> Moreover, it is not strictly correct to say that Lua has 1-based indexing.
Mixed 1-based and 0-based indexing is the worst possible state of affairs regarding this for a programming system.
It's not if there is proper justification. 0-based indexing should be an "offset". It's justified in C because C array indexing is always an "offset". You can write:
1[a] = 5;
*(a+2) = 6;
Not the case for all languages' arrays.