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: 2000/04/07 10:00:28 $
14 * ------------------------------------------------------------------------*/
16 #include "hugsbasictypes.h"
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,Cell );
35 static List local resolveImportList ( Module,Cell );
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, Module );
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 * ------------------------------------------------------------------------*/
258 Void startModule ( Module m ) /* switch to a new module */
260 if (isNull(m)) internal("startModule");
264 Void setExportList(exps) /* Add export list to current module */
266 module(currentModule).exports = exps;
269 Void addQualImport(orig,new) /* Add to qualified import list */
270 Cell orig; /* Original name of module */
271 Cell new; { /* Name module is called within this module (or NIL) */
272 module(currentModule).qualImports =
273 cons(pair(isNull(new)?orig:new,orig),module(currentModule).qualImports);
276 Void addUnqualImport(mod,entities) /* Add to unqualified import list */
277 Cell mod; /* Name of module */
278 List entities; { /* List of entity names */
279 unqualImports = cons(pair(mod,entities),unqualImports);
282 static Void local checkQualImport(i) /* Process qualified import */
284 Module m = findModid(snd(i));
286 ERRMSG(0) "Module \"%s\" not previously loaded",
287 textToStr(textOf(snd(i)))
293 static Void local checkUnqualImport(i) /* Process unqualified import */
295 Module m = findModid(fst(i));
297 ERRMSG(0) "Module \"%s\" not previously loaded",
298 textToStr(textOf(fst(i)))
304 static Name local lookupName(t,nms) /* find text t in list of Names */
306 List nms; { /* :: [Name] */
307 for(; nonNull(nms); nms=tl(nms)) {
308 if (t == name(hd(nms)).text)
314 static List local checkSubentities(imports,named,wanted,description,textParent)
316 List named; /* :: [ Q?(Var|Con)(Id|Op) ] */
317 List wanted; /* :: [Name] */
318 String description; /* "<constructor>|<member> of <type>|<class>" */
320 for(; nonNull(named); named=tl(named)) {
322 /* ToDo: ignores qualifier; doesn't check that entity is in scope */
323 Text t = isPair(snd(x)) ? qtextOf(x) : textOf(x);
324 Name n = lookupName(t,wanted);
326 ERRMSG(0) "Entity \"%s\" is not a %s \"%s\"",
329 textToStr(textParent)
332 imports = cons(n,imports);
337 static List local checkImportEntity(imports,exporter,entity)
338 List imports; /* Accumulated list of things to import */
340 Cell entity; { /* Entry from import list */
341 List oldImports = imports;
342 Text t = isIdent(entity) ? textOf(entity) : textOf(fst(entity));
344 es = module(exporter).exports;
346 for(; nonNull(es); es=tl(es)) {
347 Cell e = hd(es); /* :: Entity
348 | (Entity, NIL|DOTDOT)
355 if (tycon(f).text == t) {
356 imports = cons(f,imports);
357 if (!isIdent(entity)) {
358 switch (tycon(f).what) {
361 if (DOTDOT == snd(entity)) {
362 imports = dupOnto(tycon(f).defn,imports);
364 imports = checkSubentities(
365 imports,snd(entity),tycon(f).defn,
366 "constructor of type",t);
370 /* deliberate fall thru */
374 } else if (isClass(f)) {
375 if (cclass(f).text == t) {
376 imports = cons(f,imports);
377 if (!isIdent(entity)) {
378 if (DOTDOT == snd(entity)) {
379 return dupOnto(cclass(f).members,imports);
381 return checkSubentities(
382 imports,snd(entity),cclass(f).members,
383 "member of class",t);
388 internal("checkImportEntity2");
390 } else if (isName(e)) {
391 if (isIdent(entity) && name(e).text == t) {
392 imports = cons(e,imports);
395 internal("checkImportEntity3");
398 if (imports == oldImports) {
399 ERRMSG(0) "Unknown entity \"%s\" imported from module \"%s\"",
401 textToStr(module(exporter ).text)
407 static List local resolveImportList(m,impList)
408 Module m; /* exporting module */
411 if (DOTDOT == impList) {
412 List es = module(m).exports;
413 for(; nonNull(es); es=tl(es)) {
416 imports = cons(e,imports);
419 List subentities = NIL;
420 imports = cons(c,imports);
422 && (tycon(c).what == DATATYPE
423 || tycon(c).what == NEWTYPE))
424 subentities = tycon(c).defn;
426 subentities = cclass(c).members;
427 if (DOTDOT == snd(e)) {
428 imports = dupOnto(subentities,imports);
433 map1Accum(checkImportEntity,imports,m,impList);
438 static Void local checkImportList(importSpec) /*Import a module unqualified*/
440 Module m = fst(importSpec);
441 Cell impList = snd(importSpec);
443 List imports = NIL; /* entities we want to import */
444 List hidden = NIL; /* entities we want to hide */
446 if (isPair(impList) && HIDDEN == fst(impList)) {
447 /* Somewhat inefficient - but obviously correct:
448 * imports = importsOf("module Foo") `setDifference` hidden;
450 hidden = resolveImportList(m, snd(impList));
451 imports = resolveImportList(m, DOTDOT);
453 imports = resolveImportList(m, impList);
456 for(; nonNull(imports); imports=tl(imports)) {
457 Cell e = hd(imports);
458 if (!cellIsMember(e,hidden))
461 /* ToDo: hang onto the imports list for processing export list entries
462 * of the form "module Foo"
466 static Void local importEntity(source,e)
470 case NAME : importName(source,e);
473 case TYCON : importTycon(source,e);
475 case CLASS : importClass(source,e);
477 default: internal("importEntity");
481 static Void local importName(source,n)
484 Name clash = addName(n);
485 if (nonNull(clash) && clash!=n) {
486 ERRMSG(0) "Entity \"%s\" imported from module \"%s\""
487 " already defined in module \"%s\"",
488 textToStr(name(n).text),
489 textToStr(module(source).text),
490 textToStr(module(name(clash).mod).text)
495 static Void local importTycon(source,tc)
498 Tycon clash=addTycon(tc);
499 if (nonNull(clash) && clash!=tc) {
500 ERRMSG(0) "Tycon \"%s\" imported from \"%s\" already defined in module \"%s\"",
501 textToStr(tycon(tc).text),
502 textToStr(module(source).text),
503 textToStr(module(tycon(clash).mod).text)
506 if (nonNull(findClass(tycon(tc).text))) {
507 ERRMSG(0) "Import of type constructor \"%s\" clashes with class in module \"%s\"",
508 textToStr(tycon(tc).text),
509 textToStr(module(tycon(tc).mod).text)
514 static Void local importClass(source,c)
517 Class clash=addClass(c);
518 if (nonNull(clash) && clash!=c) {
519 ERRMSG(0) "Class \"%s\" imported from \"%s\" already defined in module \"%s\"",
520 textToStr(cclass(c).text),
521 textToStr(module(source).text),
522 textToStr(module(cclass(clash).mod).text)
525 if (nonNull(findTycon(cclass(c).text))) {
526 ERRMSG(0) "Import of class \"%s\" clashes with type constructor in module \"%s\"",
527 textToStr(cclass(c).text),
528 textToStr(module(source).text)
533 static List local checkExportTycon(exports,mt,spec,tc)
538 if (DOTDOT == spec || SYNONYM == tycon(tc).what) {
539 return cons(pair(tc,DOTDOT), exports);
541 return cons(pair(tc,NIL), exports);
545 static List local checkExportClass(exports,mt,spec,cl)
550 if (DOTDOT == spec) {
551 return cons(pair(cl,DOTDOT), exports);
553 return cons(pair(cl,NIL), exports);
557 static List local checkExport(exports,mt,e) /* Process entry in export list*/
563 List origExports = exports;
564 if (nonNull(export=findQualName(e))) {
565 exports=cons(export,exports);
567 if (isQCon(e) && nonNull(export=findQualTycon(e))) {
568 exports = checkExportTycon(exports,mt,NIL,export);
570 if (isQCon(e) && nonNull(export=findQualClass(e))) {
571 /* opaque class export */
572 exports = checkExportClass(exports,mt,NIL,export);
574 if (exports == origExports) {
575 ERRMSG(0) "Unknown entity \"%s\" exported from module \"%s\"",
581 } else if (MODULEENT == fst(e)) {
582 Module m = findModid(snd(e));
583 /* ToDo: shouldn't allow export of module we didn't import */
585 ERRMSG(0) "Unknown module \"%s\" exported from module \"%s\"",
586 textToStr(textOf(snd(e))),
590 if (m == currentModule) {
591 /* Exporting the current module exports local definitions */
593 for(xs=module(m).classes; nonNull(xs); xs=tl(xs)) {
594 if (cclass(hd(xs)).mod==m)
595 exports = checkExportClass(exports,mt,DOTDOT,hd(xs));
597 for(xs=module(m).tycons; nonNull(xs); xs=tl(xs)) {
598 if (tycon(hd(xs)).mod==m)
599 exports = checkExportTycon(exports,mt,DOTDOT,hd(xs));
601 for(xs=module(m).names; nonNull(xs); xs=tl(xs)) {
602 if (name(hd(xs)).mod==m)
603 exports = cons(hd(xs),exports);
606 /* Exporting other modules imports all things imported
607 * unqualified from it.
608 * ToDo: we reexport everything exported by a module -
609 * whether we imported it or not. This gives the wrong
610 * result for "module M(module N) where import N(x)"
612 exports = dupOnto(module(m).exports,exports);
616 Cell ident = fst(e); /* class name or type name */
617 Cell parts = snd(e); /* members or constructors */
619 if (isQCon(ident) && nonNull(nm=findQualTycon(ident))) {
620 switch (tycon(nm).what) {
623 ERRMSG(0) "Explicit constructor list given for type synonym"
624 " \"%s\" in export list of module \"%s\"",
629 return cons(pair(nm,DOTDOT),exports);
631 ERRMSG(0) "Transparent export of restricted type synonym"
632 " \"%s\" in export list of module \"%s\"",
636 return exports; /* Not reached */
640 return cons(pair(nm,DOTDOT),exports);
642 exports = checkSubentities(exports,parts,tycon(nm).defn,
643 "constructor of type",
645 return cons(pair(nm,DOTDOT), exports);
648 internal("checkExport1");
650 } else if (isQCon(ident) && nonNull(nm=findQualClass(ident))) {
651 if (DOTDOT == parts) {
652 return cons(pair(nm,DOTDOT),exports);
654 exports = checkSubentities(exports,parts,cclass(nm).members,
655 "member of class",cclass(nm).text);
656 return cons(pair(nm,DOTDOT), exports);
659 ERRMSG(0) "Explicit export list given for non-class/datatype \"%s\" in export list of module \"%s\"",
665 return exports; /* NOTUSED */
668 static List local checkExports ( List exports, Module thisModule )
670 Module m = thisModule;
671 Text mt = module(m).text;
674 map1Accum(checkExport,es,mt,exports);
677 for(xs=es; nonNull(xs); xs=tl(xs)) {
678 Printf(" %s", textToStr(textOfEntity(hd(xs))));
685 /* --------------------------------------------------------------------------
686 * Static analysis of type declarations:
688 * Type declarations come in two forms:
689 * - data declarations - define new constructed data types
690 * - type declarations - define new type synonyms
692 * A certain amount of work is carried out as the declarations are
693 * read during parsing. In particular, for each type constructor
694 * definition encountered:
695 * - check that there is no previous definition of constructor
696 * - ensure type constructor not previously used as a class name
697 * - make a new entry in the type constructor table
698 * - record line number of declaration
699 * - Build separate lists of newly defined constructors for later use.
700 * ------------------------------------------------------------------------*/
702 Void tyconDefn(line,lhs,rhs,what) /* process new type definition */
703 Int line; /* definition line number */
704 Cell lhs; /* left hand side of definition */
705 Cell rhs; /* right hand side of definition */
706 Cell what; { /* SYNONYM/DATATYPE/etc... */
707 Text t = textOf(getHead(lhs));
709 if (nonNull(findTycon(t))) {
710 ERRMSG(line) "Repeated definition of type constructor \"%s\"",
714 else if (nonNull(findClass(t))) {
715 ERRMSG(line) "\"%s\" used as both class and type constructor",
720 Tycon nw = newTycon(t);
721 tyconDefns = cons(nw,tyconDefns);
722 tycon(nw).line = line;
723 tycon(nw).arity = argCount;
724 tycon(nw).what = what;
725 if (what==RESTRICTSYN) {
726 h98DoesntSupport(line,"restricted type synonyms");
727 typeInDefns = cons(pair(nw,snd(rhs)),typeInDefns);
730 tycon(nw).defn = pair(lhs,rhs);
734 Void setTypeIns(bs) /* set local synonyms for given */
735 List bs; { /* binding group */
736 List cvs = typeInDefns;
737 for (; nonNull(cvs); cvs=tl(cvs)) {
738 Tycon c = fst(hd(cvs));
739 List vs = snd(hd(cvs));
740 for (tycon(c).what = RESTRICTSYN; nonNull(vs); vs=tl(vs)) {
741 if (nonNull(findBinding(textOf(hd(vs)),bs))) {
742 tycon(c).what = SYNONYM;
749 Void clearTypeIns() { /* clear list of local synonyms */
750 for (; nonNull(typeInDefns); typeInDefns=tl(typeInDefns))
751 tycon(fst(hd(typeInDefns))).what = RESTRICTSYN;
754 /* --------------------------------------------------------------------------
755 * Further analysis of Type declarations:
757 * In order to allow the definition of mutually recursive families of
758 * data types, the static analysis of the right hand sides of type
759 * declarations cannot be performed until all of the type declarations
762 * Once parsing is complete, we carry out the following:
764 * - check format of lhs, extracting list of bound vars and ensuring that
765 * there are no repeated variables and no Skolem variables.
766 * - run dependency analysis on rhs to check that only bound type vars
767 * appear in type and that all constructors are defined.
768 * Replace type variables by offsets, constructors by Tycons.
769 * - use list of dependents to sort into strongly connected components.
770 * - ensure that there is not more than one synonym in each group.
771 * - kind-check each group of type definitions.
773 * - check that there are no previous definitions for constructor
774 * functions in data type definitions.
775 * - install synonym expansions and constructor definitions.
