484 mapProc(kindTC,tcs);
2487 emptySubstitution();
2490 static Void local initTCKind(c) /* build initial kind/arity for c */
2492 if (isTycon(c)) { /* Initial kind of tycon is: */
2493 Int beta = newKindvars(1); /* v1 -> ... -> vn -> vn+1 */
2494 varKind(tycon(c).arity); /* where n is the arity of c. */
2495 bindTv(beta,typeIs,typeOff); /* For data definitions, vn+1 == * */
2496 switch (whatIs(tycon(c).what)) {
2498 case DATATYPE : bindTv(typeOff+tycon(c).arity,STAR,0);
2500 tycon(c).kind = mkInt(beta);
2502 Int n = cclass(c).arity;
2503 Int beta = newKindvars(n);
2504 cclass(c).kinds = NIL;
2507 cclass(c).kinds = pair(mkInt(beta+n),cclass(c).kinds);
2512 static Void local kindTC(c) /* check each part of a tycon/class*/
2513 Cell c; { /* is well-kinded */
2515 static String cfun = "constructor function";
2516 static String tsyn = "synonym definition";
2517 Int line = tycon(c).line;
2518 Int beta = tyvar(intOf(tycon(c).kind))->offs;
2519 Int m = tycon(c).arity;
2520 switch (whatIs(tycon(c).what)) {
2522 case DATATYPE : { List cs = tycon(c).defn;
2523 if (isQualType(cs)) {
2524 map3Proc(kindPred,line,beta,m,
2526 tycon(c).defn = cs = snd(snd(cs));
2528 for (; hasCfun(cs); cs=tl(cs)) {
2529 kindType(line,cfun,name(hd(cs)).type);
2534 default : checkKind(line,beta,m,tycon(c).defn,NIL,
2538 else { /* scan type exprs in class defn to*/
2539 List ms = fst(cclass(c).members);
2540 Int m = cclass(c).arity; /* determine the class signature */
2541 Int beta = newKindvars(m);
2542 kindPred(cclass(c).line,beta,m,cclass(c).head);
2543 map3Proc(kindPred,cclass(c).line,beta,m,cclass(c).supers);
2544 for (; nonNull(ms); ms=tl(ms)) {
2545 Int line = intOf(fst3(hd(ms)));
2546 Type type = thd3(hd(ms));
2547 kindType(line,"member function type signature",type);
2552 static Void local genTC(c) /* generalise kind inferred for */
2553 Cell c; { /* given tycon/class */
2555 tycon(c).kind = copyKindvar(intOf(tycon(c).kind));
2557 Printf("%s :: ",textToStr(tycon(c).text));
2558 printKind(stdout,tycon(c).kind);
2562 Kinds ks = cclass(c).kinds;
2563 for (; nonNull(ks); ks=tl(ks)) {
2564 hd(ks) = copyKindvar(intOf(hd(ks)));
2567 Printf("%s :: ",textToStr(cclass(c).text));
2568 printKinds(stdout,cclass(c).kinds);
2574 /* --------------------------------------------------------------------------
2575 * Static analysis of instance declarations:
2577 * The first part of the static analysis is performed as the declarations
2578 * are read during parsing:
2579 * - make new entry in instance table
2580 * - record line number of declaration
2581 * - build list of instances defined in current script for use in later
2582 * stages of static analysis.
2583 * ------------------------------------------------------------------------*/
2585 Void instDefn(line,head,ms) /* process new instance definition */
2586 Int line; /* definition line number */
2587 Cell head; /* inst header :: (context,Class) */
2588 List ms; { /* instance members */
2589 Inst nw = newInst();
2590 inst(nw).line = line;
2591 inst(nw).specifics = fst(head);
2592 inst(nw).head = snd(head);
2593 inst(nw).implements = ms;
2594 instDefns = cons(nw,instDefns);
2597 /* --------------------------------------------------------------------------
2598 * Further static analysis of instance declarations:
2600 * Makes the following checks:
2601 * - Class part of header has form C (T a1 ... an) where C is a known
2602 * class, and T is a known datatype constructor (or restricted synonym),
2603 * and there is no previous C-T instance, and (T a1 ... an) has a kind
2604 * appropriate for the class C.
2605 * - Each element of context is a valid class expression, with type vars
2606 * drawn from a1, ..., an.
2607 * - All bindings are function bindings
2608 * - All bindings define member functions for class C
2609 * - Arrange bindings into appropriate order for member list
2610 * - No top level type signature declarations
2611 * ------------------------------------------------------------------------*/
2613 Bool allowOverlap = FALSE; /* TRUE => allow overlapping insts */
2614 Name nameListMonad = NIL; /* builder function for List Monad */
2616 static Void local checkInstDefn(in) /* Validate instance declaration */
2618 Int line = inst(in).line;
2619 List tyvars = typeVarsIn(inst(in).head,NIL,NIL,NIL);
2620 List tvps = NIL, tvts = NIL;
2623 if (haskell98) { /* Check for `simple' type */
2625 Cell t = arg(inst(in).head);
2626 for (; isAp(t); t=fun(t)) {
2627 if (!isVar(arg(t))) {
2629 "syntax error in instance head (variable expected)"
2632 if (varIsMember(textOf(arg(t)),tvs)) {
2633 ERRMSG(line) "repeated type variable \"%s\" in instance head",
2634 textToStr(textOf(arg(t)))
2637 tvs = cons(arg(t),tvs);
2641 "syntax error in instance head (constructor expected)"
2646 /* add in the tyvars from the `specifics' so that we don't
2647 prematurely complain about undefined tyvars */
2648 tyvars = typeVarsIn(inst(in).specifics,NIL,NIL,tyvars);
2649 inst(in).head = depPredExp(line,tyvars,inst(in).head);
2652 Type h = getHead(arg(inst(in).head));
2654 ERRMSG(line) "Cannot use type synonym in instance head"
2659 map2Over(depPredExp,line,tyvars,inst(in).specifics);
2661 /* OK, now we start over, and test for ambiguity */
2662 tvts = offsetTyvarsIn(inst(in).head,NIL);
2663 tvps = offsetTyvarsIn(inst(in).specifics,NIL);
2664 fds = calcFunDeps(inst(in).specifics);
2665 tvts = oclose(fds,tvts);
2666 tvts = odiff(tvps,tvts);
2667 if (!isNull(tvts)) {
2668 ERRMSG(line) "Undefined type variable \"%s\"",
2669 textToStr(textOf(nth(offsetOf(hd(tvts)),tyvars)))
2673 h98CheckCtxt(line,"instance definition",FALSE,inst(in).specifics,NIL);
2674 inst(in).numSpecifics = length(inst(in).specifics);
2675 inst(in).c = getHead(inst(in).head);
2676 if (!isClass(inst(in).c)) {
2677 ERRMSG(line) "Illegal predicate in instance declaration"
2681 if (nonNull(cclass(inst(in).c).fds)) {
2682 List fds = cclass(inst(in).c).fds;
2683 for (; nonNull(fds); fds=tl(fds)) {
2684 List as = otvars(inst(in).head, fst(hd(fds)));
2685 List bs = otvars(inst(in).head, snd(hd(fds)));
2686 List fs = calcFunDeps(inst(in).specifics);
2688 if (!osubset(bs,as)) {
2689 ERRMSG(inst(in).line)
2690 "Instance is more general than a dependency allows"
2692 ERRTEXT "\n*** Instance : "
2693 ETHEN ERRPRED(inst(in).head);
2694 ERRTEXT "\n*** For class : "
2695 ETHEN ERRPRED(cclass(inst(in).c).head);
2696 ERRTEXT "\n*** Under dependency : "
2697 ETHEN ERRFD(hd(fds));
2704 kindInst(in,length(tyvars));
2707 if (nonNull(extractSigdecls(inst(in).implements))) {
2709 "Type signature declarations not permitted in instance declaration"
2712 if (nonNull(extractFixdecls(inst(in).implements))) {
2714 "Fixity declarations not permitted in instance declaration"
2717 inst(in).implements = classBindings("instance",
2719 extractBindings(inst(in).implements));
2720 inst(in).builder = newInstImp(in);
2721 if (!preludeLoaded && isNull(nameListMonad) && isAp(inst(in).head)
2722 && fun(inst(in).head)==classMonad && arg(inst(in).head)==typeList) {
2723 nameListMonad = inst(in).builder;
2727 static Void local insertInst(in) /* Insert instance into class */
2729 Class c = inst(in).c;
2730 List ins = cclass(c).instances;
2733 if (nonNull(cclass(c).fds)) { /* Check for conflicts with fds */
2734 List ins1 = cclass(c).instances;
2735 for (; nonNull(ins1); ins1=tl(ins1)) {
2736 List fds = cclass(c).fds;
2737 substitution(RESET);
2738 for (; nonNull(fds); fds=tl(fds)) {
2739 Int alpha = newKindedVars(inst(in).kinds);
2740 Int beta = newKindedVars(inst(hd(ins1)).kinds);
2741 List as = fst(hd(fds));
2743 for (; same && nonNull(as); as=tl(as)) {
2744 Int n = offsetOf(hd(as));
2745 same &= unify(nthArg(n,inst(in).head),alpha,
2746 nthArg(n,inst(hd(ins1)).head),beta);
2748 if (isNull(as) && same) {
2749 for (as=snd(hd(fds)); same && nonNull(as); as=tl(as)) {
2750 Int n = offsetOf(hd(as));
2751 same &= sameType(nthArg(n,inst(in).head),alpha,
2752 nthArg(n,inst(hd(ins1)).head),beta);
2755 ERRMSG(inst(in).line)
2756 "Instances are not consistent with dependencies"
2758 ERRTEXT "\n*** This instance : "
2759 ETHEN ERRPRED(inst(in).head);
2760 ERRTEXT "\n*** Conflicts with : "
2761 ETHEN ERRPRED(inst(hd(ins)).head);
2762 ERRTEXT "\n*** For class : "
2763 ETHEN ERRPRED(cclass(c).head);
2764 ERRTEXT "\n*** Under dependency : "
2765 ETHEN ERRFD(hd(fds));
2775 substitution(RESET);
2776 while (nonNull(ins)) { /* Look for overlap w/ other insts */
2777 Int alpha = newKindedVars(inst(in).kinds);
