jack is a HTML generator library for Emacs Lisp.

To install it put jack.el file in your load path and require jack like this:

(require 'jack)

jack provides the function jack-html that takes a data structure as input representing the HTML tree you want to generate and generates it as a string.

For instance:

(jack-html '(:section (:div (:p "foo"))))
;; "<section><div><p>foo</p></div></section>"

HTML attributes are specified in a list starting by the @ sign

(jack-html '(:div (@ :id "id" :class "class" :style "color:red;") "foo"))
;; "<div id=\"id\" class=\"class\" style=\"color:red;\">foo</div>"

In the keyword defining the HTML tag you can use / to declare its id and . to declare its classes like this:

(jack-html '(:div/id.class-1.class-2
             (@ :class "class-3" :style "color:red;")
             "foo"))
;; "<div id=\"id\" class=\"class-1 class-2 class-3\" style=\"color:red;\">foo</div>"

Note that I would have prefered to use # for declaring the id but it has to be escaped in keywords which is ugly.

Tag content can be lists of components:

(jack-html '(:ul ((:li "1") (:li "2"))))
;; "<ul><li>1</li><li>2</li></ul>"

(jack-html '(:ul (@ :id "id") ((:li "1") (:li "2"))))
;; "<ul id=\"id\"><li>1</li><li>2</li></ul>"

Components can be generated by a forms:

(jack-html `(:p ,(concat "foo-" "bar")))
;; "<p>foo-bar</p>"

(jack-html (mapcar (lambda (n) `(:p ,n)) '(1 2 3)))
;; "<p>1</p><p>2</p><p>3</p>"

Tag content can be forms:

(jack-html `(:ul ,(mapcar (lambda (n) `(:li ,n)) '(1 2))))
;; "<ul><li>1</li><li>2</li></ul>"

(jack-html `(:ul (@ :id "id")
             ,(mapcar (lambda (n) `(:li ,n)) '(1 2))))
;; "<ul id=\"id\"><li>1</li><li>2</li></ul>"

Tag content and attributes can be variables:

(let ((x "foo") (y "bar"))
  (jack-html `(:p (@ :id ,x) ,y)))
;; "<p id=\"foo\">bar</p>"

(jack-html
 (let ((x "foo") (y "bar"))
   `(:p (@ :id ,x) ,y)))
;; "<p id=\"foo\">bar</p>"

If the variable jack-html-raise-error-p is set to nil, which is the default value, jack-html processes non component object as the empty string.

Let’s consider the case of the vector like [a b c] that is not a component for jack-html.

We have

(let ((jack-html-raise-error-p nil))
  (jack-html "foo" [a b c] "bar"))
;; "foobar"

and,

(let ((jack-html-raise-error-p t))
  (jack-html "foo" [a b c] "bar"))

which raises the error:

Object '[a b c]' of type 'vector' can't be a component in 'jack-html'