776 * ------------------------------------------------------------------------*/
778 static List tcDeps = NIL; /* list of dependent tycons/classes*/
780 static Void local checkTyconDefn(d) /* validate type constructor defn */
782 Cell lhs = fst(tycon(d).defn);
783 Cell rhs = snd(tycon(d).defn);
784 Int line = tycon(d).line;
785 List tyvars = getArgs(lhs);
787 /* check for repeated tyvars on lhs*/
788 for (temp=tyvars; nonNull(temp); temp=tl(temp))
789 if (nonNull(varIsMember(textOf(hd(temp)),tl(temp)))) {
790 ERRMSG(line) "Repeated type variable \"%s\" on left hand side",
791 textToStr(textOf(hd(temp)))
795 tcDeps = NIL; /* find dependents */
796 switch (whatIs(tycon(d).what)) {
798 case SYNONYM : rhs = depTypeExp(line,tyvars,rhs);
799 if (cellIsMember(d,tcDeps)) {
800 ERRMSG(line) "Recursive type synonym \"%s\"",
801 textToStr(tycon(d).text)
807 case NEWTYPE : depConstrs(d,tyvars,rhs);
811 default : internal("checkTyconDefn");
816 tycon(d).kind = tcDeps;
820 static Void local depConstrs(t,tyvars,cd)
821 Tycon t; /* Define constructor functions and*/
822 List tyvars; /* do dependency analysis for data */
823 Cell cd; { /* definitions (w or w/o deriving) */
824 Int line = tycon(t).line;
829 List derivs = snd(cd);
830 List compTypes = NIL;
834 for (i=0; i<tycon(t).arity; ++i) /* build representation for tycon */
835 lhs = ap(lhs,mkOffset(i)); /* applied to full comp. of args */
837 if (isQualType(cs)) { /* allow for possible context */
840 map2Over(depPredExp,line,tyvars,ctxt);
841 h98CheckCtxt(line,"context",TRUE,ctxt,NIL);
844 if (nonNull(cs) && isNull(tl(cs))) /* Single constructor datatype? */
847 for (; nonNull(cs); cs=tl(cs)) { /* For each constructor function: */
849 List sig = dupList(tyvars);
850 List evs = NIL; /* locally quantified vars */
851 List lps = NIL; /* locally bound predicates */
852 List ctxt1 = ctxt; /* constructor function context */
853 List scs = NIL; /* strict components */
854 List fs = NONE; /* selector names */
855 Type type = lhs; /* constructor function type */
856 Int arity = 0; /* arity of constructor function */
857 Int nr2 = 0; /* Number of rank 2 args */
858 Name n; /* name for constructor function */
860 if (whatIs(con)==POLYTYPE) { /* Locally quantified vars */
863 sig = checkQuantVars(line,evs,sig,con);
866 if (isQualType(con)) { /* Local predicates */
869 for (us = typeVarsIn(lps,NIL,NIL,NIL); nonNull(us); us=tl(us))
870 if (!varIsMember(textOf(hd(us)),evs)) {
872 "Variable \"%s\" in constraint is not locally bound",
873 textToStr(textOf(hd(us)))
876 map2Over(depPredExp,line,sig,lps);
881 if (whatIs(con)==LABC) { /* Skeletize constr components */
882 Cell fls = snd(snd(con)); /* get field specifications */
885 for (; nonNull(fls); fls=tl(fls)) { /* for each field spec: */
886 List vs = fst(hd(fls));
887 Type t = snd(hd(fls)); /* - scrutinize type */
888 Bool banged = whatIs(t)==BANG;
889 t = depCompType(line,sig,(banged ? arg(t) : t));
890 while (nonNull(vs)) { /* - add named components */
898 scs = cons(mkInt(arity),scs);
902 scs = rev(scs); /* put strict comps in ascend ord */
904 else { /* Non-labelled constructor */
907 for (; isAp(c); c=fun(c))
909 for (compNo=arity, c=con; isAp(c); c=fun(c)) {
911 if (whatIs(t)==BANG) {
912 scs = cons(mkInt(compNo),scs);
916 arg(c) = depCompType(line,sig,t);
920 if (nonNull(ctxt1)) /* Extract relevant part of context*/
921 ctxt1 = selectCtxt(ctxt1,offsetTyvarsIn(con,NIL));
923 for (i=arity; isAp(con); i--) { /* Calculate type of constructor */
926 fun(con) = typeArrow;
927 if (isPolyOrQualType(cmp)) {
928 if (nonNull(derivs)) {
929 ERRMSG(line) "Cannot derive instances for types" ETHEN
930 ERRTEXT " with polymorphic or qualified components"
936 if (nonNull(derivs)) /* and build list of components */
937 compTypes = cons(cmp,compTypes);
942 if (nr2>0) { /* Add rank 2 annotation */
943 type = ap(RANK2,pair(mkInt(nr2-length(lps)),type));
946 if (nonNull(evs)) { /* Add existential annotation */
947 if (nonNull(derivs)) {
948 ERRMSG(line) "Cannot derive instances for types" ETHEN
949 ERRTEXT " with existentially typed components"
954 "Cannot use selectors with existentially typed components"
957 type = ap(EXIST,pair(mkInt(length(evs)),type));
960 if (nonNull(lps)) { /* Add local preds part to type */
961 type = ap(CDICTS,pair(lps,type));
964 if (nonNull(ctxt1)) { /* Add context part to type */
965 type = ap(QUAL,pair(ctxt1,type));
968 if (nonNull(sig)) { /* Add quantifiers to type */
970 for (; nonNull(ts1); ts1=tl(ts1)) {
973 type = mkPolyType(sig,type);
976 n = findName(textOf(con)); /* Allocate constructor fun name */
978 n = newName(textOf(con),NIL);
979 } else if (name(n).defn!=PREDEFINED) {
980 duplicateError(line,name(n).mod,name(n).text,
981 "constructor function");
983 name(n).arity = arity; /* Save constructor fun details */
986 name(n).number = cfunNo(conNo++);
988 if (tycon(t).what==NEWTYPE) {
991 "A newtype constructor cannot have class constraints"
996 "A newtype constructor must have exactly one argument"
1001 "Illegal strictess annotation for newtype constructor"
1004 name(n).defn = nameId;
1006 implementCfun(n,scs);
1007 name(n).hasStrict = nonNull(scs);
1012 sels = addSels(line,n,fs,sels);
1016 if (nonNull(sels)) {
1018 fst(cd) = appendOnto(fst(cd),sels);
1019 selDefns = cons(sels,selDefns);
1022 if (nonNull(derivs)) { /* Generate derived instances */
1023 map3Proc(checkDerive,t,ctxt,compTypes,derivs);
1027 Int userArity(c) /* Find arity for cfun, ignoring */
1028 Name c; { /* CDICTS parameters */
1029 Int a = name(c).arity;
1030 Type t = name(c).type;
1032 if (isPolyType(t)) {
1035 if ((w=whatIs(t))==QUAL) {
1036 w = whatIs(t=snd(snd(t)));
1039 a -= length(fst(snd(t)));
1045 static List local addSels(line,c,fs,ss) /* Add fields to selector list */
1046 Int line; /* line number of constructor */
1047 Name c; /* corresponding constr function */
1048 List fs; /* list of fields (varids) */
1049 List ss; { /* list of existing selectors */
1051 cfunSfuns = cons(pair(c,fs),cfunSfuns);
1052 for (; nonNull(fs); fs=tl(fs), ++sn) {
1054 Text t = textOf(hd(fs));
1056 if (nonNull(varIsMember(t,tl(fs)))) {
1057 ERRMSG(line) "Repeated field name \"%s\" for constructor \"%s\"",
1058 textToStr(t), textToStr(name(c).text)
1062 while (nonNull(ns) && t!=name(hd(ns)).text) {
1067 name(hd(ns)).defn = cons(pair(c,mkInt(sn)),name(hd(ns)).defn);
1069 Name n = findName(t);
1071 ERRMSG(line) "Repeated definition for selector \"%s\"",
1076 name(n).line = line;
1077 name(n).number = SELNAME;
1078 name(n).defn = singleton(pair(c,mkInt(sn)));
1085 static List local selectCtxt(ctxt,vs) /* calculate subset of context */
1092 for (; nonNull(ctxt); ctxt=tl(ctxt)) {
1093 List us = offsetTyvarsIn(hd(ctxt),NIL);
1094 for (; nonNull(us) && cellIsMember(hd(us),vs); us=tl(us)) {
1097 ps = cons(hd(ctxt),ps);
1104 static Void local checkSynonyms(ts) /* Check for mutually recursive */
1105 List ts; { /* synonyms */
1107 for (; nonNull(ts); ts=tl(ts)) { /* build list of all synonyms */
1109 switch (whatIs(tycon(t).what)) {
1111 case RESTRICTSYN : syns = cons(t,syns);
1115 while (nonNull(syns)) { /* then visit each synonym */
1116 syns = visitSyn(NIL,hd(syns),syns);
1120 static List local visitSyn(path,t,syns) /* visit synonym definition to look*/
1121 List path; /* for cycles */
1124 if (cellIsMember(t,path)) { /* every elt in path depends on t */
1125 ERRMSG(tycon(t).line)
1126 "Type synonyms \"%s\" and \"%s\" are mutually recursive",
1127 textToStr(tycon(t).text), textToStr(tycon(hd(path)).text)
1130 List ds = tycon(t).kind;
1132 for (; nonNull(ds); ds=tl(ds)) {
1133 if (cellIsMember(hd(ds),syns)) {
1134 if (isNull(path1)) {
1135 path1 = cons(t,path);
1137 syns = visitSyn(path1,hd(ds),syns);
1141 tycon(t).defn = fullExpand(tycon(t).defn);
1142 return removeCell(t,syns);
1145 /* --------------------------------------------------------------------------
1146 * Expanding out all type synonyms in a type expression:
1147 * ------------------------------------------------------------------------*/
1149 Type fullExpand(t) /* find full expansion of type exp */
1150 Type t; { /* assuming that all relevant */
1151 Cell h = t; /* synonym defns of lower rank have*/
1152 Int n = 0; /* already been fully expanded */
1154 for (args=NIL; isAp(h); h=fun(h), n++) {
1155 args = cons(fullExpand(arg(h)),args);
1157 t = applyToArgs(h,args);
1158 if (isSynonym(h) && n>=tycon(h).arity) {
1159 if (n==tycon(h).arity) {
1160 t = instantiateSyn(tycon(h).defn,t);
1163 while (--n > tycon(h).arity) {
1166 fun(p) = instantiateSyn(tycon(h).defn,fun(p));
1172 static Type local instantiateSyn(t,env) /* instantiate type according using*/
1173 Type t; /* env to determine appropriate */
1174 Type env; { /* values for OFFSET type vars */
1175 switch (whatIs(t)) {
1176 case AP : return ap(instantiateSyn(fun(t),env),
1177 instantiateSyn(arg(t),env));
1179 case OFFSET : return nthArg(offsetOf(t),env);
1185 /* --------------------------------------------------------------------------
1186 * Static analysis of class declarations:
1188 * Performed in a similar manner to that used for type declarations.
1190 * The first part of the static analysis is performed as the declarations
1191 * are read during parsing. The parser ensures that:
1192 * - the class header and all superclass predicates are of the form
1195 * The classDefn() function:
1196 * - ensures that there is no previous definition for class
1197 * - checks that class name has not previously been used as a type constr.
1198 * - make new entry in class table
1199 * - record line number of declaration
1200 * - build list of classes defined in current script for use in later
1201 * stages of static analysis.
1202 * ------------------------------------------------------------------------*/
1204 Void classDefn(line,head,ms,fds) /* process new class definition */
1205 Int line; /* definition line number */
1206 Cell head; /* class header :: ([Supers],Class) */
1207 List ms; /* class definition body */
1208 List fds; { /* functional dependencies */
1209 Text ct = textOf(getHead(snd(head)));
1210 Int arity = argCount;
1212 if (nonNull(findClass(ct))) {
1213 ERRMSG(line) "Repeated definition of class \"%s\"",
1216 } else if (nonNull(findTycon(ct))) {
1217 ERRMSG(line) "\"%s\" used as both class and type constructor",
1221 Class nw = newClass(ct);
1222 cclass(nw).line = line;
1223 cclass(nw).arity = arity;
1224 cclass(nw).head = snd(head);
1225 cclass(nw).supers = fst(head);
1226 cclass(nw).members = ms;
1227 cclass(nw).level = 0;
1228 cclass(nw).fds = fds;
1229 cclass(nw).xfds = NIL;
1230 classDefns = cons(nw,classDefns);
1232 h98DoesntSupport(line,"multiple parameter classes");
1236 /* --------------------------------------------------------------------------
1237 * Further analysis of class declarations:
1239 * Full static analysis of class definitions must be postponed until the
1240 * complete script has been read and all static analysis on type definitions
1241 * has been completed.
1243 * Once this has been achieved, we carry out the following checks on each
1245 * - check that variables in header are distinct
1246 * - replace head by skeleton
1247 * - check superclass declarations, replace by skeletons
1248 * - split body of class into members and declarations
1249 * - make new name entry for each member function
1250 * - record member function number (eventually an offset into dictionary!)
1251 * - no member function has a previous definition ...
1252 * - no member function is mentioned more than once in the list of members
1253 * - each member function type is valid, replace vars by offsets
1254 * - qualify each member function type by class header
1255 * - only bindings for members appear in defaults
1256 * - only function bindings appear in defaults
1257 * - check that extended class hierarchy does not contain any cycles
1258 * ------------------------------------------------------------------------*/
1260 static Void local checkClassDefn(c) /* validate class definition */
1263 Int args = cclass(c).arity - 1;
1264 Cell temp = cclass(c).head;
1268 for (; isAp(temp); temp=fun(temp)) {
1269 if (!isVar(arg(temp))) {
1270 ERRMSG(cclass(c).line) "Type variable required in class head"
1273 if (nonNull(varIsMember(textOf(arg(temp)),tyvars))) {
1274 ERRMSG(cclass(c).line)
1275 "Repeated type variable \"%s\" in class head",
1276 textToStr(textOf(arg(temp)))
1279 tyvars = cons(arg(temp),tyvars);
1282 for (fs=cclass(c).fds; nonNull(fs); fs=tl(fs)) {
1286 /* Check for trivial dependency
1289 ERRMSG(cclass(c).line) "Functional dependency is trivial"
1293 /* Check for duplicated vars on right hand side, and for vars on
1294 * right that also appear on the left:
1296 for (vs=snd(fd); nonNull(vs); vs=tl(vs)) {
1297 if (varIsMember(textOf(hd(vs)),fst(fd))) {
1298 ERRMSG(cclass(c).line)
1299 "Trivial dependency for variable \"%s\"",
1300 textToStr(textOf(hd(vs)))
1303 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1304 ERRMSG(cclass(c).line)
1305 "Repeated variable \"%s\" in functional dependency",
1306 textToStr(textOf(hd(vs)))
1309 hd(vs) = depTypeVar(cclass(c).line,tyvars,textOf(hd(vs)));
1312 /* Check for duplicated vars on left hand side:
1314 for (vs=fst(fd); nonNull(vs); vs=tl(vs)) {
1315 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1316 ERRMSG(cclass(c).line)
1317 "Repeated variable \"%s\" in functional dependency",
1318 textToStr(textOf(hd(vs)))
1321 hd(vs) = depTypeVar(cclass(c).line,tyvars,textOf(hd(vs)));
1325 if (cclass(c).arity==0) {
1328 Int args = cclass(c).arity - 1;
1329 for (temp=cclass(c).head; args>0; temp=fun(temp), args--) {
1330 arg(temp) = mkOffset(args);
1332 arg(temp) = mkOffset(0);
1336 tcDeps = NIL; /* find dependents */
1337 map2Over(depPredExp,cclass(c).line,tyvars,cclass(c).supers);
1338 h98CheckCtxt(cclass(c).line,"class definition",FALSE,cclass(c).supers,NIL);
1339 cclass(c).numSupers = length(cclass(c).supers);
1340 cclass(c).defaults = extractBindings(cclass(c).members); /* defaults*/
1341 ss = extractSigdecls(cclass(c).members);
1342 fs = extractFixdecls(cclass(c).members);
1343 cclass(c).members = pair(ss,fs);
1344 map2Proc(checkMems,c,tyvars,ss);
1346 cclass(c).kinds = tcDeps;
1351 /* --------------------------------------------------------------------------
1352 * Functional dependencies are inherited from superclasses.
1353 * For example, if I've got the following classes:
1355 * class C a b | a -> b
1356 * class C [b] a => D a b
1358 * then C will have the dependency ([a], [b]) as expected, and D will inherit
1359 * the dependency ([b], [a]) from C.
1360 * When doing pairwise improvement, we have to consider not just improving
1361 * when we see a pair of Cs or a pair of Ds in the context, but when we've
1362 * got a C and a D as well. In this case, we only improve when the
1363 * predicate in question matches the type skeleton in the relevant superclass
1364 * constraint. E.g., we improve the pair (C [Int] a, D b Int) (unifying
1365 * a and b), but we don't improve the pair (C Int a, D b Int).
1366 * To implement functional dependency inheritance, we calculate
1367 * the closure of all functional dependencies, and store the result
1368 * in an additional field `xfds' (extended functional dependencies).
1369 * The `xfds' field is a list of functional dependency lists, annotated
1370 * with a list of predicate skeletons constraining when improvement can
1371 * happen against this dependency list. For example, the xfds field
1372 * for C above would be:
1373 * [([C a b], [([a], [b])])]
1374 * and the xfds field for D would be:
1375 * [([C [b] a, D a b], [([b], [a])])]
1376 * Self-improvement (of a C with a C, or a D with a D) is treated as a
1377 * special case of an inherited dependency.
1378 * ------------------------------------------------------------------------*/
1379 static List local inheritFundeps ( Class c, Cell pi, Int o )
1381 Int alpha = newKindedVars(cclass(c).kinds);
1382 List scs = cclass(c).supers;
1385 /* better not fail ;-) */
1386 if (!matchPred(pi,o,cclass(c).head,alpha))
1387 internal("inheritFundeps - predicate failed to match it's own head!");
1388 this = copyPred(pi,o);
1389 for (; nonNull(scs); scs=tl(scs)) {
1390 Class s = getHead(hd(scs));
1392 List sfds = inheritFundeps(s,hd(scs),alpha);
1393 for (; nonNull(sfds); sfds=tl(sfds)) {
1395 xfds = cons(pair(cons(this,fst(h)),snd(h)),xfds);
1399 if (nonNull(cclass(c).fds)) {
1400 List fds = NIL, fs = cclass(c).fds;
1401 for (; nonNull(fs); fs=tl(fs)) {
1402 fds = cons(pair(otvars(this,fst(hd(fs))),
1403 otvars(this,snd(hd(fs)))),fds);
1405 xfds = cons(pair(cons(this,NIL),fds),xfds);
1410 static Void local extendFundeps ( Class c )
1413 emptySubstitution();
1414 alpha = newKindedVars(cclass(c).kinds);
1415 cclass(c).xfds = inheritFundeps(c,cclass(c).head,alpha);
1417 /* we can now check for ambiguity */
1418 map1Proc(checkMems2,c,fst(cclass(c).members));
1422 static Cell local depPredExp(line,tyvars,pred)
1429 for (; isAp(h); args++) {
1430 arg(h) = depTypeExp(line,tyvars,arg(h));
1436 h98DoesntSupport(line,"tag classes");
1437 } else if (args!=1) {
1438 h98DoesntSupport(line,"multiple parameter classes");
1441 if (isQCon(h)) { /* standard class constraint */
1442 Class c = findQualClass(h);
1444 ERRMSG(line) "Undefined class \"%s\"", identToStr(h)
1452 if (args!=cclass(c).arity) {
1453 ERRMSG(line) "Wrong number of arguments for class \"%s\"",
1454 textToStr(cclass(c).text)
1457 if (cellIsMember(c,classDefns) && !cellIsMember(c,tcDeps)) {
1458 tcDeps = cons(c,tcDeps);
1462 else if (isExt(h)) { /* Lacks predicate */
1463 if (args!=1) { /* parser shouldn't let this happen*/
1464 ERRMSG(line) "Wrong number of arguments for lacks predicate"
1471 if (whatIs(h) != IPCELL)
1474 internal("depPredExp");
1479 static Void local checkMems(c,tyvars,m) /* check member function details */
1483 Int line = intOf(fst3(m));
1490 if (isPolyType(t)) {
1496 tyvars = typeVarsIn(t,NIL,xtvs,tyvars);
1497 /* Look for extra type vars. */
1498 checkOptQuantVars(line,xtvs,tyvars);
1500 if (isQualType(t)) { /* Overloaded member signatures? */
1501 map2Over(depPredExp,line,tyvars,fst(snd(t)));
1503 t = ap(QUAL,pair(NIL,t));
1506 fst(snd(t)) = cons(cclass(c).head,fst(snd(t)));/* Add main predicate */
1507 snd(snd(t)) = depTopType(line,tyvars,snd(snd(t)));
1509 for (tvs=tyvars; nonNull(tvs); tvs=tl(tvs)){/* Quantify */
1513 t = mkPolyType(sig,t);
1515 thd3(m) = t; /* Save type */
1516 take(cclass(c).arity,tyvars); /* Delete extra type vars */
1518 if (isAmbiguous(t)) {
1519 ambigError(line,"class declaration",hd(vs),t);
1521 h98CheckType(line,"member type",hd(vs),t);
1524 static Void local checkMems2(c,m) /* check member function details */
1527 Int line = intOf(fst3(m));
1532 static Void local addMembers(c) /* Add definitions of member funs */
1533 Class c; { /* and other parts of class struct.*/
1534 List ms = fst(cclass(c).members);
1535 List fs = snd(cclass(c).members);
1536 List ns = NIL; /* List of names */
1537 Int mno; /* Member function number */
1539 for (mno=0; mno<cclass(c).numSupers; mno++) {
1540 ns = cons(newDSel(c,mno),ns);
1542 cclass(c).dsels = rev(ns); /* Save dictionary selectors */
1544 for (mno=1, ns=NIL; nonNull(ms); ms=tl(ms)) {
1545 Int line = intOf(fst3(hd(ms)));
1546 List vs = rev(snd3(hd(ms)));
1547 Type t = thd3(hd(ms));
1548 for (; nonNull(vs); vs=tl(vs)) {
1549 ns = cons(newMember(line,mno++,hd(vs),t,c),ns);
1552 cclass(c).members = rev(ns); /* Save list of members */
1553 cclass(c).numMembers = length(cclass(c).members);
1555 for (; nonNull(fs); fs=tl(fs)) { /* fixity declarations */
1556 Int line = intOf(fst3(hd(fs)));
1557 List ops = snd3(hd(fs));
1558 Syntax s = intOf(thd3(hd(fs)));
1559 for (; nonNull(ops); ops=tl(ops)) {
1560 Name n = nameIsMember(textOf(hd(ops)),cclass(c).members);
1562 missFixity(line,textOf(hd(ops)));
1563 } else if (name(n).syntax!=NO_SYNTAX) {
1564 dupFixity(line,textOf(hd(ops)));
1570 /* Not actually needed just yet; for the time being, dictionary code will
1571 not be passed through the type checker.
