diff --git a/src/twopass.rs b/src/twopass.rs
index a8ec575..5a6cc04 100644
--- a/src/twopass.rs
+++ b/src/twopass.rs
@@ -124,7 +124,21 @@ impl BuildContext<'_> {
 }
 
 fn lookup(scope: &BuildContext<'_>, loc: &ast::Location) -> Location {
-	todo!()
+	match loc {
+		ast::Location::Variable { name } => {
+			if let Some(id) = scope.request(name) {
+				return Location::Variable { id };
+			};
+			let env = scope
+				.request(&"_ENV".into())
+				.expect("_ENV must be always available");
+			Location::Field {
+				table: Box::new(Location::Variable { id: env }),
+				index: Box::new(Expression::Constant(ast::Constant::String(name.clone()))),
+			}
+		}
+		ast::Location::Field { table, index } => todo!(),
+	}
 }
 
 fn build_expression(scope: &BuildContext<'_>, code: &ast::Expression) -> Expression {