Better diagnosis for loose @ forms.

* eval.c (op_meta_error): New static function.
(eval_init): Register sys:var and sys:expr as operators
that throw error.

* parser.y (sym_helper): Take parser_t instead of scanner_t
argument so we have access to the name and line number.
Obtain scanner internally from parser. Add source location
info to (sys:var ...) form.
(symhlpr): Retarget macro to pass parser rather than scanner to
sm_helper.

1 files changed, 7 insertions, 0 deletions

diff --git a/eval.c b/eval.c
index bb701106..398955f0 100644
--- a/eval.c
+++ b/eval.c
@@ -1163,6 +1163,11 @@ static val op_error(val form, val env)
   abort();
 }
 
+static val op_meta_error(val form, val env)
+{
+  eval_error(form, lit("meta with no meaning: ~s"), form, nao);
+}
+
 static val op_quote(val form, val env)
 {
   val d = cdr(form);
@@ -4090,6 +4095,8 @@ void eval_init(void)
   with_saved_vars_s = intern(lit("with-saved-vars"), system_package);
   reg_op(macrolet_s, op_error);
   reg_op(symacrolet_s, op_error);
+  reg_op(var_s, op_meta_error);
+  reg_op(expr_s, op_meta_error);
   reg_op(quote_s, op_quote);
   reg_op(qquote_s, op_qquote_error);
   reg_op(sys_qquote_s, op_qquote_error);