1573 cclass(c).dtycon = addPrimTycon(generateText("Dict.%s",c),
1580 mno = cclass(c).numSupers + cclass(c).numMembers;
1581 /* cclass(c).dcon = addPrimCfun(generateText("Make.%s",c),mno,0,NIL); */
1582 cclass(c).dcon = addPrimCfun(generateText(":D%s",c),mno,0,NIL);
1583 /* implementCfun(cclass(c).dcon,NIL);
1584 Don't manufacture a wrapper fn for dictionary constructors.
1585 Applications of dictionary constructors are always saturated,
1586 and translate.c:stgExpr() special-cases saturated constructor apps.
1589 if (mno==1) { /* Single entry dicts use newtype */
1590 name(cclass(c).dcon).defn = nameId;
1591 if (nonNull(cclass(c).members)) {
1592 name(hd(cclass(c).members)).number = mfunNo(0);
1595 cclass(c).defaults = classBindings("class",c,cclass(c).defaults);
1598 static Name local newMember(l,no,v,t,parent)
1599 Int l; /* Make definition for member fn */
1604 Name m = findName(textOf(v));
1607 m = newName(textOf(v),parent);
1608 } else if (name(m).defn!=PREDEFINED) {
1609 ERRMSG(l) "Repeated definition for member function \"%s\"",
1610 textToStr(name(m).text)
1616 name(m).number = mfunNo(no);
1621 Name newDSel(c,no) /* Make definition for dict selectr*/
1627 /* sprintf(buf,"sc%d.%s",no,"%s"); */
1628 sprintf(buf,"$p%d%s",no+1,"%s");
1629 s = newName(generateText(buf,c),c);
1630 name(s).line = cclass(c).line;
1632 name(s).number = DFUNNAME;
1638 static Text local generateText(sk,c) /* We need to generate names for */
1639 String sk; /* certain objects corresponding */
1640 Class c; { /* to each class. */
1641 String cname = textToStr(cclass(c).text);
1642 char buffer[MAX_GEN+1];
1644 if ((strlen(sk)+strlen(cname))>=MAX_GEN) {
1645 ERRMSG(0) "Please use a shorter name for class \"%s\"", cname
1648 sprintf(buffer,sk,cname);
1649 return findText(buffer);
1652 Int visitClass(c) /* visit class defn to check that */
1653 Class c; { /* class hierarchy is acyclic */
1655 if (isExt(c)) { /* special case for lacks preds */
1659 if (cclass(c).level < 0) { /* already visiting this class? */
1660 ERRMSG(cclass(c).line) "Class hierarchy for \"%s\" is not acyclic",
1661 textToStr(cclass(c).text)
1663 } else if (cclass(c).level == 0) { /* visiting class for first time */
1664 List scs = cclass(c).supers;
1666 cclass(c).level = (-1);
1667 for (; nonNull(scs); scs=tl(scs)) {
1668 Int l = visitClass(getHead(hd(scs)));
1671 cclass(c).level = 1+lev; /* level = 1 + max level of supers */
1673 return cclass(c).level;
1676 /* --------------------------------------------------------------------------
1677 * Process class and instance declaration binding groups:
1678 * ------------------------------------------------------------------------*/
1680 static List local classBindings(where,c,bs)
1681 String where; /* Check validity of bindings bs */
1682 Class c; /* for class c (or an inst of c) */
1683 List bs; { /* sort into approp. member order */
1686 for (; nonNull(bs); bs=tl(bs)) {
1688 Cell body = snd(snd(b));
1691 if (!isVar(fst(b))) { /* Only allow function bindings */
1692 ERRMSG(rhsLine(snd(body)))
1693 "Pattern binding illegal in %s declaration", where
1697 if (isNull(mnm=memberName(c,textOf(fst(b))))) {
1698 ERRMSG(rhsLine(snd(hd(body))))
1699 "No member \"%s\" in class \"%s\"",
1700 textToStr(textOf(fst(b))), textToStr(cclass(c).text)
1704 nbs = numInsert(mfunOf(mnm)-1,b,nbs);
1709 static Name local memberName(c,t) /* return name of member function */
1710 Class c; /* with name t in class c */
1711 Text t; { /* return NIL if not a member */
1712 List ms = cclass(c).members;
1713 for (; nonNull(ms); ms=tl(ms)) {
1714 if (t==name(hd(ms)).text) {
1721 static List local numInsert(n,x,xs) /* insert x at nth position in xs, */
1722 Int n; /* filling gaps with NIL */
1725 List start = isNull(xs) ? cons(NIL,NIL) : xs;
1727 for (xs=start; 0<n--; xs=tl(xs)) {
1728 if (isNull(tl(xs))) {
1729 tl(xs) = cons(NIL,NIL);
1736 /* --------------------------------------------------------------------------
1737 * Calculate set of variables appearing in a given type expression (possibly
1738 * qualified) as a list of distinct values. The order in which variables
1739 * appear in the list is the same as the order in which those variables
1740 * occur in the type expression when read from left to right.
1741 * ------------------------------------------------------------------------*/
1743 List local typeVarsIn(ty,us,ws,vs) /*Calculate list of type variables*/
1744 Cell ty; /* used in type expression, reading*/
1745 List us; /* from left to right ignoring any */
1746 List ws; /* listed in us. */
1747 List vs; { /* ws = explicitly quantified vars */
1748 if (isNull(ty)) return vs;
1749 switch (whatIs(ty)) {
1750 case DICTAP : return typeVarsIn(snd(snd(ty)),us,ws,vs);
1751 case UNBOXEDTUP: return typeVarsIn(snd(ty),us,ws,vs);
1753 case AP : return typeVarsIn(snd(ty),us,ws,
1754 typeVarsIn(fst(ty),us,ws,vs));
1757 case VAROPCELL : if ((nonNull(findBtyvs(textOf(ty)))
1758 && !varIsMember(textOf(ty),ws))
1759 || varIsMember(textOf(ty),us)) {
1762 return maybeAppendVar(ty,vs);
1765 case POLYTYPE : return typeVarsIn(monotypeOf(ty),polySigOf(ty),ws,vs);
1767 case QUAL : { vs = typeVarsIn(fst(snd(ty)),us,ws,vs);
1768 return typeVarsIn(snd(snd(ty)),us,ws,vs);
1771 case BANG : return typeVarsIn(snd(ty),us,ws,vs);
1773 case LABC : { List fs = snd(snd(ty));
1774 for (; nonNull(fs); fs=tl(fs)) {
1775 vs = typeVarsIn(snd(hd(fs)),us,ws,vs);
1782 case QUALIDENT: return vs;
1784 default: fprintf(stderr, " bad tag = %d\n", whatIs(ty));internal("typeVarsIn");
1789 static List local maybeAppendVar(v,vs) /* append variable to list if not */
1790 Cell v; /* already included */
1796 while (nonNull(c)) {
1797 if (textOf(hd(c))==t) {
1805 tl(p) = cons(v,NIL);
1813 /* --------------------------------------------------------------------------
1814 * Static analysis for type expressions is required to:
1815 * - ensure that each type constructor or class used has been defined.
1816 * - replace type variables by offsets, constructor names by Tycons.
1817 * - ensure that the type is well-kinded.
1818 * ------------------------------------------------------------------------*/
1820 static Type local checkSigType(line,where,e,type)
1821 Int line; /* Check validity of type expr in */
1822 String where; /* explicit type signature */
1829 if (isPolyType(type)) {
1830 xtvs = fst(snd(type));
1831 type = monotypeOf(type);
1833 tvs = typeVarsIn(type,NIL,xtvs,NIL);
1835 checkOptQuantVars(line,xtvs,tvs);
1837 if (isQualType(type)) {
1838 map2Over(depPredExp,line,tvs,fst(snd(type)));
1839 snd(snd(type)) = depTopType(line,tvs,snd(snd(type)));
1841 if (isAmbiguous(type)) {
1842 ambigError(line,where,e,type);
1845 type = depTopType(line,tvs,type);
1849 if (length(tvs) >= (OFF_MAX-OFF_MIN+1)) {
1850 ERRMSG(line) "Too many type variables in %s\n", where
1854 for (; nonNull(ts); ts=tl(ts)) {
1857 type = mkPolyType(tvs,type);
1862 kindType(line,"type expression",type);
1866 h98CheckType(line,where,e,type);
1870 static Void local checkOptQuantVars(line,xtvs,tvs)
1872 List xtvs; /* Explicitly quantified vars */
1873 List tvs; { /* Implicitly quantified vars */
1874 if (nonNull(xtvs)) {
1876 for (; nonNull(vs); vs=tl(vs)) {
1877 if (!varIsMember(textOf(hd(vs)),xtvs)) {
1878 ERRMSG(line) "Quantifier does not mention type variable \"%s\"",
1879 textToStr(textOf(hd(vs)))
1883 for (vs=xtvs; nonNull(vs); vs=tl(vs)) {
1884 if (!varIsMember(textOf(hd(vs)),tvs)) {
1885 ERRMSG(line) "Quantified type variable \"%s\" is not used",
1886 textToStr(textOf(hd(vs)))
1889 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1890 ERRMSG(line) "Quantified type variable \"%s\" is repeated",
1891 textToStr(textOf(hd(vs)))
1898 static Type local depTopType(l,tvs,t) /* Check top-level of type sig */
1906 for (; getHead(t1)==typeArrow && argCount==2; ++i) {
1907 arg(fun(t1)) = depCompType(l,tvs,arg(fun(t1)));
1908 if (isPolyOrQualType(arg(fun(t1)))) {
1914 if (nonNull(prev)) {
1915 arg(prev) = depTypeExp(l,tvs,t1);
1917 t = depTypeExp(l,tvs,t1);
1920 t = ap(RANK2,pair(mkInt(nr2),t));
1925 static Type local depCompType(l,tvs,t) /* Check component type for constr */
1929 Int ntvs = length(tvs);
1931 if (isPolyType(t)) {
1932 List vs = fst(snd(t));
1934 tvs = checkQuantVars(l,vs,tvs,t);
1935 nfr = replicate(length(vs),NIL);
1937 if (isQualType(t)) {
1938 map2Over(depPredExp,l,tvs,fst(snd(t)));
1939 snd(snd(t)) = depTypeExp(l,tvs,snd(snd(t)));
1940 if (isAmbiguous(t)) {
1941 ambigError(l,"type component",NIL,t);
1944 t = depTypeExp(l,tvs,t);
1950 return mkPolyType(nfr,t);
1953 static Type local depTypeExp(line,tyvars,type)
1957 switch (whatIs(type)) {
1958 case AP : fst(type) = depTypeExp(line,tyvars,fst(type));
1959 snd(type) = depTypeExp(line,tyvars,snd(type));
1962 case VARIDCELL : return depTypeVar(line,tyvars,textOf(type));
1964 case QUALIDENT : if (isQVar(type)) {
1965 ERRMSG(line) "Qualified type variables not allowed"
1968 /* deliberate fall through */
1969 case CONIDCELL : { Tycon tc = findQualTycon(type);
1972 "Undefined type constructor \"%s\"",
1976 if (cellIsMember(tc,tyconDefns) &&
1977 !cellIsMember(tc,tcDeps)) {
1978 tcDeps = cons(tc,tcDeps);
1984 case EXT : h98DoesntSupport(line,"extensible records");
1989 default : internal("depTypeExp");
1994 static Type local depTypeVar(line,tyvars,tv)
2001 for (; nonNull(tyvars); offset++) {
2002 if (tv==textOf(hd(tyvars))) {
2005 tyvars = tl(tyvars);
2008 Cell vt = findBtyvs(tv);
2012 ERRMSG(line) "Undefined type variable \"%s\"", textToStr(tv)
2015 return mkOffset(found);
2018 static List local checkQuantVars(line,vs,tvs,body)
2020 List vs; /* variables to quantify over */
2021 List tvs; /* variables already in scope */
2022 Cell body; { /* type/constr for scope of vars */
2024 List bvs = typeVarsIn(body,NIL,NIL,NIL);
2026 for (; nonNull(us); us=tl(us)) {
2027 Text u = textOf(hd(us));
2028 if (varIsMember(u,tl(us))) {
2029 ERRMSG(line) "Duplicated quantified variable %s",
2034 if (varIsMember(u,tvs)) {
2035 ERRMSG(line) "Local quantifier for %s hides an outer use",
2040 if (!varIsMember(u,bvs)) {
2041 ERRMSG(line) "Locally quantified variable %s is not used",
2046 tvs = appendOnto(tvs,vs);
2051 /* --------------------------------------------------------------------------
2052 * Check for ambiguous types:
2053 * A type Preds => type is ambiguous if not (TV(P) `subset` TV(type))
2054 * ------------------------------------------------------------------------*/
2056 List offsetTyvarsIn(t,vs) /* add list of offset tyvars in t */
2057 Type t; /* to list vs */
2059 switch (whatIs(t)) {
2060 case AP : return offsetTyvarsIn(fun(t),
2061 offsetTyvarsIn(arg(t),vs));
2063 case OFFSET : if (cellIsMember(t,vs))
2068 case QUAL : return offsetTyvarsIn(snd(t),vs);
2070 case POLYTYPE : return offsetTyvarsIn(monotypeOf(t),vs);
2071 /* slightly inaccurate, but won't matter here */
2074 case RANK2 : return offsetTyvarsIn(snd(snd(t)),vs);
2076 default : return vs;
2080 List zonkTyvarsIn(t,vs)
2083 switch (whatIs(t)) {
2084 case AP : return zonkTyvarsIn(fun(t),
2085 zonkTyvarsIn(arg(t),vs));
2087 case INTCELL : if (cellIsMember(t,vs))
2092 /* this case will lead to a type error --
2093 much better than reporting an internal error ;-) */
2094 /* case OFFSET : internal("zonkTyvarsIn"); */
2096 default : return vs;
2100 static List local otvars(pi,os) /* os is a list of offsets that */
2101 Cell pi; /* refer to the arguments of pi; */
2102 List os; { /* find list of offsets in those */
2103 List us = NIL; /* positions */
2104 for (; nonNull(os); os=tl(os)) {
2105 us = offsetTyvarsIn(nthArg(offsetOf(hd(os)),pi),us);
2110 static List local otvarsZonk(pi,os,o) /* same as above, but zonks */
2114 for (; nonNull(os); os=tl(os)) {
2115 Type t = zonkType(nthArg(offsetOf(hd(os)),pi),o);
2116 us = zonkTyvarsIn(t,us);
2121 static Bool local odiff(us,vs)
2123 while (nonNull(us) && cellIsMember(hd(us),vs)) {
2129 static Bool local osubset(us,vs) /* Determine whether us is subset */
2130 List us, vs; { /* of vs */
2131 while (nonNull(us) && cellIsMember(hd(us),vs)) {
2137 List oclose(fds,vs) /* Compute closure of vs wrt to fds*/
2140 Bool changed = TRUE;
2144 while (nonNull(fds)) {
2146 List next = tl(fds);
2147 if (osubset(fst(fd),vs)) { /* Test if fd applies */
2149 for (; nonNull(os); os=tl(os)) {
2150 if (!cellIsMember(hd(os),vs)) {
2151 vs = cons(hd(os),vs);
2155 } else { /* Didn't apply this time, so keep */
2166 Bool isAmbiguous(type) /* Determine whether type is */
2167 Type type; { /* ambiguous */
2168 if (isPolyType(type)) {
2169 type = monotypeOf(type);
2171 if (isQualType(type)) { /* only qualified types can be */
2172 List ps = fst(snd(type)); /* ambiguous */
2173 List tvps = offsetTyvarsIn(ps,NIL);
2174 List tvts = offsetTyvarsIn(snd(snd(type)),NIL);
2175 List fds = calcFunDeps(ps);
2177 tvts = oclose(fds,tvts); /* Close tvts under fds */
2178 return !osubset(tvps,tvts);
2183 List calcFunDeps(ps)
2186 for (; nonNull(ps); ps=tl(ps)) {/* Calc functional dependencies */
2188 Cell c = getHead(pi);
2190 List xfs = cclass(c).xfds;
2191 for (; nonNull(xfs); xfs=tl(xfs)) {
2192 List fs = snd(hd(xfs));
2193 for (; nonNull(fs); fs=tl(fs)) {
2194 fds = cons(pair(otvars(pi,fst(hd(fs))),
2195 otvars(pi,snd(hd(fs)))),fds);
2201 fds = cons(pair(NIL,offsetTyvarsIn(arg(pi),NIL)),fds);
2208 List calcFunDepsPreds(ps)
2211 for (; nonNull(ps); ps=tl(ps)) {/* Calc functional dependencies */
2213 Cell pi = fst3(pi3);
2214 Cell c = getHead(pi);
2215 Int o = intOf(snd3(pi3));
2217 List xfs = cclass(c).xfds;
2218 for (; nonNull(xfs); xfs=tl(xfs)) {
2219 List fs = snd(hd(xfs));
2220 for (; nonNull(fs); fs=tl(fs)) {
2221 fds = cons(pair(otvarsZonk(pi,fst(hd(fs)),o),
2222 otvarsZonk(pi,snd(hd(fs)),o)),fds);
2228 fds = cons(pair(NIL,zonkTyvarsIn(arg(pi),NIL)),fds);
2235 Void ambigError(line,where,e,type) /* produce error message for */
2236 Int line; /* ambiguity */
2240 ERRMSG(line) "Ambiguous type signature in %s", where ETHEN
2241 ERRTEXT "\n*** ambiguous type : " ETHEN ERRTYPE(type);
2243 ERRTEXT "\n*** assigned to : " ETHEN ERREXPR(e);
2249 /* --------------------------------------------------------------------------
2250 * Kind inference for simple types:
2251 * ------------------------------------------------------------------------*/
2253 static Void local kindConstr(line,alpha,m,c)
2254 Int line; /* Determine kind of constructor */
2258 Cell h = getHead(c);
2262 Printf("kindConstr: alpha=%d, m=%d, c=",alpha,m);
2263 printType(stdout,c);
2267 switch (whatIs(h)) {
2268 case POLYTYPE : if (n!=0) {
2269 internal("kindConstr1");
2271 static String pt = "polymorphic type";
2272 Type t = dropRank1(c,alpha,m);
2273 Kinds ks = polySigOf(t);
2276 for (; isAp(ks); ks=tl(ks)) {
2279 beta = newKindvars(m1);
2280 unkindTypes = cons(pair(mkInt(beta),t),unkindTypes);
2281 checkKind(line,beta,m1,monotypeOf(t),NIL,pt,STAR,0);
2286 case QUAL : if (n!=0) {
2287 internal("kindConstr2");
2289 map3Proc(kindPred,line,alpha,m,fst(snd(c)));
2290 kindConstr(line,alpha,m,snd(snd(c)));
2294 case RANK2 : kindConstr(line,alpha,m,snd(snd(c)));
2298 case EXT : if (n!=2) {
2300 "Illegal use of row in " ETHEN ERRTYPE(c);
2307 case TYCON : if (isSynonym(h) && n<tycon(h).arity) {
2309 "Not enough arguments for type synonym \"%s\"",
2310 textToStr(tycon(h).text)
2316 if (n==0) { /* trivial case, no arguments */
2317 typeIs = kindAtom(alpha,c);
2318 } else { /* non-trivial application */
2319 static String app = "constructor application";
2329 typeIs = kindAtom(alpha,h); /* h :: v1 -> ... -> vn -> w */
2330 shouldKind(line,h,c,app,k,beta);
2332 for (i=n; i>0; --i) { /* ci :: vi for each 1 <- 1..n */
