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: 2000/06/02 16:19:47 $
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 /* add in the tyvars from the `supers' so that we don't
1326 prematurely complain about undefined tyvars */
1327 tyvars = typeVarsIn(cclass(c).supers,NIL,NIL,tyvars);
1329 if (cclass(c).arity==0) {
1332 Int args = cclass(c).arity - 1;
1333 for (temp=cclass(c).head; args>0; temp=fun(temp), args--) {
1334 arg(temp) = mkOffset(args);
1336 arg(temp) = mkOffset(0);
1340 tcDeps = NIL; /* find dependents */
1341 map2Over(depPredExp,cclass(c).line,tyvars,cclass(c).supers);
1343 { /* depPredExp instantiates class names to class structs, so
1344 * now we have enough info to check for ambiguity
1346 List tvts = offsetTyvarsIn(cclass(c).head,NIL);
1347 List tvps = offsetTyvarsIn(cclass(c).supers,NIL);
1348 List fds = calcFunDeps(cclass(c).supers);
1349 tvts = oclose(fds,tvts);
1350 tvts = odiff(tvps,tvts);
1352 if (!isNull(tvts)) {
1353 ERRMSG(cclass(c).line) "Undefined type variable \"%s\"",
1354 textToStr(textOf(nth(offsetOf(hd(tvts)),tyvars)))
1359 h98CheckCtxt(cclass(c).line,"class definition",FALSE,cclass(c).supers,NIL);
1360 cclass(c).numSupers = length(cclass(c).supers);
1361 cclass(c).defaults = extractBindings(cclass(c).members); /* defaults*/
1362 ss = extractSigdecls(cclass(c).members);
1363 fs = extractFixdecls(cclass(c).members);
1364 cclass(c).members = pair(ss,fs);
1365 map2Proc(checkMems,c,tyvars,ss);
1367 cclass(c).kinds = tcDeps;
1372 /* --------------------------------------------------------------------------
1373 * Functional dependencies are inherited from superclasses.
1374 * For example, if I've got the following classes:
1376 * class C a b | a -> b
1377 * class C [b] a => D a b
1379 * then C will have the dependency ([a], [b]) as expected, and D will inherit
1380 * the dependency ([b], [a]) from C.
1381 * When doing pairwise improvement, we have to consider not just improving
1382 * when we see a pair of Cs or a pair of Ds in the context, but when we've
1383 * got a C and a D as well. In this case, we only improve when the
1384 * predicate in question matches the type skeleton in the relevant superclass
1385 * constraint. E.g., we improve the pair (C [Int] a, D b Int) (unifying
1386 * a and b), but we don't improve the pair (C Int a, D b Int).
1387 * To implement functional dependency inheritance, we calculate
1388 * the closure of all functional dependencies, and store the result
1389 * in an additional field `xfds' (extended functional dependencies).
1390 * The `xfds' field is a list of functional dependency lists, annotated
1391 * with a list of predicate skeletons constraining when improvement can
1392 * happen against this dependency list. For example, the xfds field
1393 * for C above would be:
1394 * [([C a b], [([a], [b])])]
1395 * and the xfds field for D would be:
1396 * [([C [b] a, D a b], [([b], [a])])]
1397 * Self-improvement (of a C with a C, or a D with a D) is treated as a
1398 * special case of an inherited dependency.
1399 * ------------------------------------------------------------------------*/
1400 static List local inheritFundeps ( Class c, Cell pi, Int o )
1402 Int alpha = newKindedVars(cclass(c).kinds);
1403 List scs = cclass(c).supers;
1406 /* better not fail ;-) */
1407 if (!matchPred(pi,o,cclass(c).head,alpha))
1408 internal("inheritFundeps - predicate failed to match it's own head!");
1409 this = copyPred(pi,o);
1410 for (; nonNull(scs); scs=tl(scs)) {
1411 Class s = getHead(hd(scs));
1413 List sfds = inheritFundeps(s,hd(scs),alpha);
1414 for (; nonNull(sfds); sfds=tl(sfds)) {
1416 xfds = cons(pair(cons(this,fst(h)),snd(h)),xfds);
1420 if (nonNull(cclass(c).fds)) {
1421 List fds = NIL, fs = cclass(c).fds;
1422 for (; nonNull(fs); fs=tl(fs)) {
1423 fds = cons(pair(otvars(this,fst(hd(fs))),
1424 otvars(this,snd(hd(fs)))),fds);
1426 xfds = cons(pair(cons(this,NIL),fds),xfds);
1431 static Void local extendFundeps ( Class c )
1434 emptySubstitution();
1435 alpha = newKindedVars(cclass(c).kinds);
1436 cclass(c).xfds = inheritFundeps(c,cclass(c).head,alpha);
1438 /* we can now check for ambiguity */
1439 map1Proc(checkMems2,c,fst(cclass(c).members));
1443 static Cell local depPredExp(line,tyvars,pred)
1450 for (; isAp(h); args++) {
1451 arg(h) = depTypeExp(line,tyvars,arg(h));
1457 h98DoesntSupport(line,"tag classes");
1458 } else if (args!=1) {
1459 h98DoesntSupport(line,"multiple parameter classes");
1462 if (isQCon(h)) { /* standard class constraint */
1463 Class c = findQualClass(h);
1465 ERRMSG(line) "Undefined class \"%s\"", identToStr(h)
1473 if (args!=cclass(c).arity) {
1474 ERRMSG(line) "Wrong number of arguments for class \"%s\"",
1475 textToStr(cclass(c).text)
1478 if (cellIsMember(c,classDefns) && !cellIsMember(c,tcDeps)) {
1479 tcDeps = cons(c,tcDeps);
1483 else if (isExt(h)) { /* Lacks predicate */
1484 if (args!=1) { /* parser shouldn't let this happen*/
1485 ERRMSG(line) "Wrong number of arguments for lacks predicate"
1492 if (whatIs(h) != IPCELL)
1495 internal("depPredExp");
1500 static Void local checkMems(c,tyvars,m) /* check member function details */
1504 Int line = intOf(fst3(m));
1511 if (isPolyType(t)) {
1517 tyvars = typeVarsIn(t,NIL,xtvs,tyvars);
1518 /* Look for extra type vars. */
1519 checkOptQuantVars(line,xtvs,tyvars);
1521 if (isQualType(t)) { /* Overloaded member signatures? */
1522 map2Over(depPredExp,line,tyvars,fst(snd(t)));
1524 t = ap(QUAL,pair(NIL,t));
1527 fst(snd(t)) = cons(cclass(c).head,fst(snd(t)));/* Add main predicate */
1528 snd(snd(t)) = depTopType(line,tyvars,snd(snd(t)));
1530 for (tvs=tyvars; nonNull(tvs); tvs=tl(tvs)){/* Quantify */
1534 t = mkPolyType(sig,t);
1536 thd3(m) = t; /* Save type */
1537 take(cclass(c).arity,tyvars); /* Delete extra type vars */
1539 h98CheckType(line,"member type",hd(vs),t);
1542 static Void local checkMems2(c,m) /* check member function details */
1545 Int line = intOf(fst3(m));
1549 if (isAmbiguous(t)) {
1550 ambigError(line,"class declaration",hd(vs),t);
1554 static Void local addMembers(c) /* Add definitions of member funs */
1555 Class c; { /* and other parts of class struct.*/
1556 List ms = fst(cclass(c).members);
1557 List fs = snd(cclass(c).members);
1558 List ns = NIL; /* List of names */
1559 Int mno; /* Member function number */
1561 for (mno=0; mno<cclass(c).numSupers; mno++) {
1562 ns = cons(newDSel(c,mno),ns);
1564 cclass(c).dsels = rev(ns); /* Save dictionary selectors */
1566 for (mno=1, ns=NIL; nonNull(ms); ms=tl(ms)) {
1567 Int line = intOf(fst3(hd(ms)));
1568 List vs = rev(snd3(hd(ms)));
1569 Type t = thd3(hd(ms));
1570 for (; nonNull(vs); vs=tl(vs)) {
1571 ns = cons(newMember(line,mno++,hd(vs),t,c),ns);
1574 cclass(c).members = rev(ns); /* Save list of members */
1575 cclass(c).numMembers = length(cclass(c).members);
1577 for (; nonNull(fs); fs=tl(fs)) { /* fixity declarations */
1578 Int line = intOf(fst3(hd(fs)));
1579 List ops = snd3(hd(fs));
1580 Syntax s = intOf(thd3(hd(fs)));
1581 for (; nonNull(ops); ops=tl(ops)) {
1582 Name n = nameIsMember(textOf(hd(ops)),cclass(c).members);
1584 missFixity(line,textOf(hd(ops)));
1585 } else if (name(n).syntax!=NO_SYNTAX) {
1586 dupFixity(line,textOf(hd(ops)));
1592 /* Not actually needed just yet; for the time being, dictionary code will
1593 not be passed through the type checker.
1595 cclass(c).dtycon = addPrimTycon(generateText("Dict.%s",c),
1602 mno = cclass(c).numSupers + cclass(c).numMembers;
1603 /* cclass(c).dcon = addPrimCfun(generateText("Make.%s",c),mno,0,NIL); */
1604 cclass(c).dcon = addPrimCfun(generateText(":D%s",c),mno,0,NIL);
1605 /* implementCfun(cclass(c).dcon,NIL);
1606 Don't manufacture a wrapper fn for dictionary constructors.
1607 Applications of dictionary constructors are always saturated,
1608 and translate.c:stgExpr() special-cases saturated constructor apps.
1611 if (mno==1) { /* Single entry dicts use newtype */
1612 name(cclass(c).dcon).defn = nameId;
1613 if (nonNull(cclass(c).members)) {
1614 name(hd(cclass(c).members)).number = mfunNo(0);
1617 cclass(c).defaults = classBindings("class",c,cclass(c).defaults);
1620 static Name local newMember(l,no,v,t,parent)
1621 Int l; /* Make definition for member fn */
1626 Name m = findName(textOf(v));
1629 m = newName(textOf(v),parent);
1630 } else if (name(m).defn!=PREDEFINED) {
1631 ERRMSG(l) "Repeated definition for member function \"%s\"",
1632 textToStr(name(m).text)
1638 name(m).number = mfunNo(no);
1643 Name newDSel(c,no) /* Make definition for dict selectr*/
1649 /* sprintf(buf,"sc%d.%s",no,"%s"); */
1650 sprintf(buf,"$p%d%s",no+1,"%s");
1651 s = newName(generateText(buf,c),c);
1652 name(s).line = cclass(c).line;
1654 name(s).number = DFUNNAME;
1660 static Text local generateText(sk,c) /* We need to generate names for */
1661 String sk; /* certain objects corresponding */
1662 Class c; { /* to each class. */
1663 String cname = textToStr(cclass(c).text);
1664 char buffer[MAX_GEN+1];
1666 if ((strlen(sk)+strlen(cname))>=MAX_GEN) {
1667 ERRMSG(0) "Please use a shorter name for class \"%s\"", cname
1670 sprintf(buffer,sk,cname);
1671 return findText(buffer);
1674 Int visitClass(c) /* visit class defn to check that */
1675 Class c; { /* class hierarchy is acyclic */
1677 if (isExt(c)) { /* special case for lacks preds */
1681 if (cclass(c).level < 0) { /* already visiting this class? */
1682 ERRMSG(cclass(c).line) "Class hierarchy for \"%s\" is not acyclic",
1683 textToStr(cclass(c).text)
1685 } else if (cclass(c).level == 0) { /* visiting class for first time */
1686 List scs = cclass(c).supers;
1688 cclass(c).level = (-1);
1689 for (; nonNull(scs); scs=tl(scs)) {
1690 Int l = visitClass(getHead(hd(scs)));
1693 cclass(c).level = 1+lev; /* level = 1 + max level of supers */
1695 return cclass(c).level;
1698 /* --------------------------------------------------------------------------
1699 * Process class and instance declaration binding groups:
1700 * ------------------------------------------------------------------------*/
1702 static List local classBindings(where,c,bs)
1703 String where; /* Check validity of bindings bs */
1704 Class c; /* for class c (or an inst of c) */
1705 List bs; { /* sort into approp. member order */
1708 for (; nonNull(bs); bs=tl(bs)) {
1710 Cell body = snd(snd(b));
1713 if (!isVar(fst(b))) { /* Only allow function bindings */
1714 ERRMSG(rhsLine(snd(body)))
1715 "Pattern binding illegal in %s declaration", where
1719 if (isNull(mnm=memberName(c,textOf(fst(b))))) {
1720 ERRMSG(rhsLine(snd(hd(body))))
1721 "No member \"%s\" in class \"%s\"",
1722 textToStr(textOf(fst(b))), textToStr(cclass(c).text)
1726 nbs = numInsert(mfunOf(mnm)-1,b,nbs);
1731 static Name local memberName(c,t) /* return name of member function */
1732 Class c; /* with name t in class c */
1733 Text t; { /* return NIL if not a member */
1734 List ms = cclass(c).members;
1735 for (; nonNull(ms); ms=tl(ms)) {
1736 if (t==name(hd(ms)).text) {
1743 static List local numInsert(n,x,xs) /* insert x at nth position in xs, */
1744 Int n; /* filling gaps with NIL */
1747 List start = isNull(xs) ? cons(NIL,NIL) : xs;
1749 for (xs=start; 0<n--; xs=tl(xs)) {
1750 if (isNull(tl(xs))) {
1751 tl(xs) = cons(NIL,NIL);
1758 /* --------------------------------------------------------------------------
1759 * Calculate set of variables appearing in a given type expression (possibly
1760 * qualified) as a list of distinct values. The order in which variables
1761 * appear in the list is the same as the order in which those variables
1762 * occur in the type expression when read from left to right.
