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| -rw-r--r-- | elisp.html.markdown | 79 |
1 files changed, 59 insertions, 20 deletions
diff --git a/elisp.html.markdown b/elisp.html.markdown index d5ba376d..87368bc7 100644 --- a/elisp.html.markdown +++ b/elisp.html.markdown @@ -2,11 +2,11 @@ language: elisp contributors: - ["Bastien Guerry", "http://bzg.fr"] -filename: elisp.el +filename: learn-emacs-lisp.el --- ```elisp -;; This gives an introduction to Emacs Lisp in 15 minutes. +;; This gives an introduction to Emacs Lisp in 15 minutes (v0.2) ;; ;; First make sure you read this text by Peter Norvig: ;; http://norvig.com/21-days.html @@ -19,10 +19,20 @@ filename: elisp.el ;; ;; More general information can be found at: ;; http://www.gnu.org/software/emacs/#Obtaining + +;; Important warning: +;; +;; Going through this tutorial won't damage your computer unless +;; you get so angry that you throw it on the floor. In that case, +;; I hereby decline any responsability. Have fun! + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; ;; Fire up Emacs. ;; -;; Look at the gray line at the bottom of the window: +;; Hit the `q' key to dismiss the welcome message. +;; +;; Now look at the gray line at the bottom of the window: ;; ;; "*scratch*" is the name of the editing space you are now in. ;: This editing space is called a "buffer". @@ -33,12 +43,14 @@ filename: elisp.el ;; ;; "Lisp interaction" refers to a set of commands available here. ;; -;; This set of command is loaded on top of core Emacs commands. -;; For exemple, `save-buffer' is a core Emacs command to save a -;; buffer to its associated file, and `eval-defun' is a command -;; loaded from the `lisp-interaction-mode' you are now in. +;; Emacs has a built-in set of commands available in every buffer, +;; and several subsets of commands available when you activate a +;; specific mode. Here we use the `lisp-interaction-mode', which +;; comes with commands to evaluate and navigate within Elisp code. + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; -;; Semi-columns start comments anywhere on a line. +;; Semi-colons start comments anywhere on a line. ;; ;; Elisp programs are made of symbolic expressions ("sexps"): (+ 2 2) @@ -54,7 +66,7 @@ filename: elisp.el ;; From `lisp-interaction-mode' you can evaluate sexps. ;; Put the cursor right after the closing parenthesis then -;; hit the control and the j keys ("C-j" for short). +;; hold down the control and hit the j keys ("C-j" for short). (+ 3 (+ 1 2)) ;; ^ cursor here @@ -109,13 +121,17 @@ filename: elisp.el ;; Take a breath. +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;; ;; Now switch to a new buffer named "*test*" in another window: (switch-to-buffer-other-window "*test*") ;; `C-xC-e' ;: => [screen has two windows and cursor is in the *test* buffer] -;; Use the mouse to go back to the window where you code. +;; Mouse over the top window and left-click to go back. Or you can +;; use `C-xo' (i.e. hold down control-x and hit j) to go to the other +;; window interactively. ;; You can combine several sexps with `progn': (progn @@ -127,11 +143,13 @@ filename: elisp.el ;; Now if you don't mind, I'll stop asking you to hit `C-xC-e': do it ;; for every sexp that follows. +;; Always go back to the *scratch* buffer with the mouse or `C-xo'. + ;; It's often useful to erase the buffer: (progn (switch-to-buffer-other-window "*test*") (erase-buffer) - (hello "you")) + (hello "there")) ;; Or to go back to the other window: (progn @@ -166,9 +184,9 @@ filename: elisp.el (defun greeting (name) (let ((your-name "Bastien")) (insert (format "Hello %s!\n\nI'am %s." - name ; the argument of the function - your-name ; the let-bound variable "Roger" - )))) + name ; the argument of the function + your-name ; the let-bound variable "Bastien" + )))) ;; And evaluate it: (greeting "you") @@ -182,9 +200,9 @@ filename: elisp.el (defun greeting (from-name) (let ((your-name (read-from-minibuffer "Enter your name: "))) (insert (format "Hello!\n\I am %s and you are %s." - from-name ; the argument of the function - your-name ; the let-bound var, entered at prompt - )))) + from-name ; the argument of the function + your-name ; the let-bound var, entered at prompt + )))) (greeting "Bastien") @@ -201,8 +219,10 @@ filename: elisp.el ;; Take a breath. +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;; ;; Let's store a list of names: -(setq list-of-names '("Sarah" "Chloe")) +(setq list-of-names '("Sarah" "Chloe" "Mathilde")) ;; Get the first element of this list with `car': (car list-of-names) @@ -214,6 +234,8 @@ filename: elisp.el (push "Stephanie" list-of-names) ;; NOTE: `car' and `cdr' don't modify the list, but `push' does. +;; This is an important difference: some functions don't have any +;; side-effects (like `car') while others have (like `push'). ;; Let's call `hello' for each element in `list-of-names': (mapcar 'hello list-of-names) @@ -283,8 +305,8 @@ filename: elisp.el (goto-char (point-min)) (while (re-search-forward "Bonjour \\(.+\\)!" nil t) (add-text-properties (match-beginning 1) - (match-end 1) - (list 'face 'bold))) + (match-end 1) + (list 'face 'bold))) (other-window 1)) ;; This functions introduces `re-search-forward': instead of @@ -306,4 +328,21 @@ filename: elisp.el ;; OK, we are done. Happy hacking! +;; If you want to know more about a variable or a function: +;; +;; C-h v a-variable RET +;; C-h f a-function RET +;; +;; To read the Emacs Lisp manual with Emacs: +;; +;; C-h i m elisp RET +;; +;; To read an online introduction to Emacs Lisp: +;; https://www.gnu.org/software/emacs/manual/html_node/eintr/index.html + +;; Thanks to these people for their feedback and suggestions: +;; - Wes Hardaker +;; - notbob +;; - Kevin Montuori +;; - Arne Babenhauserheide ``` |