This variable is obsolete and will be removed in future versions.
@end defvar
-@defun backtrace-frame frame-number
+@defun backtrace-frame frame-number &optional base
The function @code{backtrace-frame} is intended for use in Lisp
debuggers. It returns information about what computation is happening
in the stack frame @var{frame-number} levels down.
case of a macro call. If the function has a @code{&rest} argument, that
is represented as the tail of the list @var{arg-values}.
+If @var{base} is specified, @var{frame-number} counts relative to
+the topmost frame whose @var{function} is @var{base}.
+
If @var{frame-number} is out of range, @code{backtrace-frame} returns
@code{nil}.
@end defun
+@defun mapbacktrace function &optional base
+The function @code{mapbacktrace} calls @var{function} once for each
+frame in the backtrace, starting at the first frame whose function is
+@var{base} (or from the top if @var{base} is omitted or @code{nil}).
+
+@var{function} is called with four arguments: @var{evald}, @var{func},
+@var{args}, and @var{flags}.
+
+If a frame has not evaluated its arguments yet or is a special form,
+@var{evald} is @code{nil} and @var{args} is a list of forms.
+
+If a frame has evaluated its arguments and called its function
+already, @var{evald} is @code{t} and @var{args} is a list of values.
+@var{flags} is a plist of properties of the current frame: currently,
+the only supported property is @code{:debug-on-exit}, which is
+@code{t} if the stack frame's @code{debug-on-exit} flag is set.
+@end defun
+
@include edebug.texi
@node Syntax Errors
(put symbol 'sendfunc sendfunc)
(put symbol 'abortfunc (or abortfunc 'kill-buffer))
(put symbol 'hookvar (or hookvar 'mail-send-hook)))
+
+\f
+(defun backtrace--print-frame (evald func args flags)
+ "Print a trace of a single stack frame to `standard-output'.
+EVALD, FUNC, ARGS, FLAGS are as in `mapbacktrace'."
+ (princ (if (plist-get flags :debug-on-exit) "* " " "))
+ (cond
+ ((and evald (not debugger-stack-frame-as-list))
+ (prin1 func)
+ (if args (prin1 args) (princ "()")))
+ (t
+ (prin1 (cons func args))))
+ (princ "\n"))
+
+(defun backtrace ()
+ "Print a trace of Lisp function calls currently active.
+Output stream used is value of `standard-output'."
+ (let ((print-level (or print-level 8)))
+ (mapbacktrace #'backtrace--print-frame 'backtrace)))
+
+(defun backtrace-frames (&optional base)
+ "Collect all frames of current backtrace into a list.
+If non-nil, BASE should be a function, and frames before its
+nearest activation frames are discarded."
+ (let ((frames nil))
+ (mapbacktrace (lambda (&rest frame) (push frame frames))
+ (or base 'backtrace-frames))
+ (nreverse frames)))
+
+(defun backtrace-frame (nframes &optional base)
+ "Return the function and arguments NFRAMES up from current execution point.
+If non-nil, BASE should be a function, and NFRAMES counts from its
+nearest activation frame.
+If the frame has not evaluated the arguments yet (or is a special form),
+the value is (nil FUNCTION ARG-FORMS...).
+If the frame has evaluated its arguments and called its function already,
+the value is (t FUNCTION ARG-VALUES...).
+A &rest arg is represented as the tail of the list ARG-VALUES.
+FUNCTION is whatever was supplied as car of evaluated list,
+or a lambda expression for macro calls.
+If NFRAMES is more than the number of frames, the value is nil."
+ (backtrace-frame--internal
+ (lambda (evald func args _) `(,evald ,func ,@args))
+ nframes (or base 'backtrace-frame)))
+
\f
(defvar called-interactively-p-functions nil
"Special hook called to skip special frames in `called-interactively-p'.
}
\f
-DEFUN ("backtrace-debug", Fbacktrace_debug, Sbacktrace_debug, 2, 2, 0,
- doc: /* Set the debug-on-exit flag of eval frame LEVEL levels down to FLAG.
-The debugger is entered when that frame exits, if the flag is non-nil. */)
- (Lisp_Object level, Lisp_Object flag)
-{
- union specbinding *pdl = backtrace_top ();
- register EMACS_INT i;
-
- CHECK_NUMBER (level);
-
- for (i = 0; backtrace_p (pdl) && i < XINT (level); i++)
- pdl = backtrace_next (pdl);
-
- if (backtrace_p (pdl))
- set_backtrace_debug_on_exit (pdl, !NILP (flag));
-
- return flag;
-}
-
-DEFUN ("backtrace", Fbacktrace, Sbacktrace, 0, 0, "",
- doc: /* Print a trace of Lisp function calls currently active.