1763 * ------------------------------------------------------------------------*/
1765 List local typeVarsIn(ty,us,ws,vs) /*Calculate list of type variables*/
1766 Cell ty; /* used in type expression, reading*/
1767 List us; /* from left to right ignoring any */
1768 List ws; /* listed in us. */
1769 List vs; { /* ws = explicitly quantified vars */
1770 if (isNull(ty)) return vs;
1771 switch (whatIs(ty)) {
1772 case DICTAP : return typeVarsIn(snd(snd(ty)),us,ws,vs);
1773 case UNBOXEDTUP: return typeVarsIn(snd(ty),us,ws,vs);
1775 case AP : return typeVarsIn(snd(ty),us,ws,
1776 typeVarsIn(fst(ty),us,ws,vs));
1779 case VAROPCELL : if ((nonNull(findBtyvs(textOf(ty)))
1780 && !varIsMember(textOf(ty),ws))
1781 || varIsMember(textOf(ty),us)) {
1784 return maybeAppendVar(ty,vs);
1787 case POLYTYPE : return typeVarsIn(monotypeOf(ty),polySigOf(ty),ws,vs);
1789 case QUAL : { vs = typeVarsIn(fst(snd(ty)),us,ws,vs);
1790 return typeVarsIn(snd(snd(ty)),us,ws,vs);
1793 case BANG : return typeVarsIn(snd(ty),us,ws,vs);
1795 case LABC : { List fs = snd(snd(ty));
1796 for (; nonNull(fs); fs=tl(fs)) {
1797 vs = typeVarsIn(snd(hd(fs)),us,ws,vs);
1804 case QUALIDENT: return vs;
1806 default: fprintf(stderr, " bad tag = %d\n", whatIs(ty));internal("typeVarsIn");
1811 static List local maybeAppendVar(v,vs) /* append variable to list if not */
1812 Cell v; /* already included */
1818 while (nonNull(c)) {
1819 if (textOf(hd(c))==t) {
1827 tl(p) = cons(v,NIL);
1835 /* --------------------------------------------------------------------------
1836 * Static analysis for type expressions is required to:
1837 * - ensure that each type constructor or class used has been defined.
1838 * - replace type variables by offsets, constructor names by Tycons.
1839 * - ensure that the type is well-kinded.
1840 * ------------------------------------------------------------------------*/
1842 static Type local checkSigType(line,where,e,type)
1843 Int line; /* Check validity of type expr in */
1844 String where; /* explicit type signature */
1851 if (isPolyType(type)) {
1852 xtvs = fst(snd(type));
1853 type = monotypeOf(type);
1855 tvs = typeVarsIn(type,NIL,xtvs,NIL);
1857 checkOptQuantVars(line,xtvs,tvs);
1859 if (isQualType(type)) {
1860 map2Over(depPredExp,line,tvs,fst(snd(type)));
1861 snd(snd(type)) = depTopType(line,tvs,snd(snd(type)));
1863 if (isAmbiguous(type)) {
1864 ambigError(line,where,e,type);
1867 type = depTopType(line,tvs,type);
1871 if (length(tvs) >= (OFF_MAX-OFF_MIN+1)) {
1872 ERRMSG(line) "Too many type variables in %s\n", where
1876 for (; nonNull(ts); ts=tl(ts)) {
1879 type = mkPolyType(tvs,type);
1884 kindType(line,"type expression",type);
1888 h98CheckType(line,where,e,type);
1892 static Void local checkOptQuantVars(line,xtvs,tvs)
1894 List xtvs; /* Explicitly quantified vars */
1895 List tvs; { /* Implicitly quantified vars */
1896 if (nonNull(xtvs)) {
1898 for (; nonNull(vs); vs=tl(vs)) {
1899 if (!varIsMember(textOf(hd(vs)),xtvs)) {
1900 ERRMSG(line) "Quantifier does not mention type variable \"%s\"",
1901 textToStr(textOf(hd(vs)))
1905 for (vs=xtvs; nonNull(vs); vs=tl(vs)) {
1906 if (!varIsMember(textOf(hd(vs)),tvs)) {
1907 ERRMSG(line) "Quantified type variable \"%s\" is not used",
1908 textToStr(textOf(hd(vs)))
1911 if (varIsMember(textOf(hd(vs)),tl(vs))) {
1912 ERRMSG(line) "Quantified type variable \"%s\" is repeated",
1913 textToStr(textOf(hd(vs)))
1920 static Type local depTopType(l,tvs,t) /* Check top-level of type sig */
1928 for (; getHead(t1)==typeArrow && argCount==2; ++i) {
1929 arg(fun(t1)) = depCompType(l,tvs,arg(fun(t1)));
1930 if (isPolyOrQualType(arg(fun(t1)))) {
1936 if (nonNull(prev)) {
1937 arg(prev) = depTypeExp(l,tvs,t1);
1939 t = depTypeExp(l,tvs,t1);
1942 t = ap(RANK2,pair(mkInt(nr2),t));
1947 static Type local depCompType(l,tvs,t) /* Check component type for constr */
1951 Int ntvs = length(tvs);
1953 if (isPolyType(t)) {
1954 List vs = fst(snd(t));
1956 tvs = checkQuantVars(l,vs,tvs,t);
1957 nfr = replicate(length(vs),NIL);
1959 if (isQualType(t)) {
1960 map2Over(depPredExp,l,tvs,fst(snd(t)));
1961 snd(snd(t)) = depTypeExp(l,tvs,snd(snd(t)));
1962 if (isAmbiguous(t)) {
1963 ambigError(l,"type component",NIL,t);
1966 t = depTypeExp(l,tvs,t);
1972 return mkPolyType(nfr,t);
1975 static Type local depTypeExp(line,tyvars,type)
1979 switch (whatIs(type)) {
1980 case AP : fst(type) = depTypeExp(line,tyvars,fst(type));
1981 snd(type) = depTypeExp(line,tyvars,snd(type));
1984 case VARIDCELL : return depTypeVar(line,tyvars,textOf(type));
1986 case QUALIDENT : if (isQVar(type)) {
1987 ERRMSG(line) "Qualified type variables not allowed"
1990 /* deliberate fall through */
1991 case CONIDCELL : { Tycon tc = findQualTycon(type);
1994 "Undefined type constructor \"%s\"",
1998 if (cellIsMember(tc,tyconDefns) &&
1999 !cellIsMember(tc,tcDeps)) {
2000 tcDeps = cons(tc,tcDeps);
2006 case EXT : h98DoesntSupport(line,"extensible records");
2011 default : internal("depTypeExp");
2016 static Type local depTypeVar(line,tyvars,tv)
2023 for (; nonNull(tyvars); offset++) {
2024 if (tv==textOf(hd(tyvars))) {
2027 tyvars = tl(tyvars);
2030 Cell vt = findBtyvs(tv);
2034 ERRMSG(line) "Undefined type variable \"%s\"", textToStr(tv)
2037 return mkOffset(found);
2040 static List local checkQuantVars(line,vs,tvs,body)
2042 List vs; /* variables to quantify over */
2043 List tvs; /* variables already in scope */
2044 Cell body; { /* type/constr for scope of vars */
2046 List bvs = typeVarsIn(body,NIL,NIL,NIL);
2048 for (; nonNull(us); us=tl(us)) {
2049 Text u = textOf(hd(us));
2050 if (varIsMember(u,tl(us))) {
2051 ERRMSG(line) "Duplicated quantified variable %s",
2056 if (varIsMember(u,tvs)) {
2057 ERRMSG(line) "Local quantifier for %s hides an outer use",
2062 if (!varIsMember(u,bvs)) {
2063 ERRMSG(line) "Locally quantified variable %s is not used",
2068 tvs = appendOnto(tvs,vs);
2073 /* --------------------------------------------------------------------------
2074 * Check for ambiguous types:
2075 * A type Preds => type is ambiguous if not (TV(P) `subset` TV(type))
2076 * ------------------------------------------------------------------------*/
2078 List offsetTyvarsIn(t,vs) /* add list of offset tyvars in t */
2079 Type t; /* to list vs */
2081 switch (whatIs(t)) {
2082 case AP : return offsetTyvarsIn(fun(t),
2083 offsetTyvarsIn(arg(t),vs));
2085 case OFFSET : if (cellIsMember(t,vs))
2090 case QUAL : return offsetTyvarsIn(snd(t),vs);
2092 case POLYTYPE : return offsetTyvarsIn(monotypeOf(t),vs);
2093 /* slightly inaccurate, but won't matter here */
2096 case RANK2 : return offsetTyvarsIn(snd(snd(t)),vs);
2098 default : return vs;
2102 List zonkTyvarsIn(t,vs)
2105 switch (whatIs(t)) {
2106 case AP : return zonkTyvarsIn(fun(t),
2107 zonkTyvarsIn(arg(t),vs));
2109 case INTCELL : if (cellIsMember(t,vs))
2114 /* this case will lead to a type error --
2115 much better than reporting an internal error ;-) */
2116 /* case OFFSET : internal("zonkTyvarsIn"); */
2118 default : return vs;
2122 static List local otvars(pi,os) /* os is a list of offsets that */
2123 Cell pi; /* refer to the arguments of pi; */
2124 List os; { /* find list of offsets in those */
2125 List us = NIL; /* positions */
2126 for (; nonNull(os); os=tl(os)) {
2127 us = offsetTyvarsIn(nthArg(offsetOf(hd(os)),pi),us);
2132 static List local otvarsZonk(pi,os,o) /* same as above, but zonks */
2136 for (; nonNull(os); os=tl(os)) {
2137 Type t = zonkType(nthArg(offsetOf(hd(os)),pi),o);
2138 us = zonkTyvarsIn(t,us);
2143 static Bool local odiff(us,vs)
2145 while (nonNull(us) && cellIsMember(hd(us),vs)) {
2151 static Bool local osubset(us,vs) /* Determine whether us is subset */
2152 List us, vs; { /* of vs */
2153 while (nonNull(us) && cellIsMember(hd(us),vs)) {
2159 List oclose(fds,vs) /* Compute closure of vs wrt to fds*/
2162 Bool changed = TRUE;
2166 while (nonNull(fds)) {
2168 List next = tl(fds);
2169 if (osubset(fst(fd),vs)) { /* Test if fd applies */
2171 for (; nonNull(os); os=tl(os)) {
2172 if (!cellIsMember(hd(os),vs)) {
2173 vs = cons(hd(os),vs);
2177 } else { /* Didn't apply this time, so keep */
2188 Bool isAmbiguous(type) /* Determine whether type is */
2189 Type type; { /* ambiguous */
2190 if (isPolyType(type)) {
2191 type = monotypeOf(type);
2193 if (isQualType(type)) { /* only qualified types can be */
2194 List ps = fst(snd(type)); /* ambiguous */
2195 List tvps = offsetTyvarsIn(ps,NIL);
2196 List tvts = offsetTyvarsIn(snd(snd(type)),NIL);
2197 List fds = calcFunDeps(ps);
2199 tvts = oclose(fds,tvts); /* Close tvts under fds */
2200 return !osubset(tvps,tvts);
2205 List calcFunDeps(ps)
2208 for (; nonNull(ps); ps=tl(ps)) {/* Calc functional dependencies */
2210 Cell c = getHead(pi);
2212 List xfs = cclass(c).xfds;
2213 for (; nonNull(xfs); xfs=tl(xfs)) {
2214 List fs = snd(hd(xfs));
2215 for (; nonNull(fs); fs=tl(fs)) {
2216 fds = cons(pair(otvars(pi,fst(hd(fs))),
2217 otvars(pi,snd(hd(fs)))),fds);
2223 fds = cons(pair(NIL,offsetTyvarsIn(arg(pi),NIL)),fds);
2230 List calcFunDepsPreds(ps)
2233 for (; nonNull(ps); ps=tl(ps)) {/* Calc functional dependencies */
2235 Cell pi = fst3(pi3);
2236 Cell c = getHead(pi);
2237 Int o = intOf(snd3(pi3));
2239 List xfs = cclass(c).xfds;
2240 for (; nonNull(xfs); xfs=tl(xfs)) {
2241 List fs = snd(hd(xfs));
2242 for (; nonNull(fs); fs=tl(fs)) {
2243 fds = cons(pair(otvarsZonk(pi,fst(hd(fs)),o),
2244 otvarsZonk(pi,snd(hd(fs)),o)),fds);
2250 fds = cons(pair(NIL,zonkTyvarsIn(arg(pi),NIL)),fds);
2257 Void ambigError(line,where,e,type) /* produce error message for */
2258 Int line; /* ambiguity */
2262 ERRMSG(line) "Ambiguous type signature in %s", where ETHEN
2263 ERRTEXT "\n*** ambiguous type : " ETHEN ERRTYPE(type);
2265 ERRTEXT "\n*** assigned to : " ETHEN ERREXPR(e);
2271 /* --------------------------------------------------------------------------
2272 * Kind inference for simple types:
2273 * ------------------------------------------------------------------------*/
2275 static Void local kindConstr(line,alpha,m,c)
2276 Int line; /* Determine kind of constructor */
2280 Cell h = getHead(c);
2284 Printf("kindConstr: alpha=%d, m=%d, c=",alpha,m);
2285 printType(stdout,c);
2289 switch (whatIs(h)) {
2290 case POLYTYPE : if (n!=0) {
2291 internal("kindConstr1");
2293 static String pt = "polymorphic type";
2294 Type t = dropRank1(c,alpha,m);
2295 Kinds ks = polySigOf(t);
2298 for (; isAp(ks); ks=tl(ks)) {
2301 beta = newKindvars(m1);
2302 unkindTypes = cons(pair(mkInt(beta),t),unkindTypes);
2303 checkKind(line,beta,m1,monotypeOf(t),NIL,pt,STAR,0);
2308 case QUAL : if (n!=0) {
2309 internal("kindConstr2");
2311 map3Proc(kindPred,line,alpha,m,fst(snd(c)));
2312 kindConstr(line,alpha,m,snd(snd(c)));
2316 case RANK2 : kindConstr(line,alpha,m,snd(snd(c)));
2320 case EXT : if (n!=2) {
2322 "Illegal use of row in " ETHEN ERRTYPE(c);
2329 case TYCON : if (isSynonym(h) && n<tycon(h).arity) {
2331 "Not enough arguments for type synonym \"%s\"",
2332 textToStr(tycon(h).text)
2338 if (n==0) { /* trivial case, no arguments */
2339 typeIs = kindAtom(alpha,c);
2340 } else { /* non-trivial application */
2341 static String app = "constructor application";
2351 typeIs = kindAtom(alpha,h); /* h :: v1 -> ... -> vn -> w */
2352 shouldKind(line,h,c,app,k,beta);
2354 for (i=n; i>0; --i) { /* ci :: vi for each 1 <- 1..n */
2355 checkKind(line,alpha,m,arg(a),c,app,aVar,beta+i-1);
2358 tyvarType(beta+n); /* inferred kind is w */
2362 static Kind local kindAtom(alpha,c) /* Find kind of atomic constructor */
2365 switch (whatIs(c)) {
2366 case TUPLE : return simpleKind(tupleOf(c)); /*(,)::* -> * -> * */
2367 case OFFSET : return mkInt(alpha+offsetOf(c));
2368 case TYCON : return tycon(c).kind;
2369 case INTCELL : return c;
2371 case VAROPCELL : { Cell vt = findBtyvs(textOf(c));
2377 case EXT : return extKind;
2381 Printf("kindAtom(%d,whatIs(%d)) on ",alpha,whatIs(c));
2382 printType(stdout,c);
2385 internal("kindAtom");
2386 return STAR;/* not reached */
2389 static Void local kindPred(l,alpha,m,pi)/* Check kinds of arguments in pred*/
2395 if (isAp(pi) && isExt(fun(pi))) {
2396 static String lackspred = "lacks predicate";
2397 checkKind(l,alpha,m,arg(pi),NIL,lackspred,ROW,0);
2402 if (isAp(pi) && whatIs(fun(pi)) == IPCELL) {
2403 static String ippred = "iparam predicate";
2404 checkKind(l,alpha,m,arg(pi),NIL,ippred,STAR,0);
2408 { static String predicate = "class constraint";
2409 Class c = getHead(pi);
2410 List as = getArgs(pi);
2411 Kinds ks = cclass(c).kinds;
2413 while (nonNull(ks)) {
2414 checkKind(l,alpha,m,hd(as),NIL,predicate,hd(ks),0);
2421 static Void local kindType(line,wh,type)/* check that (poss qualified) type*/
2422 Int line; /* is well-kinded */
2425 checkKind(line,0,0,type,NIL,wh,STAR,0);
2428 static Void local fixKinds() { /* add kind annotations to types */
2429 for (; nonNull(unkindTypes); unkindTypes=tl(unkindTypes)) {
2430 Pair pr = hd(unkindTypes);
2431 Int beta = intOf(fst(pr));
2432 Cell qts = polySigOf(snd(pr));
2434 if (isNull(hd(qts))) {
2435 hd(qts) = copyKindvar(beta++);
2437 internal("fixKinds");
2439 if (nonNull(tl(qts))) {
2447 Printf("Type expression: ");
2448 printType(stdout,snd(pr));
2450 printKind(stdout,polySigOf(snd(pr)));
2456 /* --------------------------------------------------------------------------
2457 * Kind checking of groups of type constructors and classes:
2458 * ------------------------------------------------------------------------*/
