How do I search for line containing an unclosed parenthesis?

Question

How to search for line containing unclosed parenthesis.

/([^)]*$

works only for non-nested parenthesis.

If the closing parenthesis is present in the next lines, it should still be a match.

for example :

foo( bar, bar
     bar, bar );

should be a match.

Answer 1

It is hard to match balanced parentheses with regular expressions, but fortunately, Vim has built-in motions for ( and {. See :help [( and :help [{.

Answer 2

Done it myself

function Unclosed(pattern, pattern2)

    " Store current pos
    let l:matchpos = getpos('.')

    " Initialize return
    let l:ret = 0 

    " Search Pattern, no wrap
    while search(a:pattern, "W", "", "") > 0 

        " Search for pair only in current line
        if eval(searchpair(a:pattern, '', a:pattern2, '', '', line(".")))
            continue
        endif

        " found store position and line
        let l:matchpos = getpos('.')
        let l:ret = line(".")
        break
    endwhile

    " Set cursor to position and return
    call setpos('.', l:matchpos)
    return l:ret
endfunction