Search and Replace with incremented values in Vim

Question

Lets say I wrote a simple CSS rule like this:

.star_10 {   background: url(stars.png) no-repeat 0 0; } 

And I need 10, so I copied it 9 times.

.star_10 {   background: url(stars.png) no-repeat 0 0; } .star_10 {   background: url(stars.png) no-repeat 0 0; } .star_10 {   background: url(stars.png) no-repeat 0 0; } .star_10 {   background: url(stars.png) no-repeat 0 0; } .star_10 {   background: url(stars.png) no-repeat 0 0; } 

etc.

Now I want to change the star_10 and 0 0 with incremented values so it looks like this:

.star_10 {   background: url(stars.png) no-repeat 0 0; } .star_9 {   background: url(stars.png) no-repeat 0 -18px; } .star_8 {   background: url(stars.png) no-repeat 0 -36px; } .star_7 {   background: url(stars.png) no-repeat 0 -54px; } 

and so on...

So how can I search/replace every instance, do a calculation and write it?

Answer 1

You can do it easily with a macro. Lets say you have only this:

.star_10 {   background: url(stars.png) no-repeat 0 0; } 

Place your cursor over the first dot (in .star10) and type the following in normal mode:

qa3yy3jp^Xjt;18^Xk0q 

Explaining:

1. qa will start a macro recording in register "a".
2. 3yy will yank (copy) the following 3 lines.
3. 3j will place the cursor 3 lines down.
4. p will paste the past yanked text.
5. ^X (ctrl+x) will decrement the star class number.
6. j will place your cursor one line down.
7. t; will place your cursor before the next ; in the current line.
8. 18^X will decrement the y coordinate of backround by 18;
9. k will put the cursor one line up,
10. 0 will put the cursor at the beggining of the line.
11. q will finish the macro recording.

After that, you may have something like this.

.star_10 {   background: url(stars.png) no-repeat 0 0; }  .star_9 {   background: url(stars.png) no-repeat 0 -18; } 

That's it. Just place your cursor at the dot on .star_9 and press 8@a to execute the macro recorded in register a eight more times.

Answer 2

You can use the s/pattern/replace construct with the \= symbol in order to evaluate a function or expression, as shown:

Decrementing the .star_10:

let g:decr = 11  fu! Decr()    let g:decr = g:decr - 1   return g:decr endfu  :%s/.star_10/\=".star_" . Decr()/ 

Similarly, you'd do

let g:decr_18 = 18 fu! Decr18()    let g:decr_18 = g:decr_18 - 18   return g:decr_18 endfu 

and then replace the 0 0; with a

:%s/no-repeat 0 0;/\="no-repeat 0 " . Decr18() . "px"/ 

For both functions, a (global) variable is declared that is manipulated within the functions and returned. The functin itself is called for every line matching the pattern. the pattern is substituted with the expression following the \=.