Feature request: A way to get a traceback to a buffer or a string

[Lennart Borgman (gmail)]

In some situations you may know that a function call will cause an 
error. You may then want to get a traceback from this particular call, 
without user intervention. I have attached a macro that can give this. I 
would find it practical if this were included in Emacs.

(defmacro mumamo-get-backtrace (bodyform)
  "Evaluate BODYFORM, return backtrace as a string.
If there is an error in BODYFORM then return the backtrace as a
string, otherwise return nil."
  `(let ((debugger (lambda (&rest debugger-args)
                     (setq debugger-ret (with-output-to-string 
(backtrace)))))
         (debug-on-error t)
         (debug-on-signal t)
         (debugger-ret nil))
     (condition-case err
         (progn
           ,bodyform
           nil)
       (error
        (let* ((errmsg (error-message-string err))
               (debugger-lines (split-string debugger-ret "\n"))
               (dbg-ret (mapconcat 'identity (nthcdr 6 debugger-lines) 
"\n")))
          (concat errmsg "\n" dbg-ret))))))