Implement some form of error guards. It may not be perfect yet

1 files changed, 57 insertions, 6 deletions

diff --git a/symbol.c b/symbol.c
index 6e9aa4a..8e51ba9 100644
--- a/symbol.c
+++ b/symbol.c
@@ -8,6 +8,8 @@
 Symtab *globalsymtab;
 
 Symtab *newsymtab(void);
+Symbol *dupsymbol(Symbol *);
+Symtab *dupsymtab(Symtab *);
 void freesymtab(Symtab *);
 
 Datum *getalpha(void);
@@ -65,6 +67,28 @@ newsymtab(void)
 	return tab;
 }
 
+Symbol *
+dupsymbol(Symbol *s)
+{
+	Symbol *new = emalloc(sizeof(Symbol));
+	memcpy(new, s, sizeof(Symbol));
+	new->name = runestrdup(s->name);
+	if(new->value)
+		incdatumref(new->value);
+	return new;
+}
+
+Symtab *
+dupsymtab(Symtab *tab)
+{
+	Symtab *new = newsymtab();
+	memcpy(new, tab, sizeof(Symtab));
+	new->syms = emalloc(sizeof(Symbol*) * new->nsyms);
+	for(int i = 0; i < tab->nsyms; i++)
+		new->syms[i] = dupsymbol(tab->syms[i]);
+	return new;
+}
+
 void
 freesymtab(Symtab *tab)
 {
@@ -130,22 +154,49 @@ pushdfnframe(Rune *code, DfnFrame *scope, Datum *lefto, Datum *righto, Array *le
 	incarrayref(right);
 	new->prev = td->currentdfn;
 	new->chain = scope;
+	new->errorguards = nil;
 	td->currentdfn = new;
 	return new;
 }
 
+DfnFrame *
+dupdfnframe(DfnFrame *f)
+{
+	DfnFrame *new = emalloc(sizeof(DfnFrame));
+	memcpy(new, f, sizeof(DfnFrame));
+	new->code = runestrdup(f->code);
+	new->symtab = dupsymtab(f->symtab);
+	if(f->lefto)
+		incdatumref(f->lefto);
+	if(f->righto)
+		incdatumref(f->righto);
+	if(f->left)
+		incdatumref(f->left);
+	if(f->right)
+		incarrayref(f->right);
+	return new;
+}
+
+void
+freedfnframe(DfnFrame *f, int keeperrorguards)
+{
+	freesymtab(f->symtab);
+	freedatum(f->lefto);
+	freedatum(f->righto);
+	freedatum(f->left);
+	freearray(f->right);
+	if(!keeperrorguards)
+		freeerrorguards(f->errorguards);
+	free(f);
+}
+
 void
 popdfnframe(void)
 {
 	ThreadData *td = getthreaddata();
 	if(td->currentdfn != nil){
 		DfnFrame *prev = td->currentdfn->prev;
-		freesymtab(td->currentdfn->symtab);
-		freedatum(td->currentdfn->lefto);
-		freedatum(td->currentdfn->righto);
-		freedatum(td->currentdfn->left);
-		freearray(td->currentdfn->right);
-		free(td->currentdfn);
+		freedfnframe(td->currentdfn, 0);
 		td->currentdfn = prev;
 	}
 }