-Output stream used is value of `standard-output'. */)
- (void)
+static union specbinding *
+get_backtrace_starting_at (Lisp_Object base)
{
union specbinding *pdl = backtrace_top ();
- Lisp_Object tem;
- Lisp_Object old_print_level = Vprint_level;
- if (NILP (Vprint_level))
- XSETFASTINT (Vprint_level, 8);
-
- while (backtrace_p (pdl))
- {
- write_string (backtrace_debug_on_exit (pdl) ? "* " : " ");
- if (backtrace_nargs (pdl) == UNEVALLED)
- {
- Fprin1 (Fcons (backtrace_function (pdl), *backtrace_args (pdl)),
- Qnil);
- write_string ("\n");
- }
- else
- {
- tem = backtrace_function (pdl);
- if (debugger_stack_frame_as_list)
- write_string ("(");
- Fprin1 (tem, Qnil); /* This can QUIT. */
- if (!debugger_stack_frame_as_list)
- write_string ("(");
- {
- ptrdiff_t i;
- for (i = 0; i < backtrace_nargs (pdl); i++)
- {
- if (i || debugger_stack_frame_as_list)
- write_string(" ");
- Fprin1 (backtrace_args (pdl)[i], Qnil);
- }
- }
- write_string (")\n");
- }
- pdl = backtrace_next (pdl);
+ if (!NILP (base))
+ { /* Skip up to `base'. */
+ base = Findirect_function (base, Qt);
+ while (backtrace_p (pdl)
+ && !EQ (base, Findirect_function (backtrace_function (pdl), Qt)))
+ pdl = backtrace_next (pdl);
}
- Vprint_level = old_print_level;
- return Qnil;
+ return pdl;
}
static union specbinding *
get_backtrace_frame (Lisp_Object nframes, Lisp_Object base)
{
- union specbinding *pdl = backtrace_top ();
register EMACS_INT i;
CHECK_NATNUM (nframes);
-
- if (!NILP (base))
- { /* Skip up to `base'. */
- base = Findirect_function (base, Qt);
- while (backtrace_p (pdl)
- && !EQ (base, Findirect_function (backtrace_function (pdl), Qt)))
- pdl = backtrace_next (pdl);
- }
+ union specbinding *pdl = get_backtrace_starting_at (base);
/* Find the frame requested. */
for (i = XFASTINT (nframes); i > 0 && backtrace_p (pdl); i--)
return pdl;
}
-DEFUN ("backtrace-frame", Fbacktrace_frame, Sbacktrace_frame, 1, 2, NULL,
- doc: /* Return the function and arguments NFRAMES up from current execution point.
-If that frame has not evaluated the arguments yet (or is a special form),
-the value is (nil FUNCTION ARG-FORMS...).
-If that frame has evaluated its arguments and called its function already,
-the value is (t FUNCTION ARG-VALUES...).
-A &rest arg is represented as the tail of the list ARG-VALUES.
-FUNCTION is whatever was supplied as car of evaluated list,
-or a lambda expression for macro calls.
-If NFRAMES is more than the number of frames, the value is nil.
-If BASE is non-nil, it should be a function and NFRAMES counts from its
-nearest activation frame. */)
- (Lisp_Object nframes, Lisp_Object base)
+static Lisp_Object
+backtrace_frame_apply (Lisp_Object function, union specbinding *pdl)
{
- union specbinding *pdl = get_backtrace_frame (nframes, base);
-
if (!backtrace_p (pdl))
return Qnil;
+
+ Lisp_Object flags = Qnil;
+ if (backtrace_debug_on_exit (pdl))
+ flags = Fcons (QCdebug_on_exit, Fcons (Qt, Qnil));
+
if (backtrace_nargs (pdl) == UNEVALLED)
- return Fcons (Qnil,
- Fcons (backtrace_function (pdl), *backtrace_args (pdl)));
+ return call4 (function, Qnil, backtrace_function (pdl), *backtrace_args (pdl), flags);
else
{
Lisp_Object tem = Flist (backtrace_nargs (pdl), backtrace_args (pdl));
+ return call4 (function, Qt, backtrace_function (pdl), tem, flags);
+ }
+}
- return Fcons (Qt, Fcons (backtrace_function (pdl), tem));
+DEFUN ("backtrace-debug", Fbacktrace_debug, Sbacktrace_debug, 2, 2, 0,
+ doc: /* Set the debug-on-exit flag of eval frame LEVEL levels down to FLAG.
+The debugger is entered when that frame exits, if the flag is non-nil. */)
+ (Lisp_Object level, Lisp_Object flag)
+{
+ CHECK_NUMBER (level);
+ union specbinding *pdl = get_backtrace_frame(level, Qnil);
+
+ if (backtrace_p (pdl))
+ set_backtrace_debug_on_exit (pdl, !NILP (flag));
+
+ return flag;
+}
+
+DEFUN ("mapbacktrace", Fmapbacktrace, Smapbacktrace, 1, 2, 0,
+ doc: /* Call FUNCTION for each frame in backtrace.