2333 checkKind(line,alpha,m,arg(a),c,app,aVar,beta+i-1);
2336 tyvarType(beta+n); /* inferred kind is w */
2340 static Kind local kindAtom(alpha,c) /* Find kind of atomic constructor */
2343 switch (whatIs(c)) {
2344 case TUPLE : return simpleKind(tupleOf(c)); /*(,)::* -> * -> * */
2345 case OFFSET : return mkInt(alpha+offsetOf(c));
2346 case TYCON : return tycon(c).kind;
2347 case INTCELL : return c;
2349 case VAROPCELL : { Cell vt = findBtyvs(textOf(c));
2355 case EXT : return extKind;
2359 Printf("kindAtom(%d,whatIs(%d)) on ",alpha,whatIs(c));
2360 printType(stdout,c);
2363 internal("kindAtom");
2364 return STAR;/* not reached */
2367 static Void local kindPred(l,alpha,m,pi)/* Check kinds of arguments in pred*/
2373 if (isAp(pi) && isExt(fun(pi))) {
2374 static String lackspred = "lacks predicate";
2375 checkKind(l,alpha,m,arg(pi),NIL,lackspred,ROW,0);
2380 if (isAp(pi) && whatIs(fun(pi)) == IPCELL) {
2381 static String ippred = "iparam predicate";
2382 checkKind(l,alpha,m,arg(pi),NIL,ippred,STAR,0);
2386 { static String predicate = "class constraint";
2387 Class c = getHead(pi);
2388 List as = getArgs(pi);
2389 Kinds ks = cclass(c).kinds;
2391 while (nonNull(ks)) {
2392 checkKind(l,alpha,m,hd(as),NIL,predicate,hd(ks),0);
2399 static Void local kindType(line,wh,type)/* check that (poss qualified) type*/
2400 Int line; /* is well-kinded */
2403 checkKind(line,0,0,type,NIL,wh,STAR,0);
2406 static Void local fixKinds() { /* add kind annotations to types */
2407 for (; nonNull(unkindTypes); unkindTypes=tl(unkindTypes)) {
2408 Pair pr = hd(unkindTypes);
2409 Int beta = intOf(fst(pr));
2410 Cell qts = polySigOf(snd(pr));
2412 if (isNull(hd(qts))) {
2413 hd(qts) = copyKindvar(beta++);
2415 internal("fixKinds");
2417 if (nonNull(tl(qts))) {
2425 Printf("Type expression: ");
2426 printType(stdout,snd(pr));
2428 printKind(stdout,polySigOf(snd(pr)));
2434 /* --------------------------------------------------------------------------
2435 * Kind checking of groups of type constructors and classes:
2436 * ------------------------------------------------------------------------*/
2438 static Void local kindTCGroup(tcs) /* find kinds for mutually rec. gp */
2439 List tcs; { /* of tycons and classes */
2440 emptySubstitution();
2442 mapProc(initTCKind,tcs);
2443 mapProc(kindTC,tcs);
2446 emptySubstitution();
2449 static Void local initTCKind(c) /* build initial kind/arity for c */
2451 if (isTycon(c)) { /* Initial kind of tycon is: */
2452 Int beta = newKindvars(1); /* v1 -> ... -> vn -> vn+1 */
2453 varKind(tycon(c).arity); /* where n is the arity of c. */
2454 bindTv(beta,typeIs,typeOff); /* For data definitions, vn+1 == * */
2455 switch (whatIs(tycon(c).what)) {
2457 case DATATYPE : bindTv(typeOff+tycon(c).arity,STAR,0);
2459 tycon(c).kind = mkInt(beta);
2461 Int n = cclass(c).arity;
2462 Int beta = newKindvars(n);
2463 cclass(c).kinds = NIL;
2466 cclass(c).kinds = pair(mkInt(beta+n),cclass(c).kinds);
2471 static Void local kindTC(c) /* check each part of a tycon/class*/
2472 Cell c; { /* is well-kinded */
2474 static String cfun = "constructor function";
2475 static String tsyn = "synonym definition";
2476 Int line = tycon(c).line;
2477 Int beta = tyvar(intOf(tycon(c).kind))->offs;
2478 Int m = tycon(c).arity;
2479 switch (whatIs(tycon(c).what)) {
2481 case DATATYPE : { List cs = tycon(c).defn;
2482 if (isQualType(cs)) {
2483 map3Proc(kindPred,line,beta,m,
2485 tycon(c).defn = cs = snd(snd(cs));
2487 for (; hasCfun(cs); cs=tl(cs)) {
2488 kindType(line,cfun,name(hd(cs)).type);
2493 default : checkKind(line,beta,m,tycon(c).defn,NIL,
2497 else { /* scan type exprs in class defn to*/
2498 List ms = fst(cclass(c).members);
2499 Int m = cclass(c).arity; /* determine the class signature */
2500 Int beta = newKindvars(m);
2501 kindPred(cclass(c).line,beta,m,cclass(c).head);
2502 map3Proc(kindPred,cclass(c).line,beta,m,cclass(c).supers);
2503 for (; nonNull(ms); ms=tl(ms)) {
2504 Int line = intOf(fst3(hd(ms)));
2505 Type type = thd3(hd(ms));
2506 kindType(line,"member function type signature",type);
2511 static Void local genTC(c) /* generalise kind inferred for */
2512 Cell c; { /* given tycon/class */
2514 tycon(c).kind = copyKindvar(intOf(tycon(c).kind));
2516 Printf("%s :: ",textToStr(tycon(c).text));
2517 printKind(stdout,tycon(c).kind);
2521 Kinds ks = cclass(c).kinds;
2522 for (; nonNull(ks); ks=tl(ks)) {
2523 hd(ks) = copyKindvar(intOf(hd(ks)));
2526 Printf("%s :: ",textToStr(cclass(c).text));
2527 printKinds(stdout,cclass(c).kinds);
2533 /* --------------------------------------------------------------------------
2534 * Static analysis of instance declarations:
2536 * The first part of the static analysis is performed as the declarations
2537 * are read during parsing:
2538 * - make new entry in instance table
2539 * - record line number of declaration
2540 * - build list of instances defined in current script for use in later
2541 * stages of static analysis.
2542 * ------------------------------------------------------------------------*/
2544 Void instDefn(line,head,ms) /* process new instance definition */
2545 Int line; /* definition line number */
2546 Cell head; /* inst header :: (context,Class) */
2547 List ms; { /* instance members */
2548 Inst nw = newInst();
2549 inst(nw).line = line;
2550 inst(nw).specifics = fst(head);
2551 inst(nw).head = snd(head);
2552 inst(nw).implements = ms;
2553 instDefns = cons(nw,instDefns);
2556 /* --------------------------------------------------------------------------
2557 * Further static analysis of instance declarations:
2559 * Makes the following checks:
2560 * - Class part of header has form C (T a1 ... an) where C is a known
2561 * class, and T is a known datatype constructor (or restricted synonym),
2562 * and there is no previous C-T instance, and (T a1 ... an) has a kind
2563 * appropriate for the class C.
2564 * - Each element of context is a valid class expression, with type vars
2565 * drawn from a1, ..., an.
2566 * - All bindings are function bindings
2567 * - All bindings define member functions for class C
2568 * - Arrange bindings into appropriate order for member list
2569 * - No top level type signature declarations
2570 * ------------------------------------------------------------------------*/
2572 Bool allowOverlap = FALSE; /* TRUE => allow overlapping insts */
2573 Name nameListMonad = NIL; /* builder function for List Monad */
2575 static Void local checkInstDefn(in) /* Validate instance declaration */
2577 Int line = inst(in).line;
2578 List tyvars = typeVarsIn(inst(in).head,NIL,NIL,NIL);
2579 List tvps = NIL, tvts = NIL;
2582 if (haskell98) { /* Check for `simple' type */
2584 Cell t = arg(inst(in).head);
2585 for (; isAp(t); t=fun(t)) {
2586 if (!isVar(arg(t))) {
2588 "syntax error in instance head (variable expected)"
2591 if (varIsMember(textOf(arg(t)),tvs)) {
2592 ERRMSG(line) "repeated type variable \"%s\" in instance head",
2593 textToStr(textOf(arg(t)))
2596 tvs = cons(arg(t),tvs);
2600 "syntax error in instance head (constructor expected)"
2605 /* add in the tyvars from the `specifics' so that we don't
2606 prematurely complain about undefined tyvars */
2607 tyvars = typeVarsIn(inst(in).specifics,NIL,NIL,tyvars);
2608 inst(in).head = depPredExp(line,tyvars,inst(in).head);
2611 Type h = getHead(arg(inst(in).head));
2613 ERRMSG(line) "Cannot use type synonym in instance head"
2618 map2Over(depPredExp,line,tyvars,inst(in).specifics);
2620 /* OK, now we start over, and test for ambiguity */
2621 tvts = offsetTyvarsIn(inst(in).head,NIL);
2622 tvps = offsetTyvarsIn(inst(in).specifics,NIL);
2623 fds = calcFunDeps(inst(in).specifics);
2624 tvts = oclose(fds,tvts);
2625 tvts = odiff(tvps,tvts);
2626 if (!isNull(tvts)) {
2627 ERRMSG(line) "Undefined type variable \"%s\"",
2628 textToStr(textOf(nth(offsetOf(hd(tvts)),tyvars)))
2632 h98CheckCtxt(line,"instance definition",FALSE,inst(in).specifics,NIL);
2633 inst(in).numSpecifics = length(inst(in).specifics);
2634 inst(in).c = getHead(inst(in).head);
2635 if (!isClass(inst(in).c)) {
2636 ERRMSG(line) "Illegal predicate in instance declaration"
2640 if (nonNull(cclass(inst(in).c).fds)) {
2641 List fds = cclass(inst(in).c).fds;
2642 for (; nonNull(fds); fds=tl(fds)) {
2643 List as = otvars(inst(in).head, fst(hd(fds)));
2644 List bs = otvars(inst(in).head, snd(hd(fds)));
2645 List fs = calcFunDeps(inst(in).specifics);
2647 if (!osubset(bs,as)) {
2648 ERRMSG(inst(in).line)
2649 "Instance is more general than a dependency allows"
2651 ERRTEXT "\n*** Instance : "
2652 ETHEN ERRPRED(inst(in).head);
2653 ERRTEXT "\n*** For class : "
2654 ETHEN ERRPRED(cclass(inst(in).c).head);
2655 ERRTEXT "\n*** Under dependency : "
2656 ETHEN ERRFD(hd(fds));
2663 kindInst(in,length(tyvars));
2666 if (nonNull(extractSigdecls(inst(in).implements))) {
2668 "Type signature declarations not permitted in instance declaration"
2671 if (nonNull(extractFixdecls(inst(in).implements))) {
2673 "Fixity declarations not permitted in instance declaration"
2676 inst(in).implements = classBindings("instance",
2678 extractBindings(inst(in).implements));
2679 inst(in).builder = newInstImp(in);
2680 if (!preludeLoaded && isNull(nameListMonad) && isAp(inst(in).head)
2681 && fun(inst(in).head)==classMonad && arg(inst(in).head)==typeList) {
2682 nameListMonad = inst(in).builder;
2686 static Void local insertInst(in) /* Insert instance into class */
2688 Class c = inst(in).c;
2689 List ins = cclass(c).instances;
2692 if (nonNull(cclass(c).fds)) { /* Check for conflicts with fds */
2693 List ins1 = cclass(c).instances;
2694 for (; nonNull(ins1); ins1=tl(ins1)) {
2695 List fds = cclass(c).fds;
2696 substitution(RESET);
2697 for (; nonNull(fds); fds=tl(fds)) {
2698 Int alpha = newKindedVars(inst(in).kinds);
2699 Int beta = newKindedVars(inst(hd(ins1)).kinds);
2700 List as = fst(hd(fds));
2702 for (; same && nonNull(as); as=tl(as)) {
2703 Int n = offsetOf(hd(as));
2704 same &= unify(nthArg(n,inst(in).head),alpha,
2705 nthArg(n,inst(hd(ins1)).head),beta);
2707 if (isNull(as) && same) {
2708 for (as=snd(hd(fds)); same && nonNull(as); as=tl(as)) {
2709 Int n = offsetOf(hd(as));
2710 same &= sameType(nthArg(n,inst(in).head),alpha,
2711 nthArg(n,inst(hd(ins1)).head),beta);
2714 ERRMSG(inst(in).line)
2715 "Instances are not consistent with dependencies"
2717 ERRTEXT "\n*** This instance : "
2718 ETHEN ERRPRED(inst(in).head);
2719 ERRTEXT "\n*** Conflicts with : "
2720 ETHEN ERRPRED(inst(hd(ins)).head);
2721 ERRTEXT "\n*** For class : "
2722 ETHEN ERRPRED(cclass(c).head);
2723 ERRTEXT "\n*** Under dependency : "
2724 ETHEN ERRFD(hd(fds));
2734 substitution(RESET);
2735 while (nonNull(ins)) { /* Look for overlap w/ other insts */
2736 Int alpha = newKindedVars(inst(in).kinds);
2737 Int beta = newKindedVars(inst(hd(ins)).kinds);
2738 if (unifyPred(inst(in).head,alpha,inst(hd(ins)).head,beta)) {
2739 Cell pi = copyPred(inst(in).head,alpha);
2740 if (allowOverlap && !haskell98) {
2741 Bool bef = instCompare(in,hd(ins));
2742 Bool aft = instCompare(hd(ins),in);
2743 if (bef && !aft) { /* in comes strictly before hd(ins)*/
2746 if (aft && !bef) { /* in comes strictly after hd(ins) */
2753 if (multiInstRes && nonNull(inst(in).specifics)) {
2757 ERRMSG(inst(in).line) "Overlapping instances for class \"%s\"",
2758 textToStr(cclass(c).text)
2760 ERRTEXT "\n*** This instance : " ETHEN ERRPRED(inst(in).head);
2761 ERRTEXT "\n*** Overlaps with : " ETHEN
2762 ERRPRED(inst(hd(ins)).head);
2763 ERRTEXT "\n*** Common instance : " ETHEN
2771 prev = ins; /* No overlap detected, so move on */
2772 ins = tl(ins); /* to next instance */
2774 substitution(RESET);
2776 if (nonNull(prev)) { /* Insert instance at this point */
2777 tl(prev) = cons(in,ins);
2779 cclass(c).instances = cons(in,ins);
2783 static Bool local instCompare(ia,ib) /* See if ia is an instance of ib */
2785 Int alpha = newKindedVars(inst(ia).kinds);
2786 Int beta = newKindedVars(inst(ib).kinds);
2787 return matchPred(inst(ia).head,alpha,inst(ib).head,beta);
2790 static Name local newInstImp(in) /* Make definition for inst builder*/
2792 Name b = newName(inventText(),in);
2793 name(b).line = inst(in).line;
2794 name(b).arity = inst(in).numSpecifics;
2795 name(b).number = DFUNNAME;
2799 /* --------------------------------------------------------------------------
2800 * Kind checking of instance declaration headers:
2801 * ------------------------------------------------------------------------*/
2803 static Void local kindInst(in,freedom) /* check predicates in instance */
2808 emptySubstitution();
2809 beta = newKindvars(freedom);
2810 kindPred(inst(in).line,beta,freedom,inst(in).head);
2811 if (whatIs(inst(in).specifics)!=DERIVE) {
2812 map3Proc(kindPred,inst(in).line,beta,freedom,inst(in).specifics);
2814 for (inst(in).kinds = NIL; 0<freedom--; ) {
2815 inst(in).kinds = cons(copyKindvar(beta+freedom),inst(in).kinds);
2818 Printf("instance ");
2819 printPred(stdout,inst(in).head);
2821 printKinds(stdout,inst(in).kinds);
2824 emptySubstitution();
2827 /* --------------------------------------------------------------------------
2828 * Process derived instance requests:
2829 * ------------------------------------------------------------------------*/
2831 static List derivedInsts; /* list of derived instances */
2833 static Void local checkDerive(t,p,ts,ct)/* verify derived instance request */
2834 Tycon t; /* for tycon t, with explicit */
2835 List p; /* context p, component types ts */
2836 List ts; /* and named class ct */
2838 Int line = tycon(t).line;
2839 Class c = findQualClass(ct);
2841 ERRMSG(line) "Unknown class \"%s\" in derived instance",
2845 addDerInst(line,c,p,dupList(ts),t,tycon(t).arity);
2848 static Void local addDerInst(line,c,p,cts,t,a) /* Add a derived instance */
2855 Cell head = t; /* Build instance head */
2859 head = ap(head,mkOffset(i));
2865 inst(in).line = line;
2866 inst(in).head = head;
2867 inst(in).specifics = ap(DERIVE,pair(dupList(p),cts));
2868 inst(in).implements = NIL;
2869 inst(in).kinds = mkInt(a);
2870 derivedInsts = cons(in,derivedInsts);
2873 Void addTupInst(c,n) /* Request derived instance of c */
2874 Class c; /* for mkTuple(n) constructor */
2879 cts = cons(mkOffset(m),cts);
2882 addDerInst(0,c,NIL,cts,mkTuple(n),n);
2886 Inst addRecShowInst(c,e) /* Generate instance for ShowRecRow*/
2887 Class c; /* c *must* be ShowRecRow */
2889 Inst in = newInst();
2891 inst(in).head = ap(c,ap2(e,aVar,bVar));
2892 inst(in).kinds = extKind;
2893 inst(in).specifics = cons(ap(classShow,aVar),
2895 cons(ap(c,bVar),NIL)));
2896 inst(in).numSpecifics = 3;
2897 inst(in).builder = implementRecShw(extText(e),in);
2898 cclass(c).instances = appendOnto(cclass(c).instances,singleton(in));
2902 Inst addRecEqInst(c,e) /* Generate instance for EqRecRow */
2903 Class c; /* c *must* be EqRecRow */
2905 Inst in = newInst();
2907 inst(in).head = ap(c,ap2(e,aVar,bVar));
2908 inst(in).kinds = extKind;
2909 inst(in).specifics = cons(ap(classEq,aVar),
2911 cons(ap(c,bVar),NIL)));
2912 inst(in).numSpecifics = 3;
2913 inst(in).builder = implementRecEq(extText(e),in);
2914 cclass(c).instances = appendOnto(cclass(c).instances,singleton(in));
2919 /* --------------------------------------------------------------------------
2920 * Calculation of contexts for derived instances:
2922 * Allowing arbitrary types to appear in contexts makes it rather harder
2923 * to decide what the context for a derived instance should be. For
2926 * data T a = MkT [a] deriving Show,
2928 * we could have either of the following:
2930 * instance (Show [a]) => Show (T a) where ...
