char(
...) ->str,err
Convert one or more Unicode codepoints to a UTF-8 string
Converts each integer argument (a Unicode codepoint) to its UTF-8 byte representation and concatenates the results. Accepts any value in the range 0–0x10FFFF (the full Unicode range). Returns nil and an error message for any out-of-range codepoint.
Port of Lua-5.1-UTF-8 by willox.