2778 Int beta = newKindedVars(inst(hd(ins)).kinds);
2779 if (unifyPred(inst(in).head,alpha,inst(hd(ins)).head,beta)) {
2780 Cell pi = copyPred(inst(in).head,alpha);
2781 if (allowOverlap && !haskell98) {
2782 Bool bef = instCompare(in,hd(ins));
2783 Bool aft = instCompare(hd(ins),in);
2784 if (bef && !aft) { /* in comes strictly before hd(ins)*/
2787 if (aft && !bef) { /* in comes strictly after hd(ins) */
2794 if (multiInstRes && nonNull(inst(in).specifics)) {
2798 ERRMSG(inst(in).line) "Overlapping instances for class \"%s\"",
2799 textToStr(cclass(c).text)
2801 ERRTEXT "\n*** This instance : " ETHEN ERRPRED(inst(in).head);
2802 ERRTEXT "\n*** Overlaps with : " ETHEN
2803 ERRPRED(inst(hd(ins)).head);
2804 ERRTEXT "\n*** Common instance : " ETHEN
2812 prev = ins; /* No overlap detected, so move on */
2813 ins = tl(ins); /* to next instance */
2815 substitution(RESET);
2817 if (nonNull(prev)) { /* Insert instance at this point */
2818 tl(prev) = cons(in,ins);
2820 cclass(c).instances = cons(in,ins);
2824 static Bool local instCompare(ia,ib) /* See if ia is an instance of ib */
2826 Int alpha = newKindedVars(inst(ia).kinds);
2827 Int beta = newKindedVars(inst(ib).kinds);
2828 return matchPred(inst(ia).head,alpha,inst(ib).head,beta);
2831 static Name local newInstImp(in) /* Make definition for inst builder*/
2833 Name b = newName(inventText(),in);
2834 name(b).line = inst(in).line;
2835 name(b).arity = inst(in).numSpecifics;
2836 name(b).number = DFUNNAME;
2840 /* --------------------------------------------------------------------------
2841 * Kind checking of instance declaration headers:
2842 * ------------------------------------------------------------------------*/
2844 static Void local kindInst(in,freedom) /* check predicates in instance */
2849 emptySubstitution();
2850 beta = newKindvars(freedom);
2851 kindPred(inst(in).line,beta,freedom,inst(in).head);
2852 if (whatIs(inst(in).specifics)!=DERIVE) {
2853 map3Proc(kindPred,inst(in).line,beta,freedom,inst(in).specifics);
2855 for (inst(in).kinds = NIL; 0<freedom--; ) {
2856 inst(in).kinds = cons(copyKindvar(beta+freedom),inst(in).kinds);
2859 Printf("instance ");
2860 printPred(stdout,inst(in).head);
2862 printKinds(stdout,inst(in).kinds);
2865 emptySubstitution();
2868 /* --------------------------------------------------------------------------
2869 * Process derived instance requests:
2870 * ------------------------------------------------------------------------*/
2872 static List derivedInsts; /* list of derived instances */
2874 static Void local checkDerive(t,p,ts,ct)/* verify derived instance request */
2875 Tycon t; /* for tycon t, with explicit */
2876 List p; /* context p, component types ts */
2877 List ts; /* and named class ct */
2879 Int line = tycon(t).line;
2880 Class c = findQualClass(ct);
2882 ERRMSG(line) "Unknown class \"%s\" in derived instance",
2886 addDerInst(line,c,p,dupList(ts),t,tycon(t).arity);
2889 static Void local addDerInst(line,c,p,cts,t,a) /* Add a derived instance */
2896 Cell head = t; /* Build instance head */
2900 head = ap(head,mkOffset(i));
2906 inst(in).line = line;
2907 inst(in).head = head;
2908 inst(in).specifics = ap(DERIVE,pair(dupList(p),cts));
2909 inst(in).implements = NIL;
2910 inst(in).kinds = mkInt(a);
2911 derivedInsts = cons(in,derivedInsts);
2914 Void addTupInst(c,n) /* Request derived instance of c */
2915 Class c; /* for mkTuple(n) constructor */
2920 cts = cons(mkOffset(m),cts);
2923 addDerInst(0,c,NIL,cts,mkTuple(n),n);
2927 Inst addRecShowInst(c,e) /* Generate instance for ShowRecRow*/
2928 Class c; /* c *must* be ShowRecRow */
2930 Inst in = newInst();
2932 inst(in).head = ap(c,ap2(e,aVar,bVar));
2933 inst(in).kinds = extKind;
2934 inst(in).specifics = cons(ap(classShow,aVar),
2936 cons(ap(c,bVar),NIL)));
2937 inst(in).numSpecifics = 3;
2938 inst(in).builder = implementRecShw(extText(e),in);
2939 cclass(c).instances = appendOnto(cclass(c).instances,singleton(in));
2943 Inst addRecEqInst(c,e) /* Generate instance for EqRecRow */
2944 Class c; /* c *must* be EqRecRow */
2946 Inst in = newInst();
2948 inst(in).head = ap(c,ap2(e,aVar,bVar));
2949 inst(in).kinds = extKind;
2950 inst(in).specifics = cons(ap(classEq,aVar),
2952 cons(ap(c,bVar),NIL)));
2953 inst(in).numSpecifics = 3;
2954 inst(in).builder = implementRecEq(extText(e),in);
2955 cclass(c).instances = appendOnto(cclass(c).instances,singleton(in));
2960 /* --------------------------------------------------------------------------
2961 * Calculation of contexts for derived instances:
2963 * Allowing arbitrary types to appear in contexts makes it rather harder
2964 * to decide what the context for a derived instance should be. For
2967 * data T a = MkT [a] deriving Show,
2969 * we could have either of the following:
2971 * instance (Show [a]) => Show (T a) where ...
2972 * instance (Show a) => Show (T a) where ...
2974 * (assuming, of course, that instance (Show a) => Show [a]). For now, we
2975 * choose to reduce contexts in the hope of detecting errors at an earlier
2976 * stage---in contrast with value definitions, there is no way for a user
2977 * to provide something analogous to a `type signature' by which they might
2978 * be able to control this behaviour themselves. We eliminate tautological
2979 * predicates, but only allow predicates to appear in the final result if
2980 * they have at least one argument with a variable at its head.
2982 * In general, we have to deal with mutually recursive instance declarations.
2983 * We find a solution in the obvious way by iterating to find a fixed point.
2984 * Of course, without restrictions on the form of instance declarations, we
2985 * cannot be sure that this will always terminate!
2987 * For each instance we maintain a pair of the form DERIVE (ctxt,ps).
2988 * Ctxt is a list giving the parts of the context that have been produced
2989 * so far in the form of predicate skeletons. During the calculation of
2990 * derived instances, we attach a dummy NIL value to the end of the list
2991 * which acts as a kind of `variable': other parts of the system maintain
2992 * pointers to this variable, and use it to detect when the context has
2993 * been extended with new elements. Meanwhile, ps is a list containing
2994 * predicates (pi,o) together with (delayed) substitutions of the form
2995 * (o,xs) where o is an offset and xs is one of the context variables
2996 * described above, which may have been partially instantiated.
2997 * ------------------------------------------------------------------------*/
2999 static Bool instsChanged;
3001 static Void local deriveContexts(is) /* Calc contexts for derived insts */
3003 emptySubstitution();
3004 mapProc(initDerInst,is); /* Prepare derived instances */
3006 do { /* Main calculation of contexts */
3007 instsChanged = FALSE;
3008 mapProc(calcInstPreds,is);
3009 } while (instsChanged);
3011 mapProc(tidyDerInst,is); /* Tidy up results */
3014 static Void local initDerInst(in) /* Prepare instance for calculation*/
3015 Inst in; { /* of derived instance context */
3016 Cell spcs = inst(in).specifics;
3017 Int beta = newKindedVars(inst(in).kinds);
3018 if (whatIs(spcs)!=DERIVE) {
3019 internal("initDerInst");
3021 fst(snd(spcs)) = appendOnto(fst(snd(spcs)),singleton(NIL));
3022 for (spcs=snd(snd(spcs)); nonNull(spcs); spcs=tl(spcs)) {
3023 hd(spcs) = ap2(inst(in).c,hd(spcs),mkInt(beta));
3025 inst(in).numSpecifics = beta;
3027 #ifdef DEBUG_DERIVING
3028 Printf("initDerInst: ");
3029 printPred(stdout,inst(in).head);
3031 printContext(stdout,snd(snd(inst(in).specifics)));
3036 static Void local calcInstPreds(in) /* Calculate next approximation */
3037 Inst in; { /* of the context for a derived */
3038 List retain = NIL; /* instance */
3039 List ps = snd(snd(inst(in).specifics));
3040 List spcs = fst(snd(inst(in).specifics));
3041 Int beta = inst(in).numSpecifics;
3043 Int factor = 1+length(ps);
3045 #ifdef DEBUG_DERIVING
3046 Printf("calcInstPreds: ");
3047 printPred(stdout,inst(in).head);
3051 while (nonNull(ps)) {
3054 if (its++ >= factor*cutoff) {
3055 Cell bpi = inst(in).head;
3056 ERRMSG(inst(in).line) "\n*** Cannot derive " ETHEN ERRPRED(bpi);
3057 ERRTEXT " after %d iterations.", its-1 ETHEN
3059 "\n*** This may indicate that the problem is undecidable. However,\n"
3061 "*** you may still try to increase the cutoff limit using the -c\n"
3063 "*** option and then try again. (The current setting is -c%d)\n",
3067 if (isInt(fst(p))) { /* Delayed substitution? */
