With Emacs only very few things are as easy as they sound. But Emacs users know that there is always help available from Emacs itself.
The SLIME Manual Section 3.4 Completion Commands
tells me that I shall use M-TAB to complete symbols. But if I press M-TAB, my window manager (fvwm2) shows me a list of all open windows, while in Emacs happens nothing, because the M-TAB never reaches Emacs at all.
But maybe M-TAB works for you (try this first).
If M-TAB doesn't work, then first the easy method:
- If there is a SLIME menu in your Emacs menu bar in Lisp source code buffers then just simply look-up the key binding of the "Complete Symbol" entry in the SLIME menu.
Because Emacs key bindings can depend on the specific (X)Emacs or SLIME versions here is the full story:
- The page of the SLIME Manual (same link as above) tells me that the SLIME Emacs function is called `slime-complete-symbol'.
- If I press C-h b (describe-bindings) in a Lisp code buffer then a second buffer pops up with all current key bindings of the Lisp code buffer.
- In the key bindings buffer I search for `slime-complete-symbol' and find that the function in my Emacs is also bound to C-c TAB.
If I type "(string-" in the Lisp code buffer and press C-c TAB then the same completion buffer like in the SLIME REPL pops up. If there appears no SLIME menu in Lisp code buffers and no `slime-...' functions in the key bindings buffer then there's something wrong with your SLIME setup.