How to overload functions string.byte and string.char to support Unicode UTF-8?

Question

I have custom functions utf8Char (decimal) and utf8Byte(char).

How can I overload the functions string.char(...) and string.byte(s, i, j) in Lua?

Here is an example function what I mean:

local originalStringCharFunction = string.char

-- new function:
function string.char(...)
    local args = {...}
    local chars = {}
    for i, codepoint in ipairs(args) do
        chars[i] = utf8Char(codepoint, originalStringCharFunction)
    end
    return table.concat(chars)
end

Answer 1

i hope this is can help you.

local override = {
    char = function()
        -- whatever you want here
        print("Hello")
    end,
    byte = function()
        -- whatever you want here
        print("World")
    end
}

local str = {};
str.__index = string;
string = setmetatable(override, str);

string.char() -- Hello
string.byte() -- World
print(string.lower("HELLO WORLD!")) -- Old string functions still work