Modifying a character in a string in Lua

Question

Is there any way to replace a character at position N in a string in Lua.

This is what I\'ve come up with so far:

function replace_char(pos, str, r)
         


        

Answer 1

With luajit, you can use the FFI library to cast the string to a list of unsigned charts:

local ffi = require 'ffi'
txt = 'test'
ptr = ffi.cast('uint8_t*', txt)
ptr[1] = string.byte('o')