2460 static Void local kindTCGroup(tcs) /* find kinds for mutually rec. gp */
2461 List tcs; { /* of tycons and classes */
2462 emptySubstitution();
2464 mapProc(initTCKind,tcs);
2465 mapProc(kindTC,tcs);
2468 emptySubstitution();
2471 static Void local initTCKind(c) /* build initial kind/arity for c */
2473 if (isTycon(c)) { /* Initial kind of tycon is: */
2474 Int beta = newKindvars(1); /* v1 -> ... -> vn -> vn+1 */
2475 varKind(tycon(c).arity); /* where n is the arity of c. */
2476 bindTv(beta,typeIs,typeOff); /* For data definitions, vn+1 == * */
2477 switch (whatIs(tycon(c).what)) {
2479 case DATATYPE : bindTv(typeOff+tycon(c).arity,STAR,0);
2481 tycon(c).kind = mkInt(beta);
2483 Int n = cclass(c).arity;
2484 Int beta = newKindvars(n);
2485 cclass(c).kinds = NIL;
2488 cclass(c).kinds = pair(mkInt(beta+n),cclass(c).kinds);
2493 static Void local kindTC(c) /* check each part of a tycon/class*/
2494 Cell c; { /* is well-kinded */
2496 static String cfun = "constructor function";
2497 static String tsyn = "synonym definition";
2498 Int line = tycon(c).line;
2499 Int beta = tyvar(intOf(tycon(c).kind))->offs;
2500 Int m = tycon(c).arity;
2501 switch (whatIs(tycon(c).what)) {
2503 case DATATYPE : { List cs = tycon(c).defn;
2504 if (isQualType(cs)) {
2505 map3Proc(kindPred,line,beta,m,
2507 tycon(c).defn = cs = snd(snd(cs));
2509 for (; hasCfun(cs); cs=tl(cs)) {
2510 kindType(line,cfun,name(hd(cs)).type);
2515 default : checkKind(line,beta,m,tycon(c).defn,NIL,
2519 else { /* scan type exprs in class defn to*/
2520 List ms = fst(cclass(c).members);
2521 Int m = cclass(c).arity; /* determine the class signature */
2522 Int beta = newKindvars(m);
2523 kindPred(cclass(c).line,beta,m,cclass(c).head);
2524 map3Proc(kindPred,cclass(c).line,beta,m,cclass(c).supers);
2525 for (; nonNull(ms); ms=tl(ms)) {
2526 Int line = intOf(fst3(hd(ms)));
2527 Type type = thd3(hd(ms));
2528 kindType(line,"member function type signature",type);
2533 static Void local genTC(c) /* generalise kind inferred for */
2534 Cell c; { /* given tycon/class */
2536 tycon(c).kind = copyKindvar(intOf(tycon(c).kind));
2538 Printf("%s :: ",textToStr(tycon(c).text));
2539 printKind(stdout,tycon(c).kind);
2543 Kinds ks = cclass(c).kinds;
2544 for (; nonNull(ks); ks=tl(ks)) {
2545 hd(ks) = copyKindvar(intOf(hd(ks)));
2548 Printf("%s :: ",textToStr(cclass(c).text));
2549 printKinds(stdout,cclass(c).kinds);
2555 /* --------------------------------------------------------------------------
2556 * Static analysis of instance declarations:
2558 * The first part of the static analysis is performed as the declarations
2559 * are read during parsing:
2560 * - make new entry in instance table
2561 * - record line number of declaration
2562 * - build list of instances defined in current script for use in later
2563 * stages of static analysis.
2564 * ------------------------------------------------------------------------*/
2566 Void instDefn(line,head,ms) /* process new instance definition */
2567 Int line; /* definition line number */
2568 Cell head; /* inst header :: (context,Class) */
2569 List ms; { /* instance members */
2570 Inst nw = newInst();
2571 inst(nw).line = line;
2572 inst(nw).specifics = fst(head);
2573 inst(nw).head = snd(head);
2574 inst(nw).implements = ms;
2575 instDefns = cons(nw,instDefns);
2578 /* --------------------------------------------------------------------------
2579 * Further static analysis of instance declarations:
2581 * Makes the following checks:
2582 * - Class part of header has form C (T a1 ... an) where C is a known
2583 * class, and T is a known datatype constructor (or restricted synonym),
2584 * and there is no previous C-T instance, and (T a1 ... an) has a kind
2585 * appropriate for the class C.
2586 * - Each element of context is a valid class expression, with type vars
2587 * drawn from a1, ..., an.
2588 * - All bindings are function bindings
2589 * - All bindings define member functions for class C
2590 * - Arrange bindings into appropriate order for member list
2591 * - No top level type signature declarations
2592 * ------------------------------------------------------------------------*/
2594 Bool allowOverlap = FALSE; /* TRUE => allow overlapping insts */
2595 Name nameListMonad = NIL; /* builder function for List Monad */
2597 static Void local checkInstDefn(in) /* Validate instance declaration */
2599 Int line = inst(in).line;
2600 List tyvars = typeVarsIn(inst(in).head,NIL,NIL,NIL);
2601 List tvps = NIL, tvts = NIL;
2604 if (haskell98) { /* Check for `simple' type */
2606 Cell t = arg(inst(in).head);
2607 for (; isAp(t); t=fun(t)) {
2608 if (!isVar(arg(t))) {
2610 "syntax error in instance head (variable expected)"
2613 if (varIsMember(textOf(arg(t)),tvs)) {
2614 ERRMSG(line) "repeated type variable \"%s\" in instance head",
2615 textToStr(textOf(arg(t)))
2618 tvs = cons(arg(t),tvs);
2622 "syntax error in instance head (constructor expected)"
2627 /* add in the tyvars from the `specifics' so that we don't
2628 prematurely complain about undefined tyvars */
2629 tyvars = typeVarsIn(inst(in).specifics,NIL,NIL,tyvars);
2630 inst(in).head = depPredExp(line,tyvars,inst(in).head);
2633 Type h = getHead(arg(inst(in).head));
2635 ERRMSG(line) "Cannot use type synonym in instance head"
2640 map2Over(depPredExp,line,tyvars,inst(in).specifics);
2642 /* OK, now we start over, and test for ambiguity */
2643 tvts = offsetTyvarsIn(inst(in).head,NIL);
2644 tvps = offsetTyvarsIn(inst(in).specifics,NIL);
2645 fds = calcFunDeps(inst(in).specifics);
2646 tvts = oclose(fds,tvts);
2647 tvts = odiff(tvps,tvts);
2648 if (!isNull(tvts)) {
2649 ERRMSG(line) "Undefined type variable \"%s\"",
2650 textToStr(textOf(nth(offsetOf(hd(tvts)),tyvars)))
2654 h98CheckCtxt(line,"instance definition",FALSE,inst(in).specifics,NIL);
2655 inst(in).numSpecifics = length(inst(in).specifics);
2656 inst(in).c = getHead(inst(in).head);
2657 if (!isClass(inst(in).c)) {
2658 ERRMSG(line) "Illegal predicate in instance declaration"
2662 if (nonNull(cclass(inst(in).c).fds)) {
2663 List fds = cclass(inst(in).c).fds;
2664 for (; nonNull(fds); fds=tl(fds)) {
2665 List as = otvars(inst(in).head, fst(hd(fds)));
2666 List bs = otvars(inst(in).head, snd(hd(fds)));
2667 List fs = calcFunDeps(inst(in).specifics);
2669 if (!osubset(bs,as)) {
2670 ERRMSG(inst(in).line)
2671 "Instance is more general than a dependency allows"
2673 ERRTEXT "\n*** Instance : "
2674 ETHEN ERRPRED(inst(in).head);
2675 ERRTEXT "\n*** For class : "
2676 ETHEN ERRPRED(cclass(inst(in).c).head);
2677 ERRTEXT "\n*** Under dependency : "
2678 ETHEN ERRFD(hd(fds));
2685 kindInst(in,length(tyvars));
2688 if (nonNull(extractSigdecls(inst(in).implements))) {
2690 "Type signature declarations not permitted in instance declaration"
2693 if (nonNull(extractFixdecls(inst(in).implements))) {
2695 "Fixity declarations not permitted in instance declaration"
2698 inst(in).implements = classBindings("instance",
2700 extractBindings(inst(in).implements));
2701 inst(in).builder = newInstImp(in);
2702 if (!preludeLoaded && isNull(nameListMonad) && isAp(inst(in).head)
2703 && fun(inst(in).head)==classMonad && arg(inst(in).head)==typeList) {
2704 nameListMonad = inst(in).builder;
2708 static Void local insertInst(in) /* Insert instance into class */
2710 Class c = inst(in).c;
2711 List ins = cclass(c).instances;
2714 if (nonNull(cclass(c).fds)) { /* Check for conflicts with fds */
2715 List ins1 = cclass(c).instances;
2716 for (; nonNull(ins1); ins1=tl(ins1)) {
2717 List fds = cclass(c).fds;
2718 substitution(RESET);
2719 for (; nonNull(fds); fds=tl(fds)) {
2720 Int alpha = newKindedVars(inst(in).kinds);
2721 Int beta = newKindedVars(inst(hd(ins1)).kinds);
2722 List as = fst(hd(fds));
2724 for (; same && nonNull(as); as=tl(as)) {
2725 Int n = offsetOf(hd(as));
2726 same &= unify(nthArg(n,inst(in).head),alpha,
2727 nthArg(n,inst(hd(ins1)).head),beta);
2729 if (isNull(as) && same) {
2730 for (as=snd(hd(fds)); same && nonNull(as); as=tl(as)) {
2731 Int n = offsetOf(hd(as));
2732 same &= sameType(nthArg(n,inst(in).head),alpha,
2733 nthArg(n,inst(hd(ins1)).head),beta);
2736 ERRMSG(inst(in).line)
2737 "Instances are not consistent with dependencies"
2739 ERRTEXT "\n*** This instance : "
2740 ETHEN ERRPRED(inst(in).head);
2741 ERRTEXT "\n*** Conflicts with : "
2742 ETHEN ERRPRED(inst(hd(ins)).head);
2743 ERRTEXT "\n*** For class : "
2744 ETHEN ERRPRED(cclass(c).head);
2745 ERRTEXT "\n*** Under dependency : "
2746 ETHEN ERRFD(hd(fds));
2756 substitution(RESET);
2757 while (nonNull(ins)) { /* Look for overlap w/ other insts */
2758 Int alpha = newKindedVars(inst(in).kinds);
2759 Int beta = newKindedVars(inst(hd(ins)).kinds);
2760 if (unifyPred(inst(in).head,alpha,inst(hd(ins)).head,beta)) {
2761 Cell pi = copyPred(inst(in).head,alpha);
2762 if (allowOverlap && !haskell98) {
2763 Bool bef = instCompare(in,hd(ins));
2764 Bool aft = instCompare(hd(ins),in);
2765 if (bef && !aft) { /* in comes strictly before hd(ins)*/
2768 if (aft && !bef) { /* in comes strictly after hd(ins) */
2775 if (multiInstRes && nonNull(inst(in).specifics)) {
2779 ERRMSG(inst(in).line) "Overlapping instances for class \"%s\"",
2780 textToStr(cclass(c).text)
2782 ERRTEXT "\n*** This instance : " ETHEN ERRPRED(inst(in).head);
2783 ERRTEXT "\n*** Overlaps with : " ETHEN
2784 ERRPRED(inst(hd(ins)).head);
2785 ERRTEXT "\n*** Common instance : " ETHEN
2793 prev = ins; /* No overlap detected, so move on */
2794 ins = tl(ins); /* to next instance */
2796 substitution(RESET);
2798 if (nonNull(prev)) { /* Insert instance at this point */
2799 tl(prev) = cons(in,ins);
2801 cclass(c).instances = cons(in,ins);
2805 static Bool local instCompare(ia,ib) /* See if ia is an instance of ib */
2807 Int alpha = newKindedVars(inst(ia).kinds);
2808 Int beta = newKindedVars(inst(ib).kinds);
2809 return matchPred(inst(ia).head,alpha,inst(ib).head,beta);
2812 static Name local newInstImp(in) /* Make definition for inst builder*/
2814 Name b = newName(inventText(),in);
2815 name(b).line = inst(in).line;
2816 name(b).arity = inst(in).numSpecifics;
2817 name(b).number = DFUNNAME;
2821 /* --------------------------------------------------------------------------
2822 * Kind checking of instance declaration headers:
2823 * ------------------------------------------------------------------------*/
2825 static Void local kindInst(in,freedom) /* check predicates in instance */
2830 emptySubstitution();
2831 beta = newKindvars(freedom);
2832 kindPred(inst(in).line,beta,freedom,inst(in).head);
2833 if (whatIs(inst(in).specifics)!=DERIVE) {
2834 map3Proc(kindPred,inst(in).line,beta,freedom,inst(in).specifics);
2836 for (inst(in).kinds = NIL; 0<freedom--; ) {
2837 inst(in).kinds = cons(copyKindvar(beta+freedom),inst(in).kinds);
2840 Printf("instance ");
2841 printPred(stdout,inst(in).head);
2843 printKinds(stdout,inst(in).kinds);
2846 emptySubstitution();
2849 /* --------------------------------------------------------------------------
2850 * Process derived instance requests:
2851 * ------------------------------------------------------------------------*/
2853 static List derivedInsts; /* list of derived instances */
2855 static Void local checkDerive(t,p,ts,ct)/* verify derived instance request */
2856 Tycon t; /* for tycon t, with explicit */
2857 List p; /* context p, component types ts */
2858 List ts; /* and named class ct */
2860 Int line = tycon(t).line;
2861 Class c = findQualClass(ct);
2863 ERRMSG(line) "Unknown class \"%s\" in derived instance",
2867 addDerInst(line,c,p,dupList(ts),t,tycon(t).arity);
2870 static Void local addDerInst(line,c,p,cts,t,a) /* Add a derived instance */
2877 Cell head = t; /* Build instance head */
2881 head = ap(head,mkOffset(i));
2887 inst(in).line = line;
2888 inst(in).head = head;
2889 inst(in).specifics = ap(DERIVE,pair(dupList(p),cts));
2890 inst(in).implements = NIL;
2891 inst(in).kinds = mkInt(a);
2892 derivedInsts = cons(in,derivedInsts);
2895 Void addTupInst(c,n) /* Request derived instance of c */
2896 Class c; /* for mkTuple(n) constructor */
2901 cts = cons(mkOffset(m),cts);
2904 addDerInst(0,c,NIL,cts,mkTuple(n),n);
2908 Inst addRecShowInst(c,e) /* Generate instance for ShowRecRow*/
2909 Class c; /* c *must* be ShowRecRow */
2911 Inst in = newInst();
2913 inst(in).head = ap(c,ap2(e,aVar,bVar));
2914 inst(in).kinds = extKind;
2915 inst(in).specifics = cons(ap(classShow,aVar),
2917 cons(ap(c,bVar),NIL)));
2918 inst(in).numSpecifics = 3;
2919 inst(in).builder = implementRecShw(extText(e),in);
2920 cclass(c).instances = appendOnto(cclass(c).instances,singleton(in));
2924 Inst addRecEqInst(c,e) /* Generate instance for EqRecRow */
2925 Class c; /* c *must* be EqRecRow */
2927 Inst in = newInst();
2929 inst(in).head = ap(c,ap2(e,aVar,bVar));
2930 inst(in).kinds = extKind;
2931 inst(in).specifics = cons(ap(classEq,aVar),
2933 cons(ap(c,bVar),NIL)));
2934 inst(in).numSpecifics = 3;
2935 inst(in).builder = implementRecEq(extText(e),in);
2936 cclass(c).instances = appendOnto(cclass(c).instances,singleton(in));
2941 /* --------------------------------------------------------------------------
2942 * Calculation of contexts for derived instances:
2944 * Allowing arbitrary types to appear in contexts makes it rather harder
2945 * to decide what the context for a derived instance should be. For
2948 * data T a = MkT [a] deriving Show,
2950 * we could have either of the following:
2952 * instance (Show [a]) => Show (T a) where ...
