RE: emacs and window placement

[Drew Adams]

> I'm trying to bind f6 key to toggle 'pop-up-frames' variable
> by insert following line in my .emacs file:
> (global-set-key [f6] (lambda () (setq pop-up-frames (not pop-up-frames)))
> and after restart emacs and press f6, emacs says "Wrong type argument:
> commandp, (lambda nil (setq pop-up-frames (not pop-up-frames)))"

What you bind to a key must be a command. For a function to be a command, it
must have an `interactive' spec. So you need this:

 (global-set-key [f6]
   (lambda () (interactive) (setq pop-up-frames (not pop-up-frames)))

See the Elisp manual, node `Defining Commands'.