3069 for (; nonNull(hd(qs)); qs=tl(qs)) {
3070 ps = cons(pair(hd(qs),fst(p)),ps);
3072 retain = cons(pair(fst(p),qs),retain);
3075 else if (isExt(fun(fst(p)))) { /* Lacks predicate */
3076 Text l = extText(fun(fst(p)));
3077 Type t = arg(fst(p));
3078 Int o = intOf(snd(p));
3083 h = getDerefHead(t,o);
3084 while (isExt(h) && argCount==2 && l!=extText(h)) {
3087 h = getDerefHead(t,o);
3089 if (argCount==0 && isOffset(h)) {
3090 maybeAddPred(ap(fun(fun(p)),h),o,beta,spcs);
3091 } else if (argCount!=0 || h!=typeNoRow) {
3092 Cell bpi = inst(in).head;
3093 Cell pi = copyPred(fun(p),intOf(snd(p)));
3094 ERRMSG(inst(in).line) "Cannot derive " ETHEN ERRPRED(bpi);
3095 ERRTEXT " because predicate " ETHEN ERRPRED(pi);
3096 ERRTEXT " does not hold\n"
3101 else { /* Class predicate */
3103 Int o = intOf(snd(p));
3104 Inst in1 = findInstFor(pi,o);
3106 List qs = inst(in1).specifics;
3107 Int off = mkInt(typeOff);
3108 if (whatIs(qs)==DERIVE) { /* Still being derived */
3109 for (qs=fst(snd(qs)); nonNull(hd(qs)); qs=tl(qs)) {
3110 ps = cons(pair(hd(qs),off),ps);
3112 retain = cons(pair(off,qs),retain);
3113 } else { /* Previously def'd inst */
3114 for (; nonNull(qs); qs=tl(qs)) {
3115 ps = cons(pair(hd(qs),off),ps);
3118 } else { /* No matching instance */
3120 while (isAp(qi) && isOffset(getDerefHead(arg(qi),o))) {
3124 Cell bpi = inst(in).head;
3125 pi = copyPred(pi,o);
3126 ERRMSG(inst(in).line) "An instance of " ETHEN ERRPRED(pi);
3127 ERRTEXT " is required to derive " ETHEN ERRPRED(bpi);
3131 maybeAddPred(pi,o,beta,spcs);
3136 snd(snd(inst(in).specifics)) = retain;
3139 static Void local maybeAddPred(pi,o,beta,ps)
3140 Cell pi; /* Add predicate pi to the list ps,*/
3141 Int o; /* setting the instsChanged flag if*/
3142 Int beta; /* pi is not already a member and */
3143 List ps; { /* using beta to adjust vars */
3144 Cell c = getHead(pi);
3145 for (; nonNull(ps); ps=tl(ps)) {
3146 if (isNull(hd(ps))) { /* reached the `dummy' end of list?*/
3147 hd(ps) = copyAdj(pi,o,beta);
3148 tl(ps) = pair(NIL,NIL);
3149 instsChanged = TRUE;
3151 } else if (c==getHead(hd(ps)) && samePred(pi,o,hd(ps),beta)) {
3157 static Cell local copyAdj(c,o,beta) /* Copy (c,o), replacing vars with */
3158 Cell c; /* offsets relative to beta. */
3161 switch (whatIs(c)) {
3162 case AP : { Cell l = copyAdj(fst(c),o,beta);
3163 Cell r = copyAdj(snd(c),o,beta);
3167 case OFFSET : { Int vn = o+offsetOf(c);
3168 Tyvar *tyv = tyvar(vn);
3170 return copyAdj(tyv->bound,tyv->offs,beta);
3173 if (vn<0 || vn>=NUM_OFFSETS) {
3174 internal("copyAdj");
3176 return mkOffset(vn);
3182 static Void local tidyDerInst(in) /* Tidy up results of derived inst */
3183 Inst in; { /* calculations */
3184 Int o = inst(in).numSpecifics;
3185 List ps = tl(rev(fst(snd(inst(in).specifics))));
3187 copyPred(inst(in).head,o);
3188 inst(in).specifics = simpleContext(ps,o);
3189 h98CheckCtxt(inst(in).line,"derived instance",FALSE,inst(in).specifics,in);
3190 inst(in).numSpecifics = length(inst(in).specifics);
3192 #ifdef DEBUG_DERIVING
3193 Printf("Derived instance: ");
3194 printContext(stdout,inst(in).specifics);
3196 printPred(stdout,inst(in).head);
3201 /* --------------------------------------------------------------------------
3202 * Generate code for derived instances:
3203 * ------------------------------------------------------------------------*/
3205 static Void local addDerivImp(in)
3208 Type t = getHead(arg(inst(in).head));
3209 Class c = inst(in).c;
3212 } else if (c==classOrd) {
3214 } else if (c==classEnum) {
3215 imp = deriveEnum(t);
3216 } else if (c==classIx) {
3218 } else if (c==classShow) {
3219 imp = deriveShow(t);
3220 } else if (c==classRead) {
3221 imp = deriveRead(t);
3222 } else if (c==classBounded) {
3223 imp = deriveBounded(t);
3225 ERRMSG(inst(in).line) "Cannot derive instances of class \"%s\"",
3226 textToStr(cclass(inst(in).c).text)
3230 kindInst(in,intOf(inst(in).kinds));
3232 inst(in).builder = newInstImp(in);
3233 inst(in).implements = classBindings("derived instance",
3239 /* --------------------------------------------------------------------------
3240 * Default definitions; only one default definition is permitted in a
3241 * given script file. If no default is supplied, then a standard system
3242 * default will be used where necessary.
3243 * ------------------------------------------------------------------------*/
3245 Void defaultDefn(line,defs) /* Handle default types definition */
3248 if (defaultLine!=0) {
3249 ERRMSG(line) "Multiple default declarations are not permitted in" ETHEN
3250 ERRTEXT "a single script file.\n"
3253 defaultDefns = defs;
3257 static Void local checkDefaultDefns() { /* check that default types are */
3258 List ds = NIL; /* well-kinded instances of Num */
3260 if (defaultLine!=0) {
3261 map2Over(depTypeExp,defaultLine,NIL,defaultDefns);
3262 emptySubstitution();
3264 map2Proc(kindType,defaultLine,"default type",defaultDefns);
3266 emptySubstitution();
3267 mapOver(fullExpand,defaultDefns);
3269 defaultDefns = stdDefaults;
3272 if (isNull(classNum)) {
3273 classNum = findClass(findText("Num"));
3276 for (ds=defaultDefns; nonNull(ds); ds=tl(ds)) {
3277 if (isNull(provePred(NIL,NIL,ap(classNum,hd(ds))))) {
3279 "Default types must be instances of the Num class"
3286 /* --------------------------------------------------------------------------
3287 * Foreign import declarations are Hugs' equivalent of GHC's ccall mechanism.
3288 * They are used to "import" C functions into a module.
3289 * They are usually not written by hand but, rather, generated automatically
3290 * by GreenCard, IDL compilers or whatever. We support foreign import
3291 * (static) and foreign import dynamic. In the latter case, extName==NIL.
3293 * Foreign export declarations generate C wrappers for Hugs functions.
3294 * Hugs only provides "foreign export dynamic" because it's not obvious
3295 * what "foreign export static" would mean in an interactive setting.
3296 * ------------------------------------------------------------------------*/
3298 Void foreignImport(line,callconv,extName,intName,type)
3299 /* Handle foreign imports */
3305 Text t = textOf(intName);
3306 Name n = findName(t);
3307 Int l = intOf(line);
3311 } else if (name(n).defn!=PREDEFINED) {
3312 ERRMSG(l) "Redeclaration of foreign \"%s\"", textToStr(t)
3316 name(n).defn = extName;
3317 name(n).type = type;
3318 name(n).callconv = callconv;
3319 foreignImports = cons(n,foreignImports);
3322 static Void local checkForeignImport(p) /* Check foreign import */
3324 emptySubstitution();
3325 name(p).type = checkSigType(name(p).line,
3326 "foreign import declaration",
3329 /* We don't expand synonyms here because we don't want the IO
3330 * part to be expanded.
3331 * name(p).type = fullExpand(name(p).type);
3333 implementForeignImport(p);
3336 Void foreignExport(line,callconv,extName,intName,type)
3337 /* Handle foreign exports */
3343 Text t = textOf(intName);
3344 Name n = findName(t);
3345 Int l = intOf(line);
3349 } else if (name(n).defn!=PREDEFINED) {
3350 ERRMSG(l) "Redeclaration of foreign \"%s\"", textToStr(t)
3354 name(n).defn = NIL; /* nothing to say */
3355 name(n).type = type;
3356 name(n).callconv = callconv;
3357 foreignExports = cons(n,foreignExports);
3360 static Void local checkForeignExport(p) /* Check foreign export */
3362 emptySubstitution();
3363 name(p).type = checkSigType(name(p).line,
3364 "foreign export declaration",
3367 implementForeignExport(p);
3372 /* --------------------------------------------------------------------------
3373 * Static analysis of patterns:
3375 * Patterns are parsed as ordinary (atomic) expressions. Static analysis
3376 * makes the following checks:
3377 * - Patterns are well formed (according to pattern syntax), including the
3378 * special case of (n+k) patterns.
3379 * - All constructor functions have been defined and are used with the
3380 * correct number of arguments.
3381 * - No variable name is used more than once in a pattern.
3383 * The list of pattern variables occuring in each pattern is accumulated in
3384 * a global list `patVars', which must be initialised to NIL at appropriate
3385 * points before using these routines to check for valid patterns. This
3386 * mechanism enables the pattern checking routine to be mapped over a list
3387 * of patterns, ensuring that no variable occurs more than once in the
3388 * complete pattern list (as is required on the lhs of a function defn).
