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@skeeto skeeto/
Last active Nov 18, 2015

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Show java.awt.Color colors in java-mode.
;;; java-color-mode.el --- show java.awt.Color colors live in the buffer
;; This is free and unencumbered software released into the public domain.
;;; Commentary:
;; Requires Emacs 24.3 are higher.
;;; Code:
(require 'cl-lib)
(defvar java-color-regexp
(let* ((num "\\(\\(?:0x\\)?[0-9a-f]+\\)")
(args (format "(\\s *%s\\s *,\\s *%s\\s *,\\s *%s\\s *)" num num num)))
(concat "new\\s \\(?:java\\.awt\\.\\)?Color\\s *" args))
"Regexp matching java.awt.Color expressions.")
(defvar-local java-color-overlays ()
"List of java-color-mode overlays in the current buffer.")
(defun java-color-make-overlays ()
"Put a color overlay over every java.awt.Color."
(setf (point) (point-min))
(while (search-forward-regexp java-color-regexp nil t)
(let* ((beg (match-beginning 0))
(end (match-end 0))
(overlay (make-overlay beg end)))
(push overlay java-color-overlays)
(cl-loop for i from 1 to 3
for match = (match-string i)
for value = (read (replace-regexp-in-string "0x" "#x" match))
collect (format "%02x" value) into values
finally (let ((color (apply #'concat "#" values)))
(overlay-put overlay
'face `((:background ,color)))))))))
(defun java-color-clear-overlays ()
"Remove all java-color-mode overlays in the buffer."
(while java-color-overlays
(delete-overlay (pop java-color-overlays))))
(defun java-color-function (&optional _pos _beg _end)
"Function to run after every change."
(define-minor-mode java-color-mode
"Show java.awt.Color colors right in the buffer."
:lighter " jcolor"
(if java-color-mode
(add-hook 'after-change-functions #'java-color-function nil t)
(remove-hook 'after-change-functions #'java-color-function t)))
(provide 'java-color-mode)
;;; java-color-mode.el ends here
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