;;; haml-mode.el --- Major mode for editing Haml files
;; Copyright (c) 2007, 2008 Nathan Weizenbaum
;; Author: Nathan Weizenbaum
;; URL: http://github.com/nex3/haml/tree/master
;; Version: 1.0
;; Keywords: markup, language
;;; Commentary:
;; Because Haml's indentation schema is similar
;; to that of YAML and Python, many indentation-related
;; functions are similar to those in yaml-mode and python-mode.
;; To install, save this on your load path and add the following to
;; your .emacs file:
;;
;; (require 'haml-mode)
;;; Code:
(eval-when-compile (require 'cl))
(require 'ruby-mode)
;; User definable variables
(defgroup haml nil
"Support for the Haml template language."
:group 'languages
:prefix "haml-")
(defcustom haml-mode-hook nil
"Hook run when entering Haml mode."
:type 'hook
:group 'haml)
(defcustom haml-indent-offset 2
"Amount of offset per level of indentation."
:type 'integer
:group 'haml)
(defcustom haml-backspace-backdents-nesting t
"Non-nil to have `haml-electric-backspace' re-indent all code
nested beneath the backspaced line be re-indented along with the
line itself."
:type 'boolean
:group 'haml)
(defface haml-tab-face
'((((class color)) (:background "hotpink"))
(t (:reverse-video t)))
"Face to use for highlighting tabs in Haml files."
:group 'faces
:group 'haml)
(defvar haml-indent-function 'haml-indent-p
"This function should look at the current line and return t
if the next line could be nested within this line.
The function can also return a positive integer to indicate
a specific level to which the current line could be indented.")
(defconst haml-tag-beg-re
"^ *\\(?:[%\\.#][a-z0-9_:\\-]*\\)+\\(?:(.*)\\|{.*}\\|\\[.*\\]\\)*"
"A regexp matching the beginning of a Haml tag, through (), {}, and [].")
(defvar haml-block-openers
`(,(concat haml-tag-beg-re "[><]*[ \t]*$")
"^ *[&!]?[-=~].*do[ \t]*\\(|.*|[ \t]*\\)?$"
,(concat "^ *[&!]?[-=~][ \t]*\\("
(regexp-opt '("if" "unless" "while" "until" "else"
"begin" "elsif" "rescue" "ensure" "when"))
"\\)")
"^ */\\(\\[.*\\]\\)?[ \t]*$"
"^ *-#"
"^ *:")
"A list of regexps that match lines of Haml that could have
text nested beneath them.")
;; Font lock
(defun haml-nested-regexp (re)
(concat "^\\( *\\)" re "\\(\n\\(?:\\(?:\\1 .*\\| *\\)\n\\)*\\(?:\\1 .*\\| *\\)?\\)?"))
(defconst haml-font-lock-keywords
`((,(haml-nested-regexp "\\(?:-#\\|/\\).*") 0 font-lock-comment-face)
(,(haml-nested-regexp ":\\w+") 0 font-lock-string-face)
(haml-highlight-interpolation 1 font-lock-variable-name-face prepend)
(haml-highlight-ruby-tag 1 font-lock-preprocessor-face)
(haml-highlight-ruby-script 1 font-lock-preprocessor-face)
("^ *\\(\t\\)" 1 'haml-tab-face)
("^!!!.*" 0 font-lock-constant-face)
("| *$" 0 font-lock-string-face)))
(defconst haml-filter-re "^ *:\\w+")
(defconst haml-comment-re "^ *\\(?:-\\#\\|/\\)")
(defun haml-fontify-region-as-ruby (beg end)
"Use Ruby's font-lock variables to fontify the region between BEG and END."
(save-excursion
(save-match-data
(let ((font-lock-keywords ruby-font-lock-keywords)
(font-lock-syntactic-keywords ruby-font-lock-syntactic-keywords)
font-lock-keywords-only
font-lock-extend-region-functions
font-lock-keywords-case-fold-search)
;; font-lock-fontify-region apparently isn't inclusive,
;; so we have to move the beginning back one char
(font-lock-fontify-region (- beg 1) end)))))
(defun haml-highlight-ruby-script (limit)
"Highlight a Ruby script expression (-, =, or ~)."
(when (re-search-forward "^ *\\(-\\|[&!]?[=~]\\) \\(.*\\)$" limit t)
(haml-fontify-region-as-ruby (match-beginning 2) (match-end 2))))
(defun haml-highlight-ruby-tag (limit)
"Highlight Ruby code within a Haml tag.
This highlights the tag attributes and object refs of the tag,
as well as the script expression (-, =, or ~) following the tag.
