Chain the symbol tables, not the dfn frames

1 files changed, 55 insertions, 49 deletions

diff --git a/symbol.c b/symbol.c
index 5d88f96..3cb8a9b 100644
--- a/symbol.c
+++ b/symbol.c
@@ -6,10 +6,9 @@
 
 Symtab *globalsymtab;
 
-Symtab *newsymtab(void);
+Symtab *newsymtab(Symtab *);
 Symbol *dupsymbol(Symbol *);
 Symtab *dupsymtab(Symtab *);
-void freesymtab(Symtab *);
 
 Datum *getalpha(void);
 Datum *getomega(void);
@@ -21,28 +20,21 @@ void setsyntaxerr(Datum *);
 Symbol *
 getsym(Rune *name, int fresh)
 {
-	ThreadData *td = getthreaddata();
-	DfnFrame *dfn = td->currentdfn;
 	Symtab *tab;
-	int done = 0;
-	do{
-		if(dfn != nil)
-			tab = dfn->symtab;
-		else
-			tab = globalsymtab;
+	for(tab = getcurrentsymtab(); tab; tab = tab->chain){
 		for(int i = 0; i < tab->nsyms; i++){
-			if(runestrcmp(tab->syms[i]->name, name) == 0)
+			if(runestrcmp(tab->syms[i]->name, name) == 0){
+				freesymtab(tab);
 				return tab->syms[i];
+			}
 		}
-		if(dfn)
-			dfn = dfn->chain;
-		else
-			done = 1;
-	}while(!done && !fresh);
+		if(fresh)
+			break;
+	}
 
 	/* make sure to allocate in the most local scope if the symbol is not found */
-	if(td->currentdfn)
-		tab = td->currentdfn->symtab;
+	freesymtab(tab);
+	tab = getcurrentsymtab();
 
 	tab->nsyms++;
 	tab->syms = erealloc(tab->syms, sizeof(Symbol *) * tab->nsyms);
@@ -51,17 +43,23 @@ getsym(Rune *name, int fresh)
 	tab->syms[tab->nsyms-1]->getfn = nil;
 	tab->syms[tab->nsyms-1]->setfn = nil;
 	tab->syms[tab->nsyms-1]->value = nil;
+
+	freesymtab(tab);
 	return tab->syms[tab->nsyms-1];
 }
 
 Symtab *
-newsymtab(void)
+newsymtab(Symtab *chain)
 {
 	Symtab *tab = emalloc(sizeof(Symtab));
 	tab->nsyms = 0;
 	tab->syms = nil;
 	tab->io = globalIO();
 	tab->div = globalDIV();
+	tab->refs = 1;
+	tab->chain = chain;
+	if(chain)
+		chain->refs++;
 
 	return tab;
 }
@@ -80,8 +78,9 @@ dupsymbol(Symbol *s)
 Symtab *
 dupsymtab(Symtab *tab)
 {
-	Symtab *new = newsymtab();
+	Symtab *new = newsymtab(tab->chain);
 	memcpy(new, tab, sizeof(Symtab));
+	new->refs = 1;
 	new->syms = emalloc(sizeof(Symbol*) * new->nsyms);
 	for(int i = 0; i < tab->nsyms; i++)
 		new->syms[i] = dupsymbol(tab->syms[i]);
@@ -91,12 +90,21 @@ dupsymtab(Symtab *tab)
 void
 freesymtab(Symtab *tab)
 {
+	if(tab == nil)
+		return;
+	if(tab->refs-- > 1)
+		return;
+
+	if(tab == globalsymtab)
+		return;
+
 	int i;
 	for(i = 0; i < tab->nsyms; i++){
 		Symbol *s = tab->syms[i];
 		freedatum(s->value);
 		free(s->name);
 	}
+	freesymtab(tab->chain);
 	free(tab->syms);
 	free(tab);
 }
@@ -104,7 +112,7 @@ freesymtab(Symtab *tab)
 void
 initsymtab(void)
 {
-	globalsymtab = newsymtab();
+	globalsymtab = newsymtab(nil);
 	Symbol *s;
 	s = getsym(L"⍺", 1);
 	s->getfn = getalpha;
@@ -131,12 +139,12 @@ getcurrentdfn(void)
 }
 
