VimCasts.org

In the previous lesson, we replaced both occurrences of obstacleToBeRemoved with the word collection using Visual mode:

collection = getCollection();
process(obstacleToBeRemoved, target);
apply(obstacleToBeRemoved, target);

Here’s another way of doing it. Once again, we’ll start by yanking the word collection (yiw). That sets the contents of the default and yank registers:

:reg "0
"" collection
"0 collection

[search: /obst]

Now let’s use the ciw “sea-eye-doubleyou” command to delete the obstacleToBeRemoved and switch to Insert mode. From Insert mode we can insert the contents of the yank register by pressing <C-r>0 “control-are-zero”. We’re done with Insert mode now, so I’ll press escape to return to Normal mode.

The beauty of this approach is that we can jump to the next match with n, then repeat the last change with the dot command.

If we take a look at our registers:

:reg "0
"" obstacleToBeRemoved
"0 collection

The yank register still contains the text that we yanked, but the default register contains the text that we removed using the ciw command. That’s because the change command copies text into the default register before removing it from the document.

We used <C-r>0 “control-are-zero” to paste the contents of the yank register from insert mode.

:h i_ctrl-r

We could use the same technique to paste the contents from any register. Vim’s documentation for this command includes a handy summary of registers.

---

The same command works just as well at Vim’s command line. For example, suppose that want to try out this mapping from a vimrc file. I’ll just yank that line, then press colon to dial up the command line. Now I can put the text from the yank register by pressing <C-r>0. Presto!

---

The <C-r> command has a surprising limitation. To demonstrate, I’m going to attempt to solve the Vimgolf challenge Words in parens, which requires me to wrap each of these words in parens:

one two
three

Remember: this is Vimgolf, so we can’t use the surround plugin!

Let’s see if we can solve this using the dot command. I’ll use cw to delete the first word and switch to insert mode. Then I’ll type an opening paren, use <C-r>" “control-are-doublequote” to paste the default register, then type the closing paren and leave Insert mode. That looks ok, but watch this. I’ll jump to the next word, and when I use the dot command, it reproduces the result of the last insertion. That’s disappointing!

[undo the changes]

Let’s try again, but this time we’ll use a variation of the “control-r” command “control-are-control-oh”:

:h i_ctrl-r_ctrl-o

This one inserts the contents of the register, LITERALLY! Let’s try using this command, while keeping everything else the same as before.

Now when I use the dot command, it uses the current value of the default register, producing a more dynamic result. That’s good to know about!