Vim search in C/C++ code lines - vim

Question

Is there any way to search a string in a C/C++ source file while skipping commented lines?

Answer 1

This is an intriguing question.
I think #sixtyfootersdude has the right idea -- let Vim's syntax highlighting tell you what's a comment and what's not, and then search for matches within the non-comments.
Let's start with a function that mimics Vim's built-in search() routine, but also provides a "skip" parameter to let it ignore some matches:
function! SearchWithSkip(pattern, flags, stopline, timeout, skip)
"
" Returns true if a match is found for {pattern}, but ignores matches
" where {skip} evaluates to false. This allows you to do nifty things
" like, say, only matching outside comments, only on odd-numbered lines,
" or whatever else you like.
"
" Mimics the built-in search() function, but adds a {skip} expression
" like that available in searchpair() and searchpairpos().
" (See the Vim help on search() for details of the other parameters.)
"
" Note the current position, so that if there are no unskipped
" matches, the cursor can be restored to this location.
"
let l:matchpos = getpos('.')
" Loop as long as {pattern} continues to be found.
"
while search(a:pattern, a:flags, a:stopline, a:timeout) > 0
" If {skip} is true, ignore this match and continue searching.
"
if eval(a:skip)
continue
endif
" If we get here, {pattern} was found and {skip} is false,
" so this is a match we don't want to ignore. Update the
" match position and stop searching.
"
let l:matchpos = getpos('.')
break
endwhile
" Jump to the position of the unskipped match, or to the original
" position if there wasn't one.
"
call setpos('.', l:matchpos)
endfunction
Here are a couple of functions that build on SearchWithSkip() to implement syntax-sensitive searches:
function! SearchOutside(synName, pattern)
"
" Searches for the specified pattern, but skips matches that
" exist within the specified syntax region.
"
call SearchWithSkip(a:pattern, '', '', '',
\ 'synIDattr(synID(line("."), col("."), 0), "name") =~? "' . a:synName . '"' )
endfunction
function! SearchInside(synName, pattern)
"
" Searches for the specified pattern, but skips matches that don't
" exist within the specified syntax region.
"
call SearchWithSkip(a:pattern, '', '', '',
\ 'synIDattr(synID(line("."), col("."), 0), "name") !~? "' . a:synName . '"' )
endfunction
Here are commands that make the syntax-sensitive search functions easier to use:
command! -nargs=+ -complete=command SearchOutside call SearchOutside(<f-args>)
command! -nargs=+ -complete=command SearchInside call SearchInside(<f-args>)
That was a long way to go, but now we can do stuff like this:
:SearchInside String hello
That searches for hello, but only within text that Vim considers a string.
And (finally!) this searches for double everywhere except comments:
:SearchOutside Comment double
To repeat a search, use the #: macro to execute the same command repeatedly, like pressing n to repeat a search.
(Thanks for asking this question, by the way. Now that I've built these routines, I expect to use them a lot.)

Answer 2

This pattern searches for a string that is not preceded by the two C++ commenting conventions. I've also excluded '*' as the first non-whitespace character, as that's a common convention for multi-line comments.
/\(\(\/\*\|\/\/\|^\s*\*[^/]\).*\)\#<!foo
Only the first and fourth foo are matched.
foo
/* foo
* baz foo
*/ foo
// bar baz foo
Putting \v at the beginning of the pattern eliminates a bunch of backslashes:
/\v((\/\*|\/\/|^\s*\*[^/]).*)#<!foo
You can bind a hotkey to this pattern by putting this in your .vimrc
"ctrl+s to search uncommented code
noremap <c-s> <c-o>/\v((\/\*\|\/\/\|^\s*\*[^/]).*)#<!

Answer 3

Not sure if this is helpful but when you type :syn it has all the formatting that is used in your file type. Maybe you can refer to that somehow. You could say something like:
map n betterN
function betterN{
n keystroke
while currentLine matches comment class
do another n keystroke
}

Answer 4

Here is how I would proceed:
Delete all C/C++ comments (using the replace command %s)
Proceed to the search using regular search command /
Set a mark at the position using m a (to set the mark "a")
Undo the deletion of the comments using u
Jump to the mark "a" using ``a`
Eventually deleting the mark using delm a (it would be overwritten in the case you don't delete it, so no big deal)
Of course you can do that in one big operation/function. I do not master Vim scripting good enough to give an example of that though.
I admit my solution is a bit "lazy" (and you can probably do it way better) but that's all I came to.
Hope it helps.