lua/json/decode/others.lua

   1 --[[
   2         Licensed according to the included 'LICENSE' document
   3         Author: Thomas Harning Jr <harningt@gmail.com>
   4 ]]
   5 local lpeg = require("lpeg")
   6 local jsonutil = require("json.util")
   7 local merge = jsonutil.merge
   8 local util = require("json.decode.util")
   9
  10 -- Container module for other JavaScript types (bool, null, undefined)
  11
  12 local _ENV = nil
  13
  14 -- For null and undefined, use the util.null value to preserve null-ness
  15 local booleanCapture =
  16         lpeg.P("true") * lpeg.Cc(true)
  17         + lpeg.P("false") * lpeg.Cc(false)
  18
  19 local nullCapture = lpeg.P("null")
  20 local undefinedCapture = lpeg.P("undefined")
  21
  22 local defaultOptions = {
  23         allowUndefined = true,
  24         null = jsonutil.null,
  25         undefined = jsonutil.undefined
  26 }
  27
  28 local modeOptions = {}
  29
  30 modeOptions.simple = {
  31         null = false,     -- Mapped to nil
  32         undefined = false -- Mapped to nil
  33 }
  34 modeOptions.strict = {
  35         allowUndefined = false
  36 }
  37
  38 local function mergeOptions(options, mode)
  39         jsonutil.doOptionMerge(options, false, 'others', defaultOptions, mode and modeOptions[mode])
  40 end
  41
  42 local function generateLexer(options)
  43         -- The 'or nil' clause allows false to map to a nil value since 'nil' cannot be merged
  44         options = options.others
  45         local valueCapture = (
  46                 booleanCapture
  47                 + nullCapture * lpeg.Cc(options.null or nil)
  48         )
  49         if options.allowUndefined then
  50                 valueCapture = valueCapture + undefinedCapture * lpeg.Cc(options.undefined or nil)
  51         else
  52                 valueCapture = valueCapture + #undefinedCapture * util.denied("undefined", "others.allowUndefined")
  53         end
  54         return valueCapture
  55 end
  56
  57 local others = {
  58         mergeOptions = mergeOptions,
  59         generateLexer = generateLexer
  60 }
  61
  62 return others