2953 * instance (Show a) => Show (T a) where ...
2955 * (assuming, of course, that instance (Show a) => Show [a]). For now, we
2956 * choose to reduce contexts in the hope of detecting errors at an earlier
2957 * stage---in contrast with value definitions, there is no way for a user
2958 * to provide something analogous to a `type signature' by which they might
2959 * be able to control this behaviour themselves. We eliminate tautological
2960 * predicates, but only allow predicates to appear in the final result if
2961 * they have at least one argument with a variable at its head.
2963 * In general, we have to deal with mutually recursive instance declarations.
2964 * We find a solution in the obvious way by iterating to find a fixed point.
2965 * Of course, without restrictions on the form of instance declarations, we
2966 * cannot be sure that this will always terminate!
2968 * For each instance we maintain a pair of the form DERIVE (ctxt,ps).
2969 * Ctxt is a list giving the parts of the context that have been produced
2970 * so far in the form of predicate skeletons. During the calculation of
2971 * derived instances, we attach a dummy NIL value to the end of the list
2972 * which acts as a kind of `variable': other parts of the system maintain
2973 * pointers to this variable, and use it to detect when the context has
2974 * been extended with new elements. Meanwhile, ps is a list containing
2975 * predicates (pi,o) together with (delayed) substitutions of the form
2976 * (o,xs) where o is an offset and xs is one of the context variables
2977 * described above, which may have been partially instantiated.
2978 * ------------------------------------------------------------------------*/
2980 static Bool instsChanged;
2982 static Void local deriveContexts(is) /* Calc contexts for derived insts */
2984 emptySubstitution();
2985 mapProc(initDerInst,is); /* Prepare derived instances */
2987 do { /* Main calculation of contexts */
2988 instsChanged = FALSE;
2989 mapProc(calcInstPreds,is);
2990 } while (instsChanged);
2992 mapProc(tidyDerInst,is); /* Tidy up results */
2995 static Void local initDerInst(in) /* Prepare instance for calculation*/
2996 Inst in; { /* of derived instance context */
2997 Cell spcs = inst(in).specifics;
2998 Int beta = newKindedVars(inst(in).kinds);
2999 if (whatIs(spcs)!=DERIVE) {
3000 internal("initDerInst");
3002 fst(snd(spcs)) = appendOnto(fst(snd(spcs)),singleton(NIL));
3003 for (spcs=snd(snd(spcs)); nonNull(spcs); spcs=tl(spcs)) {
3004 hd(spcs) = ap2(inst(in).c,hd(spcs),mkInt(beta));
3006 inst(in).numSpecifics = beta;
3008 #ifdef DEBUG_DERIVING
3009 Printf("initDerInst: ");
3010 printPred(stdout,inst(in).head);
3012 printContext(stdout,snd(snd(inst(in).specifics)));
3017 static Void local calcInstPreds(in) /* Calculate next approximation */
3018 Inst in; { /* of the context for a derived */
3019 List retain = NIL; /* instance */
3020 List ps = snd(snd(inst(in).specifics));
3021 List spcs = fst(snd(inst(in).specifics));
3022 Int beta = inst(in).numSpecifics;
3024 Int factor = 1+length(ps);
3026 #ifdef DEBUG_DERIVING
3027 Printf("calcInstPreds: ");
3028 printPred(stdout,inst(in).head);
3032 while (nonNull(ps)) {
3035 if (its++ >= factor*cutoff) {
3036 Cell bpi = inst(in).head;
3037 ERRMSG(inst(in).line) "\n*** Cannot derive " ETHEN ERRPRED(bpi);
3038 ERRTEXT " after %d iterations.", its-1 ETHEN
3040 "\n*** This may indicate that the problem is undecidable. However,\n"
3042 "*** you may still try to increase the cutoff limit using the -c\n"
3044 "*** option and then try again. (The current setting is -c%d)\n",
3048 if (isInt(fst(p))) { /* Delayed substitution? */
3050 for (; nonNull(hd(qs)); qs=tl(qs)) {
3051 ps = cons(pair(hd(qs),fst(p)),ps);
3053 retain = cons(pair(fst(p),qs),retain);
3056 else if (isExt(fun(fst(p)))) { /* Lacks predicate */
3057 Text l = extText(fun(fst(p)));
3058 Type t = arg(fst(p));
3059 Int o = intOf(snd(p));
3064 h = getDerefHead(t,o);
3065 while (isExt(h) && argCount==2 && l!=extText(h)) {
3068 h = getDerefHead(t,o);
3070 if (argCount==0 && isOffset(h)) {
3071 maybeAddPred(ap(fun(fun(p)),h),o,beta,spcs);
3072 } else if (argCount!=0 || h!=typeNoRow) {
3073 Cell bpi = inst(in).head;
3074 Cell pi = copyPred(fun(p),intOf(snd(p)));
3075 ERRMSG(inst(in).line) "Cannot derive " ETHEN ERRPRED(bpi);
3076 ERRTEXT " because predicate " ETHEN ERRPRED(pi);
3077 ERRTEXT " does not hold\n"
3082 else { /* Class predicate */
3084 Int o = intOf(snd(p));
3085 Inst in1 = findInstFor(pi,o);
3087 List qs = inst(in1).specifics;
3088 Int off = mkInt(typeOff);
3089 if (whatIs(qs)==DERIVE) { /* Still being derived */
3090 for (qs=fst(snd(qs)); nonNull(hd(qs)); qs=tl(qs)) {
3091 ps = cons(pair(hd(qs),off),ps);
3093 retain = cons(pair(off,qs),retain);
3094 } else { /* Previously def'd inst */
3095 for (; nonNull(qs); qs=tl(qs)) {
3096 ps = cons(pair(hd(qs),off),ps);
3099 } else { /* No matching instance */
3101 while (isAp(qi) && isOffset(getDerefHead(arg(qi),o))) {
3105 Cell bpi = inst(in).head;
3106 pi = copyPred(pi,o);
3107 ERRMSG(inst(in).line) "An instance of " ETHEN ERRPRED(pi);
3108 ERRTEXT " is required to derive " ETHEN ERRPRED(bpi);
3112 maybeAddPred(pi,o,beta,spcs);
3117 snd(snd(inst(in).specifics)) = retain;
3120 static Void local maybeAddPred(pi,o,beta,ps)
3121 Cell pi; /* Add predicate pi to the list ps,*/
3122 Int o; /* setting the instsChanged flag if*/
3123 Int beta; /* pi is not already a member and */
3124 List ps; { /* using beta to adjust vars */
3125 Cell c = getHead(pi);
3126 for (; nonNull(ps); ps=tl(ps)) {
3127 if (isNull(hd(ps))) { /* reached the `dummy' end of list?*/
3128 hd(ps) = copyAdj(pi,o,beta);
3129 tl(ps) = pair(NIL,NIL);
3130 instsChanged = TRUE;
3132 } else if (c==getHead(hd(ps)) && samePred(pi,o,hd(ps),beta)) {
3138 static Cell local copyAdj(c,o,beta) /* Copy (c,o), replacing vars with */
3139 Cell c; /* offsets relative to beta. */
3142 switch (whatIs(c)) {
3143 case AP : { Cell l = copyAdj(fst(c),o,beta);
3144 Cell r = copyAdj(snd(c),o,beta);
3148 case OFFSET : { Int vn = o+offsetOf(c);
3149 Tyvar *tyv = tyvar(vn);
3151 return copyAdj(tyv->bound,tyv->offs,beta);
3154 if (vn<0 || vn>=(OFF_MAX-OFF_MIN+1)) {
3155 internal("copyAdj");
3157 return mkOffset(vn);
3163 static Void local tidyDerInst(in) /* Tidy up results of derived inst */
3164 Inst in; { /* calculations */
3165 Int o = inst(in).numSpecifics;
3166 List ps = tl(rev(fst(snd(inst(in).specifics))));
3168 copyPred(inst(in).head,o);
3169 inst(in).specifics = simpleContext(ps,o);
3170 h98CheckCtxt(inst(in).line,"derived instance",FALSE,inst(in).specifics,in);
3171 inst(in).numSpecifics = length(inst(in).specifics);
3173 #ifdef DEBUG_DERIVING
3174 Printf("Derived instance: ");
3175 printContext(stdout,inst(in).specifics);
3177 printPred(stdout,inst(in).head);
3182 /* --------------------------------------------------------------------------
3183 * Generate code for derived instances:
3184 * ------------------------------------------------------------------------*/
3186 static Void local addDerivImp(in)
3189 Type t = getHead(arg(inst(in).head));
3190 Class c = inst(in).c;
3193 } else if (c==classOrd) {
3195 } else if (c==classEnum) {
3196 imp = deriveEnum(t);
3197 } else if (c==classIx) {
3199 } else if (c==classShow) {
3200 imp = deriveShow(t);
3201 } else if (c==classRead) {
3202 imp = deriveRead(t);
3203 } else if (c==classBounded) {
3204 imp = deriveBounded(t);
3206 ERRMSG(inst(in).line) "Cannot derive instances of class \"%s\"",
3207 textToStr(cclass(inst(in).c).text)
3211 kindInst(in,intOf(inst(in).kinds));
3213 inst(in).builder = newInstImp(in);
3214 inst(in).implements = classBindings("derived instance",
3220 /* --------------------------------------------------------------------------
3221 * Default definitions; only one default definition is permitted in a
3222 * given script file. If no default is supplied, then a standard system
3223 * default will be used where necessary.
3224 * ------------------------------------------------------------------------*/
3226 Void defaultDefn(line,defs) /* Handle default types definition */
3229 if (defaultLine!=0) {
3230 ERRMSG(line) "Multiple default declarations are not permitted in" ETHEN
3231 ERRTEXT "a single script file.\n"
3234 defaultDefns = defs;
3238 static Void local checkDefaultDefns() { /* check that default types are */
3239 List ds = NIL; /* well-kinded instances of Num */
3241 if (defaultLine!=0) {
3242 map2Over(depTypeExp,defaultLine,NIL,defaultDefns);
3243 emptySubstitution();
3245 map2Proc(kindType,defaultLine,"default type",defaultDefns);
3247 emptySubstitution();
3248 mapOver(fullExpand,defaultDefns);
3250 defaultDefns = stdDefaults;
3253 if (isNull(classNum)) {
3254 classNum = findClass(findText("Num"));
3257 for (ds=defaultDefns; nonNull(ds); ds=tl(ds)) {
3258 if (isNull(provePred(NIL,NIL,ap(classNum,hd(ds))))) {
3260 "Default types must be instances of the Num class"
3267 /* --------------------------------------------------------------------------
3268 * Foreign import declarations are Hugs' equivalent of GHC's ccall mechanism.
