Problem with mapping a key to multiple characters (Unicode + diacritic symbol)

[Pierre-Luc Angles]

Dear ĸen, dear all,

Thanks a lot for your nice and long answer.

In the meantime, I have also found another thread in the archives of 
this list that could be also relevant for my problem:

https://lists.freedesktop.org/archives/xorg/2013-February/055490.html

and

https://lists.freedesktop.org/archives/xorg/2013-February/055491.html

but since I have no idea how IBUS is working and that it seems to be 
quite complicated, I would like maybe to try something with XCompose, 
unless it does not work in a long term vision or in a stable way for a 
combination of a letter and a diacritic sign...

As a temporary solution, I have indeed mapped the dead keys like 
dead_belowmacron and dead_belowcircumflex, but I would prefer to have 
these keys mapped with a modifier, i.e. in a third keysym (i.e. with 
AltGr) for this keycode with a modifier like the example that I already 
gave:

key <AE01>    { [        ampersand,                1, 
i_breve_below,                   U032F ] };

It means that I would like to type i with an inverted breve below in the 
AE01 key by pressing the AltGr modifier before that.


> 
> So for your i with breve below, on the right side I would put
>   : "ḭ" U1E2D

Please note that all the compositions that I have created in XCompose 
correspond to characters that have currently no Unicode number assigned 
to. So U1E2D is for i with a tilde below and not for i with inverted 
breve below. All the other examples that you kindly gave me are also 
already numbered Unicode characters, which is here not the case.

Thanks again!

Best,

Pierre-Luc