[racket] Documentation enhancement suggestions

At Mon, 2 Jan 2012 14:49:34 +0000,
Erich Rast wrote:
> But here is another suggestion that I would find
> tremendously helpful: an auto-hover live help that pops up information
> about function definitions plus a short explanation of what the function
> does directly in the IDE,

Similar to that, I really like Emacs's eldoc.

When the cursor is inside a function call and the operator is
recognized by eldoc (both standard library functions and user-defined
functions defined in the same file), the function's header and (if
known) return type is displayed in the minibuffer.

For example if the cursor is here
(<= |2 3)
eldoc displays
(<= x1 x2 ...) => bool
in the minibuffer.

Often, that gives me all the information I need, and I don't need to
search the docs (or my source file).

Something similar for DrRacket would be great.

Vincent