src/json/decode/number.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 tonumber = tonumber
   7 local util = require("json.decode.util")
   8
   9 module("json.decode.number")
  10
  11 local space = util.space
  12
  13 local digit  = lpeg.R("09")
  14 local digits = digit^1
  15
  16 -- Deviation from JSON spec: Leading zeroes, inf number negatives w/ space
  17 int = lpeg.P('-')^0 * space^0 * digits
  18 local int = int
  19 local strictInt = (lpeg.P('-') + 0) * (lpeg.R("19") * digits + digit)
  20
  21 local frac = lpeg.P('.') * digits
  22
  23 local exp = lpeg.S("Ee") * (lpeg.S("-+") + 0) * digits
  24
  25 local nan = lpeg.S("Nn") * lpeg.S("Aa") * lpeg.S("Nn")
  26 local inf = lpeg.S("Ii") * lpeg.P("nfinity")
  27
  28 local defaultOptions = {
  29         nan = true,
  30         inf = true,
  31         frac = true,
  32         exp = true
  33 }
  34
  35 default = {}
  36 strict = {
  37         nan = false,
  38         inf = false,
  39         strict = true
  40 }
  41 --[[
  42         Options: configuration options for number rules
  43                 nan: match NaN
  44                 inf: match Infinity
  45          strict: for integer portion, only match [-]([0-9]|[1-9][0-9]*)
  46            frac: match fraction portion (.0)
  47             exp: match exponent portion  (e1)
  48         DEFAULT: nan, inf, frac, exp
  49                 Must be set to false
  50 ]]
  51 function buildMatch(options)
  52         options = util.merge({}, defaultOptions, options)
  53         local ret = options.strict and strictInt or int
  54         if options.frac then
  55                 ret = ret * (frac + 0)
  56         end
  57         if options.exp then
  58                 ret = ret * (exp + 0)
  59         end
  60         if options.nan then
  61                 ret = ret + nan
  62         end
  63         if options.inf then
  64                 ret = ret + inf
  65         end
  66         return ret
  67 end
  68
  69 function buildCapture(options)
  70         return buildMatch(options) / tonumber
  71 end