JSON.lua

JSON = {}
    
function JSON:new (o)
  o = o or {}
  setmetatable(o, self)
  self.__index = self
  return o
end

function JSON:stringify(depthLimit, depth)
  depthLimit = depthLimit or 10
  depth = depth or 1
  local temp = {}
  local index = 1
  local indent = string.rep("\t",depth)
  local indentP = string.rep("\t",depth+1)
  for i,v in pairs(self) do
    if type(v)=="table" then
      if getmetatable(v)==getmetatable(self) then
        --object
        temp[index] = string.format("%q: ",i) .. v:stringify(depthLimit,depth+1)
      else
        --array
        temp[index] = string.format("%q: ",i) .. '[\n' .. indentP .. '"' .. table.concat(v,'",\n'..indentP..'"') .. '"\n' .. indent .. ']'
      end
    else
      temp[index] = string.format("%q: %q",i, v)
    end
    index=index+1
  end
  return "{\n"..indent..table.concat(temp,",\n"..indent).."\n"..string.rep("\t",depth-1).."}"
end

function JSON:set(index,value)
  self[index] = value
end

function JSON:append(index,value)
  self[index] = self[index] or {}
  self[index][#self[index]+1] = value
end

obj = JSON:new()
obj:set("thing",JSON:new())
obj["thing"]:set("number",5)
obj["thing"]:set("array",{"a","b","c","d","e"})
obj:set("foo","bar")
obj:append("otherArray","x")
obj:append("otherArray","y")
obj:append("otherArray","z")

print(obj["thing"]:stringify())
print(obj:stringify())

Output:

{
    "number": "5",
    "array": [
        "a",
        "b",
        "c",
        "d",
        "e"
    ]
}
{
    "foo": "bar",
    "otherArray": [
        "x",
        "y",
        "z"
    ],
    "thing": {
        "number": "5",
        "array": [
            "a",
            "b",
            "c",
            "d",
            "e"
        ]
    }
}