· 9 years ago · Feb 20, 2017, 08:30 PM
1-- -*- coding: utf-8 -*-
2--
3-- Simple JSON encoding and decoding in pure Lua.
4--
5-- Copyright 2010-2016 Jeffrey Friedl
6-- http://regex.info/blog/
7-- Latest version: http://regex.info/blog/lua/json
8--
9-- This code is released under a Creative Commons CC-BY "Attribution" License:
10-- http://creativecommons.org/licenses/by/3.0/deed.en_US
11--
12-- It can be used for any purpose so long as:
13-- 1) the copyright notice above is maintained
14-- 2) the web-page links above are maintained
15-- 3) the 'AUTHOR_NOTE' string below is maintained
16--
17local VERSION = '20161109.21' -- version history at end of file
18local AUTHOR_NOTE = "-[ JSON.lua package by Jeffrey Friedl (http://regex.info/blog/lua/json) version 20161109.21 ]-"
19
20--
21-- The 'AUTHOR_NOTE' variable exists so that information about the source
22-- of the package is maintained even in compiled versions. It's also
23-- included in OBJDEF below mostly to quiet warnings about unused variables.
24--
25local OBJDEF = {
26 VERSION = VERSION,
27 AUTHOR_NOTE = AUTHOR_NOTE,
28}
29
30
31--
32-- Simple JSON encoding and decoding in pure Lua.
33-- JSON definition: http://www.json.org/
34--
35--
36-- JSON = assert(loadfile "JSON.lua")() -- one-time load of the routines
37--
38-- local lua_value = JSON:decode(raw_json_text)
39--
40-- local raw_json_text = JSON:encode(lua_table_or_value)
41-- local pretty_json_text = JSON:encode_pretty(lua_table_or_value) -- "pretty printed" version for human readability
42--
43--
44--
45-- DECODING (from a JSON string to a Lua table)
46--
47--
48-- JSON = assert(loadfile "JSON.lua")() -- one-time load of the routines
49--
50-- local lua_value = JSON:decode(raw_json_text)
51--
52-- If the JSON text is for an object or an array, e.g.
53-- { "what": "books", "count": 3 }
54-- or
55-- [ "Larry", "Curly", "Moe" ]
56--
57-- the result is a Lua table, e.g.
58-- { what = "books", count = 3 }
59-- or
60-- { "Larry", "Curly", "Moe" }
61--
62--
63-- The encode and decode routines accept an optional second argument,
64-- "etc", which is not used during encoding or decoding, but upon error
65-- is passed along to error handlers. It can be of any type (including nil).
66--
67--
68--
69-- ERROR HANDLING
70--
71-- With most errors during decoding, this code calls
72--
73-- JSON:onDecodeError(message, text, location, etc)
74--
75-- with a message about the error, and if known, the JSON text being
76-- parsed and the byte count where the problem was discovered. You can
77-- replace the default JSON:onDecodeError() with your own function.
78--
79-- The default onDecodeError() merely augments the message with data
80-- about the text and the location if known (and if a second 'etc'
81-- argument had been provided to decode(), its value is tacked onto the
82-- message as well), and then calls JSON.assert(), which itself defaults
83-- to Lua's built-in assert(), and can also be overridden.
84--
85-- For example, in an Adobe Lightroom plugin, you might use something like
86--
87-- function JSON:onDecodeError(message, text, location, etc)
88-- LrErrors.throwUserError("Internal Error: invalid JSON data")
89-- end
90--
91-- or even just
92--
93-- function JSON.assert(message)
94-- LrErrors.throwUserError("Internal Error: " .. message)
95-- end
96--
97-- If JSON:decode() is passed a nil, this is called instead:
98--
99-- JSON:onDecodeOfNilError(message, nil, nil, etc)
100--
101-- and if JSON:decode() is passed HTML instead of JSON, this is called:
102--
103-- JSON:onDecodeOfHTMLError(message, text, nil, etc)
104--
105-- The use of the fourth 'etc' argument allows stronger coordination
106-- between decoding and error reporting, especially when you provide your
107-- own error-handling routines. Continuing with the the Adobe Lightroom
108-- plugin example:
109--
110-- function JSON:onDecodeError(message, text, location, etc)
111-- local note = "Internal Error: invalid JSON data"
112-- if type(etc) = 'table' and etc.photo then
113-- note = note .. " while processing for " .. etc.photo:getFormattedMetadata('fileName')
114-- end
115-- LrErrors.throwUserError(note)
116-- end
117--
118-- :
119-- :
120--
121-- for i, photo in ipairs(photosToProcess) do
122-- :
123-- :
124-- local data = JSON:decode(someJsonText, { photo = photo })
125-- :
126-- :
127-- end
128--
129--
130--
131-- If the JSON text passed to decode() has trailing garbage (e.g. as with the JSON "[123]xyzzy"),
132-- the method
133--
134-- JSON:onTrailingGarbage(json_text, location, parsed_value, etc)
135--
136-- is invoked, where:
137--
138-- json_text is the original JSON text being parsed,
139-- location is the count of bytes into json_text where the garbage starts (6 in the example),
140-- parsed_value is the Lua result of what was successfully parsed ({123} in the example),
141-- etc is as above.