3389 * ------------------------------------------------------------------------*/
3391 static List patVars; /* List of vars bound in pattern */
3393 static Cell local checkPat(line,p) /* Check valid pattern syntax */
3396 switch (whatIs(p)) {
3398 case VAROPCELL : addToPatVars(line,p);
3401 case INFIX : return checkPat(line,tidyInfix(line,snd(p)));
3403 case AP : return checkMaybeCnkPat(line,p);
3408 case CONOPCELL : return checkApPat(line,0,p);
3413 case FLOATCELL : break;
3414 case INTCELL : break;
3416 case ASPAT : addToPatVars(line,fst(snd(p)));
3417 snd(snd(p)) = checkPat(line,snd(snd(p)));
3420 case LAZYPAT : snd(p) = checkPat(line,snd(p));
3423 case FINLIST : map1Over(checkPat,line,snd(p));
3426 case CONFLDS : depConFlds(line,p,TRUE);
3429 case ESIGN : snd(snd(p)) = checkPatType(line,
3433 fst(snd(p)) = checkPat(line,fst(snd(p)));
3436 default : ERRMSG(line) "Illegal pattern syntax"
3442 static Cell local checkMaybeCnkPat(l,p)/* Check applicative pattern with */
3443 Int l; /* the possibility of n+k pattern */
3445 Cell h = getHead(p);
3447 if (argCount==2 && isVar(h) && textOf(h)==textPlus) { /* n+k */
3448 Cell v = arg(fun(p));
3449 if (!isInt(arg(p))) {
3450 ERRMSG(l) "Second argument in (n+k) pattern must be an integer"
3453 if (intOf(arg(p))<=0) {
3454 ERRMSG(l) "Integer k in (n+k) pattern must be > 0"
3457 fst(fun(p)) = ADDPAT;
3458 intValOf(fun(p)) = intOf(arg(p));
3459 arg(p) = checkPat(l,v);
3462 return checkApPat(l,0,p);
3465 static Cell local checkApPat(line,args,p)
3466 Int line; /* check validity of application */
3467 Int args; /* of constructor to arguments */
3469 switch (whatIs(p)) {
3470 case AP : fun(p) = checkApPat(line,args+1,fun(p));
3471 arg(p) = checkPat(line,arg(p));
3474 case TUPLE : if (tupleOf(p)!=args) {
3475 ERRMSG(line) "Illegal tuple pattern"
3481 case EXT : h98DoesntSupport(line,"extensible records");
3483 ERRMSG(line) "Illegal record pattern"
3489 case QUALIDENT : if (!isQCon(p)) {
3491 "Illegal use of qualified variable in pattern"
3494 /* deliberate fall through */
3496 case CONOPCELL : p = conDefined(line,p);
3497 checkCfunArgs(line,p,args);
3500 case NAME : checkIsCfun(line,p);
3501 checkCfunArgs(line,p,args);
3504 default : ERRMSG(line) "Illegal pattern syntax"
3510 static Void local addToPatVars(line,v) /* Add variable v to list of vars */
3511 Int line; /* in current pattern, checking */
3512 Cell v; { /* for repeated variables. */
3517 for (; nonNull(n); p=n, n=tl(n)) {
3518 if (textOf(hd(n))==t) {
3519 ERRMSG(line) "Repeated variable \"%s\" in pattern",
3526 patVars = cons(v,NIL);
3528 tl(p) = cons(v,NIL);
3532 static Name local conDefined(line,nm) /* check that nm is the name of a */
3533 Int line; /* previously defined constructor */
3534 Cell nm; { /* function. */
3535 Name n = findQualName(nm);
3537 ERRMSG(line) "Undefined constructor function \"%s\"", identToStr(nm)
3540 checkIsCfun(line,n);
3544 static Void local checkIsCfun(line,c) /* Check that c is a constructor fn */
3548 ERRMSG(line) "\"%s\" is not a constructor function",
3549 textToStr(name(c).text)
3554 static Void local checkCfunArgs(line,c,args)
3555 Int line; /* Check constructor applied with */
3556 Cell c; /* correct number of arguments */
3558 Int a = userArity(c);
3561 "Constructor \"%s\" must have exactly %d argument%s in pattern",
3562 textToStr(name(c).text), a, ((a==1)?"":"s")
3567 static Cell local checkPatType(l,wh,e,t)/* Check type appearing in pattern */
3572 List tvs = typeVarsIn(t,NIL,NIL,NIL);
3573 h98DoesntSupport(l,"pattern type annotations");
3574 for (; nonNull(tvs); tvs=tl(tvs)) {
3575 Int beta = newKindvars(1);
3576 hd(btyvars) = cons(pair(hd(tvs),mkInt(beta)), hd(btyvars));
3578 t = checkSigType(l,"pattern type",e,t);
3579 if (isPolyOrQualType(t) || whatIs(t)==RANK2) {
3580 ERRMSG(l) "Illegal syntax in %s type annotation", wh
3586 static Cell local applyBtyvs(pat) /* Record bound type vars in pat */
3588 List bts = hd(btyvars);
3591 pat = ap(BIGLAM,pair(bts,pat));
3592 for (; nonNull(bts); bts=tl(bts)) {
3593 snd(hd(bts)) = copyKindvar(intOf(snd(hd(bts))));
3599 /* --------------------------------------------------------------------------
3600 * Maintaining lists of bound variables and local definitions, for
3601 * dependency and scope analysis.
3602 * ------------------------------------------------------------------------*/
3604 static List bounds; /* list of lists of bound vars */
3605 static List bindings; /* list of lists of binds in scope */
3606 static List depends; /* list of lists of dependents */
3608 /* bounds :: [[Var]] -- var equality used on Vars */
3609 /* bindings :: [[([Var],?)]] -- var equality used on Vars */
3610 /* depends :: [[Var]] -- pointer equality used on Vars */
3612 #define saveBvars() hd(bounds) /* list of bvars in current scope */
3613 #define restoreBvars(bs) hd(bounds)=bs /* restore list of bound variables */
3615 static Cell local bindPat(line,p) /* add new bound vars for pattern */
3619 p = checkPat(line,p);
3620 hd(bounds) = revOnto(patVars,hd(bounds));
3624 static Void local bindPats(line,ps) /* add new bound vars for patterns */
3628 map1Over(checkPat,line,ps);
3629 hd(bounds) = revOnto(patVars,hd(bounds));
3632 /* --------------------------------------------------------------------------
3633 * Before processing value and type signature declarations, all data and
3634 * type definitions have been processed so that:
3635 * - all valid type constructors (with their arities) are known.
3636 * - all valid constructor functions (with their arities and types) are
3639 * The result of parsing a list of value declarations is a list of Eqns:
3640 * Eqn ::= (SIGDECL,(Line,[Var],type))
3641 * | (FIXDECL,(Line,[Op],SyntaxInt))
3643 * The ordering of the equations in this list is the reverse of the original
3644 * ordering in the script parsed. This is a consequence of the structure of
3645 * the parser ... but also turns out to be most convenient for the static
3648 * As the first stage of the static analysis of value declarations, each
3649 * list of Eqns is converted to a list of Bindings. As part of this
3651 * - The ordering of the list of Bindings produced is the same as in the
3653 * - When a variable (function) is defined over a number of lines, all
3654 * of the definitions should appear together and each should give the
3655 * same arity to the variable being defined.
3656 * - No variable can have more than one definition.
3657 * - For pattern bindings:
3658 * - Each lhs is a valid pattern/function lhs, all constructor functions
3659 * have been defined and are used with the correct number of arguments.
3660 * - Each lhs contains no repeated pattern variables.
3661 * - Each equation defines at least one variable (e.g. True = False is
3663 * - Types appearing in type signatures are well formed:
3664 * - Type constructors used are defined and used with correct number
3666 * - type variables are replaced by offsets, type constructor names
3668 * - Every variable named in a type signature declaration is defined by
3669 * one or more equations elsewhere in the script.
3670 * - No variable has more than one type declaration.
3671 * - Similar properties for fixity declarations.
3673 * ------------------------------------------------------------------------*/
3675 #define bindingAttr(b) fst(snd(b)) /* type(s)/fixity(ies) for binding */
3676 #define fbindAlts(b) snd(snd(b)) /* alternatives for function binding*/
3678 static List local extractSigdecls(es) /* Extract the SIGDECLS from list */
3679 List es; { /* of equations */
3680 List sigdecls = NIL; /* :: [(Line,[Var],Type)] */
3682 for(; nonNull(es); es=tl(es)) {
3683 if (fst(hd(es))==SIGDECL) { /* type-declaration? */
3684 Pair sig = snd(hd(es));
3685 Int line = intOf(fst3(sig));
3686 List vs = snd3(sig);
3687 for(; nonNull(vs); vs=tl(vs)) {
3688 if (isQualIdent(hd(vs))) {
3689 ERRMSG(line) "Type signature for qualified variable \"%s\" is not allowed",
3694 sigdecls = cons(sig,sigdecls); /* discard SIGDECL tag*/
3700 static List local extractFixdecls(es) /* Extract the FIXDECLS from list */
3701 List es; { /* of equations */
3702 List fixdecls = NIL; /* :: [(Line,SyntaxInt,[Op])] */
3704 for(; nonNull(es); es=tl(es)) {
3705 if (fst(hd(es))==FIXDECL) { /* fixity declaration?*/
3706 fixdecls = cons(snd(hd(es)),fixdecls); /* discard FIXDECL tag*/
3712 static List local extractBindings(ds) /* extract untyped bindings from */
3713 List ds; { /* given list of equations */
3714 Cell lastVar = NIL; /* = var def'd in last eqn (if any)*/
3715 Int lastArity = 0; /* = number of args in last defn */
3716 List bs = NIL; /* :: [Binding] */
3718 for(; nonNull(ds); ds=tl(ds)) {
3720 if (fst(d)==FUNBIND) { /* Function bindings */
3721 Cell rhs = snd(snd(d));
3722 Int line = rhsLine(rhs);
3723 Cell lhs = fst(snd(d));
3724 Cell v = getHead(lhs);
