AutoHotKey v2.0 script to handle compose key sequences. Also contains a script to parse the Xorg Compose Key database and generate a data structure used by the ComposeKey.ahk script to handle compose key sequences (nested maps).
Use an autohotkey bind like:
#include ComposeKey.ahk
RAlt::do_compose_key()
And assuming right alt is your compose key, here are some example sequences:
<RAlt> <?> <?> = ¿
<RAlt> <e> <'> = é
<RAlt> <'> <e> = é
<RAlt> <,> <c> = ç
<RAlt> <"> <u> = ü
License for the Compose.pre file is Xorg MIT style license. Taken from here.