142--
143-- If JSON:onTrailingGarbage() does not abort, it should return the value decode() should return,
144-- or nil + an error message.
145--
146-- local new_value, error_message = JSON:onTrailingGarbage()
147--
148-- The default handler just invokes JSON:onDecodeError("trailing garbage"...), but you can have
149-- this package ignore trailing garbage via
150--
151-- function JSON:onTrailingGarbage(json_text, location, parsed_value, etc)
152-- return parsed_value
153-- end
154--
155--
156-- DECODING AND STRICT TYPES
157--
158-- Because both JSON objects and JSON arrays are converted to Lua tables,
159-- it's not normally possible to tell which original JSON type a
160-- particular Lua table was derived from, or guarantee decode-encode
161-- round-trip equivalency.
162--
163-- However, if you enable strictTypes, e.g.
164--
165-- JSON = assert(loadfile "JSON.lua")() --load the routines
166-- JSON.strictTypes = true
167--
168-- then the Lua table resulting from the decoding of a JSON object or
169-- JSON array is marked via Lua metatable, so that when re-encoded with
170-- JSON:encode() it ends up as the appropriate JSON type.
171--
172-- (This is not the default because other routines may not work well with
173-- tables that have a metatable set, for example, Lightroom API calls.)
174--
175--
176-- ENCODING (from a lua table to a JSON string)
177--
178-- JSON = assert(loadfile "JSON.lua")() -- one-time load of the routines
179--
180-- local raw_json_text = JSON:encode(lua_table_or_value)
181-- local pretty_json_text = JSON:encode_pretty(lua_table_or_value) -- "pretty printed" version for human readability
182-- local custom_pretty = JSON:encode(lua_table_or_value, etc, { pretty = true, indent = "| ", align_keys = false })
183--
184-- On error during encoding, this code calls:
185--
186-- JSON:onEncodeError(message, etc)
187--
188-- which you can override in your local JSON object.
189--
190-- The 'etc' in the error call is the second argument to encode()
191-- and encode_pretty(), or nil if it wasn't provided.
192--
193--
194-- ENCODING OPTIONS
195--
196-- An optional third argument, a table of options, can be provided to encode().
197--
198-- encode_options = {
199-- -- options for making "pretty" human-readable JSON (see "PRETTY-PRINTING" below)
200-- pretty = true,
201-- indent = " ",
202-- align_keys = false,
203--
204-- -- other output-related options
205-- null = "\0", -- see "ENCODING JSON NULL VALUES" below
206-- stringsAreUtf8 = false, -- see "HANDLING UNICODE LINE AND PARAGRAPH SEPARATORS FOR JAVA" below
207-- }
208--
209-- json_string = JSON:encode(mytable, etc, encode_options)
210--
211--
212--
213-- For reference, the defaults are:
214--
215-- pretty = false
216-- null = nil,
217-- stringsAreUtf8 = false,
218--
219--
220--
221-- PRETTY-PRINTING
222--
223-- Enabling the 'pretty' encode option helps generate human-readable JSON.
224--
225-- pretty = JSON:encode(val, etc, {
226-- pretty = true,
227-- indent = " ",
228-- align_keys = false,
229-- })
230--
231-- encode_pretty() is also provided: it's identical to encode() except
232-- that encode_pretty() provides a default options table if none given in the call:
233--
234-- { pretty = true, align_keys = false, indent = " " }
235--
236-- For example, if
237--
238-- JSON:encode(data)
239--
240-- produces:
241--
242-- {"city":"Kyoto","climate":{"avg_temp":16,"humidity":"high","snowfall":"minimal"},"country":"Japan","wards":11}
243--
244-- then
245--
246-- JSON:encode_pretty(data)
247--
248-- produces:
249--
250-- {
251-- "city": "Kyoto",
252-- "climate": {
253-- "avg_temp": 16,
254-- "humidity": "high",
255-- "snowfall": "minimal"
256-- },
257-- "country": "Japan",
258-- "wards": 11
259-- }
260--
261-- The following three lines return identical results:
262-- JSON:encode_pretty(data)
263-- JSON:encode_pretty(data, nil, { pretty = true, align_keys = false, indent = " " })
264-- JSON:encode (data, nil, { pretty = true, align_keys = false, indent = " " })
265--
266-- An example of setting your own indent string:
267--
268-- JSON:encode_pretty(data, nil, { pretty = true, indent = "| " })
269--
270-- produces:
271--
272-- {
273-- | "city": "Kyoto",
274-- | "climate": {
275-- | | "avg_temp": 16,
276-- | | "humidity": "high",
277-- | | "snowfall": "minimal"
278-- | },
279-- | "country": "Japan",
280-- | "wards": 11
281-- }
282--
283-- An example of setting align_keys to true:
284--
285-- JSON:encode_pretty(data, nil, { pretty = true, indent = " ", align_keys = true })
286--
287-- produces:
288--
289-- {
290-- "city": "Kyoto",
291-- "climate": {
292-- "avg_temp": 16,
293-- "humidity": "high",
294-- "snowfall": "minimal"
295-- },
296-- "country": "Japan",
297-- "wards": 11
298-- }
299--
300-- which I must admit is kinda ugly, sorry. This was the default for
301-- encode_pretty() prior to version 20141223.14.