2931 * instance (Show a) => Show (T a) where ...
2933 * (assuming, of course, that instance (Show a) => Show [a]). For now, we
2934 * choose to reduce contexts in the hope of detecting errors at an earlier
2935 * stage---in contrast with value definitions, there is no way for a user
2936 * to provide something analogous to a `type signature' by which they might
2937 * be able to control this behaviour themselves. We eliminate tautological
2938 * predicates, but only allow predicates to appear in the final result if
2939 * they have at least one argument with a variable at its head.
2941 * In general, we have to deal with mutually recursive instance declarations.
2942 * We find a solution in the obvious way by iterating to find a fixed point.
2943 * Of course, without restrictions on the form of instance declarations, we
2944 * cannot be sure that this will always terminate!
2946 * For each instance we maintain a pair of the form DERIVE (ctxt,ps).
2947 * Ctxt is a list giving the parts of the context that have been produced
2948 * so far in the form of predicate skeletons. During the calculation of
2949 * derived instances, we attach a dummy NIL value to the end of the list
2950 * which acts as a kind of `variable': other parts of the system maintain
2951 * pointers to this variable, and use it to detect when the context has
2952 * been extended with new elements. Meanwhile, ps is a list containing
2953 * predicates (pi,o) together with (delayed) substitutions of the form
2954 * (o,xs) where o is an offset and xs is one of the context variables
2955 * described above, which may have been partially instantiated.
2956 * ------------------------------------------------------------------------*/
2958 static Bool instsChanged;
2960 static Void local deriveContexts(is) /* Calc contexts for derived insts */
2962 emptySubstitution();
2963 mapProc(initDerInst,is); /* Prepare derived instances */
2965 do { /* Main calculation of contexts */
2966 instsChanged = FALSE;
2967 mapProc(calcInstPreds,is);
2968 } while (instsChanged);
2970 mapProc(tidyDerInst,is); /* Tidy up results */
2973 static Void local initDerInst(in) /* Prepare instance for calculation*/
2974 Inst in; { /* of derived instance context */
2975 Cell spcs = inst(in).specifics;
2976 Int beta = newKindedVars(inst(in).kinds);
2977 if (whatIs(spcs)!=DERIVE) {
2978 internal("initDerInst");
2980 fst(snd(spcs)) = appendOnto(fst(snd(spcs)),singleton(NIL));
2981 for (spcs=snd(snd(spcs)); nonNull(spcs); spcs=tl(spcs)) {
2982 hd(spcs) = ap2(inst(in).c,hd(spcs),mkInt(beta));
2984 inst(in).numSpecifics = beta;
2986 #ifdef DEBUG_DERIVING
2987 Printf("initDerInst: ");
2988 printPred(stdout,inst(in).head);
2990 printContext(stdout,snd(snd(inst(in).specifics)));
2995 static Void local calcInstPreds(in) /* Calculate next approximation */
2996 Inst in; { /* of the context for a derived */
2997 List retain = NIL; /* instance */
2998 List ps = snd(snd(inst(in).specifics));
2999 List spcs = fst(snd(inst(in).specifics));
3000 Int beta = inst(in).numSpecifics;
3002 Int factor = 1+length(ps);
3004 #ifdef DEBUG_DERIVING
3005 Printf("calcInstPreds: ");
3006 printPred(stdout,inst(in).head);
3010 while (nonNull(ps)) {
3013 if (its++ >= factor*cutoff) {
3014 Cell bpi = inst(in).head;
3015 ERRMSG(inst(in).line) "\n*** Cannot derive " ETHEN ERRPRED(bpi);
3016 ERRTEXT " after %d iterations.", its-1 ETHEN
3018 "\n*** This may indicate that the problem is undecidable. However,\n"
3020 "*** you may still try to increase the cutoff limit using the -c\n"
3022 "*** option and then try again. (The current setting is -c%d)\n",
3026 if (isInt(fst(p))) { /* Delayed substitution? */
3028 for (; nonNull(hd(qs)); qs=tl(qs)) {
3029 ps = cons(pair(hd(qs),fst(p)),ps);
3031 retain = cons(pair(fst(p),qs),retain);
3034 else if (isExt(fun(fst(p)))) { /* Lacks predicate */
3035 Text l = extText(fun(fst(p)));
3036 Type t = arg(fst(p));
3037 Int o = intOf(snd(p));
3042 h = getDerefHead(t,o);
3043 while (isExt(h) && argCount==2 && l!=extText(h)) {
3046 h = getDerefHead(t,o);
3048 if (argCount==0 && isOffset(h)) {
3049 maybeAddPred(ap(fun(fun(p)),h),o,beta,spcs);
3050 } else if (argCount!=0 || h!=typeNoRow) {
3051 Cell bpi = inst(in).head;
3052 Cell pi = copyPred(fun(p),intOf(snd(p)));
3053 ERRMSG(inst(in).line) "Cannot derive " ETHEN ERRPRED(bpi);
3054 ERRTEXT " because predicate " ETHEN ERRPRED(pi);
3055 ERRTEXT " does not hold\n"
3060 else { /* Class predicate */
3062 Int o = intOf(snd(p));
3063 Inst in1 = findInstFor(pi,o);
3065 List qs = inst(in1).specifics;
3066 Int off = mkInt(typeOff);
3067 if (whatIs(qs)==DERIVE) { /* Still being derived */
3068 for (qs=fst(snd(qs)); nonNull(hd(qs)); qs=tl(qs)) {
3069 ps = cons(pair(hd(qs),off),ps);
3071 retain = cons(pair(off,qs),retain);
3072 } else { /* Previously def'd inst */
3073 for (; nonNull(qs); qs=tl(qs)) {
3074 ps = cons(pair(hd(qs),off),ps);
3077 } else { /* No matching instance */
3079 while (isAp(qi) && isOffset(getDerefHead(arg(qi),o))) {
3083 Cell bpi = inst(in).head;
3084 pi = copyPred(pi,o);
3085 ERRMSG(inst(in).line) "An instance of " ETHEN ERRPRED(pi);
3086 ERRTEXT " is required to derive " ETHEN ERRPRED(bpi);
3090 maybeAddPred(pi,o,beta,spcs);
3095 snd(snd(inst(in).specifics)) = retain;
3098 static Void local maybeAddPred(pi,o,beta,ps)
3099 Cell pi; /* Add predicate pi to the list ps,*/
3100 Int o; /* setting the instsChanged flag if*/
3101 Int beta; /* pi is not already a member and */
3102 List ps; { /* using beta to adjust vars */
3103 Cell c = getHead(pi);
3104 for (; nonNull(ps); ps=tl(ps)) {
3105 if (isNull(hd(ps))) { /* reached the `dummy' end of list?*/
3106 hd(ps) = copyAdj(pi,o,beta);
3107 tl(ps) = pair(NIL,NIL);
3108 instsChanged = TRUE;
3110 } else if (c==getHead(hd(ps)) && samePred(pi,o,hd(ps),beta)) {
3116 static Cell local copyAdj(c,o,beta) /* Copy (c,o), replacing vars with */
3117 Cell c; /* offsets relative to beta. */
3120 switch (whatIs(c)) {
3121 case AP : { Cell l = copyAdj(fst(c),o,beta);
3122 Cell r = copyAdj(snd(c),o,beta);
3126 case OFFSET : { Int vn = o+offsetOf(c);
3127 Tyvar *tyv = tyvar(vn);
3129 return copyAdj(tyv->bound,tyv->offs,beta);
3132 if (vn<0 || vn>=(OFF_MAX-OFF_MIN+1)) {
3133 internal("copyAdj");
3135 return mkOffset(vn);
3141 static Void local tidyDerInst(in) /* Tidy up results of derived inst */
3142 Inst in; { /* calculations */
3143 Int o = inst(in).numSpecifics;
3144 List ps = tl(rev(fst(snd(inst(in).specifics))));
3146 copyPred(inst(in).head,o);
3147 inst(in).specifics = simpleContext(ps,o);
3148 h98CheckCtxt(inst(in).line,"derived instance",FALSE,inst(in).specifics,in);
3149 inst(in).numSpecifics = length(inst(in).specifics);
3151 #ifdef DEBUG_DERIVING
3152 Printf("Derived instance: ");
3153 printContext(stdout,inst(in).specifics);
3155 printPred(stdout,inst(in).head);
3160 /* --------------------------------------------------------------------------
3161 * Generate code for derived instances:
3162 * ------------------------------------------------------------------------*/
3164 static Void local addDerivImp(in)
3167 Type t = getHead(arg(inst(in).head));
3168 Class c = inst(in).c;
3171 } else if (c==classOrd) {
3173 } else if (c==classEnum) {
3174 imp = deriveEnum(t);
3175 } else if (c==classIx) {
3177 } else if (c==classShow) {
3178 imp = deriveShow(t);
3179 } else if (c==classRead) {
3180 imp = deriveRead(t);
3181 } else if (c==classBounded) {
3182 imp = deriveBounded(t);
3184 ERRMSG(inst(in).line) "Cannot derive instances of class \"%s\"",
3185 textToStr(cclass(inst(in).c).text)
3189 kindInst(in,intOf(inst(in).kinds));
3191 inst(in).builder = newInstImp(in);
3192 inst(in).implements = classBindings("derived instance",
3198 /* --------------------------------------------------------------------------
3199 * Default definitions; only one default definition is permitted in a
3200 * given script file. If no default is supplied, then a standard system
3201 * default will be used where necessary.
3202 * ------------------------------------------------------------------------*/
3204 Void defaultDefn(line,defs) /* Handle default types definition */
3207 if (defaultLine!=0) {
3208 ERRMSG(line) "Multiple default declarations are not permitted in" ETHEN
3209 ERRTEXT "a single script file.\n"
3212 defaultDefns = defs;
3216 static Void local checkDefaultDefns() { /* check that default types are */
3217 List ds = NIL; /* well-kinded instances of Num */
3219 if (defaultLine!=0) {
3220 map2Over(depTypeExp,defaultLine,NIL,defaultDefns);
3221 emptySubstitution();
3223 map2Proc(kindType,defaultLine,"default type",defaultDefns);
3225 emptySubstitution();
3226 mapOver(fullExpand,defaultDefns);
3228 defaultDefns = stdDefaults;
3231 if (isNull(classNum)) {
3232 classNum = findClass(findText("Num"));
3235 for (ds=defaultDefns; nonNull(ds); ds=tl(ds)) {
3236 if (isNull(provePred(NIL,NIL,ap(classNum,hd(ds))))) {
3238 "Default types must be instances of the Num class"
3245 /* --------------------------------------------------------------------------
3246 * Foreign import declarations are Hugs' equivalent of GHC's ccall mechanism.
3247 * They are used to "import" C functions into a module.
3248 * They are usually not written by hand but, rather, generated automatically
3249 * by GreenCard, IDL compilers or whatever. We support foreign import
3250 * (static) and foreign import dynamic. In the latter case, extName==NIL.
3252 * Foreign export declarations generate C wrappers for Hugs functions.
3253 * Hugs only provides "foreign export dynamic" because it's not obvious
3254 * what "foreign export static" would mean in an interactive setting.
3255 * ------------------------------------------------------------------------*/
3257 Void foreignImport(line,callconv,extName,intName,type)
3258 /* Handle foreign imports */
3264 Text t = textOf(intName);
3265 Name n = findName(t);
3269 } else if (name(n).defn!=PREDEFINED) {
3270 ERRMSG(line) "Redeclaration of foreign \"%s\"", textToStr(t)
3273 name(n).line = line;
3274 name(n).defn = extName;
3275 name(n).type = type;
3276 name(n).callconv = callconv;
3277 foreignImports = cons(n,foreignImports);
3280 static Void local checkForeignImport(p) /* Check foreign import */
3282 emptySubstitution();
3283 name(p).type = checkSigType(name(p).line,
3284 "foreign import declaration",
3287 /* We don't expand synonyms here because we don't want the IO
3288 * part to be expanded.
3289 * name(p).type = fullExpand(name(p).type);
3291 implementForeignImport(p);
3294 Void foreignExport(line,callconv,extName,intName,type)
3295 /* Handle foreign exports */
3301 Text t = textOf(intName);
3302 Name n = findName(t);
3306 } else if (name(n).defn!=PREDEFINED) {
3307 ERRMSG(line) "Redeclaration of foreign \"%s\"", textToStr(t)
3310 name(n).line = line;
3311 name(n).defn = NIL; /* nothing to say */
3312 name(n).type = type;
3313 name(n).callconv = callconv;
3314 foreignExports = cons(n,foreignExports);
3317 static Void local checkForeignExport(p) /* Check foreign export */
3319 emptySubstitution();
3320 name(p).type = checkSigType(name(p).line,
3321 "foreign export declaration",
3324 implementForeignExport(p);
3329 /* --------------------------------------------------------------------------
3330 * Static analysis of patterns:
3332 * Patterns are parsed as ordinary (atomic) expressions. Static analysis
3333 * makes the following checks:
3334 * - Patterns are well formed (according to pattern syntax), including the
3335 * special case of (n+k) patterns.
3336 * - All constructor functions have been defined and are used with the
3337 * correct number of arguments.
3338 * - No variable name is used more than once in a pattern.
3340 * The list of pattern variables occuring in each pattern is accumulated in
3341 * a global list `patVars', which must be initialised to NIL at appropriate
3342 * points before using these routines to check for valid patterns. This
3343 * mechanism enables the pattern checking routine to be mapped over a list
3344 * of patterns, ensuring that no variable occurs more than once in the
3345 * complete pattern list (as is required on the lhs of a function defn).
