It appears that <const> just marks a local variable as non-assignable:
> local <const> x = 5 x = 6
stdin:1: assignment to const variable 'x'
>
But the target isn't constant:
> local <const> x = {} x.foo = 1
>
To get a constant table, you would still have to use a proxy table and
intercept __index and __newindex.
-spc
As a _javascript_ programmer, this is familiar behavior.
As a C++ programmer, this is irritating. XD (C++ can have const pointers to non-const objects that match this behavior, but they're not often used.)
As a compiler author, I can totally understand the rationales behind both ways of doing it, and I think Lua's decision in this regard is the right one for its use case. There was already a mechanism for making an object immutable, but there was not a mechanism for making a variable non-reassignable. This addresses that shortcoming, so now you have the flexibility of choice to use whatever combination of behaviors is appropriate for your program.
/s/ Adam