302--
303--
304-- HANDLING UNICODE LINE AND PARAGRAPH SEPARATORS FOR JAVA
305--
306-- If the 'stringsAreUtf8' encode option is set to true, consider Lua strings not as a sequence of bytes,
307-- but as a sequence of UTF-8 characters.
308--
309-- Currently, the only practical effect of setting this option is that Unicode LINE and PARAGRAPH
310-- separators, if found in a string, are encoded with a JSON escape instead of being dumped as is.
311-- The JSON is valid either way, but encoding this way, apparently, allows the resulting JSON
312-- to also be valid Java.
313--
314-- AMBIGUOUS SITUATIONS DURING THE ENCODING
315--
316-- During the encode, if a Lua table being encoded contains both string
317-- and numeric keys, it fits neither JSON's idea of an object, nor its
318-- idea of an array. To get around this, when any string key exists (or
319-- when non-positive numeric keys exist), numeric keys are converted to
320-- strings.
321--
322-- For example,
323-- JSON:encode({ "one", "two", "three", SOMESTRING = "some string" }))
324-- produces the JSON object
325-- {"1":"one","2":"two","3":"three","SOMESTRING":"some string"}
326--
327-- To prohibit this conversion and instead make it an error condition, set
328-- JSON.noKeyConversion = true
329--
330--
331-- ENCODING JSON NULL VALUES
332--
333-- Lua tables completely omit keys whose value is nil, so without special handling there's
334-- no way to get a field in a JSON object with a null value. For example
335-- JSON:encode({ username = "admin", password = nil })
336-- produces
337-- {"username":"admin"}
338--
339-- In order to actually produce
340-- {"username":"admin", "password":null}
341-- one can include a string value for a "null" field in the options table passed to encode()....
342-- any Lua table entry with that value becomes null in the JSON output:
343-- JSON:encode({ username = "admin", password = "xyzzy" }, nil, { null = "xyzzy" })
344-- produces
345-- {"username":"admin", "password":null}
346--
347-- Just be sure to use a string that is otherwise unlikely to appear in your data.
348-- The string "\0" (a string with one null byte) may well be appropriate for many applications.
349--
350-- The "null" options also applies to Lua tables that become JSON arrays.
351-- JSON:encode({ "one", "two", nil, nil })
352-- produces
353-- ["one","two"]
354-- while
355-- NULL = "\0"
356-- JSON:encode({ "one", "two", NULL, NULL}, nil, { null = NULL })
357-- produces
358-- ["one","two",null,null]
359--
360--
361--
362--
363-- HANDLING LARGE AND/OR PRECISE NUMBERS
364--
365--
366-- Without special handling, numbers in JSON can lose precision in Lua.
367-- For example:
368--
369-- T = JSON:decode('{ "small":12345, "big":12345678901234567890123456789, "precise":9876.67890123456789012345 }')
370--
371-- print("small: ", type(T.small), T.small)
372-- print("big: ", type(T.big), T.big)
373-- print("precise: ", type(T.precise), T.precise)
374--
375-- produces
376--
377-- small: number 12345
378-- big: number 1.2345678901235e+28
379-- precise: number 9876.6789012346
380--
381-- Precision is lost with both 'big' and 'precise'.
382--
383-- This package offers ways to try to handle this better (for some definitions of "better")...
384--
385-- The most precise method is by setting the global:
386--
387-- JSON.decodeNumbersAsObjects = true
388--
389-- When this is set, numeric JSON data is encoded into Lua in a form that preserves the exact
390-- JSON numeric presentation when re-encoded back out to JSON, or accessed in Lua as a string.
