1 files changed, 28 insertions, 0 deletions

diff --git a/symbol.c b/symbol.c
index 8e51ba9..626a2db 100644
--- a/symbol.c
+++ b/symbol.c
@@ -319,4 +319,32 @@ void
 setsyntaxerr(Datum *)
 {
 	throwerror(nil, ESyntax);
+}
+
+DfnFrame *
+dupscope(DfnFrame *dfn)
+{
+	if(dfn == nil)
+		return nil;
+
+	DfnFrame *new = emallocz(sizeof(DfnFrame), 1);
+	new->symtab = newsymtab();
+
+	/* copy ALL symbols which are in scope, into the new symtab */
+	for(DfnFrame *d = dfn; d != nil; d = d->chain){
+		/* Add all new symbols */
+		for(int i = 0; i < d->symtab->nsyms; i++){
+			Symbol *sym = d->symtab->syms[i];
+			int found = 0;
+			for(int j = 0; j < new->symtab->nsyms && !found; j++)
+				if(runestrcmp(new->symtab->syms[i]->name, d->symtab->syms[j]->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);
+			}
+		}
+	}
+	return new;
 }
\ No newline at end of file