-*- mode: outline; coding: utf-8 -*-

* Variables.

Select one of:

  (set 'variable value)

  (setq variable value)

  (defvar variable value "documentation")

or (replace <colon> with :)

  # Local variables<colon>

  # variable<colon> value

  # End<colon>

* Debugging.

** What functions and variables Emacs load and from which files?

See value of variable 'load-history' (by C-h v load-history RET).

** Using edebug.

Execute 'M-x edebug-defun' (also on 'C-u C-M-x') on defun in source code to

enable debugging for desired function. When next time this function invoked

you entered to its debugging (jumped to its source code).

To start debug execute code which used debugged function.

You can disable edebug on a function by evaluating the function again using

'C-M-x'.

** How debug func?

Use M-x debug-on-entry and M-x cancel-debug-on-entry to control

which functions will enter the debugger when called.

When next time that function called automatically loaded debug-mode.

** How debug ini file?

When your ini 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.

*** Check if bug in ini file.

First run Emacs without loading anything:

  $ emacs --no-init-file --no-site-file

If bug not reproduced bug lies in ini files!

*** 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.

*** Elisp.

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

   it.

 - Try C-x check-parens.

 - Set (setq debug-on-error t).

*** CLI.

  $ emacs --no-init-file --no-site-file --debug-init

*** 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.

** Call tree.

Before byte compiling file execute

  (setq byte-compile-generate-call-tree t)

* WWW.

** Text based WWW browser.

  http://en.wikipedia.org/wiki/W3m

  http://emacs-w3m.namazu.org/

  http://www.gnu.org/software/w3/

* Tricks.

** Sort and uniquify lines.

Select region, type C-u M-| sort -u RET.

With transient-mark-mode and delete-selection-mode enabled: select region,

type M-| sort -u RET to replace selection with sorted and uniquified lines.

** Determining running environment/platform.

Check variables:

  emacs-major-version

  emacs-minor-version

  window-system             - 'nil' if in terminal, 'w32' if native Windows build, 'x' if under X Window

  window-system-version     - for windows only

  operating-system-release  - release of the operating system Emacs is running on

  system-configuration      - like configuration triplet: cpu-manufacturer-os

  system-name               - host name of the machine you are running on

  system-time-locale

  system-type               - indicating the type of operating system you are using:

                              'gnu' (GNU Hurd), 'gnu/linux', 'gnu/kfreebsd' (FreeBSD),

                              'darwin' (GNU-Darwin, Mac OS X), 'ms-dos', 'windows-nt', 'cygwin'

  system-uses-terminfo

  window-size-fixed

or check functions:

  (fboundp ...)             - return t if SYMBOL's function definition is not void

  (featurep ...)            - returns t if FEATURE is present in this Emacs

  (display-graphic-p)       - return non-nil if DISPLAY is a graphic display; graphical

                              displays are those which are capable of displaying several

                              frames and several different fonts at once

  (display-multi-font-p)    - same as 'display-graphic-p'

  (display-multi-frame-p)   - same as 'display-graphic-p'

  (display-color-p)         - return t if DISPLAY supports color

  (display-images-p)        - return non-nil if DISPLAY can display images

  (display-grayscale-p)     - return non-nil if frames on DISPLAY can display shades of gray

  (display-mouse-p)         - return non-nil if DISPLAY has a mouse available

  (display-popup-menus-p)   - return non-nil if popup menus are supported on DISPLAY

  (display-selections-p)    - return non-nil if DISPLAY supports selections

Run those checks as below:

  (when window-system ...)

  (when (eq window-system 'x) ...)

  (when (>= emacs-major-version 22) ...)

  (when (fboundp '...) ...)

  (when (featurep '...) ...)

* Finding emacs packages.

See

  http://anc.ed.ac.uk/~stephen/emacs/ell.html

  http://www.emacswiki.org/emacs/WikifiedEmacsLispList

  http://tromey.com/elpa/index.html

                Emacs Lisp Package Archive

** ELPA.

ELPA goal is to make it simple to install, use, and upgrade Emacs Lisp

packages.

  http://tromey.com/elpa/upload.html

                how to contribute

* Compiling emacs.

** Windows.

Get MSYS for POSIX shell and utilities . Get MinGW for GCC. Get Gnuwin32 for

jpeg, ungif, tiff, xpm, png, zlib libraries.

Read emacs/nt/INSTALL.

  $ cmd

  $ cd emacs\nt

  $ configure.bat --prefix %INST_ROOT% --with-gcc --cflags -I%GNUWIN32_ROOT%/include --ldflags -L%GNUWIN32_ROOT%/lib  --ldflags -lregex

  $ make bootstrap

  $ make info

  $ make install

* Documentation.

** Elisp documentation.

  ;;; <file-name>.el --- <one-line-description>

  ;; Copyright (C) <years> <person>

  ;; Author: <person> <mail>

  ;; Maintainer: <person> <mail>

  ;; Created: <date>

  ;; Version: <version>

  ;; Keywords: <look for 'finder-by-keyword' output, separate by comma>

  ;; URL: <file-location>

  ;;; Commentary:

  <bla-bla-bla>

  ;;; Code:

  <lisp-code>

  ;;; <file-name> ends here

See

  http://www.gnu.org/software/emacs/elisp-manual/html_node/Library-Headers.html

  http://www.emacswiki.org/cgi-bin/wiki/ElispAreaConventions

*** CheckDoc.

CheckDoc checks your EmacsLisp code for errors in documentation and style.

  http://cedet.sourceforge.net/checkdoc.shtml

                home page before including it into GNU Emacs

  http://www.emacswiki.org/emacs/CheckDoc

* Installing Emacs.

** From sources.

  http://ftp.gnu.org/pub/gnu/emacs

** Windows.

  http://ftp.gnu.org/pub/gnu/emacs/windows

  http://alpha.gnu.org/gnu/emacs/windows

                beta releases for windows

** Debian.

  $ apt-get install emacs

* Emacs paths.

  source-directory data-directory doc-directory exec-directory invocation-directory trash-directory

  tutorial-directory user-emacs-directory widget-image-directory

* Emacs games.

  hanoi hanoi-unix life pong tetris gomoku