[Python-mode] making stack traces clickable in gud.el pdb output.

[m h]

Hey all-

I got my original wish, compile-mode error navigation through the
python stack trace of a unittest failure.

Thanks to Gerard B for the hint.

 I'm doing this from pdbtrack (shell) instead of pure pdb, but it
should work in both I believe. You need to enable
compilation-shell-minor-mode. And have the following code in your
.emacs:

;; if compilation-shell-minor-mode is on, then these regexes
;; will make errors linkable
(defun matt-add-global-compilation-errors (list)
  (dolist (x list)
    (add-to-list 'compilation-error-regexp-alist (car x))
    (setq compilation-error-regexp-alist-alist
      (cons x
            (assq-delete-all (car x)
                             compilation-error-regexp-alist-alist)))))

(matt-add-global-compilation-errors
 `(
   (matt-python ,(concat "^ *File \\(\"?\\)\\([^,\" \n    <>]+\\)\\1"
                    ", lines? \\([0-9]+\\)-?\\([0-9]+\\)?")
           2 (3 . 4) nil 2 2)
   (matt-pdb-stack ,(concat "^>?[[:space:]]*\\(\\([-_./a-zA-Z0-9 ]+\\)"
                       "(\\([0-9]+\\))\\)"
                       "[_a-zA-Z0-9]+()[[:space:]]*->")
              2 3 nil 0 1)
   (matt-python-unittest-err "^  File \"\\([-_./a-zA-Z0-9 ]+\\)\",
line \\([0-9]+\\).*" 1 2)
   )
 )

(defun matt-set-local-compilation-errors (errors)
  "Set the buffer local compilation errors.

Ensures than any symbols given are defined in
compilation-error-regexp-alist-alist."
  (dolist (e errors)
     (when (symbolp e)
      (unless (assoc e compilation-error-regexp-alist-alist)
        (error (concat "Error %s is not listed in "
                       "compilation-error-regexp-alist-alist")
               e))))
  (set (make-local-variable 'compilation-error-regexp-alist)
       errors))

Then you can use standard compile mode navigation to zip through the
error stack trace.

cheers,

-matt