+If BASE is non-nil, it should be a function and iteration will start
+from its nearest activation frame.
+FUNCTION is called with 4 arguments: EVALD, FUNC, ARGS, and FLAGS. If
+a frame has not evaluated its arguments yet or is a special form,
+EVALD is nil and ARGS is a list of forms. If a frame has evaluated
+its arguments and called its function already, EVALD is t and ARGS is
+a list of values.
+FLAGS is a plist of properties of the current frame: currently, the
+only supported property is :debug-on-exit. `mapbacktrace' always
+returns nil. */)
+ (Lisp_Object function, Lisp_Object base)
+{
+ union specbinding *pdl = get_backtrace_starting_at (base);
+
+ while (backtrace_p (pdl))
+ {
+ backtrace_frame_apply (function, pdl);
+ pdl = backtrace_next (pdl);
}
+
+ return Qnil;
+}
+
+DEFUN ("backtrace-frame--internal", Fbacktrace_frame_internal,
+ Sbacktrace_frame_internal, 3, 3, NULL,
+ doc: /* Call FUNCTION on stack frame NFRAMES away from BASE.
+Return the result of FUNCTION, or nil if no matching frame could be found. */)
+ (Lisp_Object function, Lisp_Object nframes, Lisp_Object base)
+{
+ return backtrace_frame_apply (function, get_backtrace_frame (nframes, base));
}
/* For backtrace-eval, we want to temporarily unwind the last few elements of
defsubr (&Srun_hook_wrapped);
defsubr (&Sfetch_bytecode);
defsubr (&Sbacktrace_debug);
- defsubr (&Sbacktrace);
- defsubr (&Sbacktrace_frame);
+ DEFSYM (QCdebug_on_exit, ":debug-on-exit");
+ defsubr (&Smapbacktrace);
+ defsubr (&Sbacktrace_frame_internal);
defsubr (&Sbacktrace_eval);
defsubr (&Sbacktrace__locals);
defsubr (&Sspecial_variable_p);
(error-message-string (should-error (version-to-list "beta22_8alpha3")))
"Invalid version syntax: `beta22_8alpha3' (must start with a number)"))))
+(defun subr-test--backtrace-frames-with-backtrace-frame (base)
+ "Reference implementation of `backtrace-frames'."
+ (let ((idx 0)
+ (frame nil)
+ (frames nil))
+ (while (setq frame (backtrace-frame idx base))
+ (push frame frames)
+ (setq idx (1+ idx)))
+ (nreverse frames)))
+
+(defun subr-test--frames-2 (base)
+ (let ((_dummy nil))
+ (progn ;; Add a few frames to top of stack
+ (unwind-protect
+ (cons (mapcar (pcase-lambda (`(,evald ,func ,args ,_))
+ `(,evald ,func ,@args))
+ (backtrace-frames base))
+ (subr-test--backtrace-frames-with-backtrace-frame base))))))
+
+(defun subr-test--frames-1 (base)
+ (subr-test--frames-2 base))
+
+(ert-deftest subr-test-backtrace-simple-tests ()
+ "Test backtrace-related functions (simple tests).
+This exercises `backtrace-frame', and indirectly `mapbacktrace'."
+ ;; `mapbacktrace' returns nil
+ (should (equal (mapbacktrace #'ignore) nil))
+ ;; Unbound BASE is silently ignored
+ (let ((unbound (make-symbol "ub")))
+ (should (equal (backtrace-frame 0 unbound) nil))
+ (should (equal (mapbacktrace #'error unbound) nil)))
+ ;; First frame is backtrace-related function
+ (should (equal (backtrace-frame 0) '(t backtrace-frame 0)))
+ (should (equal (catch 'ret
+ (mapbacktrace (lambda (&rest args) (throw 'ret args))))
+ '(t mapbacktrace ((lambda (&rest args) (throw 'ret args))) nil)))
+ ;; Past-end NFRAMES is silently ignored
+ (should (equal (backtrace-frame most-positive-fixnum) nil)))
+
+(ert-deftest subr-test-backtrace-integration-test ()
+ "Test backtrace-related functions (integration test).
+This exercises `backtrace-frame', `backtrace-frames', and
+indirectly `mapbacktrace'."
+ ;; Compare two implementations of backtrace-frames
+ (let ((frame-lists (subr-test--frames-1 'subr-test--frames-2)))
+ (should (equal (car frame-lists) (cdr frame-lists)))))
+
(provide 'subr-tests)
;;; subr-tests.el ends here
projects / emacs.git / commitdiff