For example, this will highlight all of the following:
%p{:foo => 'bar'}
%p[@bar]
%p= 'baz'
%p{:foo => 'bar'}[@bar]= 'baz'"
(when (re-search-forward "^ *[%.#]" limit t)
(forward-char -1)
;; Highlight tag, classes, and ids
(while (haml-move "\\([.#%]\\)[a-z0-9_:\\-]*")
(put-text-property (match-beginning 0) (match-end 0) 'face
(case (char-after (match-beginning 1))
(?% font-lock-function-name-face)
(?# font-lock-keyword-face)
(?. font-lock-type-face))))
(block loop
(while t
(let ((eol (save-excursion (end-of-line) (point))))
(case (char-after)
;; Highlight obj refs
(?\[
(let ((beg (point)))
(haml-limited-forward-sexp eol)
(haml-fontify-region-as-ruby beg (point))))
;; Highlight new attr hashes
(?\(
(forward-char 1)
(while
(and (haml-parse-new-attr-hash
(lambda (type beg end)
(case type
(name (put-text-property beg end 'face font-lock-constant-face))
(value (haml-fontify-region-as-ruby beg end)))))
(not (eobp)))
(forward-line 1)
(beginning-of-line)))
;; Highlight old attr hashes
(?\{
(let ((beg (point)))
(haml-limited-forward-sexp eol)
;; Check for multiline
(while (and (eolp) (eq (char-before) ?,) (not (eobp)))
(forward-line)
(let ((eol (save-excursion (end-of-line) (point))))
;; If no sexps are closed,
;; we're still continuing a multiline hash
(if (>= (car (parse-partial-sexp (point) eol)) 0)
(end-of-line)
;; If sexps have been closed,
;; set the point at the end of the total sexp
(goto-char beg)
(haml-limited-forward-sexp eol))))
(haml-fontify-region-as-ruby (+ 1 beg) (point))))
(t (return-from loop))))))
;; Move past end chars
(when (looking-at "[<>&!]+") (goto-char (match-end 0)))
;; Highlight script
(if (looking-at "\\([=~]\\) \\(.*\\)$")
(haml-fontify-region-as-ruby (match-beginning 2) (match-end 2))
;; Give font-lock something to highlight
(forward-char -1)
(looking-at "\\(\\)"))
t))
(defun haml-move (re)
"Try matching and moving to the end of a regular expression."
(when (looking-at re)
(goto-char (match-end 0))
t))
(defun haml-highlight-interpolation (limit)
"Highlight Ruby interpolation (#{foo})."
(when (re-search-forward "\\(#{\\)" limit t)
(save-match-data
(forward-char -1)
(let ((beg (point)))
(haml-limited-forward-sexp limit)
(haml-fontify-region-as-ruby (+ 1 beg) (point)))
(when (eq (char-before) ?})
(put-text-property (- (point) 1) (point)
'face font-lock-variable-name-face))
t)))
(defun haml-limited-forward-sexp (limit &optional arg)
"Move forward using `forward-sexp' or to limit,
whichever comes first."
(let (forward-sexp-function)
(condition-case err
(save-restriction
(narrow-to-region (point) limit)
(forward-sexp arg))
(scan-error
(unless (equal (nth 1 err) "Unbalanced parentheses")
(signal 'scan-error (cdr err)))
(goto-char limit)))))
(defun* haml-extend-region-filters-comments ()
"Extend the font-lock region to encompass filters and comments."
(let ((old-beg font-lock-beg)
(old-end font-lock-end))
(save-excursion
(goto-char font-lock-beg)
(beginning-of-line)
(unless (or (looking-at haml-filter-re)
(looking-at haml-comment-re))
(return-from haml-extend-region-filters-comments))
(setq font-lock-beg (point))
(haml-forward-sexp)
(beginning-of-line)
(setq font-lock-end (max font-lock-end (point))))
(or (/= old-beg font-lock-beg)
(/= old-end font-lock-end))))
(defun* haml-extend-region-multiline-hashes ()
"Extend the font-lock region to encompass multiline attribute hashes."