3725 Cell newAlt = pair(getArgs(lhs),rhs);
3727 internal("FUNBIND");
3729 if (nonNull(lastVar) && textOf(v)==textOf(lastVar)) {
3730 if (argCount!=lastArity) {
3731 ERRMSG(line) "Equations give different arities for \"%s\"",
3732 textToStr(textOf(v))
3735 fbindAlts(hd(bs)) = cons(newAlt,fbindAlts(hd(bs)));
3739 lastArity = argCount;
3740 notDefined(line,bs,v);
3741 bs = cons(pair(v,pair(NIL,singleton(newAlt))),bs);
3744 } else if (fst(d)==PATBIND) { /* Pattern bindings */
3745 Cell rhs = snd(snd(d));
3746 Int line = rhsLine(rhs);
3747 Cell pat = fst(snd(d));
3748 while (whatIs(pat)==ESIGN) {/* Move type annotations to rhs */
3749 Cell p = fst(snd(pat));
3750 fst(snd(pat)) = rhs;
3751 snd(snd(d)) = rhs = pat;
3752 fst(snd(d)) = pat = p;
3755 if (isVar(pat)) { /* Convert simple pattern bind to */
3756 notDefined(line,bs,pat);/* a function binding */
3757 bs = cons(pair(pat,pair(NIL,singleton(pair(NIL,rhs)))),bs);
3759 List vs = getPatVars(line,pat,NIL);
3761 ERRMSG(line) "No variables defined in lhs pattern"
3764 map2Proc(notDefined,line,bs,vs);
3765 bs = cons(pair(vs,pair(NIL,snd(d))),bs);
3773 static List local getPatVars(line,p,vs) /* Find list of variables bound in */
3774 Int line; /* pattern p */
3777 switch (whatIs(p)) {
3779 vs = getPatVars(line,arg(p),vs);
3782 return vs; /* Ignore head of application */
3784 case CONFLDS : { List pfs = snd(snd(p));
3785 for (; nonNull(pfs); pfs=tl(pfs)) {
3786 if (isVar(hd(pfs))) {
3787 vs = addPatVar(line,hd(pfs),vs);
3789 vs = getPatVars(line,snd(hd(pfs)),vs);
3795 case FINLIST : { List ps = snd(p);
3796 for (; nonNull(ps); ps=tl(ps)) {
3797 vs = getPatVars(line,hd(ps),vs);
3802 case ESIGN : return getPatVars(line,fst(snd(p)),vs);
3807 case INFIX : return getPatVars(line,snd(p),vs);
3809 case ASPAT : return addPatVar(line,fst(snd(p)),
3810 getPatVars(line,snd(snd(p)),vs));
3813 case VAROPCELL : return addPatVar(line,p,vs);
3823 case WILDCARD : return vs;
3825 default : internal("getPatVars");
3830 static List local addPatVar(line,v,vs) /* Add var to list of previously */
3831 Int line; /* encountered variables */
3834 if (varIsMember(textOf(v),vs)) {
3835 ERRMSG(line) "Repeated use of variable \"%s\" in pattern binding",
3836 textToStr(textOf(v))
3842 static List local eqnsToBindings(es,ts,cs,ps)
3843 List es; /* Convert list of equations to */
3844 List ts; /* list of typed bindings */
3847 List bs = extractBindings(es);
3848 map1Proc(addSigdecl,bs,extractSigdecls(es));
3849 map4Proc(addFixdecl,bs,ts,cs,ps,extractFixdecls(es));
3853 static Void local notDefined(line,bs,v)/* check if name already defined in */
3854 Int line; /* list of bindings */
3857 if (nonNull(findBinding(textOf(v),bs))) {
3858 ERRMSG(line) "\"%s\" multiply defined", textToStr(textOf(v))
3863 static Cell local findBinding(t,bs) /* look for binding for variable t */
3864 Text t; /* in list of bindings bs */
3866 for (; nonNull(bs); bs=tl(bs)) {
3867 if (isVar(fst(hd(bs)))) { /* function-binding? */
3868 if (textOf(fst(hd(bs)))==t) {
3871 } else if (nonNull(varIsMember(t,fst(hd(bs))))){/* pattern-binding?*/
3878 static Cell local getAttr(bs,v) /* Locate type/fixity attribute */
3879 List bs; /* for variable v in bindings bs */
3882 Cell b = findBinding(t,bs);
3884 if (isNull(b)) { /* No binding */
3886 } else if (isVar(fst(b))) { /* func binding? */
3887 if (isNull(bindingAttr(b))) {
3888 bindingAttr(b) = pair(NIL,NIL);
3890 return bindingAttr(b);
3891 } else { /* pat binding? */
3893 List as = bindingAttr(b);
3896 bindingAttr(b) = as = replicate(length(vs),NIL);
3899 while (nonNull(vs) && t!=textOf(hd(vs))) {
3905 internal("getAttr");
3906 } else if (isNull(hd(as))) {
3907 hd(as) = pair(NIL,NIL);
3913 static Void local addSigdecl(bs,sigdecl)/* add type information to bindings*/
3914 List bs; /* :: [Binding] */
3915 Cell sigdecl; { /* :: (Line,[Var],Type) */
3916 Int l = intOf(fst3(sigdecl));
3917 List vs = snd3(sigdecl);
3918 Type type = checkSigType(l,"type declaration",hd(vs),thd3(sigdecl));
3920 for (; nonNull(vs); vs=tl(vs)) {
3922 Pair attr = getAttr(bs,v);
3924 ERRMSG(l) "Missing binding for variable \"%s\" in type signature",
3925 textToStr(textOf(v))
3927 } else if (nonNull(fst(attr))) {
3928 ERRMSG(l) "Repeated type signature for \"%s\"",
3929 textToStr(textOf(v))
3936 static Void local addFixdecl(bs,ts,cs,ps,fixdecl)
3942 Int line = intOf(fst3(fixdecl));
3943 List ops = snd3(fixdecl);
3944 Cell sy = thd3(fixdecl);
3946 for (; nonNull(ops); ops=tl(ops)) {
3948 Text t = textOf(op);
3949 Cell attr = getAttr(bs,op);
3950 if (nonNull(attr)) { /* Found name in binding? */
3951 if (nonNull(snd(attr))) {
3955 } else { /* Look in tycons, classes, prims */
3960 for (; isNull(n) && nonNull(ts1); ts1=tl(ts1)) { /* tycons */
3962 if (tycon(tc).what==DATATYPE || tycon(tc).what==NEWTYPE) {
3963 n = nameIsMember(t,tycon(tc).defn);
3966 for (; isNull(n) && nonNull(cs1); cs1=tl(cs1)) { /* classes */
3967 n = nameIsMember(t,cclass(hd(cs1)).members);
3969 for (; isNull(n) && nonNull(ps1); ps1=tl(ps1)) { /* prims */
3970 n = nameIsMember(t,hd(ps1));
3975 } else if (name(n).syntax!=NO_SYNTAX) {
3978 name(n).syntax = intOf(sy);
3983 static Void local dupFixity(line,t) /* Report repeated fixity decl */
3987 "Repeated fixity declaration for operator \"%s\"", textToStr(t)
3991 static Void local missFixity(line,t) /* Report missing op for fixity */
3995 "Cannot find binding for operator \"%s\" in fixity declaration",
4000 /* --------------------------------------------------------------------------
4001 * Dealing with infix operators:
4003 * Expressions involving infix operators or unary minus are parsed as
4004 * elements of the following type:
4006 * data InfixExp = Only Exp | Neg InfixExp | Infix InfixExp Op Exp
4008 * (The algorithms here do not assume that negation can be applied only once,
4009 * i.e., that - - x is a syntax error, as required by the Haskell report.
4010 * Instead, that restriction is captured by the grammar itself, given above.)
4012 * There are rules of precedence and grouping, expressed by two functions:
4014 * prec :: Op -> Int; assoc :: Op -> Assoc (Assoc = {L, N, R})
4016 * InfixExp values are rearranged accordingly when a complete expression
4017 * has been read using a simple shift-reduce parser whose result may be taken
4018 * to be a value of the following type:
4020 * data Exp = Atom Int | Negate Exp | Apply Op Exp Exp | Error String
4022 * The machine on which this parser is based can be defined as follows:
4024 * tidy :: InfixExp -> [(Op,Exp)] -> Exp
4025 * tidy (Only a) [] = a
4026 * tidy (Only a) ((o,b):ss) = tidy (Only (Apply o a b)) ss
4027 * tidy (Infix a o b) [] = tidy a [(o,b)]
4028 * tidy (Infix a o b) ((p,c):ss)
4029 * | shift o p = tidy a ((o,b):(p,c):ss)
4030 * | red o p = tidy (Infix a o (Apply p b c)) ss
4031 * | ambig o p = Error "ambiguous use of operators"
4032 * tidy (Neg e) [] = tidy (tidyNeg e) []
4033 * tidy (Neg e) ((o,b):ss)
4034 * | nshift o = tidy (Neg (underNeg o b e)) ss
4035 * | nred o = tidy (tidyNeg e) ((o,b):ss)
4036 * | nambig o = Error "illegal use of negation"
4038 * At each stage, the parser can either shift, reduce, accept, or error.
4039 * The transitions when dealing with juxtaposed operators o and p are
4040 * determined by the following rules:
4042 * shift o p = (prec o > prec p)
4043 * || (prec o == prec p && assoc o == L && assoc p == L)
4045 * red o p = (prec o < prec p)
4046 * || (prec o == prec p && assoc o == R && assoc p == R)
4048 * ambig o p = (prec o == prec p)
4049 * && (assoc o == N || assoc p == N || assoc o /= assoc p)
4051 * The transitions when dealing with juxtaposed unary minus and infix
4052 * operators are as follows. The precedence of unary minus (infixl 6) is
4053 * hardwired in to these definitions, as it is to the definitions of the
4054 * Haskell grammar in the official report.
4056 * nshift o = (prec o > 6)
4057 * nred o = (prec o < 6) || (prec o == 6 && assoc o == L)
4058 * nambig o = prec o == 6 && (assoc o == R || assoc o == N)
4060 * An InfixExp of the form (Neg e) means negate the last thing in
4061 * the InfixExp e; we can force this negation using:
4063 * tidyNeg :: OpExp -> OpExp
4064 * tidyNeg (Only e) = Only (Negate e)
4065 * tidyNeg (Infix a o b) = Infix a o (Negate b)
4066 * tidyNeg (Neg e) = tidyNeg (tidyNeg e)
4068 * On the other hand, if we want to sneak application of an infix operator
4069 * under a negation, then we use:
4071 * underNeg :: Op -> Exp -> OpExp -> OpExp
4072 * underNeg o b (Only e) = Only (Apply o e b)
4073 * underNeg o b (Neg e) = Neg (underNeg o b e)
4074 * underNeg o b (Infix e p f) = Infix e p (Apply o f b)
4076 * As a concession to efficiency, we lower the number of calls to syntaxOf
4077 * by keeping track of the values of sye, sys throughout the process. The
4078 * value APPLIC is used to indicate that the syntax value is unknown.