3346 * ------------------------------------------------------------------------*/
3348 static List patVars; /* List of vars bound in pattern */
3350 static Cell local checkPat(line,p) /* Check valid pattern syntax */
3353 switch (whatIs(p)) {
3355 case VAROPCELL : addToPatVars(line,p);
3358 case INFIX : return checkPat(line,tidyInfix(line,snd(p)));
3360 case AP : return checkMaybeCnkPat(line,p);
3365 case CONOPCELL : return checkApPat(line,0,p);
3370 case FLOATCELL : break;
3371 case INTCELL : break;
3373 case ASPAT : addToPatVars(line,fst(snd(p)));
3374 snd(snd(p)) = checkPat(line,snd(snd(p)));
3377 case LAZYPAT : snd(p) = checkPat(line,snd(p));
3380 case FINLIST : map1Over(checkPat,line,snd(p));
3383 case CONFLDS : depConFlds(line,p,TRUE);
3386 case ESIGN : snd(snd(p)) = checkPatType(line,
3390 fst(snd(p)) = checkPat(line,fst(snd(p)));
3393 default : ERRMSG(line) "Illegal pattern syntax"
3399 static Cell local checkMaybeCnkPat(l,p)/* Check applicative pattern with */
3400 Int l; /* the possibility of n+k pattern */
3402 Cell h = getHead(p);
3404 if (argCount==2 && isVar(h) && textOf(h)==textPlus) { /* n+k */
3405 Cell v = arg(fun(p));
3406 if (!isInt(arg(p))) {
3407 ERRMSG(l) "Second argument in (n+k) pattern must be an integer"
3410 if (intOf(arg(p))<=0) {
3411 ERRMSG(l) "Integer k in (n+k) pattern must be > 0"
3414 fst(fun(p)) = ADDPAT;
3415 intValOf(fun(p)) = intOf(arg(p));
3416 arg(p) = checkPat(l,v);
3419 return checkApPat(l,0,p);
3422 static Cell local checkApPat(line,args,p)
3423 Int line; /* check validity of application */
3424 Int args; /* of constructor to arguments */
3426 switch (whatIs(p)) {
3427 case AP : fun(p) = checkApPat(line,args+1,fun(p));
3428 arg(p) = checkPat(line,arg(p));
3431 case TUPLE : if (tupleOf(p)!=args) {
3432 ERRMSG(line) "Illegal tuple pattern"
3438 case EXT : h98DoesntSupport(line,"extensible records");
3440 ERRMSG(line) "Illegal record pattern"
3446 case QUALIDENT : if (!isQCon(p)) {
3448 "Illegal use of qualified variable in pattern"
3451 /* deliberate fall through */
3453 case CONOPCELL : p = conDefined(line,p);
3454 checkCfunArgs(line,p,args);
3457 case NAME : checkIsCfun(line,p);
3458 checkCfunArgs(line,p,args);
3461 default : ERRMSG(line) "Illegal pattern syntax"
3467 static Void local addToPatVars(line,v) /* Add variable v to list of vars */
3468 Int line; /* in current pattern, checking */
3469 Cell v; { /* for repeated variables. */
3474 for (; nonNull(n); p=n, n=tl(n)) {
3475 if (textOf(hd(n))==t) {
3476 ERRMSG(line) "Repeated variable \"%s\" in pattern",
3483 patVars = cons(v,NIL);
3485 tl(p) = cons(v,NIL);
3489 static Name local conDefined(line,nm) /* check that nm is the name of a */
3490 Int line; /* previously defined constructor */
3491 Cell nm; { /* function. */
3492 Name n = findQualName(nm);
3494 ERRMSG(line) "Undefined constructor function \"%s\"", identToStr(nm)
3497 checkIsCfun(line,n);
3501 static Void local checkIsCfun(line,c) /* Check that c is a constructor fn */
3505 ERRMSG(line) "\"%s\" is not a constructor function",
3506 textToStr(name(c).text)
3511 static Void local checkCfunArgs(line,c,args)
3512 Int line; /* Check constructor applied with */
3513 Cell c; /* correct number of arguments */
3515 Int a = userArity(c);
3518 "Constructor \"%s\" must have exactly %d argument%s in pattern",
3519 textToStr(name(c).text), a, ((a==1)?"":"s")
3524 static Cell local checkPatType(l,wh,e,t)/* Check type appearing in pattern */
3529 List tvs = typeVarsIn(t,NIL,NIL,NIL);
3530 h98DoesntSupport(l,"pattern type annotations");
3531 for (; nonNull(tvs); tvs=tl(tvs)) {
3532 Int beta = newKindvars(1);
3533 hd(btyvars) = cons(pair(hd(tvs),mkInt(beta)), hd(btyvars));
3535 t = checkSigType(l,"pattern type",e,t);
3536 if (isPolyOrQualType(t) || whatIs(t)==RANK2) {
3537 ERRMSG(l) "Illegal syntax in %s type annotation", wh
3543 static Cell local applyBtyvs(pat) /* Record bound type vars in pat */
3545 List bts = hd(btyvars);
3548 pat = ap(BIGLAM,pair(bts,pat));
3549 for (; nonNull(bts); bts=tl(bts)) {
3550 snd(hd(bts)) = copyKindvar(intOf(snd(hd(bts))));
3556 /* --------------------------------------------------------------------------
3557 * Maintaining lists of bound variables and local definitions, for
3558 * dependency and scope analysis.
3559 * ------------------------------------------------------------------------*/
3561 static List bounds; /* list of lists of bound vars */
3562 static List bindings; /* list of lists of binds in scope */
3563 static List depends; /* list of lists of dependents */
3565 /* bounds :: [[Var]] -- var equality used on Vars */
3566 /* bindings :: [[([Var],?)]] -- var equality used on Vars */
3567 /* depends :: [[Var]] -- pointer equality used on Vars */
3569 #define saveBvars() hd(bounds) /* list of bvars in current scope */
3570 #define restoreBvars(bs) hd(bounds)=bs /* restore list of bound variables */
3572 static Cell local bindPat(line,p) /* add new bound vars for pattern */
3576 p = checkPat(line,p);
3577 hd(bounds) = revOnto(patVars,hd(bounds));
3581 static Void local bindPats(line,ps) /* add new bound vars for patterns */
3585 map1Over(checkPat,line,ps);
3586 hd(bounds) = revOnto(patVars,hd(bounds));
3589 /* --------------------------------------------------------------------------
3590 * Before processing value and type signature declarations, all data and
3591 * type definitions have been processed so that:
3592 * - all valid type constructors (with their arities) are known.
3593 * - all valid constructor functions (with their arities and types) are
3596 * The result of parsing a list of value declarations is a list of Eqns:
3597 * Eqn ::= (SIGDECL,(Line,[Var],type))
3598 * | (FIXDECL,(Line,[Op],SyntaxInt))
3600 * The ordering of the equations in this list is the reverse of the original
3601 * ordering in the script parsed. This is a consequence of the structure of
3602 * the parser ... but also turns out to be most convenient for the static
3605 * As the first stage of the static analysis of value declarations, each
3606 * list of Eqns is converted to a list of Bindings. As part of this
3608 * - The ordering of the list of Bindings produced is the same as in the
3610 * - When a variable (function) is defined over a number of lines, all
3611 * of the definitions should appear together and each should give the
3612 * same arity to the variable being defined.
3613 * - No variable can have more than one definition.
3614 * - For pattern bindings:
3615 * - Each lhs is a valid pattern/function lhs, all constructor functions
3616 * have been defined and are used with the correct number of arguments.
3617 * - Each lhs contains no repeated pattern variables.
3618 * - Each equation defines at least one variable (e.g. True = False is
3620 * - Types appearing in type signatures are well formed:
3621 * - Type constructors used are defined and used with correct number
3623 * - type variables are replaced by offsets, type constructor names
3625 * - Every variable named in a type signature declaration is defined by
3626 * one or more equations elsewhere in the script.
3627 * - No variable has more than one type declaration.
3628 * - Similar properties for fixity declarations.
3630 * ------------------------------------------------------------------------*/
3632 #define bindingAttr(b) fst(snd(b)) /* type(s)/fixity(ies) for binding */
3633 #define fbindAlts(b) snd(snd(b)) /* alternatives for function binding*/
3635 static List local extractSigdecls(es) /* Extract the SIGDECLS from list */
3636 List es; { /* of equations */
3637 List sigdecls = NIL; /* :: [(Line,[Var],Type)] */
3639 for(; nonNull(es); es=tl(es)) {
3640 if (fst(hd(es))==SIGDECL) { /* type-declaration? */
3641 Pair sig = snd(hd(es));
3642 Int line = intOf(fst3(sig));
3643 List vs = snd3(sig);
3644 for(; nonNull(vs); vs=tl(vs)) {
3645 if (isQualIdent(hd(vs))) {
3646 ERRMSG(line) "Type signature for qualified variable \"%s\" is not allowed",
3651 sigdecls = cons(sig,sigdecls); /* discard SIGDECL tag*/
3657 static List local extractFixdecls(es) /* Extract the FIXDECLS from list */
3658 List es; { /* of equations */
3659 List fixdecls = NIL; /* :: [(Line,SyntaxInt,[Op])] */
3661 for(; nonNull(es); es=tl(es)) {
3662 if (fst(hd(es))==FIXDECL) { /* fixity declaration?*/
3663 fixdecls = cons(snd(hd(es)),fixdecls); /* discard FIXDECL tag*/
3669 static List local extractBindings(ds) /* extract untyped bindings from */
3670 List ds; { /* given list of equations */
3671 Cell lastVar = NIL; /* = var def'd in last eqn (if any)*/
3672 Int lastArity = 0; /* = number of args in last defn */
3673 List bs = NIL; /* :: [Binding] */
3675 for(; nonNull(ds); ds=tl(ds)) {
3677 if (fst(d)==FUNBIND) { /* Function bindings */
3678 Cell rhs = snd(snd(d));
3679 Int line = rhsLine(rhs);
3680 Cell lhs = fst(snd(d));
3681 Cell v = getHead(lhs);
3682 Cell newAlt = pair(getArgs(lhs),rhs);
3684 internal("FUNBIND");
3686 if (nonNull(lastVar) && textOf(v)==textOf(lastVar)) {
3687 if (argCount!=lastArity) {
3688 ERRMSG(line) "Equations give different arities for \"%s\"",
3689 textToStr(textOf(v))
3692 fbindAlts(hd(bs)) = cons(newAlt,fbindAlts(hd(bs)));
3696 lastArity = argCount;
3697 notDefined(line,bs,v);
3698 bs = cons(pair(v,pair(NIL,singleton(newAlt))),bs);
3701 } else if (fst(d)==PATBIND) { /* Pattern bindings */
3702 Cell rhs = snd(snd(d));
3703 Int line = rhsLine(rhs);
3704 Cell pat = fst(snd(d));
3705 while (whatIs(pat)==ESIGN) {/* Move type annotations to rhs */
3706 Cell p = fst(snd(pat));
3707 fst(snd(pat)) = rhs;
3708 snd(snd(d)) = rhs = pat;
3709 fst(snd(d)) = pat = p;
3712 if (isVar(pat)) { /* Convert simple pattern bind to */
3713 notDefined(line,bs,pat);/* a function binding */
3714 bs = cons(pair(pat,pair(NIL,singleton(pair(NIL,rhs)))),bs);
3716 List vs = getPatVars(line,pat,NIL);
3718 ERRMSG(line) "No variables defined in lhs pattern"
3721 map2Proc(notDefined,line,bs,vs);
3722 bs = cons(pair(vs,pair(NIL,snd(d))),bs);
3730 static List local getPatVars(line,p,vs) /* Find list of variables bound in */
3731 Int line; /* pattern p */
3734 switch (whatIs(p)) {
3736 vs = getPatVars(line,arg(p),vs);
3739 return vs; /* Ignore head of application */
3741 case CONFLDS : { List pfs = snd(snd(p));
3742 for (; nonNull(pfs); pfs=tl(pfs)) {
3743 if (isVar(hd(pfs))) {
3744 vs = addPatVar(line,hd(pfs),vs);
3746 vs = getPatVars(line,snd(hd(pfs)),vs);
3752 case FINLIST : { List ps = snd(p);
3753 for (; nonNull(ps); ps=tl(ps)) {
3754 vs = getPatVars(line,hd(ps),vs);
3759 case ESIGN : return getPatVars(line,fst(snd(p)),vs);
3764 case INFIX : return getPatVars(line,snd(p),vs);
3766 case ASPAT : return addPatVar(line,fst(snd(p)),
3767 getPatVars(line,snd(snd(p)),vs));
3770 case VAROPCELL : return addPatVar(line,p,vs);
3780 case WILDCARD : return vs;
3782 default : internal("getPatVars");
3787 static List local addPatVar(line,v,vs) /* Add var to list of previously */
3788 Int line; /* encountered variables */
3791 if (varIsMember(textOf(v),vs)) {
3792 ERRMSG(line) "Repeated use of variable \"%s\" in pattern binding",
3793 textToStr(textOf(v))
3799 static List local eqnsToBindings(es,ts,cs,ps)
3800 List es; /* Convert list of equations to */
3801 List ts; /* list of typed bindings */
3804 List bs = extractBindings(es);
3805 map1Proc(addSigdecl,bs,extractSigdecls(es));
3806 map4Proc(addFixdecl,bs,ts,cs,ps,extractFixdecls(es));
3810 static Void local notDefined(line,bs,v)/* check if name already defined in */
3811 Int line; /* list of bindings */
3814 if (nonNull(findBinding(textOf(v),bs))) {
3815 ERRMSG(line) "\"%s\" multiply defined", textToStr(textOf(v))
3820 static Cell local findBinding(t,bs) /* look for binding for variable t */
3821 Text t; /* in list of bindings bs */
3823 for (; nonNull(bs); bs=tl(bs)) {
3824 if (isVar(fst(hd(bs)))) { /* function-binding? */
3825 if (textOf(fst(hd(bs)))==t) {
3828 } else if (nonNull(varIsMember(t,fst(hd(bs))))){/* pattern-binding?*/
3835 static Cell local getAttr(bs,v) /* Locate type/fixity attribute */
3836 List bs; /* for variable v in bindings bs */
3839 Cell b = findBinding(t,bs);
3841 if (isNull(b)) { /* No binding */
3843 } else if (isVar(fst(b))) { /* func binding? */
3844 if (isNull(bindingAttr(b))) {
3845 bindingAttr(b) = pair(NIL,NIL);
3847 return bindingAttr(b);
3848 } else { /* pat binding? */
3850 List as = bindingAttr(b);
3853 bindingAttr(b) = as = replicate(length(vs),NIL);
3856 while (nonNull(vs) && t!=textOf(hd(vs))) {
3862 internal("getAttr");
3863 } else if (isNull(hd(as))) {
3864 hd(as) = pair(NIL,NIL);
3870 static Void local addSigdecl(bs,sigdecl)/* add type information to bindings*/
3871 List bs; /* :: [Binding] */
3872 Cell sigdecl; { /* :: (Line,[Var],Type) */
3873 Int l = intOf(fst3(sigdecl));
3874 List vs = snd3(sigdecl);
3875 Type type = checkSigType(l,"type declaration",hd(vs),thd3(sigdecl));
3877 for (; nonNull(vs); vs=tl(vs)) {
3879 Pair attr = getAttr(bs,v);
3881 ERRMSG(l) "Missing binding for variable \"%s\" in type signature",
3882 textToStr(textOf(v))
3884 } else if (nonNull(fst(attr))) {
3885 ERRMSG(l) "Repeated type signature for \"%s\"",
3886 textToStr(textOf(v))
3893 static Void local addFixdecl(bs,ts,cs,ps,fixdecl)
3899 Int line = intOf(fst3(fixdecl));
3900 List ops = snd3(fixdecl);
3901 Cell sy = thd3(fixdecl);
3903 for (; nonNull(ops); ops=tl(ops)) {
3905 Text t = textOf(op);
3906 Cell attr = getAttr(bs,op);
3907 if (nonNull(attr)) { /* Found name in binding? */
3908 if (nonNull(snd(attr))) {
3912 } else { /* Look in tycons, classes, prims */
3917 for (; isNull(n) && nonNull(ts1); ts1=tl(ts1)) { /* tycons */
3919 if (tycon(tc).what==DATATYPE || tycon(tc).what==NEWTYPE) {
3920 n = nameIsMember(t,tycon(tc).defn);
3923 for (; isNull(n) && nonNull(cs1); cs1=tl(cs1)) { /* classes */
3924 n = nameIsMember(t,cclass(hd(cs1)).members);
3926 for (; isNull(n) && nonNull(ps1); ps1=tl(ps1)) { /* prims */
3927 n = nameIsMember(t,hd(ps1));
3932 } else if (name(n).syntax!=NO_SYNTAX) {
3935 name(n).syntax = intOf(sy);
3940 static Void local dupFixity(line,t) /* Report repeated fixity decl */
3944 "Repeated fixity declaration for operator \"%s\"", textToStr(t)
3948 static Void local missFixity(line,t) /* Report missing op for fixity */
3952 "Cannot find binding for operator \"%s\" in fixity declaration",
3957 /* --------------------------------------------------------------------------
3958 * Dealing with infix operators:
3960 * Expressions involving infix operators or unary minus are parsed as
3961 * elements of the following type:
3963 * data InfixExp = Only Exp | Neg InfixExp | Infix InfixExp Op Exp
3965 * (The algorithms here do not assume that negation can be applied only once,
3966 * i.e., that - - x is a syntax error, as required by the Haskell report.
3967 * Instead, that restriction is captured by the grammar itself, given above.)
3969 * There are rules of precedence and grouping, expressed by two functions:
3971 * prec :: Op -> Int; assoc :: Op -> Assoc (Assoc = {L, N, R})
3973 * InfixExp values are rearranged accordingly when a complete expression
3974 * has been read using a simple shift-reduce parser whose result may be taken
3975 * to be a value of the following type:
3977 * data Exp = Atom Int | Negate Exp | Apply Op Exp Exp | Error String
3979 * The machine on which this parser is based can be defined as follows:
3981 * tidy :: InfixExp -> [(Op,Exp)] -> Exp
3982 * tidy (Only a) [] = a
3983 * tidy (Only a) ((o,b):ss) = tidy (Only (Apply o a b)) ss
3984 * tidy (Infix a o b) [] = tidy a [(o,b)]
3985 * tidy (Infix a o b) ((p,c):ss)
3986 * | shift o p = tidy a ((o,b):(p,c):ss)
3987 * | red o p = tidy (Infix a o (Apply p b c)) ss
3988 * | ambig o p = Error "ambiguous use of operators"
3989 * tidy (Neg e) [] = tidy (tidyNeg e) []
3990 * tidy (Neg e) ((o,b):ss)
3991 * | nshift o = tidy (Neg (underNeg o b e)) ss
3992 * | nred o = tidy (tidyNeg e) ((o,b):ss)
3993 * | nambig o = Error "illegal use of negation"
3995 * At each stage, the parser can either shift, reduce, accept, or error.
