-*- mode: outline -*-

* How debug?

When your InitFile has a bug, or when you load external files that cause

errors, the bug is often hard to find, because the Emacs Lisp reader does not

know about line numbers and files – it just knows an error happened, and

that’s it.

You have several options:

  * Binary Search – select half of the file in a region, and M-x eval-region.

  Depending on whether that causes the error or not, split this half or the

  other half again, and repeat.

  * Simplified Binary Search – add (error “No error until here”) in the

  middle of your file. If you get the error “No error until here” when

  reloading the file, move the expression towards the back of the file,

  otherwise towards the front of the file.

  * Use a keyboard macro that moves forward one expression (sexp) and

  evaluates it.

  * Try the CommandLine? switch --debug-init.

  * Shouldn’t (setq debug-on-error t) help?