How to arbitrarily manipulate key events in X

[wettstein509 at solnet.ch]

> I've written a small app that among other things allows me to let any
> key act as both a modifier key and a character key at the same time.

I want to do the same.  My approach up to now is to use an input method,
see

  https://bugs.freedesktop.org/show_bug.cgi?id=26705

But even if this was implemented, using an input method to reuse a
modifier will have drawbacks: It is not possible to create events with
nonzero status field, and while it is possible to create things like
BackSpace, not all applications interpret it correctly.  Anyway, for me,
it would be good enough.

A manipulation possibility as you describe it would be even better.
>From what I understand, the X Event Interception Extension once has been
a way, but according to the Xorg Wiki, it is dead.

Andreas