4079 * ------------------------------------------------------------------------*/
4081 static Cell local tidyInfix(line,e) /* Convert infixExp to Exp */
4083 Cell e; { /* :: OpExp */
4084 Cell s = NIL; /* :: [(Op,Exp)] */
4085 Syntax sye = APPLIC; /* Syntax of op in e (init unknown)*/
4086 Syntax sys = APPLIC; /* Syntax of op in s (init unknown)*/
4089 while (fst(d)!=ONLY) { /* Attach fixities to operators */
4093 fun(fun(d)) = attachFixity(line,fun(fun(d)));
4099 switch (whatIs(e)) {
4100 case ONLY : e = snd(e);
4101 while (nonNull(s)) {
4102 Cell next = arg(fun(s));
4104 fun(fun(s)) = snd(fun(fun(s)));
4110 case NEG : if (nonNull(s)) {
4111 if (sys==APPLIC) { /* calculate sys */
4112 sys = intOf(fst(fun(fun(s))));
4115 if (precOf(sys)==UMINUS_PREC && /* nambig */
4116 assocOf(sys)!=UMINUS_ASSOC) {
4118 "Ambiguous use of unary minus with \""
4119 ETHEN ERREXPR(snd(fun(fun(s))));
4124 if (precOf(sys)>UMINUS_PREC) { /* nshift */
4128 while (whatIs(e1)==NEG)
4130 arg(fun(t)) = arg(e1);
4131 fun(fun(t)) = snd(fun(fun(t)));
4138 /* Intentional fall-thru for nreduce and isNull(s) */
4140 { Cell prev = e; /* e := tidyNeg e */
4141 Cell temp = arg(prev);
4143 for (; whatIs(temp)==NEG; nneg++) {
4144 fun(prev) = nameNegate;
4148 if (isInt(arg(temp))) { /* special cases */
4149 if (nneg&1) /* for literals */
4150 arg(temp) = mkInt(-intOf(arg(temp)));
4152 else if (isFloat(arg(temp))) {
4154 arg(temp) = floatNegate(arg(temp));
4155 //mkFloat(-floatOf(arg(temp)));
4158 fun(prev) = nameNegate;
4159 arg(prev) = arg(temp);
4166 default : if (isNull(s)) {/* Move operation onto empty stack */
4167 Cell next = arg(fun(e));
4174 else { /* deal with pair of operators */
4176 if (sye==APPLIC) { /* calculate sys and sye */
4177 sye = intOf(fst(fun(fun(e))));
4180 sys = intOf(fst(fun(fun(s))));
4183 if (precOf(sye)==precOf(sys) && /* ambig */
4184 (assocOf(sye)!=assocOf(sys) ||
4185 assocOf(sye)==NON_ASS)) {
4186 ERRMSG(line) "Ambiguous use of operator \""
4187 ETHEN ERREXPR(snd(fun(fun(e))));
4188 ERRTEXT "\" with \""
4189 ETHEN ERREXPR(snd(fun(fun(s))));
4194 if (precOf(sye)>precOf(sys) || /* shift */
4195 (precOf(sye)==precOf(sys) &&
4196 assocOf(sye)==LEFT_ASS &&
4197 assocOf(sys)==LEFT_ASS)) {
4198 Cell next = arg(fun(e));
4206 Cell next = arg(fun(s));
4207 arg(fun(s)) = arg(e);
4208 fun(fun(s)) = snd(fun(fun(s)));
4219 static Pair local attachFixity(line,op) /* Attach fixity to operator in an */
4220 Int line; /* infix expression */
4222 Syntax sy = DEF_OPSYNTAX;
4224 switch (whatIs(op)) {
4226 case VARIDCELL : if ((sy=lookupSyntax(textOf(op)))==NO_SYNTAX) {
4227 Name n = findName(textOf(op));
4229 ERRMSG(line) "Undefined variable \"%s\"",
4230 textToStr(textOf(op))
4239 case CONIDCELL : sy = syntaxOf(op = conDefined(line,op));
4242 case QUALIDENT : { Name n = findQualName(op);
4248 "Undefined qualified variable \"%s\"",
4258 return pair(mkInt(sy),op); /* Pair fixity with (possibly) */
4259 /* translated operator */
4262 static Syntax local lookupSyntax(t) /* Try to find fixity for var in */
4263 Text t; { /* enclosing bindings */
4264 List bounds1 = bounds;
4265 List bindings1 = bindings;
4267 while (nonNull(bindings1)) {
4268 if (nonNull(varIsMember(t,hd(bounds1)))) {
4269 return DEF_OPSYNTAX;
4271 Cell b = findBinding(t,hd(bindings1));
4273 Cell a = fst(snd(b));
4274 if (isVar(fst(b))) { /* Function binding */
4275 if (nonNull(a) && nonNull(snd(a))) {
4276 return intOf(snd(a));
4278 } else { /* Pattern binding */
4280 while (nonNull(vs) && nonNull(a)) {
4281 if (t==textOf(hd(vs))) {
4282 if (nonNull(hd(a)) && isInt(snd(hd(a)))) {
4283 return intOf(snd(hd(a)));
4291 return DEF_OPSYNTAX;
4294 bounds1 = tl(bounds1);
4295 bindings1 = tl(bindings1);
4300 /* --------------------------------------------------------------------------
4301 * To facilitate dependency analysis, lists of bindings are temporarily
4302 * augmented with an additional field, which is used in two ways:
4303 * - to build the `adjacency lists' for the dependency graph. Represented by
4304 * a list of pointers to other bindings in the same list of bindings.
4305 * - to hold strictly positive integer values (depth first search numbers) of
4306 * elements `on the stack' during the strongly connected components search
4307 * algorithm, or a special value mkInt(0), once the binding has been added
4308 * to a particular strongly connected component.
4310 * Using this extra field, the type of each list of declarations during
4311 * dependency analysis is [Binding'] where:
4313 * Binding' ::= (Var, (Attr, (Dep, [Alt]))) -- function binding
4314 * | ([Var], ([Attr], (Dep, (Pat,Rhs)))) -- pattern binding
4316 * ------------------------------------------------------------------------*/
4318 #define depVal(d) (fst(snd(snd(d)))) /* Access to dependency information*/
4320 static List local dependencyAnal(bs) /* Separate lists of bindings into */
4321 List bs; { /* mutually recursive groups in */
4322 /* order of dependency */
4323 mapProc(addDepField,bs); /* add extra field for dependents */
4324 mapProc(depBinding,bs); /* find dependents of each binding */
4325 bs = bscc(bs); /* sort to strongly connected comps*/
4326 mapProc(remDepField,bs); /* remove dependency info field */
4330 static List local topDependAnal(bs) /* Like dependencyAnal(), but at */
4331 List bs; { /* top level, reporting on progress*/
4335 setGoal("Dependency analysis",(Target)(length(bs)));
4337 mapProc(addDepField,bs); /* add extra field for dependents */
4338 for (xs=bs; nonNull(xs); xs=tl(xs)) {
4339 emptySubstitution();
4341 soFar((Target)(i++));
4343 bs = bscc(bs); /* sort to strongly connected comps */
4344 mapProc(remDepField,bs); /* remove dependency info field */
4349 static Void local addDepField(b) /* add extra field to binding to */
4350 Cell b; { /* hold list of dependents */
4351 snd(snd(b)) = pair(NIL,snd(snd(b)));
4354 static Void local remDepField(bs) /* remove dependency field from */
4355 List bs; { /* list of bindings */
4356 mapProc(remDepField1,bs);
4359 static Void local remDepField1(b) /* remove dependency field from */
4360 Cell b; { /* single binding */
4361 snd(snd(b)) = snd(snd(snd(b)));
4364 static Void local clearScope() { /* initialise dependency scoping */
4370 static Void local withinScope(bs) /* Enter scope of bindings bs */
4372 bounds = cons(NIL,bounds);
4373 bindings = cons(bs,bindings);
4374 depends = cons(NIL,depends);
4377 static Void local leaveScope() { /* Leave scope of last withinScope */
4378 List bs = hd(bindings); /* Remove fixity info from binds */
4379 Bool toplevel = isNull(tl(bindings));
4380 for (; nonNull(bs); bs=tl(bs)) {
4382 if (isVar(fst(b))) { /* Variable binding */
4383 Cell a = fst(snd(b));
4386 saveSyntax(fst(b),snd(a));
4388 fst(snd(b)) = fst(a);
4390 } else { /* Pattern binding */
4392 List as = fst(snd(b));
4393 while (nonNull(vs) && nonNull(as)) {
4394 if (isPair(hd(as))) {
4396 saveSyntax(hd(vs),snd(hd(as)));
4398 hd(as) = fst(hd(as));
4405 bounds = tl(bounds);
4406 bindings = tl(bindings);
4407 depends = tl(depends);
4410 static Void local saveSyntax(v,sy) /* Save syntax of top-level var */
4411 Cell v; /* in corresponding Name */
4413 Name n = findName(textOf(v));
4414 if (isNull(n) || name(n).syntax!=NO_SYNTAX) {
4415 internal("saveSyntax");
4418 name(n).syntax = intOf(sy);
4422 /* --------------------------------------------------------------------------
4423 * As a side effect of the dependency analysis we also make the following
4425 * - Each lhs is a valid pattern/function lhs, all constructor functions
4426 * have been defined and are used with the correct number of arguments.
4427 * - No lhs contains repeated pattern variables.
4428 * - Expressions used on the rhs of an eqn should be well formed. This
4430 * - Checking for valid patterns (including repeated vars) in lambda,
4431 * case, and list comprehension expressions.
4432 * - Recursively checking local lists of equations.
4433 * - No free (i.e. unbound) variables are used in the declaration list.