391--
392-- (This is done by encoding the numeric data with a Lua table/metatable that returns
393-- the possibly-imprecise numeric form when accessed numerically, but the original precise
394-- representation when accessed as a string. You can also explicitly access
395-- via JSON:forceString() and JSON:forceNumber())
396--
397-- Consider the example above, with this option turned on:
398--
399-- JSON.decodeNumbersAsObjects = true
400--
401-- T = JSON:decode('{ "small":12345, "big":12345678901234567890123456789, "precise":9876.67890123456789012345 }')
402--
403-- print("small: ", type(T.small), T.small)
404-- print("big: ", type(T.big), T.big)
405-- print("precise: ", type(T.precise), T.precise)
406--
407-- This now produces:
408--
409-- small: table 12345
410-- big: table 12345678901234567890123456789
411-- precise: table 9876.67890123456789012345
412--
413-- However, within Lua you can still use the values (e.g. T.precise in the example above) in numeric
414-- contexts. In such cases you'll get the possibly-imprecise numeric version, but in string contexts
415-- and when the data finds its way to this package's encode() function, the original full-precision
416-- representation is used.
417--
418-- Even without using the JSON.decodeNumbersAsObjects option, you can encode numbers
419-- in your Lua table that retain high precision upon encoding to JSON, by using the JSON:asNumber()
420-- function:
421--
422-- T = {
423-- imprecise = 123456789123456789.123456789123456789,
424-- precise = JSON:asNumber("123456789123456789.123456789123456789")
425-- }
426--
427-- print(JSON:encode_pretty(T))
428--
429-- This produces:
430--
431-- {
432-- "precise": 123456789123456789.123456789123456789,
433-- "imprecise": 1.2345678912346e+17
434-- }
435--
436--
437--
438-- A different way to handle big/precise JSON numbers is to have decode() merely return
439-- the exact string representation of the number instead of the number itself.
440-- This approach might be useful when the numbers are merely some kind of opaque
441-- object identifier and you want to work with them in Lua as strings anyway.
442--
443-- This approach is enabled by setting
444--
445-- JSON.decodeIntegerStringificationLength = 10
446--
447-- The value is the number of digits (of the integer part of the number) at which to stringify numbers.
448--
449-- Consider our previous example with this option set to 10:
450--
451-- JSON.decodeIntegerStringificationLength = 10
452--
453-- T = JSON:decode('{ "small":12345, "big":12345678901234567890123456789, "precise":9876.67890123456789012345 }')
454--
455-- print("small: ", type(T.small), T.small)
456-- print("big: ", type(T.big), T.big)
457-- print("precise: ", type(T.precise), T.precise)
458--
459-- This produces:
460--
461-- small: number 12345
462-- big: string 12345678901234567890123456789
463-- precise: number 9876.6789012346
464--
465-- The long integer of the 'big' field is at least JSON.decodeIntegerStringificationLength digits
466-- in length, so it's converted not to a Lua integer but to a Lua string. Using a value of 0 or 1 ensures
467-- that all JSON numeric data becomes strings in Lua.
468--
469-- Note that unlike
470-- JSON.decodeNumbersAsObjects = true
471-- this stringification is simple and unintelligent: the JSON number simply becomes a Lua string, and that's the end of it.
472-- If the string is then converted back to JSON, it's still a string. After running the code above, adding
473-- print(JSON:encode(T))
474-- produces
475-- {"big":"12345678901234567890123456789","precise":9876.6789012346,"small":12345}
476-- which is unlikely to be desired.
477--
478-- There's a comparable option for the length of the decimal part of a number:
479--
480-- JSON.decodeDecimalStringificationLength
481--
482-- This can be used alone or in conjunction with
483--
484-- JSON.decodeIntegerStringificationLength
485--
486-- to trip stringification on precise numbers with at least JSON.decodeIntegerStringificationLength digits after
487-- the decimal point.
488--
489-- This example:
490--
491-- JSON.decodeIntegerStringificationLength = 10
492-- JSON.decodeDecimalStringificationLength = 5
493--
494-- T = JSON:decode('{ "small":12345, "big":12345678901234567890123456789, "precise":9876.67890123456789012345 }')
495--
496-- print("small: ", type(T.small), T.small)
497-- print("big: ", type(T.big), T.big)
498-- print("precise: ", type(T.precise), T.precise)
499--
500-- produces:
501--
502-- small: number 12345
503-- big: string 12345678901234567890123456789
504-- precise: string 9876.67890123456789012345
505--
506--
507--
508--
509--
510-- SUMMARY OF METHODS YOU CAN OVERRIDE IN YOUR LOCAL LUA JSON OBJECT
511--
512-- assert
513-- onDecodeError
514-- onDecodeOfNilError
515-- onDecodeOfHTMLError
516-- onTrailingGarbage
517-- onEncodeError
518--
519-- If you want to create a separate Lua JSON object with its own error handlers,
520-- you can reload JSON.lua or use the :new() method.