3996 * The transitions when dealing with juxtaposed operators o and p are
3997 * determined by the following rules:
3999 * shift o p = (prec o > prec p)
4000 * || (prec o == prec p && assoc o == L && assoc p == L)
4002 * red o p = (prec o < prec p)
4003 * || (prec o == prec p && assoc o == R && assoc p == R)
4005 * ambig o p = (prec o == prec p)
4006 * && (assoc o == N || assoc p == N || assoc o /= assoc p)
4008 * The transitions when dealing with juxtaposed unary minus and infix
4009 * operators are as follows. The precedence of unary minus (infixl 6) is
4010 * hardwired in to these definitions, as it is to the definitions of the
4011 * Haskell grammar in the official report.
4013 * nshift o = (prec o > 6)
4014 * nred o = (prec o < 6) || (prec o == 6 && assoc o == L)
4015 * nambig o = prec o == 6 && (assoc o == R || assoc o == N)
4017 * An InfixExp of the form (Neg e) means negate the last thing in
4018 * the InfixExp e; we can force this negation using:
4020 * tidyNeg :: OpExp -> OpExp
4021 * tidyNeg (Only e) = Only (Negate e)
4022 * tidyNeg (Infix a o b) = Infix a o (Negate b)
4023 * tidyNeg (Neg e) = tidyNeg (tidyNeg e)
4025 * On the other hand, if we want to sneak application of an infix operator
4026 * under a negation, then we use:
4028 * underNeg :: Op -> Exp -> OpExp -> OpExp
4029 * underNeg o b (Only e) = Only (Apply o e b)
4030 * underNeg o b (Neg e) = Neg (underNeg o b e)
4031 * underNeg o b (Infix e p f) = Infix e p (Apply o f b)
4033 * As a concession to efficiency, we lower the number of calls to syntaxOf
4034 * by keeping track of the values of sye, sys throughout the process. The
4035 * value APPLIC is used to indicate that the syntax value is unknown.
4036 * ------------------------------------------------------------------------*/
4038 static Cell local tidyInfix(line,e) /* Convert infixExp to Exp */
4040 Cell e; { /* :: OpExp */
4041 Cell s = NIL; /* :: [(Op,Exp)] */
4042 Syntax sye = APPLIC; /* Syntax of op in e (init unknown)*/
4043 Syntax sys = APPLIC; /* Syntax of op in s (init unknown)*/
4046 while (fst(d)!=ONLY) { /* Attach fixities to operators */
4050 fun(fun(d)) = attachFixity(line,fun(fun(d)));
4056 switch (whatIs(e)) {
4057 case ONLY : e = snd(e);
4058 while (nonNull(s)) {
4059 Cell next = arg(fun(s));
4061 fun(fun(s)) = snd(fun(fun(s)));
4067 case NEG : if (nonNull(s)) {
4068 if (sys==APPLIC) { /* calculate sys */
4069 sys = intOf(fst(fun(fun(s))));
4072 if (precOf(sys)==UMINUS_PREC && /* nambig */
4073 assocOf(sys)!=UMINUS_ASSOC) {
4075 "Ambiguous use of unary minus with \""
4076 ETHEN ERREXPR(snd(fun(fun(s))));
4081 if (precOf(sys)>UMINUS_PREC) { /* nshift */
4085 while (whatIs(e1)==NEG)
4087 arg(fun(t)) = arg(e1);
4088 fun(fun(t)) = snd(fun(fun(t)));
4095 /* Intentional fall-thru for nreduce and isNull(s) */
4097 { Cell prev = e; /* e := tidyNeg e */
4098 Cell temp = arg(prev);
4100 for (; whatIs(temp)==NEG; nneg++) {
4101 fun(prev) = nameNegate;
4105 if (isInt(arg(temp))) { /* special cases */
4106 if (nneg&1) /* for literals */
4107 arg(temp) = mkInt(-intOf(arg(temp)));
4109 else if (isFloat(arg(temp))) {
4111 arg(temp) = floatNegate(arg(temp));
4112 //mkFloat(-floatOf(arg(temp)));
4115 fun(prev) = nameNegate;
4116 arg(prev) = arg(temp);
4123 default : if (isNull(s)) {/* Move operation onto empty stack */
4124 Cell next = arg(fun(e));
4131 else { /* deal with pair of operators */
4133 if (sye==APPLIC) { /* calculate sys and sye */
4134 sye = intOf(fst(fun(fun(e))));
4137 sys = intOf(fst(fun(fun(s))));
4140 if (precOf(sye)==precOf(sys) && /* ambig */
4141 (assocOf(sye)!=assocOf(sys) ||
4142 assocOf(sye)==NON_ASS)) {
4143 ERRMSG(line) "Ambiguous use of operator \""
4144 ETHEN ERREXPR(snd(fun(fun(e))));
4145 ERRTEXT "\" with \""
4146 ETHEN ERREXPR(snd(fun(fun(s))));
4151 if (precOf(sye)>precOf(sys) || /* shift */
4152 (precOf(sye)==precOf(sys) &&
4153 assocOf(sye)==LEFT_ASS &&
4154 assocOf(sys)==LEFT_ASS)) {
4155 Cell next = arg(fun(e));
4163 Cell next = arg(fun(s));
4164 arg(fun(s)) = arg(e);
4165 fun(fun(s)) = snd(fun(fun(s)));
4176 static Pair local attachFixity(line,op) /* Attach fixity to operator in an */
4177 Int line; /* infix expression */
4179 Syntax sy = DEF_OPSYNTAX;
4181 switch (whatIs(op)) {
4183 case VARIDCELL : if ((sy=lookupSyntax(textOf(op)))==NO_SYNTAX) {
4184 Name n = findName(textOf(op));
4186 ERRMSG(line) "Undefined variable \"%s\"",
4187 textToStr(textOf(op))
4196 case CONIDCELL : sy = syntaxOf(op = conDefined(line,op));
4199 case QUALIDENT : { Name n = findQualName(op);
4205 "Undefined qualified variable \"%s\"",
4215 return pair(mkInt(sy),op); /* Pair fixity with (possibly) */
4216 /* translated operator */
4219 static Syntax local lookupSyntax(t) /* Try to find fixity for var in */
4220 Text t; { /* enclosing bindings */
4221 List bounds1 = bounds;
4222 List bindings1 = bindings;
4224 while (nonNull(bindings1)) {
4225 if (nonNull(varIsMember(t,hd(bounds1)))) {
4226 return DEF_OPSYNTAX;
4228 Cell b = findBinding(t,hd(bindings1));
4230 Cell a = fst(snd(b));
4231 if (isVar(fst(b))) { /* Function binding */
4232 if (nonNull(a) && nonNull(snd(a))) {
4233 return intOf(snd(a));
4235 } else { /* Pattern binding */
4237 while (nonNull(vs) && nonNull(a)) {
4238 if (t==textOf(hd(vs))) {
4239 if (nonNull(hd(a)) && isInt(snd(hd(a)))) {
4240 return intOf(snd(hd(a)));
4248 return DEF_OPSYNTAX;
4251 bounds1 = tl(bounds1);
4252 bindings1 = tl(bindings1);
4257 /* --------------------------------------------------------------------------
4258 * To facilitate dependency analysis, lists of bindings are temporarily
4259 * augmented with an additional field, which is used in two ways:
4260 * - to build the `adjacency lists' for the dependency graph. Represented by
4261 * a list of pointers to other bindings in the same list of bindings.
4262 * - to hold strictly positive integer values (depth first search numbers) of
4263 * elements `on the stack' during the strongly connected components search
4264 * algorithm, or a special value mkInt(0), once the binding has been added
4265 * to a particular strongly connected component.
4267 * Using this extra field, the type of each list of declarations during
4268 * dependency analysis is [Binding'] where:
4270 * Binding' ::= (Var, (Attr, (Dep, [Alt]))) -- function binding
4271 * | ([Var], ([Attr], (Dep, (Pat,Rhs)))) -- pattern binding
4273 * ------------------------------------------------------------------------*/
4275 #define depVal(d) (fst(snd(snd(d)))) /* Access to dependency information*/
4277 static List local dependencyAnal(bs) /* Separate lists of bindings into */
4278 List bs; { /* mutually recursive groups in */
4279 /* order of dependency */
4280 mapProc(addDepField,bs); /* add extra field for dependents */
4281 mapProc(depBinding,bs); /* find dependents of each binding */
4282 bs = bscc(bs); /* sort to strongly connected comps*/
4283 mapProc(remDepField,bs); /* remove dependency info field */
4287 static List local topDependAnal(bs) /* Like dependencyAnal(), but at */
4288 List bs; { /* top level, reporting on progress*/
4292 setGoal("Dependency analysis",(Target)(length(bs)));
4294 mapProc(addDepField,bs); /* add extra field for dependents */
4295 for (xs=bs; nonNull(xs); xs=tl(xs)) {
4296 emptySubstitution();
4298 soFar((Target)(i++));
4300 bs = bscc(bs); /* sort to strongly connected comps */
4301 mapProc(remDepField,bs); /* remove dependency info field */
4306 static Void local addDepField(b) /* add extra field to binding to */
4307 Cell b; { /* hold list of dependents */
4308 snd(snd(b)) = pair(NIL,snd(snd(b)));
4311 static Void local remDepField(bs) /* remove dependency field from */
4312 List bs; { /* list of bindings */
4313 mapProc(remDepField1,bs);
4316 static Void local remDepField1(b) /* remove dependency field from */
4317 Cell b; { /* single binding */
4318 snd(snd(b)) = snd(snd(snd(b)));
4321 static Void local clearScope() { /* initialise dependency scoping */
4327 static Void local withinScope(bs) /* Enter scope of bindings bs */
4329 bounds = cons(NIL,bounds);
4330 bindings = cons(bs,bindings);
4331 depends = cons(NIL,depends);
4334 static Void local leaveScope() { /* Leave scope of last withinScope */
4335 List bs = hd(bindings); /* Remove fixity info from binds */
4336 Bool toplevel = isNull(tl(bindings));
4337 for (; nonNull(bs); bs=tl(bs)) {
4339 if (isVar(fst(b))) { /* Variable binding */
4340 Cell a = fst(snd(b));
4343 saveSyntax(fst(b),snd(a));
4345 fst(snd(b)) = fst(a);
4347 } else { /* Pattern binding */
4349 List as = fst(snd(b));
4350 while (nonNull(vs) && nonNull(as)) {
4351 if (isPair(hd(as))) {
4353 saveSyntax(hd(vs),snd(hd(as)));
4355 hd(as) = fst(hd(as));
4362 bounds = tl(bounds);
4363 bindings = tl(bindings);
4364 depends = tl(depends);
4367 static Void local saveSyntax(v,sy) /* Save syntax of top-level var */
4368 Cell v; /* in corresponding Name */
4370 Name n = findName(textOf(v));
4371 if (isNull(n) || name(n).syntax!=NO_SYNTAX) {
4372 internal("saveSyntax");
4375 name(n).syntax = intOf(sy);
4379 /* --------------------------------------------------------------------------
4380 * As a side effect of the dependency analysis we also make the following
4382 * - Each lhs is a valid pattern/function lhs, all constructor functions
4383 * have been defined and are used with the correct number of arguments.
4384 * - No lhs contains repeated pattern variables.
4385 * - Expressions used on the rhs of an eqn should be well formed. This
4387 * - Checking for valid patterns (including repeated vars) in lambda,
4388 * case, and list comprehension expressions.
4389 * - Recursively checking local lists of equations.
4390 * - No free (i.e. unbound) variables are used in the declaration list.
4391 * ------------------------------------------------------------------------*/
4393 static Void local depBinding(b) /* find dependents of binding */
4395 Cell defpart = snd(snd(snd(b))); /* definition part of binding */
4399 if (isVar(fst(b))) { /* function-binding? */
4400 mapProc(depAlt,defpart);
4401 if (isNull(fst(snd(b)))) { /* Save dep info if no type sig */
4402 fst(snd(b)) = pair(ap(IMPDEPS,hd(depends)),NIL);
4403 } else if (isNull(fst(fst(snd(b))))) {
4404 fst(fst(snd(b))) = ap(IMPDEPS,hd(depends));
4406 } else { /* pattern-binding? */
4407 Int line = rhsLine(snd(defpart));
4410 fst(defpart) = checkPat(line,fst(defpart));
4411 depRhs(snd(defpart));
4413 if (nonNull(hd(btyvars))) {
4415 "Sorry, no type variables are allowed in pattern binding type annotations"
4419 fst(defpart) = applyBtyvs(fst(defpart));
4421 depVal(b) = hd(depends);
4424 static Void local depDefaults(c) /* dependency analysis on defaults */
4425 Class c; { /* from class definition */
4426 depClassBindings(cclass(c).defaults);
4429 static Void local depInsts(in) /* dependency analysis on instance */
4430 Inst in; { /* bindings */
4431 depClassBindings(inst(in).implements);
4434 static Void local depClassBindings(bs) /* dependency analysis on list of */
4435 List bs; { /* bindings, possibly containing */
4436 for (; nonNull(bs); bs=tl(bs)) { /* NIL bindings ... */
4437 if (nonNull(hd(bs))) { /* No need to add extra field for */
4438 mapProc(depAlt,snd(hd(bs)));/* dependency information... */
4443 static Void local depAlt(a) /* Find dependents of alternative */
4445 List obvs = saveBvars(); /* Save list of bound variables */
4447 bindPats(rhsLine(snd(a)),fst(a)); /* add new bound vars for patterns */
4448 depRhs(snd(a)); /* find dependents of rhs */
4449 fst(a) = applyBtyvs(fst(a));
4450 restoreBvars(obvs); /* restore original list of bvars */
4453 static Void local depRhs(r) /* Find dependents of rhs */
4455 switch (whatIs(r)) {
4456 case GUARDED : mapProc(depGuard,snd(r));
4459 case LETREC : fst(snd(r)) = eqnsToBindings(fst(snd(r)),NIL,NIL,NIL);
4460 withinScope(fst(snd(r)));
4461 fst(snd(r)) = dependencyAnal(fst(snd(r)));
4462 hd(depends) = fst(snd(r));
4463 depRhs(snd(snd(r)));
4467 case RSIGN : snd(snd(r)) = checkPatType(rhsLine(fst(snd(r))),
4469 rhsExpr(fst(snd(r))),
4471 depRhs(fst(snd(r)));
4474 default : snd(r) = depExpr(intOf(fst(r)),snd(r));
4479 static Void local depGuard(g) /* find dependents of single guarded*/
4480 Cell g; { /* expression */
4481 depPair(intOf(fst(g)),snd(g));
4484 static Cell local depExpr(line,e) /* find dependents of expression */
4487 //Printf( "\n\n"); print(e,100); Printf("\n");
4488 //printExp(stdout,e);
4489 switch (whatIs(e)) {
4492 case VAROPCELL : return depVar(line,e);
4495 case CONOPCELL : return conDefined(line,e);
4497 case QUALIDENT : if (isQVar(e)) {
4498 return depQVar(line,e);
4499 } else { /* QConOrConOp */
4500 return conDefined(line,e);
4503 case INFIX : return depExpr(line,tidyInfix(line,snd(e)));
4506 case RECSEL : break;
4508 case AP : if (isAp(e) && isAp(fun(e)) && isExt(fun(fun(e)))) {
4509 return depRecord(line,e);
4515 arg(a) = depExpr(line,arg(a));
4518 fun(a) = depExpr(line,fun(a));
4522 case AP : depPair(line,e);
4536 case INTCELL : break;
4538 case COND : depTriple(line,snd(e));
4541 case FINLIST : map1Over(depExpr,line,snd(e));
4544 case LETREC : fst(snd(e)) = eqnsToBindings(fst(snd(e)),NIL,NIL,NIL);
4545 withinScope(fst(snd(e)));
4546 fst(snd(e)) = dependencyAnal(fst(snd(e)));
4547 hd(depends) = fst(snd(e));
4548 snd(snd(e)) = depExpr(line,snd(snd(e)));
4552 case LAMBDA : depAlt(snd(e));
4555 case DOCOMP : /* fall-thru */
4556 case COMP : depComp(line,snd(e),snd(snd(e)));
4559 case ESIGN : fst(snd(e)) = depExpr(line,fst(snd(e)));
4560 snd(snd(e)) = checkSigType(line,
4566 case CASE : fst(snd(e)) = depExpr(line,fst(snd(e)));
4567 map1Proc(depCaseAlt,line,snd(snd(e)));
4570 case CONFLDS : depConFlds(line,e,FALSE);
4573 case UPDFLDS : depUpdFlds(line,e);
4577 case WITHEXP : depWith(line,e);
4581 case ASPAT : ERRMSG(line) "Illegal `@' in expression"
4584 case LAZYPAT : ERRMSG(line) "Illegal `~' in expression"
4587 case WILDCARD : ERRMSG(line) "Illegal `_' in expression"
4591 case EXT : ERRMSG(line) "Illegal application of record"
4595 default : internal("depExpr");
4600 static Void local depPair(line,e) /* find dependents of pair of exprs*/
4603 fst(e) = depExpr(line,fst(e));
4604 snd(e) = depExpr(line,snd(e));
4607 static Void local depTriple(line,e) /* find dependents of triple exprs */
4610 fst3(e) = depExpr(line,fst3(e));
4611 snd3(e) = depExpr(line,snd3(e));
4612 thd3(e) = depExpr(line,thd3(e));
4615 static Void local depComp(l,e,qs) /* find dependents of comprehension*/
4620 fst(e) = depExpr(l,fst(e));
4624 switch (whatIs(q)) {
4625 case FROMQUAL : { List obvs = saveBvars();
4626 snd(snd(q)) = depExpr(l,snd(snd(q)));
4628 fst(snd(q)) = bindPat(l,fst(snd(q)));
4630 fst(snd(q)) = applyBtyvs(fst(snd(q)));
4635 case QWHERE : snd(q) = eqnsToBindings(snd(q),NIL,NIL,NIL);
4636 withinScope(snd(q));
4637 snd(q) = dependencyAnal(snd(q));
4638 hd(depends) = snd(q);
4643 case DOQUAL : /* fall-thru */
4644 case BOOLQUAL : snd(q) = depExpr(l,snd(q));
4651 static Void local depCaseAlt(line,a) /* Find dependents of case altern. */
4654 List obvs = saveBvars(); /* Save list of bound variables */
4656 fst(a) = bindPat(line,fst(a)); /* Add new bound vars for pats */
4657 depRhs(snd(a)); /* Find dependents of rhs */
4658 fst(a) = applyBtyvs(fst(a));
4659 restoreBvars(obvs); /* Restore original list of bvars */
4662 static Cell local depVar(line,e) /* Register occurrence of variable */
4665 List bounds1 = bounds;
4666 List bindings1 = bindings;
4667 List depends1 = depends;
4671 while (nonNull(bindings1)) {
4672 n = varIsMember(t,hd(bounds1)); /* look for t in bound variables */
4676 n = findBinding(t,hd(bindings1)); /* look for t in var bindings */
4678 if (!cellIsMember(n,hd(depends1))) {
4679 hd(depends1) = cons(n,hd(depends1));
4681 return (isVar(fst(n)) ? fst(n) : e);
4684 bounds1 = tl(bounds1);
4685 bindings1 = tl(bindings1);
4686 depends1 = tl(depends1);
4689 if (isNull(n=findName(t))) { /* check global definitions */
4690 ERRMSG(line) "Undefined variable \"%s\"", textToStr(t)
4694 /* Later phases of the system cannot cope if we resolve references
4695 * to unprocessed objects too early. This is the main reason that
4696 * we cannot cope with recursive modules at the moment.
