lua/json/util.lua

   1 --[[
   2         Licensed according to the included 'LICENSE' document
   3         Author: Thomas Harning Jr <harningt@gmail.com>
   4 ]]
   5 local type = type
   6 local print = print
   7 local tostring = tostring
   8 local pairs = pairs
   9 local getmetatable, setmetatable = getmetatable, setmetatable
  10 local select = select
  11
  12 _ENV = nil
  13
  14 local function foreach(tab, func)
  15         for k, v in pairs(tab) do
  16                 func(k,v)
  17         end
  18 end
  19 local function printValue(tab, name)
  20         local parsed = {}
  21         local function doPrint(key, value, space)
  22                 space = space or ''
  23                 if type(value) == 'table' then
  24                         if parsed[value] then
  25                                 print(space .. key .. '= <' .. parsed[value] .. '>')
  26                         else
  27                                 parsed[value] = key
  28                                 print(space .. key .. '= {')
  29                                 space = space .. ' '
  30                                 foreach(value, function(key, value) doPrint(key, value, space) end)
  31                         end
  32                 else
  33                                         if type(value) == 'string' then
  34                                                 value = '[[' .. tostring(value) .. ']]'
  35                                         end
  36                                         print(space .. key .. '=' .. tostring(value))
  37                 end
  38         end
  39         doPrint(name, tab)
  40 end
  41
  42 local function clone(t)
  43         local ret = {}
  44         for k,v in pairs(t) do
  45                 ret[k] = v
  46         end
  47         return ret
  48 end
  49
  50 local function inner_merge(t, remaining, from, ...)
  51         if remaining == 0 then
  52                 return t
  53         end
  54         if from then
  55                 for k,v in pairs(from) do
  56                         t[k] = v
  57                 end
  58         end
  59         return inner_merge(t, remaining - 1, ...)
  60 end
  61
  62 local function merge(t, ...)
  63         return inner_merge(t, select('#', ...), ...)
  64 end
  65
  66 -- Function to insert nulls into the JSON stream
  67 local function null()
  68         return null
  69 end
  70
  71 -- Marker for 'undefined' values
  72 local function undefined()
  73         return undefined
  74 end
  75
  76 local ArrayMT = {}
  77
  78 --[[
  79         Return's true if the metatable marks it as an array..
  80         Or false if it has no array component at all
  81         Otherwise nil to get the normal detection component working
  82 ]]
  83 local function IsArray(value)
  84         if type(value) ~= 'table' then return false end
  85         local ret = getmetatable(value) == ArrayMT
  86         if not ret then
  87                 if #value == 0 then return false end
  88         else
  89                 return ret
  90         end
  91 end
  92 local function InitArray(array)
  93         setmetatable(array, ArrayMT)
  94         return array
  95 end
  96
  97 local CallMT = {}
  98
  99 local function isCall(value)
 100         return CallMT == getmetatable(value)
 101 end
 102
 103 local function buildCall(name, ...)
 104         local callData = {
 105                 name = name,
 106                 parameters = {n = select('#', ...), ...}
 107         }
 108         return setmetatable(callData, CallMT)
 109 end
 110
 111 local function decodeCall(callData)
 112         if not isCall(callData) then return nil end
 113         return callData.name, callData.parameters
 114 end
 115
 116 local function doOptionMerge(options, nested, name, defaultOptions, modeOptions)
 117         if nested then
 118                 modeOptions = modeOptions and modeOptions[name]
 119                 defaultOptions = defaultOptions and defaultOptions[name]
 120         end
 121         options[name] = merge(
 122                 {},
 123                 defaultOptions,
 124                 modeOptions,
 125                 options[name]
 126         )
 127 end
 128
 129 local json_util = {
 130         printValue = printValue,
 131         clone = clone,
 132         merge = merge,
 133         null = null,
 134         undefined = undefined,
 135         IsArray = IsArray,
 136         InitArray = InitArray,
 137         isCall = isCall,
 138         buildCall = buildCall,
 139         decodeCall = decodeCall,
 140         doOptionMerge = doOptionMerge
 141 }
 142
 143 return json_util