lua/json/encode/object.lua

   1 --[[
   2         Licensed according to the included 'LICENSE' document
   3         Author: Thomas Harning Jr <harningt@gmail.com>
   4 ]]
   5 local pairs = pairs
   6 local assert = assert
   7
   8 local type = type
   9 local tostring = tostring
  10
  11 local table_concat = require("table").concat
  12 local util_merge = require("json.util").merge
  13
  14 local is_52 = _VERSION == "Lua 5.2"
  15 local _G = _G
  16
  17 if is_52 then
  18         _ENV = nil
  19 end
  20
  21 local defaultOptions = {
  22 }
  23
  24 local default = nil
  25 local strict = nil
  26
  27 --[[
  28         Cleanup function to unmark a value as in the encoding process and return
  29         trailing results
  30 ]]
  31 local function unmarkAfterEncode(tab, state, ...)
  32         state.already_encoded[tab] = nil
  33         return ...
  34 end
  35 --[[
  36         Encode a table as a JSON Object ( keys = strings, values = anything else )
  37 ]]
  38 local function encodeTable(tab, options, state)
  39         -- Make sure this value hasn't been encoded yet
  40         state.check_unique(tab)
  41         local encode = state.encode
  42         local compositeEncoder = state.outputEncoder.composite
  43         local valueEncoder = [[
  44         local first = true
  45         for k, v in pairs(composite) do
  46                 local ti = type(k)
  47                 assert(ti == 'string' or ti == 'number' or ti == 'boolean', "Invalid object index type: " .. ti)
  48                 local name = encode(tostring(k), state, true)
  49                 if first then
  50                         first = false
  51                 else
  52                         name = ',' .. name
  53                 end
  54                 PUTVALUE(name .. ':')
  55                 local val = encode(v, state)
  56                 val = val or ''
  57                 if val then
  58                         PUTVALUE(val)
  59                 end
  60         end
  61         ]]
  62         return unmarkAfterEncode(tab, state, compositeEncoder(valueEncoder, '{', '}', nil, tab, encode, state))
  63 end
  64
  65 local function getEncoder(options)
  66         options = options and util_merge({}, defaultOptions, options) or defaultOptions
  67         return {
  68                 table = function(tab, state)
  69                         return encodeTable(tab, options, state)
  70                 end
  71         }
  72 end
  73
  74 local object = {
  75         default = default,
  76         strict = strict,
  77         getEncoder = getEncoder
  78 }
  79
  80 if not is_52 then
  81         _G.json = _G.json or {}
  82         _G.json.encode = _G.json.encode or {}
  83         _G.json.encode.object = object
  84 end
  85
  86 return object