521--
522---------------------------------------------------------------------------
523
524local default_pretty_indent = " "
525local default_pretty_options = { pretty = true, align_keys = false, indent = default_pretty_indent }
526
527local isArray = { __tostring = function() return "JSON array" end } isArray.__index = isArray
528local isObject = { __tostring = function() return "JSON object" end } isObject.__index = isObject
529
530function OBJDEF:newArray(tbl)
531 return setmetatable(tbl or {}, isArray)
532end
533
534function OBJDEF:newObject(tbl)
535 return setmetatable(tbl or {}, isObject)
536end
537
538
539
540
541local function getnum(op)
542 return type(op) == 'number' and op or op.N
543end
544
545local isNumber = {
546 __tostring = function(T) return T.S end,
547 __unm = function(op) return getnum(op) end,
548
549 __concat = function(op1, op2) return tostring(op1) .. tostring(op2) end,
550 __add = function(op1, op2) return getnum(op1) + getnum(op2) end,
551 __sub = function(op1, op2) return getnum(op1) - getnum(op2) end,
552 __mul = function(op1, op2) return getnum(op1) * getnum(op2) end,
553 __div = function(op1, op2) return getnum(op1) / getnum(op2) end,
554 __mod = function(op1, op2) return getnum(op1) % getnum(op2) end,
555 __pow = function(op1, op2) return getnum(op1) ^ getnum(op2) end,
556 __lt = function(op1, op2) return getnum(op1) < getnum(op2) end,
557 __eq = function(op1, op2) return getnum(op1) == getnum(op2) end,
558 __le = function(op1, op2) return getnum(op1) <= getnum(op2) end,
559}
560isNumber.__index = isNumber
561
562function OBJDEF:asNumber(item)
563
564 if getmetatable(item) == isNumber then
565 -- it's already a JSON number object.
566 return item
567 elseif type(item) == 'table' and type(item.S) == 'string' and type(item.N) == 'number' then
568 -- it's a number-object table that lost its metatable, so give it one
569 return setmetatable(item, isNumber)
570 else
571 -- the normal situation... given a number or a string representation of a number....
572 local holder = {
573 S = tostring(item), -- S is the representation of the number as a string, which remains precise
574 N = tonumber(item), -- N is the number as a Lua number.
575 }
576 return setmetatable(holder, isNumber)
577 end
578end
579
580--
581-- Given an item that might be a normal string or number, or might be an 'isNumber' object defined above,
582-- return the string version. This shouldn't be needed often because the 'isNumber' object should autoconvert
583-- to a string in most cases, but it's here to allow it to be forced when needed.
584--
585function OBJDEF:forceString(item)
586 if type(item) == 'table' and type(item.S) == 'string' then
587 return item.S
588 else
589 return tostring(item)
590 end
591end
592
593--
594-- Given an item that might be a normal string or number, or might be an 'isNumber' object defined above,
595-- return the numeric version.
596--
597function OBJDEF:forceNumber(item)
598 if type(item) == 'table' and type(item.N) == 'number' then
599 return item.N
600 else
601 return tonumber(item)
602 end
603end
604
605
606local function unicode_codepoint_as_utf8(codepoint)
607 --
608 -- codepoint is a number
609 --
610 if codepoint <= 127 then
611 return string.char(codepoint)
612
613 elseif codepoint <= 2047 then
614 --
615 -- 110yyyxx 10xxxxxx <-- useful notation from http://en.wikipedia.org/wiki/Utf8
616 --
617 local highpart = math.floor(codepoint / 0x40)
618 local lowpart = codepoint - (0x40 * highpart)
619 return string.char(0xC0 + highpart,
620 0x80 + lowpart)
621
622 elseif codepoint <= 65535 then
623 --
624 -- 1110yyyy 10yyyyxx 10xxxxxx
625 --
626 local highpart = math.floor(codepoint / 0x1000)
627 local remainder = codepoint - 0x1000 * highpart
628 local midpart = math.floor(remainder / 0x40)
629 local lowpart = remainder - 0x40 * midpart
630
631 highpart = 0xE0 + highpart
632 midpart = 0x80 + midpart
633 lowpart = 0x80 + lowpart
634
635 --
636 -- Check for an invalid character (thanks Andy R. at Adobe).
637 -- See table 3.7, page 93, in http://www.unicode.org/versions/Unicode5.2.0/ch03.pdf#G28070
638 --
639 if ( highpart == 0xE0 and midpart < 0xA0 ) or
640 ( highpart == 0xED and midpart > 0x9F ) or
641 ( highpart == 0xF0 and midpart < 0x90 ) or
642 ( highpart == 0xF4 and midpart > 0x8F )
643 then
644 return "?"
