allow local resolution into outer scopes

4 files changed, 25 insertions, 17 deletions

diff --git a/com.c b/com.c
index c5362cd..a3cc5a8 100644
--- a/com.c
+++ b/com.c
@@ -244,6 +244,16 @@ static void declare_local(Compiler *C, char *name) {
 	l->slot = C->stack_cur - 1;
 	// printf("declaring local %s at %d, stack_cur is %d\n",l->name, l->slot, C->stack_cur);
 }
+static Local *locate_local(Compiler *C, char *name) {
+	for (Scope *sc = C->scope; sc != NULL; sc = sc->outer) {
+		for (int i = 0; i < sc->nlocals; i++) {
+			Local *loc = &sc->locals[i];
+			if (0 == strcmp(loc->name, name)) 
+				return loc;
+		}
+	}
+	return NULL;
+}
 
 void let_form(Compiler *C, AstVec l, Op _) {
 	CHECK(l.vals[1].ty == AST_LIST, "let's first argument must be list");
@@ -345,6 +355,8 @@ static BuiltinIdent builtin_idents[] = {
 	{ 0 },
 };
 
+
+
 static void compile_node(Compiler *C, AstNode a) {
 	switch (a.ty) {
 	case AST_IDENT:;
@@ -358,21 +370,11 @@ static void compile_node(Compiler *C, AstNode a) {
 			}
 		}
 		if (!found_builtin) {
-			// read local or global variable
-			bool found_local = false;
-			if (C->scope != NULL) {
-				Scope *sc = C->scope;
-				for (int i = 0; i < sc->nlocals; i++) {
-					Local loc = sc->locals[i];
-					if (0 == strcmp(ident, loc.name)) {
-						compile_opcode(C, OP_GETLOCAL);
-						compile_byte(C, loc.slot);
-						found_local = true;
-						break;
-					}
-				}
-			}
-			if (!found_local) {
+			Local *loc = locate_local(C, ident);
+			if (loc != NULL) {
+				compile_opcode(C, OP_GETLOCAL);
+				compile_byte(C, loc->slot);
+			} else {
 				// read global
 				ObjString *o = objstring_copy_cstr(C->S, a.as.str);
 				compile_opcode(C, OP_GETGLOBAL);
diff --git a/tests/vars3.bth b/tests/vars3.bth
new file mode 100644
index 0000000..19e82fa
--- /dev/null
+++ b/tests/vars3.bth
@@ -0,0 +1,6 @@
+(do
+	(set x 1)
+	(set y 10)
+	(let (x 2)
+		(let (y 20)
+			(+ x y))))
diff --git a/tests/vars3.out b/tests/vars3.out
new file mode 100644
index 0000000..2bd5a0a
--- /dev/null
+++ b/tests/vars3.out
@@ -0,0 +1 @@
+22
diff --git a/todo b/todo
index 2e920ed..f724c3a 100644
--- a/todo
+++ b/todo
@@ -1,5 +1,4 @@
-functions, returning
-locals, lexical scoping, closures, upvalues
+closures, upvalues
 lists, hashes, other useful types
 garbage collector
 macros