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 definition, it would be cool to see the function name in Vim status line.

When we set :set ls=2 in Vim, we can get the file path (relative to the current directory), line number, etc. It would be really cool if we could see the function name too. Any ideas how to get it?

Currently I use [[ to go to start of the function and Ctrl-O to get back to the line I'm editing.

Answer 1

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 2

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.

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

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