645 else
646 return string.char(highpart,
647 midpart,
648 lowpart)
649 end
650
651 else
652 --
653 -- 11110zzz 10zzyyyy 10yyyyxx 10xxxxxx
654 --
655 local highpart = math.floor(codepoint / 0x40000)
656 local remainder = codepoint - 0x40000 * highpart
657 local midA = math.floor(remainder / 0x1000)
658 remainder = remainder - 0x1000 * midA
659 local midB = math.floor(remainder / 0x40)
660 local lowpart = remainder - 0x40 * midB
661
662 return string.char(0xF0 + highpart,
663 0x80 + midA,
664 0x80 + midB,
665 0x80 + lowpart)
666 end
667end
668
669function OBJDEF:onDecodeError(message, text, location, etc)
670 if text then
671 if location then
672 message = string.format("%s at byte %d of: %s", message, location, text)
673 else
674 message = string.format("%s: %s", message, text)
675 end
676 end
677
678 if etc ~= nil then
679 message = message .. " (" .. OBJDEF:encode(etc) .. ")"
680 end
681
682 if self.assert then
683 self.assert(false, message)
684 else
685 assert(false, message)
686 end
687end
688
689function OBJDEF:onTrailingGarbage(json_text, location, parsed_value, etc)
690 return self:onDecodeError("trailing garbage", json_text, location, etc)
691end
692
693OBJDEF.onDecodeOfNilError = OBJDEF.onDecodeError
694OBJDEF.onDecodeOfHTMLError = OBJDEF.onDecodeError
695
696function OBJDEF:onEncodeError(message, etc)
697 if etc ~= nil then
698 message = message .. " (" .. OBJDEF:encode(etc) .. ")"
699 end
700
701 if self.assert then
702 self.assert(false, message)
703 else
704 assert(false, message)
705 end
706end
707
708local function grok_number(self, text, start, options)
709 --
710 -- Grab the integer part
711 --
712 local integer_part = text:match('^-?[1-9]%d*', start)
713 or text:match("^-?0", start)
714
715 if not integer_part then
716 self:onDecodeError("expected number", text, start, options.etc)
717 return nil, start -- in case the error method doesn't abort, return something sensible
718 end
719
720 local i = start + integer_part:len()
721
722 --
723 -- Grab an optional decimal part
724 --
725 local decimal_part = text:match('^%.%d+', i) or ""
726
727 i = i + decimal_part:len()
728
729 --
730 -- Grab an optional exponential part
731 --
732 local exponent_part = text:match('^[eE][-+]?%d+', i) or ""
733
734 i = i + exponent_part:len()
735
736 local full_number_text = integer_part .. decimal_part .. exponent_part
737
738 if options.decodeNumbersAsObjects then
739 return OBJDEF:asNumber(full_number_text), i
740 end
741
742 --
743 -- If we're told to stringify under certain conditions, so do.
744 -- We punt a bit when there's an exponent by just stringifying no matter what.
745 -- I suppose we should really look to see whether the exponent is actually big enough one
746 -- way or the other to trip stringification, but I'll be lazy about it until someone asks.
747 --
748 if (options.decodeIntegerStringificationLength
749 and
750 (integer_part:len() >= options.decodeIntegerStringificationLength or exponent_part:len() > 0))
751
752 or
753
754 (options.decodeDecimalStringificationLength
755 and
756 (decimal_part:len() >= options.decodeDecimalStringificationLength or exponent_part:len() > 0))
757 then
758 return full_number_text, i -- this returns the exact string representation seen in the original JSON
759 end
760
761
762
763 local as_number = tonumber(full_number_text)
764
765 if not as_number then
766 self:onDecodeError("bad number", text, start, options.etc)
767 return nil, start -- in case the error method doesn't abort, return something sensible
768 end
769
770 return as_number, i
771end
772
773
774local function grok_string(self, text, start, options)
775
776 if text:sub(start,start) ~= '"' then
777 self:onDecodeError("expected string's opening quote", text, start, options.etc)
778 return nil, start -- in case the error method doesn't abort, return something sensible
779 end
780
781 local i = start + 1 -- +1 to bypass the initial quote
782 local text_len = text:len()
783 local VALUE = ""
784 while i <= text_len do
785 local c = text:sub(i,i)
786 if c == '"' then
787 return VALUE, i + 1
788 end
789 if c ~= '\\' then
790 VALUE = VALUE .. c
791 i = i + 1
792 elseif text:match('^\\b', i) then
793 VALUE = VALUE .. "\b"
794 i = i + 2
795 elseif text:match('^\\f', i) then
796 VALUE = VALUE .. "\f"
797 i = i + 2
798 elseif text:match('^\\n', i) then
799 VALUE = VALUE .. "\n"
800 i = i + 2
801 elseif text:match('^\\r', i) then
802 VALUE = VALUE .. "\r"
803 i = i + 2
804 elseif text:match('^\\t', i) then
805 VALUE = VALUE .. "\t"
806 i = i + 2
807 else
808 local hex = text:match('^\\u([0123456789aAbBcCdDeEfF][0123456789aAbBcCdDeEfF][0123456789aAbBcCdDeEfF][0123456789aAbBcCdDeEfF])', i)
809 if hex then
810 i = i + 6 -- bypass what we just read
811
812 -- We have a Unicode codepoint. It could be standalone, or if in the proper range and
813 -- followed by another in a specific range, it'll be a two-code surrogate pair.
