what else? ;-)

> May be i miss a command like M-x goto-definition in some mode?

well these are several questions ... point for point.

• you said the mouse is needed

  nope

  every x-action is bound to a function and can be bound to a key too, and the function word-at-point gives you the word under the cursor. So you can freely combine any mouse-action with the word-at-point .

  Tip: C-h k doesn't only show you the keybinding of the next keystrokes, but also of the following mouse actions. Hence you can see what is triggered and use it in your own scripts.

• getting all "local" subs

  cperl-mode supports imenu , which scans the current buffer for every sub declaration.

  Just go to the menu bar and click <menu-bar> <Perl> <Tools> <Imenu> and you'll see a list of all subs in the buffer.

• jumping to the sub at point

  When called interactively with M-x imenu or a key-binding like C-c i or M-Ret (personal binding) offers all alternatives in the mini-buffer (the bottom line) but defaulting to the word at point.

  For instance in my bindings M-RET RET lets me jump to that definition.

• automatically showing that a sub is local

  Cperl mode has a setting to automatically show a mini-description for any Perl construct under the cursor In the message area. See <menu-bar> <Perl> <Toggle...> <Auto-help on Perl constructs>

  One could also hack this interface to show information for the sub at point using the data from imenu

• Choroba mentioned etags/ctags

  These is necessary for bigger projects where the definition is in another file. I was only replying to the "local" requirement. ( Tags are tricky in a language which can only be parse by its own runtime engine ;)

HTH! :)

TL DR

M-x imenu