ast: implement cleanup callbacks

bshell.runtime/ast/double.c

@@ -4,13 +4,22 @@
 
 static void to_string(const struct bshell_ast_node *node, fx_bstr *out)
 {
-	struct bshell_double_ast_node *i = (struct bshell_double_ast_node *)
-		node;
+	struct bshell_double_ast_node *i
+		= (struct bshell_double_ast_node *)node;
 	fx_value_to_string(&i->n_value->tok_number, (fx_stream *)out, NULL);
 }
 
+static enum bshell_status cleanup(struct bshell_ast_node *node)
+{
+	struct bshell_double_ast_node *d
+		= (struct bshell_double_ast_node *)node;
+	bshell_lex_token_destroy(d->n_value);
+	return BSHELL_SUCCESS;
+}
+
 struct bshell_ast_node_definition double_bshell_ast_node = {
 	.def_id = BSHELL_AST_DOUBLE,
 	.def_node_size = sizeof(struct bshell_double_ast_node),
 	.def_to_string = to_string,
+	.def_cleanup = cleanup,
 };