814 local codepoint = tonumber(hex, 16)
815 if codepoint >= 0xD800 and codepoint <= 0xDBFF then
816 -- it's a hi surrogate... see whether we have a following low
817 local lo_surrogate = text:match('^\\u([dD][cdefCDEF][0123456789aAbBcCdDeEfF][0123456789aAbBcCdDeEfF])', i)
818 if lo_surrogate then
819 i = i + 6 -- bypass the low surrogate we just read
820 codepoint = 0x2400 + (codepoint - 0xD800) * 0x400 + tonumber(lo_surrogate, 16)
821 else
822 -- not a proper low, so we'll just leave the first codepoint as is and spit it out.
823 end
824 end
825 VALUE = VALUE .. unicode_codepoint_as_utf8(codepoint)
826
827 else
828
829 -- just pass through what's escaped
830 VALUE = VALUE .. text:match('^\\(.)', i)
831 i = i + 2
832 end
833 end
834 end
835
836 self:onDecodeError("unclosed string", text, start, options.etc)
837 return nil, start -- in case the error method doesn't abort, return something sensible
838end
839
840local function skip_whitespace(text, start)
841
842 local _, match_end = text:find("^[ \n\r\t]+", start) -- [http://www.ietf.org/rfc/rfc4627.txt] Section 2
843 if match_end then
844 return match_end + 1
845 else
846 return start
847 end
848end
849
850local grok_one -- assigned later
851
852local function grok_object(self, text, start, options)
853
854 if text:sub(start,start) ~= '{' then
855 self:onDecodeError("expected '{'", text, start, options.etc)
856 return nil, start -- in case the error method doesn't abort, return something sensible
857 end
858
859 local i = skip_whitespace(text, start + 1) -- +1 to skip the '{'
860
861 local VALUE = self.strictTypes and self:newObject { } or { }
862
863 if text:sub(i,i) == '}' then
864 return VALUE, i + 1
865 end
866 local text_len = text:len()
867 while i <= text_len do
868 local key, new_i = grok_string(self, text, i, options)
869
870 i = skip_whitespace(text, new_i)
871
872 if text:sub(i, i) ~= ':' then
873 self:onDecodeError("expected colon", text, i, options.etc)
874 return nil, i -- in case the error method doesn't abort, return something sensible
875 end
876
877 i = skip_whitespace(text, i + 1)
878
879 local new_val, new_i = grok_one(self, text, i, options)
880
881 VALUE[key] = new_val
882
883 --
884 -- Expect now either '}' to end things, or a ',' to allow us to continue.
885 --
886 i = skip_whitespace(text, new_i)
887
888 local c = text:sub(i,i)
889
890 if c == '}' then
891 return VALUE, i + 1
892 end
893
894 if text:sub(i, i) ~= ',' then
895 self:onDecodeError("expected comma or '}'", text, i, options.etc)
896 return nil, i -- in case the error method doesn't abort, return something sensible
897 end
898
899 i = skip_whitespace(text, i + 1)
900 end
901
902 self:onDecodeError("unclosed '{'", text, start, options.etc)
903 return nil, start -- in case the error method doesn't abort, return something sensible
904end
905
906local function grok_array(self, text, start, options)
907 if text:sub(start,start) ~= '[' then
908 self:onDecodeError("expected '['", text, start, options.etc)
909 return nil, start -- in case the error method doesn't abort, return something sensible
910 end
911
912 local i = skip_whitespace(text, start + 1) -- +1 to skip the '['
913 local VALUE = self.strictTypes and self:newArray { } or { }
914 if text:sub(i,i) == ']' then
915 return VALUE, i + 1
916 end
917
918 local VALUE_INDEX = 1
919
920 local text_len = text:len()
921 while i <= text_len do
922 local val, new_i = grok_one(self, text, i, options)
923
924 -- can't table.insert(VALUE, val) here because it's a no-op if val is nil
925 VALUE[VALUE_INDEX] = val
926 VALUE_INDEX = VALUE_INDEX + 1
927
928 i = skip_whitespace(text, new_i)
929
930 --
931 -- Expect now either ']' to end things, or a ',' to allow us to continue.
