Defining your own new input methods?

[Ken Beesley <ken beesley xrce xerox com>]

 Inquiry: Definining your own new input methods?

Over a year ago I managed to write some new
"Simple Composing Input Methods" for GTK+,
and get them installed (by piggybacking them into
gtk-im-extra).

I managed to get them working and selectable
from within gedit, but it was all more painful
than it ought to be.

I'm starting to experiment with gedit and Unicode
input methods again.  Could some kind guru please
summarize the status of Defining and Installing
Your Own New Input Methods for GNOME/GTK/gedit?

1.  Are documentation/tutorials now available?

2.  Simple Composing Input Methods are really too
simple for my needs.  They allow you to specify
a sequence of Key Presses that constitute an input
sequence, and each input sequence must map to a
_single_ Unicode character output. 

I need to define input methods that map a sequence
of one-or-more Key Events (where Key Events includes information
about which modifier keys, if any, were pressed) to
one-or-more Unicode character outputs.  There might
be one-to-one, many-to-one, one-to-many, or many-to-many.

What's the current format/API/recommendation for defining
such input methods for Gnome/GTK/gedit?

3.  Has the input-method installation procedure been simplified? 

To install a new Java Input Method, you simply copy it into the
Extensions Directory of your Java installation.  That makes it
visible to all Java applications.  When you launch a Java application,
you can also using the -D command-line flag to specify a PATH
(directory, or set of directories) where the applications should
look for extensions (input methods).

Similarly, to install a new OS X input method, you simply place
it in one of several designated folders (including your own
personal folder for input methods). 

It would be welcome news to learn that installing a new input
method for GNOME/GTK/gedit was just as easy.

Thanks,

Ken