Apply a command to each occurrence of a pattern in a range

Question

I have 'a and 'b bounding some lines of text. I want to convert all the w, h, n, and m variables to upper case. A sample line:

f(w,h,n,m) | w <= 0 | h <= 0 | n < 0 | m < 0 = 0

It seems to me that this should work:

:'a,'b g/\<[whnm]\>/normal ~

This doesn't work. It matches the line, but does not match the individual variables. It leaves the cursor at the beginning of the line and capitalizes the f there. How do I make it perform the ~ action at every match in the range?

I know this particular example can be done simply with a regex substitution. I don't want to do that. I want to run an arbitrary command at every location that matches a search pattern, which seems like something obvious to do, but so far appears impossible to do in vim.

Answer 1

You can use the the gn motion to operation on the current search pattern match and repeat your operation via the . command. Example:

• /foo - set pattern
• gUgn - uppercase (gU) the current match, gn
• n move to the next match
• . to repeat your last operation, gUgn

Note: I find this method doesn't work the best with single character matches as gn will select the current charter to the next match.

You will need Vim 7.4 to use gn motion and 7.4.110+ to use gUgn.

For more help see:

:h gn
:h gU

There is also a nice Vimcasts episode on this: Operating on search matches using gn

Answer 2

Try this:

:'a,'b s/\v(<[whnm]>)/\U\1/g

Short expl.:

\v - very magic

(...) - create 1st group

\U\1 - make 1st group uppercase

Good references: vimregex, W.A.Zintz's articles

---

To operate on each match, repeatedly, using a "normal-mode" command, you could do this instead:

/\C\v<[whnm]> ENTER
~       (<- or any other command(s) operating on the match)
qqn.q   (<- create a macro with "go to next result, repeat command(s) above")
20@q    (<- repeat the macro 20 times)

You can use any number instead of 20, ideally bigger than than the number of matches, the condition being that your command applied to the match makes it a non-match for a second search round - when the search hits bottom and starts again from the top (hence the \C - case sensitive search).

Answer 3

You can write a macro that operates on the pattern you want and run it like 500 times. For instance I had a bunch of lines like this one:

Vrvirksomhed.virksomhedMetadata.nyesteNavn.navn

That I wanted to CamelCase, so i wrote this small macro: /\.xvU, and ran it until no more changes.