3269 * They are used to "import" C functions into a module.
3270 * They are usually not written by hand but, rather, generated automatically
3271 * by GreenCard, IDL compilers or whatever. We support foreign import
3272 * (static) and foreign import dynamic. In the latter case, extName==NIL.
3274 * Foreign export declarations generate C wrappers for Hugs functions.
3275 * Hugs only provides "foreign export dynamic" because it's not obvious
3276 * what "foreign export static" would mean in an interactive setting.
3277 * ------------------------------------------------------------------------*/
3279 Void foreignImport(line,callconv,extName,intName,type)
3280 /* Handle foreign imports */
3286 Text t = textOf(intName);
3287 Name n = findName(t);
3291 } else if (name(n).defn!=PREDEFINED) {
3292 ERRMSG(line) "Redeclaration of foreign \"%s\"", textToStr(t)
3295 name(n).line = line;
3296 name(n).defn = extName;
3297 name(n).type = type;
3298 name(n).callconv = callconv;
3299 foreignImports = cons(n,foreignImports);
3302 static Void local checkForeignImport(p) /* Check foreign import */
3304 emptySubstitution();
3305 name(p).type = checkSigType(name(p).line,
3306 "foreign import declaration",
3309 /* We don't expand synonyms here because we don't want the IO
3310 * part to be expanded.
3311 * name(p).type = fullExpand(name(p).type);
3313 implementForeignImport(p);
3316 Void foreignExport(line,callconv,extName,intName,type)
3317 /* Handle foreign exports */
3323 Text t = textOf(intName);
3324 Name n = findName(t);
3328 } else if (name(n).defn!=PREDEFINED) {
3329 ERRMSG(line) "Redeclaration of foreign \"%s\"", textToStr(t)
3332 name(n).line = line;
3333 name(n).defn = NIL; /* nothing to say */
3334 name(n).type = type;
3335 name(n).callconv = callconv;
3336 foreignExports = cons(n,foreignExports);
3339 static Void local checkForeignExport(p) /* Check foreign export */
3341 emptySubstitution();
3342 name(p).type = checkSigType(name(p).line,
3343 "foreign export declaration",
3346 implementForeignExport(p);
3351 /* --------------------------------------------------------------------------
3352 * Static analysis of patterns:
3354 * Patterns are parsed as ordinary (atomic) expressions. Static analysis
3355 * makes the following checks:
3356 * - Patterns are well formed (according to pattern syntax), including the
3357 * special case of (n+k) patterns.
3358 * - All constructor functions have been defined and are used with the
3359 * correct number of arguments.
3360 * - No variable name is used more than once in a pattern.
3362 * The list of pattern variables occuring in each pattern is accumulated in
3363 * a global list `patVars', which must be initialised to NIL at appropriate
3364 * points before using these routines to check for valid patterns. This
3365 * mechanism enables the pattern checking routine to be mapped over a list
3366 * of patterns, ensuring that no variable occurs more than once in the
3367 * complete pattern list (as is required on the lhs of a function defn).
3368 * ------------------------------------------------------------------------*/
3370 static List patVars; /* List of vars bound in pattern */
3372 static Cell local checkPat(line,p) /* Check valid pattern syntax */
3375 switch (whatIs(p)) {
3377 case VAROPCELL : addToPatVars(line,p);
3380 case INFIX : return checkPat(line,tidyInfix(line,snd(p)));
3382 case AP : return checkMaybeCnkPat(line,p);
3387 case CONOPCELL : return checkApPat(line,0,p);
3392 case FLOATCELL : break;
3393 case INTCELL : break;
3395 case ASPAT : addToPatVars(line,fst(snd(p)));
3396 snd(snd(p)) = checkPat(line,snd(snd(p)));
3399 case LAZYPAT : snd(p) = checkPat(line,snd(p));
3402 case FINLIST : map1Over(checkPat,line,snd(p));
3405 case CONFLDS : depConFlds(line,p,TRUE);
3408 case ESIGN : snd(snd(p)) = checkPatType(line,
3412 fst(snd(p)) = checkPat(line,fst(snd(p)));
3415 default : ERRMSG(line) "Illegal pattern syntax"
3421 static Cell local checkMaybeCnkPat(l,p)/* Check applicative pattern with */
3422 Int l; /* the possibility of n+k pattern */
3424 Cell h = getHead(p);
3426 if (argCount==2 && isVar(h) && textOf(h)==textPlus) { /* n+k */
3427 Cell v = arg(fun(p));
3428 if (!isInt(arg(p))) {
3429 ERRMSG(l) "Second argument in (n+k) pattern must be an integer"
3432 if (intOf(arg(p))<=0) {
3433 ERRMSG(l) "Integer k in (n+k) pattern must be > 0"
3436 fst(fun(p)) = ADDPAT;
3437 intValOf(fun(p)) = intOf(arg(p));
3438 arg(p) = checkPat(l,v);
3441 return checkApPat(l,0,p);
3444 static Cell local checkApPat(line,args,p)
3445 Int line; /* check validity of application */
3446 Int args; /* of constructor to arguments */
3448 switch (whatIs(p)) {
3449 case AP : fun(p) = checkApPat(line,args+1,fun(p));
3450 arg(p) = checkPat(line,arg(p));
3453 case TUPLE : if (tupleOf(p)!=args) {
3454 ERRMSG(line) "Illegal tuple pattern"
3460 case EXT : h98DoesntSupport(line,"extensible records");
3462 ERRMSG(line) "Illegal record pattern"
3468 case QUALIDENT : if (!isQCon(p)) {
3470 "Illegal use of qualified variable in pattern"
3473 /* deliberate fall through */
3475 case CONOPCELL : p = conDefined(line,p);
3476 checkCfunArgs(line,p,args);
3479 case NAME : checkIsCfun(line,p);
3480 checkCfunArgs(line,p,args);
3483 default : ERRMSG(line) "Illegal pattern syntax"
3489 static Void local addToPatVars(line,v) /* Add variable v to list of vars */
3490 Int line; /* in current pattern, checking */
3491 Cell v; { /* for repeated variables. */
3496 for (; nonNull(n); p=n, n=tl(n)) {
3497 if (textOf(hd(n))==t) {
3498 ERRMSG(line) "Repeated variable \"%s\" in pattern",
3505 patVars = cons(v,NIL);
3507 tl(p) = cons(v,NIL);
3511 static Name local conDefined(line,nm) /* check that nm is the name of a */
3512 Int line; /* previously defined constructor */
3513 Cell nm; { /* function. */
3514 Name n = findQualName(nm);
3516 ERRMSG(line) "Undefined constructor function \"%s\"", identToStr(nm)
3519 checkIsCfun(line,n);
3523 static Void local checkIsCfun(line,c) /* Check that c is a constructor fn */
3527 ERRMSG(line) "\"%s\" is not a constructor function",
3528 textToStr(name(c).text)
3533 static Void local checkCfunArgs(line,c,args)
3534 Int line; /* Check constructor applied with */
3535 Cell c; /* correct number of arguments */
3537 Int a = userArity(c);
3540 "Constructor \"%s\" must have exactly %d argument%s in pattern",
3541 textToStr(name(c).text), a, ((a==1)?"":"s")
3546 static Cell local checkPatType(l,wh,e,t)/* Check type appearing in pattern */
3551 List tvs = typeVarsIn(t,NIL,NIL,NIL);
3552 h98DoesntSupport(l,"pattern type annotations");
3553 for (; nonNull(tvs); tvs=tl(tvs)) {
3554 Int beta = newKindvars(1);
3555 hd(btyvars) = cons(pair(hd(tvs),mkInt(beta)), hd(btyvars));
3557 t = checkSigType(l,"pattern type",e,t);
3558 if (isPolyOrQualType(t) || whatIs(t)==RANK2) {
3559 ERRMSG(l) "Illegal syntax in %s type annotation", wh
3565 static Cell local applyBtyvs(pat) /* Record bound type vars in pat */
3567 List bts = hd(btyvars);
3570 pat = ap(BIGLAM,pair(bts,pat));
3571 for (; nonNull(bts); bts=tl(bts)) {
3572 snd(hd(bts)) = copyKindvar(intOf(snd(hd(bts))));
3578 /* --------------------------------------------------------------------------
3579 * Maintaining lists of bound variables and local definitions, for
3580 * dependency and scope analysis.
3581 * ------------------------------------------------------------------------*/
3583 static List bounds; /* list of lists of bound vars */
3584 static List bindings; /* list of lists of binds in scope */
3585 static List depends; /* list of lists of dependents */
3587 /* bounds :: [[Var]] -- var equality used on Vars */
3588 /* bindings :: [[([Var],?)]] -- var equality used on Vars */
3589 /* depends :: [[Var]] -- pointer equality used on Vars */
3591 #define saveBvars() hd(bounds) /* list of bvars in current scope */
3592 #define restoreBvars(bs) hd(bounds)=bs /* restore list of bound variables */
3594 static Cell local bindPat(line,p) /* add new bound vars for pattern */
3598 p = checkPat(line,p);
3599 hd(bounds) = revOnto(patVars,hd(bounds));
3603 static Void local bindPats(line,ps) /* add new bound vars for patterns */
3607 map1Over(checkPat,line,ps);
3608 hd(bounds) = revOnto(patVars,hd(bounds));
3611 /* --------------------------------------------------------------------------
3612 * Before processing value and type signature declarations, all data and
3613 * type definitions have been processed so that:
3614 * - all valid type constructors (with their arities) are known.
3615 * - all valid constructor functions (with their arities and types) are
3618 * The result of parsing a list of value declarations is a list of Eqns:
3619 * Eqn ::= (SIGDECL,(Line,[Var],type))
3620 * | (FIXDECL,(Line,[Op],SyntaxInt))
3622 * The ordering of the equations in this list is the reverse of the original
3623 * ordering in the script parsed. This is a consequence of the structure of
3624 * the parser ... but also turns out to be most convenient for the static
3627 * As the first stage of the static analysis of value declarations, each
3628 * list of Eqns is converted to a list of Bindings. As part of this
3630 * - The ordering of the list of Bindings produced is the same as in the
3632 * - When a variable (function) is defined over a number of lines, all
3633 * of the definitions should appear together and each should give the
3634 * same arity to the variable being defined.
3635 * - No variable can have more than one definition.
3636 * - For pattern bindings:
3637 * - Each lhs is a valid pattern/function lhs, all constructor functions
3638 * have been defined and are used with the correct number of arguments.
3639 * - Each lhs contains no repeated pattern variables.
3640 * - Each equation defines at least one variable (e.g. True = False is
3642 * - Types appearing in type signatures are well formed:
3643 * - Type constructors used are defined and used with correct number
3645 * - type variables are replaced by offsets, type constructor names
3647 * - Every variable named in a type signature declaration is defined by
3648 * one or more equations elsewhere in the script.
3649 * - No variable has more than one type declaration.
3650 * - Similar properties for fixity declarations.
