Deferred warnings.

Warnings about undefined functions and variables are now
deferred during loading, so forward references do not generate
nuisance diagnostics.

* eval.c (load_recursive_s): New symbol variable.
(eval_defr_warn): New static function.
(op_defvarl, op_defun): Purge any deferred warning about the
given function or variable not being defined.
(load): Rebind the sys:*load-recursive* special var to true
around the load. After the load, dump deferred warnings
if the prior binding of sys:*load-recursive* is false.
Discard deferred warnings in the case of termination by
a nonlocal control transfer.
(do_expand): Treat unbound vars and functions as deferrable
warnings, specially tagged for individual purging frkm
the deferred list.
(eval_init): Intern sys:*load-recursive* and initialize
load_recursive_s variable.

* eval.h (load_recursive_s): Declared.

* parse.c (repl_warning): Accept variable arguments.
Check whether we are loading and if so, defer deferrable
(repl): Adjustment for altered signature of repl_warning.
warnings.

* txr.c (txr_main): dump deferred warnings after
evaluating Lisp stream.

* unwind.c (deferred_warnings): New static variable.
(uw_throw): When a deferrable warning is caught,
suppress the usual message and add it to the
deferred_warnings list.
(uw_defer_warning, uw_dump_deferred_warnings,
uw_dump_deferred_warnings, uw_purge_deferred_warnings): New
functions.
(uw_late_init): gc-protect deferred_warnings.

* unwind.h (uw_defer_warning, uw_dump_deferred_warnings,
uw_dump_deferred_warnings, uw_purge_deferred_warnings): New
functions declared.

1 files changed, 3 insertions, 0 deletions

diff --git a/unwind.h b/unwind.h
index 4ca52228..7131cbc7 100644
--- a/unwind.h
+++ b/unwind.h
@@ -128,6 +128,9 @@ noreturn val uw_throwf(val sym, val fmt, ...);
 noreturn val uw_throwfv(val sym, val fmt, struct args *);
 noreturn val uw_errorf(val fmt, ...);
 noreturn val uw_errorfv(val fmt, struct args *args);
+val uw_defer_warning(val args);
+val uw_dump_deferred_warnings(val stream);
+val uw_purge_deferred_warning(val tag);
 val uw_register_subtype(val sub, val super);
 val uw_exception_subtype_p(val sub, val sup);
 void uw_continue(uw_frame_t *target);