emacs - 如何折叠区域中的空格？

Question

假设我有这个表格文本文件:

field1        variable_length_field    variable_length_field
aaaaaa        aaaa                     aaaaaaaaa
bbbbbb        bbbbbbbbbbbbbbbbbbbb     bbbb

我怎样才能将它转换为:

field1 variable_length_field variable_length_field
aaaaaa aaaa aaaaaaaaa
bbbbbb bbbbbbbbbbbbbbbbbbbb bbbb

我知道我可以使用 replace-regexp在该地区，但 Emacs 正则表达式不是自然而然的。我正在寻找类似 delete-whitespace-rectangle 的东西，但这并没有达到我的预期，或者我正在滥用它。具有按列执行此操作的能力也是可取的，即:

field1        variable_length_field variable_length_field
aaaaaa        aaaa aaaaaaaaa
bbbbbb        bbbbbbbbbbbbbbbbbbbb bbbb

Answer 1

这个函数应该可以解决问题:

(defun just-one-space-in-region (beg end)
  "replace all whitespace in the region with single spaces"
  (interactive "r")
  (save-excursion
    (save-restriction
      (narrow-to-region beg end)
      (goto-char (point-min))
      (while (re-search-forward "\\s-+" nil t)
        (replace-match " ")))))

而且，由于问题已更新以适用于矩形中的空间，请尝试以下操作:

(require 'rect)  
(defun just-one-space-in-rect-line (start end)
  (save-restriction
    (save-match-data
      (narrow-to-region (+ (point) start)
                        (+ (point) end))
      (while (re-search-forward "\\s-+" nil t)
        (replace-match " ")))))
(defun just-one-space-in-rect (start end)
  "replace all whitespace in the rectangle with single spaces"
  (interactive "r")
  (apply-on-rectangle 'just-one-space-in-rect-line start end))