3652 * ------------------------------------------------------------------------*/
3654 #define bindingAttr(b) fst(snd(b)) /* type(s)/fixity(ies) for binding */
3655 #define fbindAlts(b) snd(snd(b)) /* alternatives for function binding*/
3657 static List local extractSigdecls(es) /* Extract the SIGDECLS from list */
3658 List es; { /* of equations */
3659 List sigdecls = NIL; /* :: [(Line,[Var],Type)] */
3661 for(; nonNull(es); es=tl(es)) {
3662 if (fst(hd(es))==SIGDECL) { /* type-declaration? */
3663 Pair sig = snd(hd(es));
3664 Int line = intOf(fst3(sig));
3665 List vs = snd3(sig);
3666 for(; nonNull(vs); vs=tl(vs)) {
3667 if (isQualIdent(hd(vs))) {
3668 ERRMSG(line) "Type signature for qualified variable \"%s\" is not allowed",
3673 sigdecls = cons(sig,sigdecls); /* discard SIGDECL tag*/
3679 static List local extractFixdecls(es) /* Extract the FIXDECLS from list */
3680 List es; { /* of equations */
3681 List fixdecls = NIL; /* :: [(Line,SyntaxInt,[Op])] */
3683 for(; nonNull(es); es=tl(es)) {
3684 if (fst(hd(es))==FIXDECL) { /* fixity declaration?*/
3685 fixdecls = cons(snd(hd(es)),fixdecls); /* discard FIXDECL tag*/
3691 static List local extractBindings(ds) /* extract untyped bindings from */
3692 List ds; { /* given list of equations */
3693 Cell lastVar = NIL; /* = var def'd in last eqn (if any)*/
3694 Int lastArity = 0; /* = number of args in last defn */
3695 List bs = NIL; /* :: [Binding] */
3697 for(; nonNull(ds); ds=tl(ds)) {
3699 if (fst(d)==FUNBIND) { /* Function bindings */
3700 Cell rhs = snd(snd(d));
3701 Int line = rhsLine(rhs);
3702 Cell lhs = fst(snd(d));
3703 Cell v = getHead(lhs);
3704 Cell newAlt = pair(getArgs(lhs),rhs);
3706 internal("FUNBIND");
3708 if (nonNull(lastVar) && textOf(v)==textOf(lastVar)) {
3709 if (argCount!=lastArity) {
3710 ERRMSG(line) "Equations give different arities for \"%s\"",
3711 textToStr(textOf(v))
3714 fbindAlts(hd(bs)) = cons(newAlt,fbindAlts(hd(bs)));
3718 lastArity = argCount;
3719 notDefined(line,bs,v);
3720 bs = cons(pair(v,pair(NIL,singleton(newAlt))),bs);
3723 } else if (fst(d)==PATBIND) { /* Pattern bindings */
3724 Cell rhs = snd(snd(d));
3725 Int line = rhsLine(rhs);
3726 Cell pat = fst(snd(d));
3727 while (whatIs(pat)==ESIGN) {/* Move type annotations to rhs */
3728 Cell p = fst(snd(pat));
3729 fst(snd(pat)) = rhs;
3730 snd(snd(d)) = rhs = pat;
3731 fst(snd(d)) = pat = p;
3734 if (isVar(pat)) { /* Convert simple pattern bind to */
3735 notDefined(line,bs,pat);/* a function binding */
3736 bs = cons(pair(pat,pair(NIL,singleton(pair(NIL,rhs)))),bs);
3738 List vs = getPatVars(line,pat,NIL);
3740 ERRMSG(line) "No variables defined in lhs pattern"
3743 map2Proc(notDefined,line,bs,vs);
3744 bs = cons(pair(vs,pair(NIL,snd(d))),bs);
3752 static List local getPatVars(line,p,vs) /* Find list of variables bound in */
3753 Int line; /* pattern p */
3756 switch (whatIs(p)) {
3758 vs = getPatVars(line,arg(p),vs);
3761 return vs; /* Ignore head of application */
3763 case CONFLDS : { List pfs = snd(snd(p));
3764 for (; nonNull(pfs); pfs=tl(pfs)) {
3765 if (isVar(hd(pfs))) {
3766 vs = addPatVar(line,hd(pfs),vs);
3768 vs = getPatVars(line,snd(hd(pfs)),vs);
3774 case FINLIST : { List ps = snd(p);
3775 for (; nonNull(ps); ps=tl(ps)) {
3776 vs = getPatVars(line,hd(ps),vs);
3781 case ESIGN : return getPatVars(line,fst(snd(p)),vs);
3786 case INFIX : return getPatVars(line,snd(p),vs);
3788 case ASPAT : return addPatVar(line,fst(snd(p)),
3789 getPatVars(line,snd(snd(p)),vs));
3792 case VAROPCELL : return addPatVar(line,p,vs);
3802 case WILDCARD : return vs;
3804 default : internal("getPatVars");
3809 static List local addPatVar(line,v,vs) /* Add var to list of previously */
3810 Int line; /* encountered variables */
3813 if (varIsMember(textOf(v),vs)) {
3814 ERRMSG(line) "Repeated use of variable \"%s\" in pattern binding",
3815 textToStr(textOf(v))
3821 static List local eqnsToBindings(es,ts,cs,ps)
3822 List es; /* Convert list of equations to */
3823 List ts; /* list of typed bindings */
3826 List bs = extractBindings(es);
3827 map1Proc(addSigdecl,bs,extractSigdecls(es));
3828 map4Proc(addFixdecl,bs,ts,cs,ps,extractFixdecls(es));
3832 static Void local notDefined(line,bs,v)/* check if name already defined in */
3833 Int line; /* list of bindings */
3836 if (nonNull(findBinding(textOf(v),bs))) {
3837 ERRMSG(line) "\"%s\" multiply defined", textToStr(textOf(v))
3842 static Cell local findBinding(t,bs) /* look for binding for variable t */
3843 Text t; /* in list of bindings bs */
3845 for (; nonNull(bs); bs=tl(bs)) {
3846 if (isVar(fst(hd(bs)))) { /* function-binding? */
3847 if (textOf(fst(hd(bs)))==t) {
3850 } else if (nonNull(varIsMember(t,fst(hd(bs))))){/* pattern-binding?*/
3857 static Cell local getAttr(bs,v) /* Locate type/fixity attribute */
3858 List bs; /* for variable v in bindings bs */
3861 Cell b = findBinding(t,bs);
3863 if (isNull(b)) { /* No binding */
3865 } else if (isVar(fst(b))) { /* func binding? */
3866 if (isNull(bindingAttr(b))) {
3867 bindingAttr(b) = pair(NIL,NIL);
3869 return bindingAttr(b);
3870 } else { /* pat binding? */
3872 List as = bindingAttr(b);
3875 bindingAttr(b) = as = replicate(length(vs),NIL);
3878 while (nonNull(vs) && t!=textOf(hd(vs))) {
3884 internal("getAttr");
3885 } else if (isNull(hd(as))) {
3886 hd(as) = pair(NIL,NIL);
3892 static Void local addSigdecl(bs,sigdecl)/* add type information to bindings*/
3893 List bs; /* :: [Binding] */
3894 Cell sigdecl; { /* :: (Line,[Var],Type) */
3895 Int l = intOf(fst3(sigdecl));
3896 List vs = snd3(sigdecl);
3897 Type type = checkSigType(l,"type declaration",hd(vs),thd3(sigdecl));
3899 for (; nonNull(vs); vs=tl(vs)) {
3901 Pair attr = getAttr(bs,v);
3903 ERRMSG(l) "Missing binding for variable \"%s\" in type signature",
3904 textToStr(textOf(v))
3906 } else if (nonNull(fst(attr))) {
3907 ERRMSG(l) "Repeated type signature for \"%s\"",
3908 textToStr(textOf(v))
3915 static Void local addFixdecl(bs,ts,cs,ps,fixdecl)
3921 Int line = intOf(fst3(fixdecl));
3922 List ops = snd3(fixdecl);
3923 Cell sy = thd3(fixdecl);
3925 for (; nonNull(ops); ops=tl(ops)) {
3927 Text t = textOf(op);
3928 Cell attr = getAttr(bs,op);
3929 if (nonNull(attr)) { /* Found name in binding? */
3930 if (nonNull(snd(attr))) {
3934 } else { /* Look in tycons, classes, prims */
3939 for (; isNull(n) && nonNull(ts1); ts1=tl(ts1)) { /* tycons */
3941 if (tycon(tc).what==DATATYPE || tycon(tc).what==NEWTYPE) {
3942 n = nameIsMember(t,tycon(tc).defn);
3945 for (; isNull(n) && nonNull(cs1); cs1=tl(cs1)) { /* classes */
3946 n = nameIsMember(t,cclass(hd(cs1)).members);
3948 for (; isNull(n) && nonNull(ps1); ps1=tl(ps1)) { /* prims */
3949 n = nameIsMember(t,hd(ps1));
3954 } else if (name(n).syntax!=NO_SYNTAX) {
3957 name(n).syntax = intOf(sy);
3962 static Void local dupFixity(line,t) /* Report repeated fixity decl */
3966 "Repeated fixity declaration for operator \"%s\"", textToStr(t)
3970 static Void local missFixity(line,t) /* Report missing op for fixity */
3974 "Cannot find binding for operator \"%s\" in fixity declaration",
3979 /* --------------------------------------------------------------------------
3980 * Dealing with infix operators:
3982 * Expressions involving infix operators or unary minus are parsed as
3983 * elements of the following type:
3985 * data InfixExp = Only Exp | Neg InfixExp | Infix InfixExp Op Exp
3987 * (The algorithms here do not assume that negation can be applied only once,
3988 * i.e., that - - x is a syntax error, as required by the Haskell report.
3989 * Instead, that restriction is captured by the grammar itself, given above.)
3991 * There are rules of precedence and grouping, expressed by two functions:
3993 * prec :: Op -> Int; assoc :: Op -> Assoc (Assoc = {L, N, R})
3995 * InfixExp values are rearranged accordingly when a complete expression
3996 * has been read using a simple shift-reduce parser whose result may be taken
3997 * to be a value of the following type:
3999 * data Exp = Atom Int | Negate Exp | Apply Op Exp Exp | Error String
4001 * The machine on which this parser is based can be defined as follows:
4003 * tidy :: InfixExp -> [(Op,Exp)] -> Exp
4004 * tidy (Only a) [] = a
4005 * tidy (Only a) ((o,b):ss) = tidy (Only (Apply o a b)) ss
4006 * tidy (Infix a o b) [] = tidy a [(o,b)]
4007 * tidy (Infix a o b) ((p,c):ss)
4008 * | shift o p = tidy a ((o,b):(p,c):ss)
4009 * | red o p = tidy (Infix a o (Apply p b c)) ss
4010 * | ambig o p = Error "ambiguous use of operators"
4011 * tidy (Neg e) [] = tidy (tidyNeg e) []
4012 * tidy (Neg e) ((o,b):ss)
4013 * | nshift o = tidy (Neg (underNeg o b e)) ss
4014 * | nred o = tidy (tidyNeg e) ((o,b):ss)
4015 * | nambig o = Error "illegal use of negation"
4017 * At each stage, the parser can either shift, reduce, accept, or error.
4018 * The transitions when dealing with juxtaposed operators o and p are
4019 * determined by the following rules:
4021 * shift o p = (prec o > prec p)
4022 * || (prec o == prec p && assoc o == L && assoc p == L)
4024 * red o p = (prec o < prec p)
4025 * || (prec o == prec p && assoc o == R && assoc p == R)
4027 * ambig o p = (prec o == prec p)
4028 * && (assoc o == N || assoc p == N || assoc o /= assoc p)
4030 * The transitions when dealing with juxtaposed unary minus and infix
4031 * operators are as follows. The precedence of unary minus (infixl 6) is
4032 * hardwired in to these definitions, as it is to the definitions of the
4033 * Haskell grammar in the official report.
4035 * nshift o = (prec o > 6)
4036 * nred o = (prec o < 6) || (prec o == 6 && assoc o == L)
4037 * nambig o = prec o == 6 && (assoc o == R || assoc o == N)
4039 * An InfixExp of the form (Neg e) means negate the last thing in
4040 * the InfixExp e; we can force this negation using:
4042 * tidyNeg :: OpExp -> OpExp
4043 * tidyNeg (Only e) = Only (Negate e)
4044 * tidyNeg (Infix a o b) = Infix a o (Negate b)
4045 * tidyNeg (Neg e) = tidyNeg (tidyNeg e)
4047 * On the other hand, if we want to sneak application of an infix operator
4048 * under a negation, then we use:
4050 * underNeg :: Op -> Exp -> OpExp -> OpExp
4051 * underNeg o b (Only e) = Only (Apply o e b)
4052 * underNeg o b (Neg e) = Neg (underNeg o b e)
4053 * underNeg o b (Infix e p f) = Infix e p (Apply o f b)
4055 * As a concession to efficiency, we lower the number of calls to syntaxOf
4056 * by keeping track of the values of sye, sys throughout the process. The
4057 * value APPLIC is used to indicate that the syntax value is unknown.
4058 * ------------------------------------------------------------------------*/
4060 static Cell local tidyInfix(line,e) /* Convert infixExp to Exp */
4062 Cell e; { /* :: OpExp */
4063 Cell s = NIL; /* :: [(Op,Exp)] */
4064 Syntax sye = APPLIC; /* Syntax of op in e (init unknown)*/
4065 Syntax sys = APPLIC; /* Syntax of op in s (init unknown)*/
4068 while (fst(d)!=ONLY) { /* Attach fixities to operators */
4072 fun(fun(d)) = attachFixity(line,fun(fun(d)));
4078 switch (whatIs(e)) {
4079 case ONLY : e = snd(e);
4080 while (nonNull(s)) {
4081 Cell next = arg(fun(s));
4083 fun(fun(s)) = snd(fun(fun(s)));
4089 case NEG : if (nonNull(s)) {
4090 if (sys==APPLIC) { /* calculate sys */
4091 sys = intOf(fst(fun(fun(s))));
4094 if (precOf(sys)==UMINUS_PREC && /* nambig */
4095 assocOf(sys)!=UMINUS_ASSOC) {
4097 "Ambiguous use of unary minus with \""
4098 ETHEN ERREXPR(snd(fun(fun(s))));
4103 if (precOf(sys)>UMINUS_PREC) { /* nshift */
4107 while (whatIs(e1)==NEG)
4109 arg(fun(t)) = arg(e1);
4110 fun(fun(t)) = snd(fun(fun(t)));
4117 /* Intentional fall-thru for nreduce and isNull(s) */
4119 { Cell prev = e; /* e := tidyNeg e */
4120 Cell temp = arg(prev);
4122 for (; whatIs(temp)==NEG; nneg++) {
4123 fun(prev) = nameNegate;
4127 if (isInt(arg(temp))) { /* special cases */
4128 if (nneg&1) /* for literals */
4129 arg(temp) = mkInt(-intOf(arg(temp)));
4131 else if (isFloat(arg(temp))) {
4133 arg(temp) = floatNegate(arg(temp));
4134 //mkFloat(-floatOf(arg(temp)));
4137 fun(prev) = nameNegate;
4138 arg(prev) = arg(temp);
4145 default : if (isNull(s)) {/* Move operation onto empty stack */
4146 Cell next = arg(fun(e));
4153 else { /* deal with pair of operators */
4155 if (sye==APPLIC) { /* calculate sys and sye */
4156 sye = intOf(fst(fun(fun(e))));
4159 sys = intOf(fst(fun(fun(s))));
4162 if (precOf(sye)==precOf(sys) && /* ambig */
4163 (assocOf(sye)!=assocOf(sys) ||
4164 assocOf(sye)==NON_ASS)) {
4165 ERRMSG(line) "Ambiguous use of operator \""
4166 ETHEN ERREXPR(snd(fun(fun(e))));
4167 ERRTEXT "\" with \""
4168 ETHEN ERREXPR(snd(fun(fun(s))));
4173 if (precOf(sye)>precOf(sys) || /* shift */
4174 (precOf(sye)==precOf(sys) &&
4175 assocOf(sye)==LEFT_ASS &&
4176 assocOf(sys)==LEFT_ASS)) {
4177 Cell next = arg(fun(e));
4185 Cell next = arg(fun(s));
4186 arg(fun(s)) = arg(e);
4187 fun(fun(s)) = snd(fun(fun(s)));
4198 static Pair local attachFixity(line,op) /* Attach fixity to operator in an */
4199 Int line; /* infix expression */
4201 Syntax sy = DEF_OPSYNTAX;
4203 switch (whatIs(op)) {
4205 case VARIDCELL : if ((sy=lookupSyntax(textOf(op)))==NO_SYNTAX) {
4206 Name n = findName(textOf(op));
4208 ERRMSG(line) "Undefined variable \"%s\"",
4209 textToStr(textOf(op))
4218 case CONIDCELL : sy = syntaxOf(op = conDefined(line,op));
4221 case QUALIDENT : { Name n = findQualName(op);
4227 "Undefined qualified variable \"%s\"",
4237 return pair(mkInt(sy),op); /* Pair fixity with (possibly) */
4238 /* translated operator */
4241 static Syntax local lookupSyntax(t) /* Try to find fixity for var in */
4242 Text t; { /* enclosing bindings */
4243 List bounds1 = bounds;
4244 List bindings1 = bindings;
4246 while (nonNull(bindings1)) {
4247 if (nonNull(varIsMember(t,hd(bounds1)))) {
4248 return DEF_OPSYNTAX;
4250 Cell b = findBinding(t,hd(bindings1));
4252 Cell a = fst(snd(b));
4253 if (isVar(fst(b))) { /* Function binding */
4254 if (nonNull(a) && nonNull(snd(a))) {
4255 return intOf(snd(a));
4257 } else { /* Pattern binding */
4259 while (nonNull(vs) && nonNull(a)) {
4260 if (t==textOf(hd(vs))) {
4261 if (nonNull(hd(a)) && isInt(snd(hd(a)))) {
4262 return intOf(snd(hd(a)));
4270 return DEF_OPSYNTAX;
4273 bounds1 = tl(bounds1);
4274 bindings1 = tl(bindings1);
4279 /* --------------------------------------------------------------------------
4280 * To facilitate dependency analysis, lists of bindings are temporarily
4281 * augmented with an additional field, which is used in two ways:
4282 * - to build the `adjacency lists' for the dependency graph. Represented by
4283 * a list of pointers to other bindings in the same list of bindings.