 DfnFrame *
-pushdfnframe(Rune *code, DfnFrame *scope, Datum *lefto, Datum *righto, Array *left, Array *right)
+pushdfnframe(Rune *code, Symtab *scope, Datum *lefto, Datum *righto, Array *left, Array *right)
 {
 	ThreadData *td = getthreaddata();
 	DfnFrame *new = emalloc(sizeof(DfnFrame));
 	new->code = code;
-	new->symtab = newsymtab();
+	new->symtab = newsymtab(scope);
 	new->lefto = lefto;
 	new->righto = righto;
 	if(lefto)
@@ -153,7 +161,6 @@ pushdfnframe(Rune *code, DfnFrame *scope, Datum *lefto, Datum *righto, Array *le
 	if(right)
 		incarrayref(right);
 	new->prev = td->currentdfn;
-	new->chain = scope;
 	new->errorguards = nil;
 	td->currentdfn = new;
 	return new;
@@ -180,9 +187,6 @@ dupdfnframe(DfnFrame *f)
 void
 freedfnframe(DfnFrame *f, int keeperrorguards)
 {
-	if(f->keep)
-		return;
-
 	freesymtab(f->symtab);
 	freedatum(f->lefto);
 	freedatum(f->righto);
@@ -324,37 +328,39 @@ setsyntaxerr(Datum *)
 	throwerror(nil, ESyntax);
 }
 
-DfnFrame *
-dupscope(DfnFrame *dfn)
+Symtab *
+dupscope(Symtab *old)
 {
-	if(dfn == nil)
-		return nil;
-
-	DfnFrame *new = emallocz(sizeof(DfnFrame), 1);
-	new->symtab = newsymtab();
+	Symtab *new = newsymtab(globalsymtab);
 
 	/* copy ALL symbols which are in scope, into the new symtab */
-	for(DfnFrame *d = dfn; d != nil; d = d->chain){
+	for(Symtab *o = old; o != globalsymtab; o = o->chain){
 		/* Add all new symbols */
-		for(int i = 0; i < d->symtab->nsyms; i++){
-			Symbol *sym = d->symtab->syms[i];
+		for(int i = 0; i < o->nsyms; i++){
+			Symbol *sym = o->syms[i];
 			int found = 0;
-			for(int j = 0; j < new->symtab->nsyms && !found; j++)
-				if(runestrcmp(new->symtab->syms[j]->name, d->symtab->syms[i]->name) == 0)
+			for(int j = 0; j < new->nsyms && !found; j++)
+				if(runestrcmp(new->syms[j]->name, o->syms[i]->name) == 0)
 					found = 1;
 			if(!found){
-				new->symtab->nsyms++;
-				new->symtab->syms = erealloc(new->symtab->syms, sizeof(Symbol *) * new->symtab->nsyms);
-				new->symtab->syms[new->symtab->nsyms-1] = dupsymbol(sym);
-				sym = new->symtab->syms[new->symtab->nsyms-1];
-				if(sym->value){
-					if(sym->value->tag == FunctionTag)
-						sym->value->func.scope->keep = 1;
-					if(sym->value->tag == MonadicOpTag || sym->value->tag == DyadicOpTag)
-						sym->value->operator.scope->keep = 1;
-				}
+				new->nsyms++;
+				new->syms = erealloc(new->syms, sizeof(Symbol *) * new->nsyms);
+				new->syms[new->nsyms-1] = dupsymbol(sym);
 			}
 		}
 	}
 	return new;
+}
+
+Symtab *
+getcurrentsymtab(void)
+{
+	DfnFrame *dfn = getcurrentdfn();
+	if(dfn == nil){
+		globalsymtab->refs++;
+		return globalsymtab;
+	}else{
+		dfn->symtab->refs++;
+		return dfn->symtab;
+	}
 }
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