1 files changed, 66 insertions, 0 deletions
diff --git a/share/txr/stdlib/debugger.tl b/share/txr/stdlib/debugger.tl
new file mode 100644
index 00000000..9afab9ef
--- /dev/null
+++ b/share/txr/stdlib/debugger.tl
@@ -0,0 +1,66 @@
+;; Copyright 2019
+;; Kaz Kylheku <kaz@kylheku.com>
+;; Vancouver, Canada
+;; All rights reserved.
+;;
+;; Redistribution and use in source and binary forms, with or without
+;; modification, are permitted provided that the following conditions are met:
+;;
+;; 1. Redistributions of source code must retain the above copyright notice, this
+;;    list of conditions and the following disclaimer.
+;;
+;; 2. Redistributions in binary form must reproduce the above copyright notice,
+;;    this list of conditions and the following disclaimer in the documentation
+;;    and/or other materials provided with the distribution.
+;;
+;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+;; ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+;; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+;; DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+;; FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+;; DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+;; SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+;; CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+;; OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+;; OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+(defmacro with-disabled-debugging (. forms)
+  (let ((state (gensym)))
+    ^(let ((,state (dbg-clear dbg-all)))
+       (unwind-protect
+         (progn ,*forms)
+         (dbg-restore ,state)))))
+
+(defun make-command-env (command-table)
+  (let ((env (make-env )))
+    (mapdo (ado env-vbind env @1 ^(,@2)) command-table)
+    env))
+
+(defparml %dbg-commands% '((usr:? debugger-help "list command summary")
+                           (usr:bt print-backtrace "print backtrace")))
+
+(defparml %dbg-command-env% (make-command-env %dbg-commands%))
+
+(defun debugger-help ()
+  (mapdo (ap pprinl `@{@1 15} @3`) %dbg-commands%))
+
+(defun print-backtrace (: (*stdout* *stdout*) (prefix ""))
+  (with-resources ((imode (set-indent-mode *stdout* indent-off)
+                          (set-indent-mode *stdout* imode)))
+    (each ((fr (find-frames-by-mask uw-fcall)))
+      (let* ((fun fr.fun)
+             (args fr.args)
+             (name (if (functionp fun)
+                     (func-get-name fun)))
+             (kind
+               (cond
+                 ((interp-fun-p fun) "I")
+                 ((vm-fun-p fun) "V")
+                 ((functionp fun) "C")
+                 (t "O"))))
+        (put-string `@prefix @kind: `)
+        (prinl ^[,(or name fun) ,*args])))))
+
+(defun debugger ()
+  (with-disabled-debugging
+    (sys:repl nil *stdin* *stdout* %dbg-command-env%)))