4434 * ------------------------------------------------------------------------*/
4436 static Void local depBinding(b) /* find dependents of binding */
4438 Cell defpart = snd(snd(snd(b))); /* definition part of binding */
4442 if (isVar(fst(b))) { /* function-binding? */
4443 mapProc(depAlt,defpart);
4444 if (isNull(fst(snd(b)))) { /* Save dep info if no type sig */
4445 fst(snd(b)) = pair(ap(IMPDEPS,hd(depends)),NIL);
4446 } else if (isNull(fst(fst(snd(b))))) {
4447 fst(fst(snd(b))) = ap(IMPDEPS,hd(depends));
4449 } else { /* pattern-binding? */
4450 Int line = rhsLine(snd(defpart));
4453 fst(defpart) = checkPat(line,fst(defpart));
4454 depRhs(snd(defpart));
4456 if (nonNull(hd(btyvars))) {
4458 "Sorry, no type variables are allowed in pattern binding type annotations"
4462 fst(defpart) = applyBtyvs(fst(defpart));
4464 depVal(b) = hd(depends);
4467 static Void local depDefaults(c) /* dependency analysis on defaults */
4468 Class c; { /* from class definition */
4469 depClassBindings(cclass(c).defaults);
4472 static Void local depInsts(in) /* dependency analysis on instance */
4473 Inst in; { /* bindings */
4474 depClassBindings(inst(in).implements);
4477 static Void local depClassBindings(bs) /* dependency analysis on list of */
4478 List bs; { /* bindings, possibly containing */
4479 for (; nonNull(bs); bs=tl(bs)) { /* NIL bindings ... */
4480 if (nonNull(hd(bs))) { /* No need to add extra field for */
4481 mapProc(depAlt,snd(hd(bs)));/* dependency information... */
4486 static Void local depAlt(a) /* Find dependents of alternative */
4488 List obvs = saveBvars(); /* Save list of bound variables */
4490 bindPats(rhsLine(snd(a)),fst(a)); /* add new bound vars for patterns */
4491 depRhs(snd(a)); /* find dependents of rhs */
4492 fst(a) = applyBtyvs(fst(a));
4493 restoreBvars(obvs); /* restore original list of bvars */
4496 static Void local depRhs(r) /* Find dependents of rhs */
4498 switch (whatIs(r)) {
4499 case GUARDED : mapProc(depGuard,snd(r));
4502 case LETREC : fst(snd(r)) = eqnsToBindings(fst(snd(r)),NIL,NIL,NIL);
4503 withinScope(fst(snd(r)));
4504 fst(snd(r)) = dependencyAnal(fst(snd(r)));
4505 hd(depends) = fst(snd(r));
4506 depRhs(snd(snd(r)));
4510 case RSIGN : snd(snd(r)) = checkPatType(rhsLine(fst(snd(r))),
4512 rhsExpr(fst(snd(r))),
4514 depRhs(fst(snd(r)));
4517 default : snd(r) = depExpr(intOf(fst(r)),snd(r));
4522 static Void local depGuard(g) /* find dependents of single guarded*/
4523 Cell g; { /* expression */
4524 depPair(intOf(fst(g)),snd(g));
4527 static Cell local depExpr(line,e) /* find dependents of expression */
4530 // Printf( "\n\n"); print(e,100); Printf("\n");
4531 //printExp(stdout,e);
4532 switch (whatIs(e)) {
4535 case VAROPCELL : return depVar(line,e);
4538 case CONOPCELL : return conDefined(line,e);
4540 case QUALIDENT : if (isQVar(e)) {
4541 return depQVar(line,e);
4542 } else { /* QConOrConOp */
4543 return conDefined(line,e);
4546 case INFIX : return depExpr(line,tidyInfix(line,snd(e)));
4549 case RECSEL : break;
4551 case AP : if (isAp(e) && isAp(fun(e)) && isExt(fun(fun(e)))) {
4552 return depRecord(line,e);
4558 arg(a) = depExpr(line,arg(a));
4561 fun(a) = depExpr(line,fun(a));
4565 case AP : depPair(line,e);
4579 case INTCELL : break;
4581 case COND : depTriple(line,snd(e));
4584 case FINLIST : map1Over(depExpr,line,snd(e));
4587 case LETREC : fst(snd(e)) = eqnsToBindings(fst(snd(e)),NIL,NIL,NIL);
4588 withinScope(fst(snd(e)));
4589 fst(snd(e)) = dependencyAnal(fst(snd(e)));
4590 hd(depends) = fst(snd(e));
4591 snd(snd(e)) = depExpr(line,snd(snd(e)));
4595 case LAMBDA : depAlt(snd(e));
4598 case DOCOMP : /* fall-thru */
4599 case COMP : depComp(line,snd(e),snd(snd(e)));
4602 case ESIGN : fst(snd(e)) = depExpr(line,fst(snd(e)));
4603 snd(snd(e)) = checkSigType(line,
4609 case CASE : fst(snd(e)) = depExpr(line,fst(snd(e)));
4610 map1Proc(depCaseAlt,line,snd(snd(e)));
4613 case CONFLDS : depConFlds(line,e,FALSE);
4616 case UPDFLDS : depUpdFlds(line,e);
4620 case WITHEXP : depWith(line,e);
4624 case ASPAT : ERRMSG(line) "Illegal `@' in expression"
4627 case LAZYPAT : ERRMSG(line) "Illegal `~' in expression"
4630 case WILDCARD : ERRMSG(line) "Illegal `_' in expression"
4634 case EXT : ERRMSG(line) "Illegal application of record"
4638 default : internal("depExpr");
4643 static Void local depPair(line,e) /* find dependents of pair of exprs*/
4646 fst(e) = depExpr(line,fst(e));
4647 snd(e) = depExpr(line,snd(e));
4650 static Void local depTriple(line,e) /* find dependents of triple exprs */
4653 fst3(e) = depExpr(line,fst3(e));
4654 snd3(e) = depExpr(line,snd3(e));
4655 thd3(e) = depExpr(line,thd3(e));
4658 static Void local depComp(l,e,qs) /* find dependents of comprehension*/
4663 fst(e) = depExpr(l,fst(e));
4667 switch (whatIs(q)) {
4668 case FROMQUAL : { List obvs = saveBvars();
4669 snd(snd(q)) = depExpr(l,snd(snd(q)));
4671 fst(snd(q)) = bindPat(l,fst(snd(q)));
4673 fst(snd(q)) = applyBtyvs(fst(snd(q)));
4678 case QWHERE : snd(q) = eqnsToBindings(snd(q),NIL,NIL,NIL);
4679 withinScope(snd(q));
4680 snd(q) = dependencyAnal(snd(q));
4681 hd(depends) = snd(q);
4686 case DOQUAL : /* fall-thru */
4687 case BOOLQUAL : snd(q) = depExpr(l,snd(q));
4694 static Void local depCaseAlt(line,a) /* Find dependents of case altern. */
4697 List obvs = saveBvars(); /* Save list of bound variables */
4699 fst(a) = bindPat(line,fst(a)); /* Add new bound vars for pats */
4700 depRhs(snd(a)); /* Find dependents of rhs */
4701 fst(a) = applyBtyvs(fst(a));
4702 restoreBvars(obvs); /* Restore original list of bvars */
4705 static Cell local depVar(line,e) /* Register occurrence of variable */
4708 List bounds1 = bounds;
4709 List bindings1 = bindings;
4710 List depends1 = depends;
4714 while (nonNull(bindings1)) {
4715 n = varIsMember(t,hd(bounds1)); /* look for t in bound variables */
4719 n = findBinding(t,hd(bindings1)); /* look for t in var bindings */
4721 if (!cellIsMember(n,hd(depends1))) {
4722 hd(depends1) = cons(n,hd(depends1));
4724 return (isVar(fst(n)) ? fst(n) : e);
4727 bounds1 = tl(bounds1);
4728 bindings1 = tl(bindings1);
4729 depends1 = tl(depends1);
4732 if (isNull(n=findName(t))) { /* check global definitions */
4733 ERRMSG(line) "Undefined variable \"%s\"", textToStr(t)
4737 if (!moduleThisScript(name(n).mod)) {
4740 /* Later phases of the system cannot cope if we resolve references
4741 * to unprocessed objects too early. This is the main reason that
4742 * we cannot cope with recursive modules at the moment.
4747 static Cell local depQVar(line,e)/* register occurrence of qualified variable */
4750 Name n = findQualName(e);
4751 if (isNull(n)) { /* check global definitions */
4752 ERRMSG(line) "Undefined qualified variable \"%s\"", identToStr(e)
4755 if (name(n).mod != currentModule) {
4758 if (fst(e) == VARIDCELL) {
4759 e = mkVar(qtextOf(e));
4761 e = mkVarop(qtextOf(e));
4763 return depVar(line,e);
4766 static Void local depConFlds(line,e,isP)/* check construction using fields */
4770 Name c = conDefined(line,fst(snd(e)));
4771 if (isNull(snd(snd(e))) ||
4772 nonNull(cellIsMember(c,depFields(line,e,snd(snd(e)),isP)))) {
4775 ERRMSG(line) "Constructor \"%s\" does not have selected fields in ",
4776 textToStr(name(c).text)
4781 if (!isP && isPair(name(c).defn)) { /* Check that banged fields defined*/
4782 List scs = fst(name(c).defn); /* List of strict components */
4783 Type t = name(c).type;
4784 Int a = userArity(c);
4785 List fs = snd(snd(e));
4787 if (isPolyType(t)) { /* Find tycon that c belongs to */
4790 if (isQualType(t)) {
4793 if (whatIs(t)==CDICTS) {
4802 for (ss=tycon(t).defn; hasCfun(ss); ss=tl(ss)) {
4804 /* Now we know the tycon t that c belongs to, and the corresponding
4805 * list of selectors for that type, ss. Now we have to check that
4806 * each of the fields identified by scs appears in fs, using ss to
4807 * cross reference, and convert integers to selector names.
4809 for (; nonNull(scs); scs=tl(scs)) {
4810 Int i = intOf(hd(scs));
4812 for (; nonNull(ss1); ss1=tl(ss1)) {
4813 List cns = name(hd(ss1)).defn;
4814 for (; nonNull(cns); cns=tl(cns)) {
4815 if (fst(hd(cns))==c) {
4819 if (nonNull(cns) && intOf(snd(hd(cns)))==i) {
4824 internal("depConFlds");
4828 for (; nonNull(fs1) && s!=fst(hd(fs1)); fs1=tl(fs1)) {
4831 ERRMSG(line) "Construction does not define strict field"
4833 ERRTEXT "\nExpression : " ETHEN ERREXPR(e);
4834 ERRTEXT "\nField : " ETHEN ERREXPR(s);
4843 static Void local depUpdFlds(line,e) /* check update using fields */
4846 if (isNull(thd3(snd(e)))) {
4847 ERRMSG(line) "Empty field list in update"
4850 fst3(snd(e)) = depExpr(line,fst3(snd(e)));
4851 snd3(snd(e)) = depFields(line,e,thd3(snd(e)),FALSE);
4854 static List local depFields(l,e,fs,isP) /* check field binding list */
4862 for (; nonNull(fs); fs=tl(fs)) { /* for each field binding */
4866 if (isVar(fb)) { /* expand var to var = var */
4867 h98DoesntSupport(l,"missing field bindings");
4868 fb = hd(fs) = pair(fb,fb);
4871 s = findQualName(fst(fb)); /* check for selector */
4872 if (nonNull(s) && isSfun(s)) {
4875 ERRMSG(l) "\"%s\" is not a selector function/field name",
4876 textToStr(textOf(fst(fb)))
4880 if (isNull(ss)) { /* for first named selector */
4881 List scs = name(s).defn; /* calculate list of constructors */
4882 for (; nonNull(scs); scs=tl(scs)) {
4883 cs = cons(fst(hd(scs)),cs);
4885 ss = singleton(s); /* initialize selector list */
4886 } else { /* for subsequent selectors */
4887 List ds = cs; /* intersect constructor lists */
4888 for (cs=NIL; nonNull(ds); ) {
4889 List scs = name(s).defn;
4890 while (nonNull(scs) && fst(hd(scs))!=hd(ds)) {
4903 if (cellIsMember(s,ss)) { /* check for repeated uses */
4904 ERRMSG(l) "Repeated field name \"%s\" in field list",
4905 textToStr(name(s).text)
4911 if (isNull(cs)) { /* Are there any matching constrs? */
4912 ERRMSG(l) "No constructor has all of the fields specified in "
4918 snd(fb) = (isP ? checkPat(l,snd(fb)) : depExpr(l,snd(fb)));
4924 static Void local depWith(line,e) /* check with using fields */
4927 fst(snd(e)) = depExpr(line,fst(snd(e)));
4928 snd(snd(e)) = depDwFlds(line,e,snd(snd(e)));
4931 static List local depDwFlds(l,e,fs)/* check field binding list */
4937 for (; nonNull(c); c=tl(c)) { /* for each field binding */
4938 snd(hd(c)) = depExpr(l,snd(hd(c)));
4945 static Cell local depRecord(line,e) /* find dependents of record and */
4946 Int line; /* sort fields into approp. order */
4947 Cell e; { /* to make construction and update */
4948 List exts = NIL; /* more efficient. */
4951 h98DoesntSupport(line,"extensible records");
4952 do { /* build up list of extensions */
4953 Text t = extText(fun(fun(r)));
4954 String s = textToStr(t);
4957 while (nonNull(nx) && strcmp(textToStr(extText(fun(fun(nx)))),s)>0) {
4961 if (nonNull(nx) && t==extText(fun(fun(nx)))) {
4962 ERRMSG(line) "Repeated label \"%s\" in record ", s
4968 exts = cons(fun(r),exts);
4970 tl(prev) = cons(fun(r),nx);
4972 extField(r) = depExpr(line,extField(r));
4974 } while (isAp(r) && isAp(fun(r)) && isExt(fun(fun(r))));
4975 r = depExpr(line,r);
4976 return revOnto(exts,r);
4981 /* --------------------------------------------------------------------------
4982 * Several parts of this program require an algorithm for sorting a list
4983 * of values (with some added dependency information) into a list of strongly
4984 * connected components in which each value appears before its dependents.