4701 static Cell local depQVar(line,e)/* register occurrence of qualified variable */
4704 Name n = findQualName(e);
4705 if (isNull(n)) { /* check global definitions */
4706 ERRMSG(line) "Undefined qualified variable \"%s\"", identToStr(e)
4709 if (name(n).mod != currentModule) {
4712 if (fst(e) == VARIDCELL) {
4713 e = mkVar(qtextOf(e));
4715 e = mkVarop(qtextOf(e));
4717 return depVar(line,e);
4720 static Void local depConFlds(line,e,isP)/* check construction using fields */
4724 Name c = conDefined(line,fst(snd(e)));
4725 if (isNull(snd(snd(e))) ||
4726 nonNull(cellIsMember(c,depFields(line,e,snd(snd(e)),isP)))) {
4729 ERRMSG(line) "Constructor \"%s\" does not have selected fields in ",
4730 textToStr(name(c).text)
4735 if (!isP && isPair(name(c).defn)) { /* Check that banged fields defined*/
4736 List scs = fst(name(c).defn); /* List of strict components */
4737 Type t = name(c).type;
4738 Int a = userArity(c);
4739 List fs = snd(snd(e));
4741 if (isPolyType(t)) { /* Find tycon that c belongs to */
4744 if (isQualType(t)) {
4747 if (whatIs(t)==CDICTS) {
4756 for (ss=tycon(t).defn; hasCfun(ss); ss=tl(ss)) {
4758 /* Now we know the tycon t that c belongs to, and the corresponding
4759 * list of selectors for that type, ss. Now we have to check that
4760 * each of the fields identified by scs appears in fs, using ss to
4761 * cross reference, and convert integers to selector names.
4763 for (; nonNull(scs); scs=tl(scs)) {
4764 Int i = intOf(hd(scs));
4766 for (; nonNull(ss1); ss1=tl(ss1)) {
4767 List cns = name(hd(ss1)).defn;
4768 for (; nonNull(cns); cns=tl(cns)) {
4769 if (fst(hd(cns))==c) {
4773 if (nonNull(cns) && intOf(snd(hd(cns)))==i) {
4778 internal("depConFlds");
4782 for (; nonNull(fs1) && s!=fst(hd(fs1)); fs1=tl(fs1)) {
4785 ERRMSG(line) "Construction does not define strict field"
4787 ERRTEXT "\nExpression : " ETHEN ERREXPR(e);
4788 ERRTEXT "\nField : " ETHEN ERREXPR(s);
4797 static Void local depUpdFlds(line,e) /* check update using fields */
4800 if (isNull(thd3(snd(e)))) {
4801 ERRMSG(line) "Empty field list in update"
4804 fst3(snd(e)) = depExpr(line,fst3(snd(e)));
4805 snd3(snd(e)) = depFields(line,e,thd3(snd(e)),FALSE);
4808 static List local depFields(l,e,fs,isP) /* check field binding list */
4816 for (; nonNull(fs); fs=tl(fs)) { /* for each field binding */
4820 if (isVar(fb)) { /* expand var to var = var */
4821 h98DoesntSupport(l,"missing field bindings");
4822 fb = hd(fs) = pair(fb,fb);
4825 s = findQualName(fst(fb)); /* check for selector */
4826 if (nonNull(s) && isSfun(s)) {
4829 ERRMSG(l) "\"%s\" is not a selector function/field name",
4830 textToStr(textOf(fst(fb)))
4834 if (isNull(ss)) { /* for first named selector */
4835 List scs = name(s).defn; /* calculate list of constructors */
4836 for (; nonNull(scs); scs=tl(scs)) {
4837 cs = cons(fst(hd(scs)),cs);
4839 ss = singleton(s); /* initialize selector list */
4840 } else { /* for subsequent selectors */
4841 List ds = cs; /* intersect constructor lists */
4842 for (cs=NIL; nonNull(ds); ) {
4843 List scs = name(s).defn;
4844 while (nonNull(scs) && fst(hd(scs))!=hd(ds)) {
4857 if (cellIsMember(s,ss)) { /* check for repeated uses */
4858 ERRMSG(l) "Repeated field name \"%s\" in field list",
4859 textToStr(name(s).text)
4865 if (isNull(cs)) { /* Are there any matching constrs? */
4866 ERRMSG(l) "No constructor has all of the fields specified in "
4872 snd(fb) = (isP ? checkPat(l,snd(fb)) : depExpr(l,snd(fb)));
4878 static Void local depWith(line,e) /* check with using fields */
4881 fst(snd(e)) = depExpr(line,fst(snd(e)));
4882 snd(snd(e)) = depDwFlds(line,e,snd(snd(e)));
4885 static List local depDwFlds(l,e,fs)/* check field binding list */
4891 for (; nonNull(c); c=tl(c)) { /* for each field binding */
4892 snd(hd(c)) = depExpr(l,snd(hd(c)));
4899 static Cell local depRecord(line,e) /* find dependents of record and */
4900 Int line; /* sort fields into approp. order */
4901 Cell e; { /* to make construction and update */
4902 List exts = NIL; /* more efficient. */
4905 h98DoesntSupport(line,"extensible records");
4906 do { /* build up list of extensions */
4907 Text t = extText(fun(fun(r)));
4908 String s = textToStr(t);
4911 while (nonNull(nx) && strcmp(textToStr(extText(fun(fun(nx)))),s)>0) {
4915 if (nonNull(nx) && t==extText(fun(fun(nx)))) {
4916 ERRMSG(line) "Repeated label \"%s\" in record ", s
4922 exts = cons(fun(r),exts);
4924 tl(prev) = cons(fun(r),nx);
4926 extField(r) = depExpr(line,extField(r));
4928 } while (isAp(r) && isAp(fun(r)) && isExt(fun(fun(r))));
4929 r = depExpr(line,r);
4930 return revOnto(exts,r);
4935 /* --------------------------------------------------------------------------
4936 * Several parts of this program require an algorithm for sorting a list
4937 * of values (with some added dependency information) into a list of strongly
4938 * connected components in which each value appears before its dependents.
4940 * Each of these algorithms is obtained by parameterising a standard
4941 * algorithm in "scc.c" as shown below.
4942 * ------------------------------------------------------------------------*/
4944 #define SCC2 tcscc /* make scc algorithm for Tycons */
4945 #define LOWLINK tclowlink
4946 #define DEPENDS(c) (isTycon(c) ? tycon(c).kind : cclass(c).kinds)
4947 #define SETDEPENDS(c,v) if(isTycon(c)) tycon(c).kind=v; else cclass(c).kinds=v
4954 #define SCC bscc /* make scc algorithm for Bindings */
4955 #define LOWLINK blowlink
4956 #define DEPENDS(t) depVal(t)
4957 #define SETDEPENDS(c,v) depVal(c)=v
4964 /* --------------------------------------------------------------------------
4965 * Main static analysis:
4966 * ------------------------------------------------------------------------*/
4968 Void checkExp() { /* Top level static check on Expr */
4969 staticAnalysis(RESET);
4970 clearScope(); /* Analyse expression in the scope */
4971 withinScope(NIL); /* of no local bindings */
4972 inputExpr = depExpr(0,inputExpr);
4974 staticAnalysis(RESET);
4977 #if EXPLAIN_INSTANCE_RESOLUTION
4978 Void checkContext(void) { /* Top level static check on Expr */
4981 staticAnalysis(RESET);
4982 clearScope(); /* Analyse expression in the scope */
4983 withinScope(NIL); /* of no local bindings */
4985 for (vs = NIL; nonNull(qs); qs=tl(qs)) {
4986 vs = typeVarsIn(hd(qs),NIL,NIL,vs);
4988 map2Proc(depPredExp,0,vs,inputContext);
4990 staticAnalysis(RESET);
4994 Void checkDefns ( Module thisModule ) { /* Top level static analysis */
4995 Text modName = module(thisModule).text;
4997 staticAnalysis(RESET);
4999 setCurrModule(thisModule);
5001 /* Resolve module references */
5002 mapProc(checkQualImport, module(thisModule).qualImports);
5003 mapProc(checkUnqualImport,unqualImports);
5004 /* Add "import Prelude" if there`s no explicit import */
5005 if (modName == textPrelPrim || modName == textPrelude) {
5007 } else if (isNull(cellAssoc(modulePrelude,unqualImports))
5008 && isNull(cellRevAssoc(modulePrelude,module(thisModule).qualImports))) {
5009 unqualImports = cons(pair(modulePrelude,DOTDOT),unqualImports);
5011 /* Every module implicitly contains "import qualified Prelude"
5013 module(thisModule).qualImports
5014 =cons(pair(mkCon(textPrelude),modulePrelude),
5015 module(thisModule).qualImports);
5017 mapProc(checkImportList, unqualImports);
5019 /* Note: there's a lot of side-effecting going on here, so
5020 don't monkey about with the order of operations here unless
5021 you know what you are doing */
5022 if (!combined) linkPreludeTC(); /* Get prelude tycons and classes */
5024 mapProc(checkTyconDefn,tyconDefns); /* validate tycon definitions */
5025 checkSynonyms(tyconDefns); /* check synonym definitions */
5026 mapProc(checkClassDefn,classDefns); /* process class definitions */
5027 mapProc(kindTCGroup,tcscc(tyconDefns,classDefns)); /* attach kinds */
5028 mapProc(visitClass,classDefns); /* check class hierarchy */
5029 mapProc(extendFundeps,classDefns); /* finish class definitions */
5030 /* (convenient if we do this after */
5031 /* calling `visitClass' so that we */
5032 /* know the class hierarchy is */
5035 mapProc(addMembers,classDefns); /* add definitions for member funs */
5037 if (!combined) linkPreludeCM(); /* Get prelude cfuns and mfuns */
5039 instDefns = rev(instDefns); /* process instance definitions */
5040 mapProc(checkInstDefn,instDefns);
5042 setCurrModule(thisModule);
5043 mapProc(addRSsigdecls,typeInDefns); /* add sigdecls for RESTRICTSYN */
5044 valDefns = eqnsToBindings(valDefns,tyconDefns,classDefns,/*primDefns*/NIL);
5045 mapProc(allNoPrevDef,valDefns); /* check against previous defns */
5046 mapProc(addDerivImp,derivedInsts); /* Add impls for derived instances */
5047 deriveContexts(derivedInsts); /* Calculate derived inst contexts */
5048 instDefns = appendOnto(instDefns,derivedInsts);
5049 checkDefaultDefns(); /* validate default definitions */
5051 mapProc(allNoPrevDef,valDefns); /* check against previous defns */
5053 if (!combined) linkPrimNames(); /* link primitive names */
5055 mapProc(checkForeignImport,foreignImports); /* check foreign imports */
5056 mapProc(checkForeignExport,foreignExports); /* check foreign exports */
5057 foreignImports = NIL;
5058 foreignExports = NIL;
5060 /* Every top-level name has now been created - so we can build the */
5061 /* export list. Note that this has to happen before dependency */
5062 /* analysis so that references to Prelude.foo will be resolved */
5063 /* when compiling the prelude. */
5064 module(thisModule).exports
5065 = checkExports ( module(thisModule).exports, thisModule );
5067 mapProc(checkTypeIn,typeInDefns); /* check restricted synonym defns */
5070 withinScope(valDefns);
5071 valDefns = topDependAnal(valDefns); /* top level dependency ordering */
5072 mapProc(depDefaults,classDefns); /* dep. analysis on class defaults */
5073 mapProc(depInsts,instDefns); /* dep. analysis on inst defns */
5076 /* ToDo: evalDefaults should match current evaluation module */
5077 evalDefaults = defaultDefns; /* Set defaults for evaluator */
5079 staticAnalysis(RESET);
5085 static Void local addRSsigdecls(pr) /* add sigdecls from TYPE ... IN ..*/
5087 List vs = snd(pr); /* get list of variables */
5088 for (; nonNull(vs); vs=tl(vs)) {
5089 if (fst(hd(vs))==SIGDECL) { /* find a sigdecl */
5090 valDefns = cons(hd(vs),valDefns); /* add to valDefns */
5091 hd(vs) = hd(snd3(snd(hd(vs)))); /* and replace with var */
5096 static Void local allNoPrevDef(b) /* ensure no previous bindings for*/
5097 Cell b; { /* variables in new binding */
5098 if (isVar(fst(b))) {
5099 noPrevDef(rhsLine(snd(hd(snd(snd(b))))),fst(b));
5101 Int line = rhsLine(snd(snd(snd(b))));
5102 map1Proc(noPrevDef,line,fst(b));
5106 static Void local noPrevDef(line,v) /* ensure no previous binding for */
5107 Int line; /* new variable */
5109 Name n = findName(textOf(v));
5112 n = newName(textOf(v),NIL);
5113 name(n).defn = PREDEFINED;
5114 } else if (name(n).defn!=PREDEFINED) {
5115 duplicateError(line,name(n).mod,name(n).text,"variable");
5117 name(n).line = line;
5120 static Void local duplicateErrorAux(line,mod,t,kind)/* report duplicate defn */
5125 if (mod == currentModule) {
5126 ERRMSG(line) "Repeated definition for %s \"%s\"", kind,
5130 ERRMSG(line) "Definition of %s \"%s\" clashes with import", kind,
5136 static Void local checkTypeIn(cvs) /* Check that vars in restricted */
5137 Pair cvs; { /* synonym are defined */
5141 for (; nonNull(vs); vs=tl(vs)) {
5142 if (isNull(findName(textOf(hd(vs))))) {
5143 ERRMSG(tycon(c).line)
5144 "No top level binding of \"%s\" for restricted synonym \"%s\"",
5145 textToStr(textOf(hd(vs))), textToStr(tycon(c).text)
5151 /* --------------------------------------------------------------------------
5152 * Haskell 98 compatibility tests:
5153 * ------------------------------------------------------------------------*/
5155 Bool h98Pred(allowArgs,pi) /* Check syntax of Hask98 predicate*/
5158 return isClass(getHead(pi)) && argCount==1 &&
5159 isOffset(getHead(arg(pi))) && (argCount==0 || allowArgs);
5162 Cell h98Context(allowArgs,ps) /* Check syntax of Hask98 context */
5165 for (; nonNull(ps); ps=tl(ps)) {
5166 if (!h98Pred(allowArgs,hd(ps))) {
5173 Void h98CheckCtxt(line,wh,allowArgs,ps,in)
5174 Int line; /* Report illegal context/predicate*/
5180 Cell pi = h98Context(allowArgs,ps);
5182 ERRMSG(line) "Illegal Haskell 98 class constraint in %s",wh ETHEN
5184 ERRTEXT "\n*** Instance : " ETHEN ERRPRED(inst(in).head);
5186 ERRTEXT "\n*** Constraint : " ETHEN ERRPRED(pi);
5187 if (nonNull(ps) && nonNull(tl(ps))) {
5188 ERRTEXT "\n*** Context : " ETHEN ERRCONTEXT(ps);
5196 Void h98CheckType(line,wh,e,t) /* Check for Haskell 98 type */
5205 if (isQualType(t)) {
5206 Cell pi = h98Context(TRUE,fst(snd(t)));
5208 ERRMSG(line) "Illegal Haskell 98 class constraint in %s",wh
5210 ERRTEXT "\n*** Expression : " ETHEN ERREXPR(e);
5211 ERRTEXT "\n*** Type : " ETHEN ERRTYPE(ty);
5219 Void h98DoesntSupport(line,wh) /* Report feature missing in H98 */
5223 ERRMSG(line) "Haskell 98 does not support %s", wh
5228 /* --------------------------------------------------------------------------
5229 * Static Analysis control:
5230 * ------------------------------------------------------------------------*/
5232 Void staticAnalysis(what)
5235 case RESET : cfunSfuns = NIL;
5248 case MARK : mark(daSccs);
5263 case POSTPREL: break;
5265 case PREPREL : staticAnalysis(RESET);
5267 extKind = pair(STAR,pair(ROW,ROW));
5272 /*-------------------------------------------------------------------------*/