Expander warns about unbound variables.

* eval.c (eval_exception): New static function.
(eval_error): Reduced to wrapper around eval_exception.
(eval_warn): New function.
(me_op): Bind the rest symbol in a shadowing env to suppress
watnings about unbound rest.
(do_expand): Throw a warning when a bindable symbol is
traversed that has no binding.
(expand): Don't install atoms as last_form_expanded.

* lib.c (warning_s, restart_s, continue_s): New symbol
variables.
(obj_init): Initialize new symbol variables.

* lib.h (warning_s, restart_s, continue_s): Declared.

* lisplib.c (except_set_entries): New entries for
ignwarn and macro-time-ignwarn.

* parser.c (repl_warning): New static function.
(repl): Use repl_warning function as a handler for
warning exceptions: to print their message and then
continue by throwing a continue exception.

* parser.y (warning_continue): New static function.
(parse_once): Use warning_continue to ignore warnings.
In other words, we suppress warnings from Lisp that is
mixed into TXR pattern language code, because this
produces too many false positives.

* share/txr/stdlib/except.tl (ignwarn, macro-time-ignwarn):
New macros.

* share/txr/stdlib/place.tl (call-update-expander,
call-clobber-expander, call-delete-expander): Ignore warnings
around calls to sys:expand, because of some gensym-related
false positives (we expand code into which we inserted some
gensyms, without having inserted the constructs which
bind them.

* tests/011/macros-2.txr: Suppress unbound variable
warnings from a test case.

* tests/012/ifa.tl: Bind unbound x y variables in one
test case.

* tests/012/struct.tl: Suppress unbound variable
warnings in some test cases.

* uwind.c (uw_throw): If a warning is unhandled, then
print its message with a "warning" prefix and then
throw a continue exception.
(uw_register_subtype): Eliminate the check for sub
already being a subtype of sup. This allows us to
officially register new types against t.
(uw_late_init): Register continue exception type as a
subtype of the restart type.
Formally register warning type.

* txr.1: Documented ignwarn.

1 files changed, 12 insertions, 0 deletions

diff --git a/parser.c b/parser.c
index 681ffe75..f4f1c1ce 100644
--- a/parser.c
+++ b/parser.c
@@ -887,6 +887,12 @@ static val get_home_path(void)
   return getenv_wrap(lit("HOME"));
 }
 
+static val repl_warning(val out_stream, val exc, val arg)
+{
+  format(out_stream, lit("** warning: ~!~a\n"), arg, nao);
+  uw_throw(continue_s, nil);
+}
+
 val repl(val bindings, val in_stream, val out_stream)
 {
   val ifd = stream_get_prop(in_stream, fd_k);
@@ -911,6 +917,7 @@ val repl(val bindings, val in_stream, val out_stream)
   val hist_len_var = lookup_global_var(listener_hist_len_s);
   val multi_line_var = lookup_global_var(listener_multi_line_p_s);
   val sel_inclusive_var = lookup_global_var(listener_sel_inclusive_p_s);
+  val rw_f = func_f2(out_stream, repl_warning);
 
   for (; bindings; bindings = cdr(bindings)) {
     val binding = car(bindings);
@@ -937,6 +944,7 @@ val repl(val bindings, val in_stream, val out_stream)
     val var_counter = mod(counter, num_fast(100));
     val var_name = format(nil, lit("*~d"), var_counter, nao);
     val var_sym = intern(var_name, user_package);
+    uw_frame_t uw_handler;
 
     char *prompt_u8 = utf8_dup_to(c_str(prompt));
 
@@ -984,6 +992,8 @@ val repl(val bindings, val in_stream, val out_stream)
 
     uw_catch_begin (catch_all, exsym, exvals);
 
+    uw_push_handler(&uw_handler, cons(warning_s, nil), rw_f);
+
     {
       val name = format(nil, lit("expr-~d"), prev_counter, nao);
       val line = string_utf8(line_u8);
@@ -1003,6 +1013,8 @@ val repl(val bindings, val in_stream, val out_stream)
       }
     }
 
+    uw_pop_frame(&uw_handler);
+
     uw_catch (exsym, exvals) {
       val exinfo = cons(exsym, exvals);
       reg_varl(var_sym, exinfo);