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31.7 Maps for Repeated Edits

[Another way to do this is with @-functions (31.4). -JP]

Not every keymap is something you want to save in your .exrc file. Some maps are handy just because you have to do a repetitive series of edits. Developing a complex map to repeat your edits can save more time than it takes. For example, assume that you have a glossary with entries like this:

map - an ex command which allows you to associate 
a complex command sequence with a single key.

You want to convert this glossary list to nroff (43.13) format, so that it looks like:

.IP "map" 10n
An ex command which allows you to associate
a complex command sequence with a single key.

The best way to define a complex map is to do the edit once manually, writing down each keystroke that you must type. Then re-create these keystrokes as a map. You want to:

  1. Insert the ms macro for an indented paragraph (.IP) at the beginning of the line. Insert the first quotation mark as well (I.IP <">).

  2. Press ESC to terminate text-input mode.

  3. Move to the end of the first word (e) and add a second quotation mark, followed by a space and the size of the indent (a<"> 10n).

  4. Press RETURN to insert a new line.

  5. Press ESC to terminate text-input mode.

  6. Remove the hyphen and two surrounding spaces (3x) and capitalize the next word (~).

That's quite an editing chore if you have to repeat it more than a few times. With map you can save the entire sequence so that it can be re-executed with a single keystroke:

map g I.IP "^[ea" 10n^M^[3x~

(To set that option during a vi session, type a colon (:) first.) Note that you have to "quote" both the ESC and RETURN characters with CTRL-v (31.6). ^[ is the sequence that appears when you type [CTRL-v] followed by [ESC] ^M is the sequence shown when you type [CTRL-v] [RETURN].

Now, simply typing g will perform the entire series of edits. At a slow data rate you can actually see the edits happening individually. At a fast data rate it will seem to happen by magic.

Don't be discouraged if your first attempt at keymapping fails. A small error in defining the map can give very different results from the ones you expect. Type u to undo the edit, and try again.

[I like to write a keymap in a temporary file and edit it there until I get it right. For instance, I write my buffer and type :e temp.so to open the temporary file temp.so. I make the keymaps, one per line - without a colon (:) first. I write this map file (:w), then read it in to the editor (:so  % (30.4)). If I don't get an error, I switch to the original file (:e  # (30.4)) and try the map. Then I usually go back to the map file (:e#) again, fix the mistake :-), and repeat the process until I get what I wanted. -JP ]

- TOR from O'Reilly & Associates' Learning the vi Editor, Chapter 7


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