(let ((old-beg font-lock-beg)
(old-end font-lock-end))
(save-excursion
(goto-char font-lock-beg)
(let ((attr-props (haml-parse-multiline-attr-hash))
multiline-end)
(when attr-props
(setq font-lock-beg (cdr (assq 'point attr-props)))
(end-of-line)
;; Move through multiline attrs
(when (eq (char-before) ?,)
(save-excursion
(while (progn (end-of-line) (eq (char-before) ?,) (not (eobp)))
(forward-line))
(forward-line -1)
(end-of-line)
(setq multiline-end (point))))
(goto-char (+ (cdr (assq 'point attr-props))
(cdr (assq 'hash-indent attr-props))
-1))
(haml-limited-forward-sexp
(or multiline-end
(save-excursion (end-of-line) (point))))
(setq font-lock-end (max font-lock-end (point))))))
(or (/= old-beg font-lock-beg)
(/= old-end font-lock-end))))
;; Mode setup
(defvar haml-mode-syntax-table
(let ((table (make-syntax-table)))
(modify-syntax-entry ?: "." table)
(modify-syntax-entry ?_ "w" table)
table)
"Syntax table in use in haml-mode buffers.")
(defvar haml-mode-map
(let ((map (make-sparse-keymap)))
(define-key map [backspace] 'haml-electric-backspace)
(define-key map "\C-?" 'haml-electric-backspace)
(define-key map "\C-c\C-f" 'haml-forward-sexp)
(define-key map "\C-c\C-b" 'haml-backward-sexp)
(define-key map "\C-c\C-u" 'haml-up-list)
(define-key map "\C-c\C-d" 'haml-down-list)
(define-key map "\C-c\C-k" 'haml-kill-line-and-indent)
(define-key map "\C-c\C-r" 'haml-output-region)
(define-key map "\C-c\C-l" 'haml-output-buffer)
map))
;;;###autoload
(define-derived-mode haml-mode fundamental-mode "Haml"
"Major mode for editing Haml files.
\\{haml-mode-map}"
(set-syntax-table haml-mode-syntax-table)
(add-to-list 'font-lock-extend-region-functions 'haml-extend-region-filters-comments)
(add-to-list 'font-lock-extend-region-functions 'haml-extend-region-multiline-hashes)
(set (make-local-variable 'font-lock-multiline) t)
(set (make-local-variable 'indent-line-function) 'haml-indent-line)
(set (make-local-variable 'indent-region-function) 'haml-indent-region)
(set (make-local-variable 'parse-sexp-lookup-properties) t)
(setq comment-start "-#")
(setq indent-tabs-mode nil)
(setq font-lock-defaults '((haml-font-lock-keywords) t t)))
;; Useful functions
(defun haml-comment-block ()
"Comment the current block of Haml code."
(interactive)
(save-excursion
(let ((indent (current-indentation)))
(back-to-indentation)
(insert "-#")
(newline)
(indent-to indent)
(beginning-of-line)
(haml-mark-sexp)
(haml-reindent-region-by haml-indent-offset))))
(defun haml-uncomment-block ()
"Uncomment the current block of Haml code."
(interactive)
(save-excursion
(beginning-of-line)
(while (not (looking-at haml-comment-re))
(haml-up-list)
(beginning-of-line))
(haml-mark-sexp)
(kill-line 1)
(haml-reindent-region-by (- haml-indent-offset))))
(defun haml-replace-region (start end)
"Replaces the current block of Haml code with the HTML equivalent."
(interactive "r")
(save-excursion
(goto-char end)
(setq end (point-marker))
(goto-char start)
(let ((ci (current-indentation)))
(while (re-search-forward "^ +" end t)
(replace-match (make-string (- (current-indentation) ci) ? ))))
(shell-command-on-region start end "haml" "haml-output" t)))
(defun haml-output-region (start end)
"Displays the HTML output for the current block of Haml code."
(interactive "r")
(kill-new (buffer-substring start end))
(with-temp-buffer
(yank)
(haml-indent-region (point-min) (point-max))
(shell-command-on-region (point-min) (point-max) "haml" "haml-output")))
(defun haml-output-buffer ()
"Displays the HTML output for entire buffer."
(interactive)
(haml-output-region (point-min) (point-max)))
;; Navigation
(defun haml-forward-through-whitespace (&optional backward)
"Move the point forward at least one line, until it reaches
either the end of the buffer or a line with no whitespace.
If `backward' is non-nil, move the point backward instead."
(let ((arg (if backward -1 1))
(endp (if backward 'bobp 'eobp)))
(loop do (forward-line arg)
while (and (not (funcall endp))
(looking-at "^[ \t]*$")))))
(defun haml-at-indent-p ()
"Returns whether or not the point is at the first
non-whitespace character in a line or whitespace preceding that
character."
(let ((opoint (point)))
(save-excursion
(back-to-indentation)
(>= (point) opoint))))
(defun haml-forward-sexp (&optional arg)
"Move forward across one nested expression.
With `arg', do it that many times. Negative arg -N means move
backward across N balanced expressions.
A sexp in Haml is defined as a line of Haml code as well as any
lines nested beneath it."
