functiontop_indexpure

pure integer function top_index(s, pattern)
    character(len=*), intent(in) :: s       !! the text
    character(len=*), intent(in) :: pattern !! the text to find
    integer :: k, depth
    character :: quote

    top_index = 0
    depth = 0
    quote = ' '
    do k = 1, len(s) - len(pattern) + 1
        if (quote /= ' ') then
            if (s(k:k) == quote) quote = ' '
            cycle
        end if
        if (depth == 0 .and. s(k:k + len(pattern) - 1) == pattern) then
            top_index = k
            return
        end if
        select case (s(k:k))
        case ('"', "'")
            quote = s(k:k)
        case ('(', '[')
            depth = depth + 1
        case (')', ']')
            depth = depth - 1
        end select
    end do
end function top_index