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, 18 insertions, 1 deletions

diff --git a/unwind.h b/unwind.h
index a09df613..1ccdbaee 100644
--- a/unwind.h
+++ b/unwind.h
@@ -31,7 +31,7 @@
 #endif
 
 typedef union uw_frame uw_frame_t;
-typedef enum uw_frtype { UW_BLOCK, UW_ENV, UW_CATCH } uw_frtype_t;
+typedef enum uw_frtype { UW_BLOCK, UW_ENV, UW_CATCH, UW_DBG } uw_frtype_t;
 
 struct uw_common {
   uw_frame_t *up;
@@ -65,11 +65,24 @@ struct uw_catch {
   jmp_buf jb;
 };
 
+struct uw_debug {
+  uw_frame_t *up;
+  uw_frtype_t type;
+  val func;
+  val args;
+  val ub_p_a_pairs;
+  val bindings;
+  val data;
+  val line;
+  val chr;
+};
+
 union uw_frame {
   struct uw_common uw;
   struct uw_block bl;
   struct uw_dynamic_env ev;
   struct uw_catch ca;
+  struct uw_debug db;
 };
 
 void uw_push_block(uw_frame_t *, val tag);
@@ -86,7 +99,11 @@ noreturn val uw_errorf(val fmt, ...);
 val uw_register_subtype(val sub, val super);
 val uw_exception_subtype_p(val sub, val sup);
 void uw_continue(uw_frame_t *curr, uw_frame_t *target);
+void uw_push_debug(uw_frame_t *, val func, val args,
+                   val ub_p_a_pairs, val bindings, val data,
+                   val line, val chr);
 void uw_pop_frame(uw_frame_t *);
+uw_frame_t *uw_current_frame(void);
 void uw_init(void);
 
 noreturn val type_mismatch(val, ...);