LuaTeX's .index is primarily intended to support getting the index of a register and is therefore hardcoded to never return values bigger than a valid register index. Since expl3 integers in this range do not correspond to register indices but are chardefs, we can use .mode to avoid this restriction.
Fixes #97.
LuaTeX's
.indexis primarily intended to support getting the index of a register and is therefore hardcoded to never return values bigger than a valid register index. Since expl3 integers in this range do not correspond to register indices but are chardefs, we can use.modeto avoid this restriction.