用于 R 注释的正则表达式 Emacs

Question

我想在 Emacs 中构建一个正则表达式来清理我的 R 代码。

我遇到的问题之一是存在不同类型的评论: 您有一定数量的空白 (1)，例如:

        # This is a comment:
# This is also a comment

或者你遇到这样的情况(2):

require(lattice) # executable while the comment is informative

这个想法是，当注释属于第二种时(在可执行的内容之后)，我想对齐注释，同时排除第一种注释。

理想情况下，它会将所有评论与第一种评论对齐，但不与第一种评论对齐。

示例:

funfun <- function(a, b) {
# This is a function
    if (a == b) { # if a equals b
      c <- 1 # c is 1 
    }
  }  
#

致:

funfun <- function(a, b) {
# This is a function
    if (a == b) { # if a equals b
      c <- 1      # c is 1 
    }
  }  
# 

我找到了一个正则表达式来替换第一种，所以我能够按段落(标记段落)对齐它们。这效果很好。

问题就出在反向替换上:

(replace-regexp "^\\s-+#+" "bla" nil (point-min) (point-max))

这将从行的开头替换为任意数量的空格和任意数量的注释字符，例如:

     #########   

进入

     bla

问题是我想将它们替换回原来的样子，所以“bla”必须返回到相同数量的空格和相同数量的#。

希望有人理解我正在尝试做的事情，并且对方法有更好的想法或知道如何解决此正则表达式部分。

Answer 1

嗯，这是一些疯狂的尝试，想做一些我认为你想做的事情。它似乎有效，但需要大量的测试和完善:

(defun has-face-at-point (face &optional position)
  (unless position (setq position (point)))
  (unless (consp face) (setq face (list face)))
  (let ((props (text-properties-at position)))
    (loop for (key value) on props by #'cddr
          do (when (and (eql key 'face) (member value face))
               (return t)))))

(defun face-start (face)
  (save-excursion
    (while (and (has-face-at-point face) (not (bolp)))
      (backward-char))
    (- (point) (save-excursion (move-beginning-of-line 1)) (if  (bolp) 0 -1))))

(defun beautify-side-comments ()
  (interactive)
  ;; Because this function does a lot of insertion, it would
  ;; be better to execute it in the temporary buffer, while
  ;; copying the original text of the file into it, such as
  ;; to prevent junk in the formatted buffer's history
  (let ((pos (cons (save-excursion
                     (beginning-of-line)
                     (count-lines (point-min) (point)))
                   (- (save-excursion (end-of-line) (point)) (point))))
        (content (buffer-string))
        (comments '(font-lock-comment-face font-lock-comment-delimiter-face)))
    (with-temp-buffer
      (insert content)
      (goto-char (point-min))
      ;; thingatpt breaks if there are overlays with their own faces
      (let* ((commentp (has-face-at-point comments))
             (margin
              (if commentp (face-start comments) 0))
             assumed-margin pre-comment commented-lines)
        (while (not (eobp))
          (move-end-of-line 1)
          (cond
           ((and (has-face-at-point comments)
                 commentp)            ; this is a comment continued from
                                        ; the previous line
            (setq assumed-margin (face-start comments)
                  pre-comment
                  (buffer-substring-no-properties
                   (save-excursion (move-beginning-of-line 1))
                   (save-excursion (beginning-of-line) 
                                   (forward-char assumed-margin) (point))))
            (if (every
                 (lambda (c) (or (char-equal c ?\ ) (char-equal c ?\t)))
                 pre-comment)
                ;; This is the comment preceded by whitespace
                (setq commentp nil margin 0 commented-lines 0)
              (if (<= assumed-margin margin)
                  ;; The comment found starts on the left of
                  ;; the margin of the comments found so far
                  (save-excursion
                    (beginning-of-line) 
                    (forward-char assumed-margin)
                    (insert (make-string (- margin assumed-margin) ?\ ))
                    (incf commented-lines))
                ;; This could be optimized by going forward and
                ;; collecting as many comments there are, but
                ;; it is simpler to return and re-indent comments
                ;; (assuming there won't be many such cases anyway.
                (setq margin assumed-margin)
                (move-end-of-line (1- (- commented-lines))))))
           ((has-face-at-point comments)
            ;; This is the fresh comment
            ;; This entire block needs refactoring, it is
            ;; a repetition of the half the previous blockp
            (setq assumed-margin (face-start comments)
                  pre-comment
                  (buffer-substring-no-properties
                   (save-excursion (move-beginning-of-line 1))
                   (save-excursion (beginning-of-line) 
                                   (forward-char assumed-margin) (point))))
            (unless (every
                     (lambda (c)
                       (or (char-equal c ?\ ) (char-equal c ?\t)))
                     pre-comment)
              (setq commentp t margin assumed-margin commented-lines 0)))
           (commentp
            ;; This is the line directly after a block of comments
            (setq commentp nil margin assumed-margin commented-lines 0)))
          (unless (eobp) (forward-char)))
        ;; Retrieve back the formatted contnent
        (setq content (buffer-string))))
    (erase-buffer)
    (insert content)
    (beginning-of-buffer)
    (forward-line (car pos))
    (end-of-line)
    (backward-char (cdr pos))))

我还在pastebin上复制了它以提高可读性:http://pastebin.com/C2L9PRDM

编辑:这应该恢复鼠标位置，但不会恢复滚动位置(也许可以，我只需要查找滚动的存储方式)。