On-line documentation

[MOON5 at MIT-AI (David A. Moon)]

A new system for on-line documentation of functions will appear soon.  Since it
is upward-compatible, you can start documenting things now.

If the first form in the body of a function is a string, and it is not the only
form in that body, then it is the documentation for the function.  As with Emacs
documentation, the first line should be able to stand alone as brief documentation.
Note that both the interpreter and the compiler will essentially ignore this
string.  You can also document any symbol by giving it a :DOCUMENTATION property
which is a string; this is mainly intended for microcode functions which have no
other place to remember their documentation.

The function FUNCTION-DOCUMENTATION, given any kind of function or function-specifier
(e.g. a "method"), will return NIL or the documentation string.  The control-top-D
command in the editor asks you for a function name and prints the first line
of its documentation at the bottom of the screen.  The meta-top-D command prints
the argument list and the entirety of the documentation at the top of the screen.
Currently you can't see this and edit at the same time, but that wil be fixed shortly.

No system functions have on-line documentation yet, but hopefully those that
need it will get some over the next couple of weeks.

Eventually all the editor self-documentation commands will be extended to the
full Lisp world, and eventually there will be a command which constructs a manual
out of the on-line documentation for a set of functions.