4986 * Each of these algorithms is obtained by parameterising a standard
4987 * algorithm in "scc.c" as shown below.
4988 * ------------------------------------------------------------------------*/
4990 #define SCC2 tcscc /* make scc algorithm for Tycons */
4991 #define LOWLINK tclowlink
4992 #define DEPENDS(c) (isTycon(c) ? tycon(c).kind : cclass(c).kinds)
4993 #define SETDEPENDS(c,v) if(isTycon(c)) tycon(c).kind=v; else cclass(c).kinds=v
5000 #define SCC bscc /* make scc algorithm for Bindings */
5001 #define LOWLINK blowlink
5002 #define DEPENDS(t) depVal(t)
5003 #define SETDEPENDS(c,v) depVal(c)=v
5010 /* --------------------------------------------------------------------------
5011 * Main static analysis:
5012 * ------------------------------------------------------------------------*/
5014 Void checkExp() { /* Top level static check on Expr */
5015 staticAnalysis(RESET);
5016 clearScope(); /* Analyse expression in the scope */
5017 withinScope(NIL); /* of no local bindings */
5018 inputExpr = depExpr(0,inputExpr);
5020 staticAnalysis(RESET);
5023 #if EXPLAIN_INSTANCE_RESOLUTION
5024 Void checkContext(void) { /* Top level static check on Expr */
5027 staticAnalysis(RESET);
5028 clearScope(); /* Analyse expression in the scope */
5029 withinScope(NIL); /* of no local bindings */
5031 for (vs = NIL; nonNull(qs); qs=tl(qs)) {
5032 vs = typeVarsIn(hd(qs),NIL,NIL,vs);
5034 map2Proc(depPredExp,0,vs,inputContext);
5036 staticAnalysis(RESET);
5040 Void checkDefns() { /* Top level static analysis */
5041 Module thisModule = lastModule();
5042 staticAnalysis(RESET);
5044 setCurrModule(thisModule);
5046 /* Resolve module references */
5047 mapProc(checkQualImport, module(thisModule).qualImports);
5048 mapProc(checkUnqualImport,unqualImports);
5049 /* Add "import Prelude" if there`s no explicit import */
5050 if (thisModule!=modulePrelude
5051 && isNull(cellAssoc(modulePrelude,unqualImports))
5052 && isNull(cellRevAssoc(modulePrelude,module(thisModule).qualImports))) {
5053 unqualImports = cons(pair(modulePrelude,DOTDOT),unqualImports);
5055 /* Every module (including the Prelude) implicitly contains
5056 * "import qualified Prelude"
5058 module(thisModule).qualImports=cons(pair(mkCon(textPrelude),modulePrelude),
5059 module(thisModule).qualImports);
5061 mapProc(checkImportList, unqualImports);
5063 /* Note: there's a lot of side-effecting going on here, so
5064 don't monkey about with the order of operations here unless
5065 you know what you are doing */
5066 if (!combined) linkPreludeTC(); /* Get prelude tycons and classes */
5068 mapProc(checkTyconDefn,tyconDefns); /* validate tycon definitions */
5069 checkSynonyms(tyconDefns); /* check synonym definitions */
5070 mapProc(checkClassDefn,classDefns); /* process class definitions */
5071 mapProc(kindTCGroup,tcscc(tyconDefns,classDefns)); /* attach kinds */
5072 mapProc(visitClass,classDefns); /* check class hierarchy */
5073 mapProc(extendFundeps,classDefns); /* finish class definitions */
5074 /* (convenient if we do this after */
5075 /* calling `visitClass' so that we */
5076 /* know the class hierarchy is */
5079 mapProc(addMembers,classDefns); /* add definitions for member funs */
5081 if (!combined) linkPreludeCM(); /* Get prelude cfuns and mfuns */
5083 instDefns = rev(instDefns); /* process instance definitions */
5084 mapProc(checkInstDefn,instDefns);
5086 setCurrModule(thisModule);
5087 mapProc(addRSsigdecls,typeInDefns); /* add sigdecls for RESTRICTSYN */
5088 valDefns = eqnsToBindings(valDefns,tyconDefns,classDefns,/*primDefns*/NIL);
5089 mapProc(allNoPrevDef,valDefns); /* check against previous defns */
5090 mapProc(addDerivImp,derivedInsts); /* Add impls for derived instances */
5091 deriveContexts(derivedInsts); /* Calculate derived inst contexts */
5092 instDefns = appendOnto(instDefns,derivedInsts);
5093 checkDefaultDefns(); /* validate default definitions */
5095 mapProc(allNoPrevDef,valDefns); /* check against previous defns */
5097 if (!combined) linkPrimNames(); /* link primitive names */
5099 mapProc(checkForeignImport,foreignImports); /* check foreign imports */
5100 mapProc(checkForeignExport,foreignExports); /* check foreign exports */
5101 foreignImports = NIL;
5102 foreignExports = NIL;
5104 /* Every top-level name has now been created - so we can build the */
5105 /* export list. Note that this has to happen before dependency */
5106 /* analysis so that references to Prelude.foo will be resolved */
5107 /* when compiling the prelude. */
5108 module(thisModule).exports = checkExports(module(thisModule).exports);
5110 mapProc(checkTypeIn,typeInDefns); /* check restricted synonym defns */
5113 withinScope(valDefns);
5114 valDefns = topDependAnal(valDefns); /* top level dependency ordering */
5115 mapProc(depDefaults,classDefns); /* dep. analysis on class defaults */
5116 mapProc(depInsts,instDefns); /* dep. analysis on inst defns */
5119 /* ToDo: evalDefaults should match current evaluation module */
5120 evalDefaults = defaultDefns; /* Set defaults for evaluator */
5122 staticAnalysis(RESET);
5128 static Void local addRSsigdecls(pr) /* add sigdecls from TYPE ... IN ..*/
5130 List vs = snd(pr); /* get list of variables */
5131 for (; nonNull(vs); vs=tl(vs)) {
5132 if (fst(hd(vs))==SIGDECL) { /* find a sigdecl */
5133 valDefns = cons(hd(vs),valDefns); /* add to valDefns */
5134 hd(vs) = hd(snd3(snd(hd(vs)))); /* and replace with var */
5139 static Void local allNoPrevDef(b) /* ensure no previous bindings for*/
5140 Cell b; { /* variables in new binding */
5141 if (isVar(fst(b))) {
5142 noPrevDef(rhsLine(snd(hd(snd(snd(b))))),fst(b));
5144 Int line = rhsLine(snd(snd(snd(b))));
5145 map1Proc(noPrevDef,line,fst(b));
5149 static Void local noPrevDef(line,v) /* ensure no previous binding for */
5150 Int line; /* new variable */
5152 Name n = findName(textOf(v));
5155 n = newName(textOf(v),NIL);
5156 name(n).defn = PREDEFINED;
5157 } else if (name(n).defn!=PREDEFINED) {
5158 duplicateError(line,name(n).mod,name(n).text,"variable");
5160 name(n).line = line;
5163 static Void local duplicateErrorAux(line,mod,t,kind)/* report duplicate defn */
5168 if (mod == currentModule) {
5169 ERRMSG(line) "Repeated definition for %s \"%s\"", kind,
5173 ERRMSG(line) "Definition of %s \"%s\" clashes with import", kind,
5179 static Void local checkTypeIn(cvs) /* Check that vars in restricted */
5180 Pair cvs; { /* synonym are defined */
5184 for (; nonNull(vs); vs=tl(vs)) {
5185 if (isNull(findName(textOf(hd(vs))))) {
5186 ERRMSG(tycon(c).line)
5187 "No top level binding of \"%s\" for restricted synonym \"%s\"",
5188 textToStr(textOf(hd(vs))), textToStr(tycon(c).text)
5194 /* --------------------------------------------------------------------------
5195 * Haskell 98 compatibility tests:
5196 * ------------------------------------------------------------------------*/
5198 Bool h98Pred(allowArgs,pi) /* Check syntax of Hask98 predicate*/
5201 return isClass(getHead(pi)) && argCount==1 &&
5202 isOffset(getHead(arg(pi))) && (argCount==0 || allowArgs);
5205 Cell h98Context(allowArgs,ps) /* Check syntax of Hask98 context */
5208 for (; nonNull(ps); ps=tl(ps)) {
5209 if (!h98Pred(allowArgs,hd(ps))) {
5216 Void h98CheckCtxt(line,wh,allowArgs,ps,in)
5217 Int line; /* Report illegal context/predicate*/
5223 Cell pi = h98Context(allowArgs,ps);
5225 ERRMSG(line) "Illegal Haskell 98 class constraint in %s",wh ETHEN
5227 ERRTEXT "\n*** Instance : " ETHEN ERRPRED(inst(in).head);
5229 ERRTEXT "\n*** Constraint : " ETHEN ERRPRED(pi);
5230 if (nonNull(ps) && nonNull(tl(ps))) {
5231 ERRTEXT "\n*** Context : " ETHEN ERRCONTEXT(ps);
5239 Void h98CheckType(line,wh,e,t) /* Check for Haskell 98 type */
5248 if (isQualType(t)) {
5249 Cell pi = h98Context(TRUE,fst(snd(t)));
5251 ERRMSG(line) "Illegal Haskell 98 class constraint in %s",wh
5253 ERRTEXT "\n*** Expression : " ETHEN ERREXPR(e);
5254 ERRTEXT "\n*** Type : " ETHEN ERRTYPE(ty);
5262 Void h98DoesntSupport(line,wh) /* Report feature missing in H98 */
5266 ERRMSG(line) "Haskell 98 does not support %s", wh
5271 /* --------------------------------------------------------------------------
5272 * Static Analysis control:
5273 * ------------------------------------------------------------------------*/
5275 Void staticAnalysis(what)
5278 case RESET : cfunSfuns = NIL;
5291 case MARK : mark(daSccs);
5306 case POSTPREL: break;
5308 case PREPREL : staticAnalysis(RESET);
5310 extKind = pair(STAR,pair(ROW,ROW));
5315 /*-------------------------------------------------------------------------*/