(interactive "p")
(or arg (setq arg 1))
(if (and (< arg 0) (not (haml-at-indent-p)))
(back-to-indentation)
(while (/= arg 0)
(let ((indent (current-indentation)))
(loop do (haml-forward-through-whitespace (< arg 0))
while (and (not (eobp))
(not (bobp))
(> (current-indentation) indent)))
(back-to-indentation)
(setq arg (+ arg (if (> arg 0) -1 1)))))))
(defun haml-backward-sexp (&optional arg)
"Move backward across one nested expression.
With ARG, do it that many times. Negative arg -N means move
forward across N balanced expressions.
A sexp in Haml is defined as a line of Haml code as well as any
lines nested beneath it."
(interactive "p")
(haml-forward-sexp (if arg (- arg) -1)))
(defun haml-up-list (&optional arg)
"Move out of one level of nesting.
With ARG, do this that many times."
(interactive "p")
(or arg (setq arg 1))
(while (> arg 0)
(let ((indent (current-indentation)))
(loop do (haml-forward-through-whitespace t)
while (and (not (bobp))
(>= (current-indentation) indent)))
(setq arg (- arg 1))))
(back-to-indentation))
(defun haml-down-list (&optional arg)
"Move down one level of nesting.
With ARG, do this that many times."
(interactive "p")
(or arg (setq arg 1))
(while (> arg 0)
(let ((indent (current-indentation)))
(haml-forward-through-whitespace)
(when (<= (current-indentation) indent)
(haml-forward-through-whitespace t)
(back-to-indentation)
(error "Nothing is nested beneath this line"))
(setq arg (- arg 1))))
(back-to-indentation))
(defun haml-mark-sexp ()
"Marks the next Haml block."
(let ((forward-sexp-function 'haml-forward-sexp))
(mark-sexp)))
(defun haml-mark-sexp-but-not-next-line ()
"Marks the next Haml block, but puts the mark at the end of the
last line of the sexp rather than the first non-whitespace
character of the next line."
(haml-mark-sexp)
(set-mark
(save-excursion
(goto-char (mark))
(forward-line -1)
(end-of-line)
(point))))
;; Indentation and electric keys
(defun* haml-indent-p ()
"Returns t if the current line can have lines nested beneath it."
(let ((attr-props (haml-parse-multiline-attr-hash)))
(when attr-props
(return-from haml-indent-p
(if (haml-unclosed-attr-hash-p) (cdr (assq 'hash-indent attr-props))
(list (+ (cdr (assq 'indent attr-props)) haml-indent-offset) nil)))))
(loop for opener in haml-block-openers
if (looking-at opener) return t
finally return nil))
(defun* haml-parse-multiline-attr-hash ()
"Parses a multiline attribute hash, and returns
an alist with the following keys:
INDENT is the indentation of the line beginning the hash.
HASH-INDENT is the indentation of the first character
within the attribute hash.
POINT is the character position at the beginning of the line
beginning the hash."
(save-excursion
(while t
(beginning-of-line)
(if (looking-at (eval-when-compile (concat haml-tag-beg-re "\\([{(]\\)")))
(progn
(goto-char (- (match-end 0) 1))
(haml-limited-forward-sexp (save-excursion (end-of-line) (point)))
(return-from haml-parse-multiline-attr-hash
(when (or (string-equal (match-string 1) "(") (eq (char-before) ?,))
`((indent . ,(current-indentation))
(hash-indent . ,(- (match-end 0) (match-beginning 0)))
(point . ,(match-beginning 0))))))
(when (bobp) (return-from haml-parse-multiline-attr-hash))
(forward-line -1)
(unless (haml-unclosed-attr-hash-p)
(return-from haml-parse-multiline-attr-hash))))))
(defun* haml-unclosed-attr-hash-p ()
"Return t if this line has an unclosed attribute hash, new or old."
(save-excursion
(end-of-line)
(when (eq (char-before) ?,) (return-from haml-unclosed-attr-hash-p t))
(re-search-backward "(\\|^")
(haml-move "(")
(haml-parse-new-attr-hash)))
(defun* haml-parse-new-attr-hash (&optional (fn (lambda (type beg end) ())))
"Parse a new-style attribute hash on this line, and returns
t if it's not finished on the current line.
FN should take three parameters: TYPE, BEG, and END.
TYPE is the type of text parsed ('name or 'value)
and BEG and END delimit that text in the buffer."
