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

There are several plugins for status line or on-demand with a mapping, e.g.:

• http://www.vim.org/scripts/script.php?script_id=1094
• http://www.vim.org/scripts/script.php?script_id=2805
• http://www.vim.org/scripts/script.php?script_id=1553

Answer 2

You can use ctags.vim for this, it will show the current function name in the title or status bar.

SOURCE: https://superuser.com/questions/279651/how-can-i-make-vim-show-the-current-class-and-method-im-editing

Answer 3

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.

Answer 4

Based on @manav m-n's answer

The 'n' flag in search() won't move the cursor, so a shorter version of this with the same functionality would be:

fun! ShowFuncName()
  echohl ModeMsg
  echo getline(search("^[^ \t#/]\\{2}.*[^:]\s*$", 'bWn'))
  echohl None
endfun
map f :call ShowFuncName() <CR>

Reference: run :help search()

Answer 5

I use https://github.com/mgedmin/chelper.vim for this. It doesn't needs a tags file, instead it parses the source code on the fly.

Answer 6

To show current function name in C programs add following in your vimrc:

fun! ShowFuncName()
  let lnum = line(".")
  let col = col(".")
  echohl ModeMsg
  echo getline(search("^[^ \t#/]\\{2}.*[^:]\s*$", 'bW'))
  echohl None
  call search("\\%" . lnum . "l" . "\\%" . col . "c")
endfun
map f :call ShowFuncName() <CR>

Or if you need the "f" key, just map the function to whatever you like.