Lua Splice strings

string_splice.lua

-- Copyright (c) 2020 Siasur

--[[

  This lua function allows you to splice a string (value) into another string (base) at a given location (position) without changing its length.
  I created this function for a now scrapped project but as I spent a long time figuring out how to do it I decided to make it a public gist.
  If you need this functionality in your script you are free to use this code as it is.

]]

local function --[[ String ]] spliceString( --[[ String ]] base, --[[ Number ]] position, --[[ String ]] value)
--  checkParam(base, "base", "string")
--  checkParam(position, "position", "number")
--  checkParam(value, "value", "string")
  
  -- We do not want to get a substring from the end so let's fix it in case position was less that 1
  if position < 1 then
    tmp = position * -1 + 2
    value = string.sub(value, tmp)
  end

  local end_front = math.max(position - 1, 0)
  local start_back =  math.max(position, 1) + #value
  local value_end = clamp(#base - position + 1, 0, #value)

  local front = string.sub(base, 0, end_front)
  local back = string.sub(base, start_back)
  value = string.sub(value, 0, value_end)

  return string.format("%s%s%s", front, value, back)
end