(let ((eol (save-excursion (end-of-line) (point))))
(while (not (haml-move ")"))
(haml-move " *")
(unless (haml-move "[a-z0-9_:\\-]+")
(return-from haml-parse-new-attr-hash (haml-move " *$")))
(funcall fn 'name (match-beginning 0) (match-end 0))
(haml-move " *")
(when (haml-move "=")
(haml-move " *")
(unless (looking-at "[\"'@a-z]") (return-from haml-parse-new-attr-hash))
(let ((beg (point)))
(haml-limited-forward-sexp eol)
(funcall fn 'value beg (point)))
(haml-move " *")))
nil))
(defun haml-compute-indentation ()
"Calculate the maximum sensible indentation for the current line."
(save-excursion
(beginning-of-line)
(if (bobp) (list 0 nil)
(haml-forward-through-whitespace t)
(let ((indent (funcall haml-indent-function)))
(cond
((consp indent) indent)
((integerp indent) (list indent t))
(indent (list (+ (current-indentation) haml-indent-offset) nil))
(t (list (current-indentation) nil)))))))
(defun haml-indent-region (start end)
"Indent each nonblank line in the region.
This is done by indenting the first line based on
`haml-compute-indentation' and preserving the relative
indentation of the rest of the region.
If this command is used multiple times in a row, it will cycle
between possible indentations."
(save-excursion
(goto-char end)
(setq end (point-marker))
(goto-char start)
(let (this-line-column current-column
(next-line-column
(if (and (equal last-command this-command) (/= (current-indentation) 0))
(* (/ (- (current-indentation) 1) haml-indent-offset) haml-indent-offset)
(car (haml-compute-indentation)))))
(while (< (point) end)
(setq this-line-column next-line-column
current-column (current-indentation))
;; Delete whitespace chars at beginning of line
(delete-horizontal-space)
(unless (eolp)
(setq next-line-column (save-excursion
(loop do (forward-line 1)
while (and (not (eobp)) (looking-at "^[ \t]*$")))
(+ this-line-column
(- (current-indentation) current-column))))
;; Don't indent an empty line
(unless (eolp) (indent-to this-line-column)))
(forward-line 1)))
(move-marker end nil)))
(defun haml-indent-line ()
"Indent the current line.
The first time this command is used, the line will be indented to the
maximum sensible indentation. Each immediately subsequent usage will
back-dent the line by `haml-indent-offset' spaces. On reaching column
0, it will cycle back to the maximum sensible indentation."
(interactive "*")
(let ((ci (current-indentation))
(cc (current-column)))
(destructuring-bind (need strict) (haml-compute-indentation)
(save-excursion
(beginning-of-line)
(delete-horizontal-space)
(if (and (not strict) (equal last-command this-command) (/= ci 0))
(indent-to (* (/ (- ci 1) haml-indent-offset) haml-indent-offset))
(indent-to need))))
(when (< (current-column) (current-indentation))
(forward-to-indentation 0))))
(defun haml-reindent-region-by (n)
"Add N spaces to the beginning of each line in the region.
If N is negative, will remove the spaces instead. Assumes all
lines in the region have indentation >= that of the first line."
(let ((ci (current-indentation)))
(save-excursion
(while (re-search-forward (concat "^" (make-string ci ?\s)) (mark) t)
(replace-match (make-string (max 0 (+ ci n)) ?\s))))))
(defun haml-electric-backspace (arg)
"Delete characters or back-dent the current line.
If invoked following only whitespace on a line, will back-dent
the line and all nested lines to the immediately previous
multiple of `haml-indent-offset' spaces.
Set `haml-backspace-backdents-nesting' to nil to just back-dent
the current line."
(interactive "*p")
(if (or (/= (current-indentation) (current-column))
(bolp)
(looking-at "^[ \t]+$"))
(backward-delete-char arg)
(save-excursion
(let ((ci (current-column)))
(beginning-of-line)
(if haml-backspace-backdents-nesting
(haml-mark-sexp-but-not-next-line)
(set-mark (save-excursion (end-of-line) (point))))
(haml-reindent-region-by (* (- arg) haml-indent-offset))
(back-to-indentation)
(pop-mark)))))
(defun haml-kill-line-and-indent ()
"Kill the current line, and re-indent all lines nested beneath it."
(interactive)
(beginning-of-line)
(haml-mark-sexp-but-not-next-line)
(kill-line 1)
(haml-reindent-region-by (* -1 haml-indent-offset)))
(defun haml-indent-string ()
"Return the indentation string for `haml-indent-offset'."
(mapconcat 'identity (make-list haml-indent-offset " ") ""))
;;;###autoload
(add-to-list 'auto-mode-alist '("\\.haml$" . haml-mode))
;; Setup/Activation
(provide 'haml-mode)
;;; haml-mode.el ends here