The module is still in todo-state and implemented as:
return {
_toCodePointArray = (function (str)
error("Not implemented: _toCodePointArray")
end),
_fromCodePointArray = (function (codePoints)
error("Not implemented: _fromCodePointArray")
end),
}
Probably this issue should be in purescript-lua-strings or in package sets repository, but both seem to have GH Issues feature disabled.