Adding a debugger. This is an experimental prototype.

* Makefile (OBJS): New object file debug.o.

* dep.mk: Updated.

* match.c (h_fun): Use debug_begin and debug_end macros
to set up a debug frame for backtracing.
(match_line, match_files): Call debug_check to give debugger a chance
to instrument call.
(v_fun): Use debug_begin and debug_end macros to set up a debug frame
for backtracing. Call debug_check to give debugger a chance to
instrument call.

* stream.c (struct strm_ops): New function pointer, flush.
(stdio_maybe_write_error): Wrong word in error message corrected.
(stdio_flush): New static function.
(stdio_ops, pipe_ops): New function entered into tables.
(flush_stream): New function.

* stream.h (flush_stream): Declared.

* txr.c (help): New options documented.
(main): call to debug_init added. New debug options parsed and
opt_debugger set accordingly.

* unwind.c (uw_push_debug, uw_current_frame): New function.

* unwind.h (uw_frtype): New enumeration member UW_DBG.
(struct uw_debug): New frame variant.
(union uw_frame): New member, db.
(uw_push_debug, uw_current_frame): Declared,

* debug.c: New file.

* debug.h: New file.

1 files changed, 21 insertions, 0 deletions

diff --git a/unwind.c b/unwind.c
index 0d8a48e4..4bb6646c 100644
--- a/unwind.c
+++ b/unwind.c
@@ -166,6 +166,22 @@ val uw_set_match_context(val context)
   return context;
 }
 
+void uw_push_debug(uw_frame_t *fr, val func, val args,
+                   val ub_p_a_pairs, val bindings, val data,
+                   val line, val chr)
+{
+  fr->db.type = UW_DBG;
+  fr->db.func = func;
+  fr->db.args = args;
+  fr->db.ub_p_a_pairs = args;
+  fr->db.bindings = bindings;
+  fr->db.data = data;
+  fr->db.line = line;
+  fr->db.chr = chr;
+  fr->db.up = uw_stack;
+  uw_stack = fr;
+}
+
 void uw_pop_frame(uw_frame_t *fr)
 {
   assert (fr == uw_stack);
@@ -176,6 +192,11 @@ void uw_pop_frame(uw_frame_t *fr)
   }
 }
 
+uw_frame_t *uw_current_frame(void)
+{
+  return uw_stack;
+}
+
 val uw_block_return(val tag, val result)
 {
   uw_frame_t *ex;