[brimworks]

Lua 5.3 has a utf8 library standard now:

http://www.lua.org/manual/5.3/manual.html#6.5

Full unicode support is rarely necessary in my experience. Lua "strings" are raw byte arrays. It is the job of the programmer to validate the byte arrays are in the character set of your choosing and doing appropriate conversions and validation when necessary.

[z92]

I would rather like my language natively supports binary string, rather than unicode string.

One can always use library functions to process the binary string as unicode.