Show function name in status line

Question

I edit a large C, C++, or Java file, say, about 15000 lines, with pretty long function definitions, say, about 400 lines. When the cursor is in middle of a function definiti

Answer 1

My solution is as follows:

set stl=%f%h%m%r\ %{Options()}%=%l,%c-%v\ %{line('$')}
fu! PlusOpt(opt)
  let option = a:opt
  if option
    return "+"
  else
    return "-"
  endif
endf

fu! Options()
  let opt="ic".PlusOpt(&ic)
  let opt=opt." ".&ff
  let opt=opt." ".&ft
  if &ft==?"cpp" || &ft==?"perl"
    let text = " {" . FindCurrentFunction() . "}"
    let opt= opt.text
  endif
  return opt

fu! FindCurrentFunction()
  let text =''

  let save_cursor = getpos(".")

  let opening_brace = searchpair('{','','}','bWr', '', '', 100)
  if opening_brace > 0
    let oldmagic = &magic
    let &magic = 1

    let operators='operator\s*\%((\s*)\|\[]\|[+*/%^&|~!=<>-]=\?\|[<>&|+-]\{2}\|>>=\|<<=\|->\*\|,\|->\|(\s*)\)\s*'
    let class_func_string = '\(\([[:alpha:]_]\w*\)\s*::\s*\)*\s*\%(\~\2\|'.operators
    let class_func_string = class_func_string . '\|[[:alpha:]_]\w*\)\ze\s*('

    let searchstring = '\_^\S.\{-}\%('.operators
    let searchstring = searchstring.'\|[[:alpha:]_]\w*\)\s*(.*\n\%(\_^\s.*\n\)*\_^{'

    let l = search(searchstring, 'bW', line(".")-20 )

    if l != 0
      let line_text = getline(l)
      let matched_text = matchstr(line_text, class_func_string)
      let matched_text = substitute(matched_text, '\s', '', 'g')
      let text = matched_text
    endif

    call setpos('.', save_cursor)

    let &magic = oldmagic
  endif

  return text
endfunction

I'm actually attempting to match the C/C++/Java allowed names for functions. This generally works for me (including for overloaded operators) but assumes that the opening { is at column 0 on a line by itself.

I just noticed today that it fails if included in a namespace {}, even if otherwise formatted as expected.