4284 * - to hold strictly positive integer values (depth first search numbers) of
4285 * elements `on the stack' during the strongly connected components search
4286 * algorithm, or a special value mkInt(0), once the binding has been added
4287 * to a particular strongly connected component.
4289 * Using this extra field, the type of each list of declarations during
4290 * dependency analysis is [Binding'] where:
4292 * Binding' ::= (Var, (Attr, (Dep, [Alt]))) -- function binding
4293 * | ([Var], ([Attr], (Dep, (Pat,Rhs)))) -- pattern binding
4295 * ------------------------------------------------------------------------*/
4297 #define depVal(d) (fst(snd(snd(d)))) /* Access to dependency information*/
4299 static List local dependencyAnal(bs) /* Separate lists of bindings into */
4300 List bs; { /* mutually recursive groups in */
4301 /* order of dependency */
4302 mapProc(addDepField,bs); /* add extra field for dependents */
4303 mapProc(depBinding,bs); /* find dependents of each binding */
4304 bs = bscc(bs); /* sort to strongly connected comps*/
4305 mapProc(remDepField,bs); /* remove dependency info field */
4309 static List local topDependAnal(bs) /* Like dependencyAnal(), but at */
4310 List bs; { /* top level, reporting on progress*/
4314 setGoal("Dependency analysis",(Target)(length(bs)));
4316 mapProc(addDepField,bs); /* add extra field for dependents */
4317 for (xs=bs; nonNull(xs); xs=tl(xs)) {
4318 emptySubstitution();
4320 soFar((Target)(i++));
4322 bs = bscc(bs); /* sort to strongly connected comps */
4323 mapProc(remDepField,bs); /* remove dependency info field */
4328 static Void local addDepField(b) /* add extra field to binding to */
4329 Cell b; { /* hold list of dependents */
4330 snd(snd(b)) = pair(NIL,snd(snd(b)));
4333 static Void local remDepField(bs) /* remove dependency field from */
4334 List bs; { /* list of bindings */
4335 mapProc(remDepField1,bs);
4338 static Void local remDepField1(b) /* remove dependency field from */
4339 Cell b; { /* single binding */
4340 snd(snd(b)) = snd(snd(snd(b)));
4343 static Void local clearScope() { /* initialise dependency scoping */
4349 static Void local withinScope(bs) /* Enter scope of bindings bs */
4351 bounds = cons(NIL,bounds);
4352 bindings = cons(bs,bindings);
4353 depends = cons(NIL,depends);
4356 static Void local leaveScope() { /* Leave scope of last withinScope */
4357 List bs = hd(bindings); /* Remove fixity info from binds */
4358 Bool toplevel = isNull(tl(bindings));
4359 for (; nonNull(bs); bs=tl(bs)) {
4361 if (isVar(fst(b))) { /* Variable binding */
4362 Cell a = fst(snd(b));
4365 saveSyntax(fst(b),snd(a));
4367 fst(snd(b)) = fst(a);
4369 } else { /* Pattern binding */
4371 List as = fst(snd(b));
4372 while (nonNull(vs) && nonNull(as)) {
4373 if (isPair(hd(as))) {
4375 saveSyntax(hd(vs),snd(hd(as)));
4377 hd(as) = fst(hd(as));
4384 bounds = tl(bounds);
4385 bindings = tl(bindings);
4386 depends = tl(depends);
4389 static Void local saveSyntax(v,sy) /* Save syntax of top-level var */
4390 Cell v; /* in corresponding Name */
4392 Name n = findName(textOf(v));
4393 if (isNull(n) || name(n).syntax!=NO_SYNTAX) {
4394 internal("saveSyntax");
4397 name(n).syntax = intOf(sy);
4401 /* --------------------------------------------------------------------------
4402 * As a side effect of the dependency analysis we also make the following
4404 * - Each lhs is a valid pattern/function lhs, all constructor functions
4405 * have been defined and are used with the correct number of arguments.
4406 * - No lhs contains repeated pattern variables.
4407 * - Expressions used on the rhs of an eqn should be well formed. This
4409 * - Checking for valid patterns (including repeated vars) in lambda,
4410 * case, and list comprehension expressions.
4411 * - Recursively checking local lists of equations.
4412 * - No free (i.e. unbound) variables are used in the declaration list.
4413 * ------------------------------------------------------------------------*/
4415 static Void local depBinding(b) /* find dependents of binding */
4417 Cell defpart = snd(snd(snd(b))); /* definition part of binding */
4421 if (isVar(fst(b))) { /* function-binding? */
4422 mapProc(depAlt,defpart);
4423 if (isNull(fst(snd(b)))) { /* Save dep info if no type sig */
4424 fst(snd(b)) = pair(ap(IMPDEPS,hd(depends)),NIL);
4425 } else if (isNull(fst(fst(snd(b))))) {
4426 fst(fst(snd(b))) = ap(IMPDEPS,hd(depends));
4428 } else { /* pattern-binding? */
4429 Int line = rhsLine(snd(defpart));
4432 fst(defpart) = checkPat(line,fst(defpart));
4433 depRhs(snd(defpart));
4435 if (nonNull(hd(btyvars))) {
4437 "Sorry, no type variables are allowed in pattern binding type annotations"
4441 fst(defpart) = applyBtyvs(fst(defpart));
4443 depVal(b) = hd(depends);
4446 static Void local depDefaults(c) /* dependency analysis on defaults */
4447 Class c; { /* from class definition */
4448 depClassBindings(cclass(c).defaults);
4451 static Void local depInsts(in) /* dependency analysis on instance */
4452 Inst in; { /* bindings */
4453 depClassBindings(inst(in).implements);
4456 static Void local depClassBindings(bs) /* dependency analysis on list of */
4457 List bs; { /* bindings, possibly containing */
4458 for (; nonNull(bs); bs=tl(bs)) { /* NIL bindings ... */
4459 if (nonNull(hd(bs))) { /* No need to add extra field for */
4460 mapProc(depAlt,snd(hd(bs)));/* dependency information... */
4465 static Void local depAlt(a) /* Find dependents of alternative */
4467 List obvs = saveBvars(); /* Save list of bound variables */
4469 bindPats(rhsLine(snd(a)),fst(a)); /* add new bound vars for patterns */
4470 depRhs(snd(a)); /* find dependents of rhs */
4471 fst(a) = applyBtyvs(fst(a));
4472 restoreBvars(obvs); /* restore original list of bvars */
4475 static Void local depRhs(r) /* Find dependents of rhs */
4477 switch (whatIs(r)) {
4478 case GUARDED : mapProc(depGuard,snd(r));
4481 case LETREC : fst(snd(r)) = eqnsToBindings(fst(snd(r)),NIL,NIL,NIL);
4482 withinScope(fst(snd(r)));
4483 fst(snd(r)) = dependencyAnal(fst(snd(r)));
4484 hd(depends) = fst(snd(r));
4485 depRhs(snd(snd(r)));
4489 case RSIGN : snd(snd(r)) = checkPatType(rhsLine(fst(snd(r))),
4491 rhsExpr(fst(snd(r))),
4493 depRhs(fst(snd(r)));
4496 default : snd(r) = depExpr(intOf(fst(r)),snd(r));
4501 static Void local depGuard(g) /* find dependents of single guarded*/
4502 Cell g; { /* expression */
4503 depPair(intOf(fst(g)),snd(g));
4506 static Cell local depExpr(line,e) /* find dependents of expression */
4509 //Printf( "\n\n"); print(e,100); Printf("\n");
4510 //printExp(stdout,e);
4511 switch (whatIs(e)) {
4514 case VAROPCELL : return depVar(line,e);
4517 case CONOPCELL : return conDefined(line,e);
4519 case QUALIDENT : if (isQVar(e)) {
4520 return depQVar(line,e);
4521 } else { /* QConOrConOp */
4522 return conDefined(line,e);
4525 case INFIX : return depExpr(line,tidyInfix(line,snd(e)));
4528 case RECSEL : break;
4530 case AP : if (isAp(e) && isAp(fun(e)) && isExt(fun(fun(e)))) {
4531 return depRecord(line,e);
4537 arg(a) = depExpr(line,arg(a));
4540 fun(a) = depExpr(line,fun(a));
4544 case AP : depPair(line,e);
4558 case INTCELL : break;
4560 case COND : depTriple(line,snd(e));
4563 case FINLIST : map1Over(depExpr,line,snd(e));
4566 case LETREC : fst(snd(e)) = eqnsToBindings(fst(snd(e)),NIL,NIL,NIL);
4567 withinScope(fst(snd(e)));
4568 fst(snd(e)) = dependencyAnal(fst(snd(e)));
4569 hd(depends) = fst(snd(e));
4570 snd(snd(e)) = depExpr(line,snd(snd(e)));
4574 case LAMBDA : depAlt(snd(e));
4577 case DOCOMP : /* fall-thru */
4578 case COMP : depComp(line,snd(e),snd(snd(e)));
4581 case ESIGN : fst(snd(e)) = depExpr(line,fst(snd(e)));
4582 snd(snd(e)) = checkSigType(line,
4588 case CASE : fst(snd(e)) = depExpr(line,fst(snd(e)));
4589 map1Proc(depCaseAlt,line,snd(snd(e)));
4592 case CONFLDS : depConFlds(line,e,FALSE);
4595 case UPDFLDS : depUpdFlds(line,e);
4599 case WITHEXP : depWith(line,e);
4603 case ASPAT : ERRMSG(line) "Illegal `@' in expression"
4606 case LAZYPAT : ERRMSG(line) "Illegal `~' in expression"
4609 case WILDCARD : ERRMSG(line) "Illegal `_' in expression"
4613 case EXT : ERRMSG(line) "Illegal application of record"
4617 default : internal("depExpr");
4622 static Void local depPair(line,e) /* find dependents of pair of exprs*/
4625 fst(e) = depExpr(line,fst(e));
4626 snd(e) = depExpr(line,snd(e));
4629 static Void local depTriple(line,e) /* find dependents of triple exprs */
4632 fst3(e) = depExpr(line,fst3(e));
4633 snd3(e) = depExpr(line,snd3(e));
4634 thd3(e) = depExpr(line,thd3(e));
4637 static Void local depComp(l,e,qs) /* find dependents of comprehension*/
4642 fst(e) = depExpr(l,fst(e));
4646 switch (whatIs(q)) {
4647 case FROMQUAL : { List obvs = saveBvars();
4648 snd(snd(q)) = depExpr(l,snd(snd(q)));
4650 fst(snd(q)) = bindPat(l,fst(snd(q)));
4652 fst(snd(q)) = applyBtyvs(fst(snd(q)));
4657 case QWHERE : snd(q) = eqnsToBindings(snd(q),NIL,NIL,NIL);
4658 withinScope(snd(q));
4659 snd(q) = dependencyAnal(snd(q));
4660 hd(depends) = snd(q);
4665 case DOQUAL : /* fall-thru */
4666 case BOOLQUAL : snd(q) = depExpr(l,snd(q));
4673 static Void local depCaseAlt(line,a) /* Find dependents of case altern. */
4676 List obvs = saveBvars(); /* Save list of bound variables */
4678 fst(a) = bindPat(line,fst(a)); /* Add new bound vars for pats */
4679 depRhs(snd(a)); /* Find dependents of rhs */
4680 fst(a) = applyBtyvs(fst(a));
4681 restoreBvars(obvs); /* Restore original list of bvars */
4684 static Cell local depVar(line,e) /* Register occurrence of variable */
4687 List bounds1 = bounds;
4688 List bindings1 = bindings;
4689 List depends1 = depends;
4693 while (nonNull(bindings1)) {
4694 n = varIsMember(t,hd(bounds1)); /* look for t in bound variables */
4698 n = findBinding(t,hd(bindings1)); /* look for t in var bindings */
4700 if (!cellIsMember(n,hd(depends1))) {
4701 hd(depends1) = cons(n,hd(depends1));
4703 return (isVar(fst(n)) ? fst(n) : e);
4706 bounds1 = tl(bounds1);
4707 bindings1 = tl(bindings1);
4708 depends1 = tl(depends1);
4711 if (isNull(n=findName(t))) { /* check global definitions */
4712 ERRMSG(line) "Undefined variable \"%s\"", textToStr(t)
4716 /* Later phases of the system cannot cope if we resolve references
4717 * to unprocessed objects too early. This is the main reason that
4718 * we cannot cope with recursive modules at the moment.
4723 static Cell local depQVar(line,e)/* register occurrence of qualified variable */
4726 Name n = findQualName(e);
4727 if (isNull(n)) { /* check global definitions */
4728 ERRMSG(line) "Undefined qualified variable \"%s\"", identToStr(e)
4731 if (name(n).mod != currentModule) {
4734 if (fst(e) == VARIDCELL) {
4735 e = mkVar(qtextOf(e));
4737 e = mkVarop(qtextOf(e));
4739 return depVar(line,e);
4742 static Void local depConFlds(line,e,isP)/* check construction using fields */
4746 Name c = conDefined(line,fst(snd(e)));
4747 if (isNull(snd(snd(e))) ||
4748 nonNull(cellIsMember(c,depFields(line,e,snd(snd(e)),isP)))) {
4751 ERRMSG(line) "Constructor \"%s\" does not have selected fields in ",
4752 textToStr(name(c).text)
4757 if (!isP && isPair(name(c).defn)) { /* Check that banged fields defined*/
4758 List scs = fst(name(c).defn); /* List of strict components */
4759 Type t = name(c).type;
4760 Int a = userArity(c);
4761 List fs = snd(snd(e));
4763 if (isPolyType(t)) { /* Find tycon that c belongs to */
4766 if (isQualType(t)) {
4769 if (whatIs(t)==CDICTS) {
4778 for (ss=tycon(t).defn; hasCfun(ss); ss=tl(ss)) {
4780 /* Now we know the tycon t that c belongs to, and the corresponding
4781 * list of selectors for that type, ss. Now we have to check that
4782 * each of the fields identified by scs appears in fs, using ss to
4783 * cross reference, and convert integers to selector names.
