Книга: Learning GNU Emacs, 3rd Edition

12.13.3 Making Changes

12.13.3 Making Changes

In addition to simply viewing the differences between files, you will sometimes want to resolve or merge them (especially if you've entered Ediff as the result of conflicts that occurred while checking in a file revision). Several commands help with this, and they generally require you to choose which buffer you want to work from. As you might have noticed in Figure 12-5, Ediff assigns each file or revision buffer a letter to identify it: A, B and sometimes C if you are comparing three things. A number of Ediff commands work with these buffer identifiers—the letter X is used to stand for these labels in the quick help window for most commands that use them.

To copy the version of the current difference found in one buffer to the other buffer, type the letter assigned to the buffer with the "right" version. For example, to copy A's version to B, type a. Ediff makes this change but keeps track of the old value in the buffer you changed. Following along in our example, if after changing buffer B like this, you change your mind and want to restore its old state, you can type r b (for "restore buffer B"). These changes are kept track of on a difference-by-difference basis, so you don't have to change your mind right away; you can jump back to that difference and restore it at a later time, as long as you're still in the same Ediff session.

Of course, to make changes to a buffer, it cannot be in read-only mode. If you are comparing a current file with a historical revision, the buffer representing the older version is read-only because you can't change the past. If you want to avoid accidentally changing a file while browsing differences, you can cause its buffer to become read-only by typing Shift and the buffer's letter label. (Shift-b to make buffer B read-only). This is a toggle, so doing it again makes a read-only buffer editable. If you do this to a buffer representing a historical revision, although Emacs will then let you edit the buffer, you're not actually affecting the revision within the version control system. So unless you're trying to confuse yourself, we'd suggest avoiding this practice.

If you're whipping through the buffers, making many changes by selecting appropriate versions to use within the Ediff control window, you may find yourself wanting to save one or the other of your difference buffers. While you can certainly click over to the difference window, move into that buffer, and use the standard C-s command to save, Ediff offers a more convenient alternative. Simply press w (write) followed by the buffer's letter label to save that buffer without leaving the control window.

Оглавление книги