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.

3 files changed, 27 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index 65a5775b..2bac16d4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+2015-08-06  Kaz Kylheku  <kaz@kylheku.com>
+
+	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.
+
 2015-08-05  Kaz Kylheku  <kaz@kylheku.com>
 
 	New filesystem object testing functions.
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);
diff --git a/parser.y b/parser.y
index e82e5b7a..f9df9531 100644
--- a/parser.y
+++ b/parser.y
@@ -47,7 +47,7 @@
 #include "stream.h"
 #include "parser.h"
 
-static val sym_helper(scanner_t *scnr, wchar_t *lexeme, val meta_allowed);
+static val sym_helper(parser_t *parser, wchar_t *lexeme, val meta_allowed);
 static val repeat_rep_helper(val sym, val args, val main, val parts);
 static val define_transform(parser_t *parser, val define_form);
 static val lit_char_helper(val litchars);
@@ -67,7 +67,7 @@ int yylex(union YYSTYPE *, yyscan_t scanner);
 
 #define rl(form, line) rlrec(parser, form, line)
 #define mkexp(sym, rest, lineno) make_expr(parser, sym, rest, lineno)
-#define symhlpr(lexeme, meta_allowed) sym_helper(scnr, lexeme, meta_allowed)
+#define symhlpr(lexeme, meta_allowed) sym_helper(parser, lexeme, meta_allowed)
 #define yyerr(msg) yyerror(scnr, parser, msg)
 #define yybadtok(tok, context) yybadtoken(parser, tok, context)
 
@@ -1027,8 +1027,9 @@ int yylex(YYSTYPE *, yyscan_t scanner);
 val rlcp(val to, val from);
 #endif
 
-static val sym_helper(scanner_t *scnr, wchar_t *lexeme, val meta_allowed)
+static val sym_helper(parser_t *parser, wchar_t *lexeme, val meta_allowed)
 {
+  scanner_t *scnr = parser->scanner;
   int leading_at = *lexeme == L'@';
   wchar_t *tokfree = lexeme;
   wchar_t *colon = wcschr(lexeme, L':');
@@ -1066,7 +1067,7 @@ static val sym_helper(scanner_t *scnr, wchar_t *lexeme, val meta_allowed)
 
   sym = intern(sym_name, package);
 
-  return leading_at ? list(var_s, sym, nao) : sym;
+  return leading_at ? rl(list(var_s, sym, nao), num(parser->lineno)) : sym;
 }
 
 static val repeat_rep_helper(val sym, val args, val main, val parts)