4785 for (; nonNull(scs); scs=tl(scs)) {
4786 Int i = intOf(hd(scs));
4788 for (; nonNull(ss1); ss1=tl(ss1)) {
4789 List cns = name(hd(ss1)).defn;
4790 for (; nonNull(cns); cns=tl(cns)) {
4791 if (fst(hd(cns))==c) {
4795 if (nonNull(cns) && intOf(snd(hd(cns)))==i) {
4800 internal("depConFlds");
4804 for (; nonNull(fs1) && s!=fst(hd(fs1)); fs1=tl(fs1)) {
4807 ERRMSG(line) "Construction does not define strict field"
4809 ERRTEXT "\nExpression : " ETHEN ERREXPR(e);
4810 ERRTEXT "\nField : " ETHEN ERREXPR(s);
4819 static Void local depUpdFlds(line,e) /* check update using fields */
4822 if (isNull(thd3(snd(e)))) {
4823 ERRMSG(line) "Empty field list in update"
4826 fst3(snd(e)) = depExpr(line,fst3(snd(e)));
4827 snd3(snd(e)) = depFields(line,e,thd3(snd(e)),FALSE);
4830 static List local depFields(l,e,fs,isP) /* check field binding list */
4838 for (; nonNull(fs); fs=tl(fs)) { /* for each field binding */
4842 if (isVar(fb)) { /* expand var to var = var */
4843 h98DoesntSupport(l,"missing field bindings");
4844 fb = hd(fs) = pair(fb,fb);
4847 s = findQualName(fst(fb)); /* check for selector */
4848 if (nonNull(s) && isSfun(s)) {
4851 ERRMSG(l) "\"%s\" is not a selector function/field name",
4852 textToStr(textOf(fst(fb)))
4856 if (isNull(ss)) { /* for first named selector */
4857 List scs = name(s).defn; /* calculate list of constructors */
4858 for (; nonNull(scs); scs=tl(scs)) {
4859 cs = cons(fst(hd(scs)),cs);
4861 ss = singleton(s); /* initialize selector list */
4862 } else { /* for subsequent selectors */
4863 List ds = cs; /* intersect constructor lists */
4864 for (cs=NIL; nonNull(ds); ) {
4865 List scs = name(s).defn;
4866 while (nonNull(scs) && fst(hd(scs))!=hd(ds)) {
4879 if (cellIsMember(s,ss)) { /* check for repeated uses */
4880 ERRMSG(l) "Repeated field name \"%s\" in field list",
4881 textToStr(name(s).text)
4887 if (isNull(cs)) { /* Are there any matching constrs? */
4888 ERRMSG(l) "No constructor has all of the fields specified in "
4894 snd(fb) = (isP ? checkPat(l,snd(fb)) : depExpr(l,snd(fb)));
4900 static Void local depWith(line,e) /* check with using fields */
4903 fst(snd(e)) = depExpr(line,fst(snd(e)));
4904 snd(snd(e)) = depDwFlds(line,e,snd(snd(e)));
4907 static List local depDwFlds(l,e,fs)/* check field binding list */
4913 for (; nonNull(c); c=tl(c)) { /* for each field binding */
4914 snd(hd(c)) = depExpr(l,snd(hd(c)));
4921 static Cell local depRecord(line,e) /* find dependents of record and */
4922 Int line; /* sort fields into approp. order */
4923 Cell e; { /* to make construction and update */
4924 List exts = NIL; /* more efficient. */
4927 h98DoesntSupport(line,"extensible records");
4928 do { /* build up list of extensions */
4929 Text t = extText(fun(fun(r)));
4930 String s = textToStr(t);
4933 while (nonNull(nx) && strcmp(textToStr(extText(fun(fun(nx)))),s)>0) {
4937 if (nonNull(nx) && t==extText(fun(fun(nx)))) {
4938 ERRMSG(line) "Repeated label \"%s\" in record ", s
4944 exts = cons(fun(r),exts);
4946 tl(prev) = cons(fun(r),nx);
4948 extField(r) = depExpr(line,extField(r));
4950 } while (isAp(r) && isAp(fun(r)) && isExt(fun(fun(r))));
4951 r = depExpr(line,r);
4952 return revOnto(exts,r);
4957 /* --------------------------------------------------------------------------
4958 * Several parts of this program require an algorithm for sorting a list
4959 * of values (with some added dependency information) into a list of strongly
4960 * connected components in which each value appears before its dependents.
4962 * Each of these algorithms is obtained by parameterising a standard
4963 * algorithm in "scc.c" as shown below.
4964 * ------------------------------------------------------------------------*/
4966 #define SCC2 tcscc /* make scc algorithm for Tycons */
4967 #define LOWLINK tclowlink
4968 #define DEPENDS(c) (isTycon(c) ? tycon(c).kind : cclass(c).kinds)
4969 #define SETDEPENDS(c,v) if(isTycon(c)) tycon(c).kind=v; else cclass(c).kinds=v
4976 #define SCC bscc /* make scc algorithm for Bindings */
4977 #define LOWLINK blowlink
4978 #define DEPENDS(t) depVal(t)
4979 #define SETDEPENDS(c,v) depVal(c)=v
4986 /* --------------------------------------------------------------------------
4987 * Main static analysis:
4988 * ------------------------------------------------------------------------*/
4990 Void checkExp() { /* Top level static check on Expr */
4991 staticAnalysis(RESET);
4992 clearScope(); /* Analyse expression in the scope */
4993 withinScope(NIL); /* of no local bindings */
4994 inputExpr = depExpr(0,inputExpr);
4996 staticAnalysis(RESET);
4999 #if EXPLAIN_INSTANCE_RESOLUTION
5000 Void checkContext(void) { /* Top level static check on Expr */
5003 staticAnalysis(RESET);
5004 clearScope(); /* Analyse expression in the scope */
5005 withinScope(NIL); /* of no local bindings */
5007 for (vs = NIL; nonNull(qs); qs=tl(qs)) {
5008 vs = typeVarsIn(hd(qs),NIL,NIL,vs);
5010 map2Proc(depPredExp,0,vs,inputContext);
5012 staticAnalysis(RESET);
5016 Void checkDefns ( Module thisModule ) { /* Top level static analysis */
5017 Text modName = module(thisModule).text;
5019 staticAnalysis(RESET);
5021 setCurrModule(thisModule);
5023 /* Resolve module references */
5024 mapProc(checkQualImport, module(thisModule).qualImports);
5025 mapProc(checkUnqualImport,unqualImports);
5026 /* Add "import Prelude" if there`s no explicit import */
5027 if (modName == textPrelPrim || modName == textPrelude) {
5029 } else if (isNull(cellAssoc(modulePrelude,unqualImports))
5030 && isNull(cellRevAssoc(modulePrelude,module(thisModule).qualImports))) {
5031 unqualImports = cons(pair(modulePrelude,DOTDOT),unqualImports);
5033 /* Every module implicitly contains "import qualified Prelude"
5035 module(thisModule).qualImports
5036 =cons(pair(mkCon(textPrelude),modulePrelude),
5037 module(thisModule).qualImports);
5039 mapProc(checkImportList, unqualImports);
5041 /* Note: there's a lot of side-effecting going on here, so
5042 don't monkey about with the order of operations here unless
5043 you know what you are doing */
5044 if (!combined) linkPreludeTC(); /* Get prelude tycons and classes */
5046 mapProc(checkTyconDefn,tyconDefns); /* validate tycon definitions */
5047 checkSynonyms(tyconDefns); /* check synonym definitions */
5048 mapProc(checkClassDefn,classDefns); /* process class definitions */
5049 mapProc(kindTCGroup,tcscc(tyconDefns,classDefns)); /* attach kinds */
5050 mapProc(visitClass,classDefns); /* check class hierarchy */
5051 mapProc(extendFundeps,classDefns); /* finish class definitions */
5052 /* (convenient if we do this after */
5053 /* calling `visitClass' so that we */
5054 /* know the class hierarchy is */
5057 mapProc(addMembers,classDefns); /* add definitions for member funs */
5059 if (!combined) linkPreludeCM(); /* Get prelude cfuns and mfuns */
5061 instDefns = rev(instDefns); /* process instance definitions */
5062 mapProc(checkInstDefn,instDefns);
5064 setCurrModule(thisModule);
5065 mapProc(addRSsigdecls,typeInDefns); /* add sigdecls for RESTRICTSYN */
5066 valDefns = eqnsToBindings(valDefns,tyconDefns,classDefns,/*primDefns*/NIL);
5067 mapProc(allNoPrevDef,valDefns); /* check against previous defns */
5068 mapProc(addDerivImp,derivedInsts); /* Add impls for derived instances */
5069 deriveContexts(derivedInsts); /* Calculate derived inst contexts */
5070 instDefns = appendOnto(instDefns,derivedInsts);
5071 checkDefaultDefns(); /* validate default definitions */
5073 mapProc(allNoPrevDef,valDefns); /* check against previous defns */
5075 if (!combined) linkPrimNames(); /* link primitive names */
5077 mapProc(checkForeignImport,foreignImports); /* check foreign imports */
5078 mapProc(checkForeignExport,foreignExports); /* check foreign exports */
5079 foreignImports = NIL;
5080 foreignExports = NIL;
5082 /* Every top-level name has now been created - so we can build the */
5083 /* export list. Note that this has to happen before dependency */
5084 /* analysis so that references to Prelude.foo will be resolved */
5085 /* when compiling the prelude. */
5086 module(thisModule).exports
5087 = checkExports ( module(thisModule).exports, thisModule );
5089 mapProc(checkTypeIn,typeInDefns); /* check restricted synonym defns */
5092 withinScope(valDefns);
5093 valDefns = topDependAnal(valDefns); /* top level dependency ordering */
5094 mapProc(depDefaults,classDefns); /* dep. analysis on class defaults */
5095 mapProc(depInsts,instDefns); /* dep. analysis on inst defns */
5098 /* ToDo: evalDefaults should match current evaluation module */
5099 evalDefaults = defaultDefns; /* Set defaults for evaluator */
5101 staticAnalysis(RESET);
5107 static Void local addRSsigdecls(pr) /* add sigdecls from TYPE ... IN ..*/
5109 List vs = snd(pr); /* get list of variables */
5110 for (; nonNull(vs); vs=tl(vs)) {
5111 if (fst(hd(vs))==SIGDECL) { /* find a sigdecl */
5112 valDefns = cons(hd(vs),valDefns); /* add to valDefns */
5113 hd(vs) = hd(snd3(snd(hd(vs)))); /* and replace with var */
5118 static Void local allNoPrevDef(b) /* ensure no previous bindings for*/
5119 Cell b; { /* variables in new binding */
5120 if (isVar(fst(b))) {
5121 noPrevDef(rhsLine(snd(hd(snd(snd(b))))),fst(b));
5123 Int line = rhsLine(snd(snd(snd(b))));
5124 map1Proc(noPrevDef,line,fst(b));
5128 static Void local noPrevDef(line,v) /* ensure no previous binding for */
5129 Int line; /* new variable */
5131 Name n = findName(textOf(v));
5134 n = newName(textOf(v),NIL);
5135 name(n).defn = PREDEFINED;
5136 } else if (name(n).defn!=PREDEFINED) {
5137 duplicateError(line,name(n).mod,name(n).text,"variable");
5139 name(n).line = line;
5142 static Void local duplicateErrorAux(line,mod,t,kind)/* report duplicate defn */
5147 if (mod == currentModule) {
5148 ERRMSG(line) "Repeated definition for %s \"%s\"", kind,
5152 ERRMSG(line) "Definition of %s \"%s\" clashes with import", kind,
5158 static Void local checkTypeIn(cvs) /* Check that vars in restricted */
5159 Pair cvs; { /* synonym are defined */
5163 for (; nonNull(vs); vs=tl(vs)) {
5164 if (isNull(findName(textOf(hd(vs))))) {
5165 ERRMSG(tycon(c).line)
5166 "No top level binding of \"%s\" for restricted synonym \"%s\"",
5167 textToStr(textOf(hd(vs))), textToStr(tycon(c).text)
5173 /* --------------------------------------------------------------------------
5174 * Haskell 98 compatibility tests:
5175 * ------------------------------------------------------------------------*/
5177 Bool h98Pred(allowArgs,pi) /* Check syntax of Hask98 predicate*/
5180 return isClass(getHead(pi)) && argCount==1 &&
5181 isOffset(getHead(arg(pi))) && (argCount==0 || allowArgs);
5184 Cell h98Context(allowArgs,ps) /* Check syntax of Hask98 context */
5187 for (; nonNull(ps); ps=tl(ps)) {
5188 if (!h98Pred(allowArgs,hd(ps))) {
5195 Void h98CheckCtxt(line,wh,allowArgs,ps,in)
5196 Int line; /* Report illegal context/predicate*/
5202 Cell pi = h98Context(allowArgs,ps);
5204 ERRMSG(line) "Illegal Haskell 98 class constraint in %s",wh ETHEN
5206 ERRTEXT "\n*** Instance : " ETHEN ERRPRED(inst(in).head);
5208 ERRTEXT "\n*** Constraint : " ETHEN ERRPRED(pi);
5209 if (nonNull(ps) && nonNull(tl(ps))) {
5210 ERRTEXT "\n*** Context : " ETHEN ERRCONTEXT(ps);
5218 Void h98CheckType(line,wh,e,t) /* Check for Haskell 98 type */
5227 if (isQualType(t)) {
5228 Cell pi = h98Context(TRUE,fst(snd(t)));
5230 ERRMSG(line) "Illegal Haskell 98 class constraint in %s",wh
5232 ERRTEXT "\n*** Expression : " ETHEN ERREXPR(e);
5233 ERRTEXT "\n*** Type : " ETHEN ERRTYPE(ty);
5241 Void h98DoesntSupport(line,wh) /* Report feature missing in H98 */
5245 ERRMSG(line) "Haskell 98 does not support %s", wh
5250 /* --------------------------------------------------------------------------
5251 * Static Analysis control:
5252 * ------------------------------------------------------------------------*/
5254 Void staticAnalysis(what)
5257 case RESET : cfunSfuns = NIL;
5270 case MARK : mark(daSccs);
5285 case POSTPREL: break;
5287 case PREPREL : staticAnalysis(RESET);
5289 extKind = pair(STAR,pair(ROW,ROW));
5294 /*-------------------------------------------------------------------------*/