932 --
933 local c = text:sub(i,i)
934 if c == ']' then
935 return VALUE, i + 1
936 end
937 if text:sub(i, i) ~= ',' then
938 self:onDecodeError("expected comma or ']'", text, i, options.etc)
939 return nil, i -- in case the error method doesn't abort, return something sensible
940 end
941 i = skip_whitespace(text, i + 1)
942 end
943 self:onDecodeError("unclosed '['", text, start, options.etc)
944 return nil, i -- in case the error method doesn't abort, return something sensible
945end
946
947
948grok_one = function(self, text, start, options)
949 -- Skip any whitespace
950 start = skip_whitespace(text, start)
951
952 if start > text:len() then
953 self:onDecodeError("unexpected end of string", text, nil, options.etc)
954 return nil, start -- in case the error method doesn't abort, return something sensible
955 end
956
957 if text:find('^"', start) then
958 return grok_string(self, text, start, options.etc)
959
960 elseif text:find('^[-0123456789 ]', start) then
961 return grok_number(self, text, start, options)
962
963 elseif text:find('^%{', start) then
964 return grok_object(self, text, start, options)
965
966 elseif text:find('^%[', start) then
967 return grok_array(self, text, start, options)
968
969 elseif text:find('^true', start) then
970 return true, start + 4
971
972 elseif text:find('^false', start) then
973 return false, start + 5
974
975 elseif text:find('^null', start) then
976 return nil, start + 4
977
978 else
979 self:onDecodeError("can't parse JSON", text, start, options.etc)
980 return nil, 1 -- in case the error method doesn't abort, return something sensible
981 end
982end
983
984function OBJDEF:decode(text, etc, options)
985 --
986 -- If the user didn't pass in a table of decode options, make an empty one.
987 --
988 if type(options) ~= 'table' then
989 options = {}
990 end
991
992 --
993 -- If they passed in an 'etc' argument, stuff it into the options.
994 -- (If not, any 'etc' field in the options they passed in remains to be used)
995 --
996 if etc ~= nil then
997 options.etc = etc
998 end
999
1000
1001 if type(self) ~= 'table' or self.__index ~= OBJDEF then
1002 local error_message = "JSON:decode must be called in method format"
1003 OBJDEF:onDecodeError(error_message, nil, nil, options.etc)
1004 return nil, error_message -- in case the error method doesn't abort, return something sensible
1005 end
1006
1007 if text == nil then
1008 local error_message = "nil passed to JSON:decode()"
1009 self:onDecodeOfNilError(error_message, nil, nil, options.etc)
1010 return nil, error_message -- in case the error method doesn't abort, return something sensible
1011
1012 elseif type(text) ~= 'string' then
1013 local error_message = "expected string argument to JSON:decode()"
1014 self:onDecodeError(string.format("%s, got %s", error_message, type(text)), nil, nil, options.etc)
1015 return nil, error_message -- in case the error method doesn't abort, return something sensible
1016 end
1017
1018 if text:match('^%s*$') then
1019 -- an empty string is nothing, but not an error
1020 return nil
1021 end
1022
1023 if text:match('^%s*<') then
1024 -- Can't be JSON... we'll assume it's HTML
1025 local error_message = "HTML passed to JSON:decode()"
1026 self:onDecodeOfHTMLError(error_message, text, nil, options.etc)
1027 return nil, error_message -- in case the error method doesn't abort, return something sensible
1028 end
1029
1030 --
1031 -- Ensure that it's not UTF-32 or UTF-16.
1032 -- Those are perfectly valid encodings for JSON (as per RFC 4627 section 3),
1033 -- but this package can't handle them.
1034 --
1035 if text:sub(1,1):byte() == 0 or (text:len() >= 2 and text:sub(2,2):byte() == 0) then
1036 local error_message = "JSON package groks only UTF-8, sorry"
1037 self:onDecodeError(error_message, text, nil, options.etc)
1038 return nil, error_message -- in case the error method doesn't abort, return something sensible
1039 end
1040
1041 --
1042 -- apply global options
1043 --
1044 if options.decodeNumbersAsObjects == nil then
1045 options.decodeNumbersAsObjects = self.decodeNumbersAsObjects
1046 end
1047 if options.decodeIntegerStringificationLength == nil then
1048 options.decodeIntegerStringificationLength = self.decodeIntegerStringificationLength
1049 end
1050 if options.decodeDecimalStringificationLength == nil then
1051 options.decodeDecimalStringificationLength = self.decodeDecimalStringificationLength
1052 end
1053
1054 --
1055 -- Finally, go parse it
1056 --
1057 local success, value, next_i = pcall(grok_one, self, text, 1, options)
1058
1059 if success then
1060
1061 local error_message = nil
1062 if next_i ~= #text + 1 then
1063 -- something's left over after we parsed the first thing.... whitespace is allowed.
1064 next_i = skip_whitespace(text, next_i)
1065
1066 -- if we have something left over now, it's trailing garbage
1067 if next_i ~= #text + 1 then
1068 value, error_message = self:onTrailingGarbage(text, next_i, value, options.etc)
1069 end
1070 end
1071 return value, error_message
1072
1073 else
1074
1075 -- If JSON:onDecodeError() didn't abort out of the pcall, we'll have received
1076 -- the error message here as "value", so pass it along as an assert.
1077 local error_message = value
1078 if self.assert then
1079 self.assert(false, error_message)
1080 else
1081 assert(false, error_message)
1082 end
1083 -- ...and if we're still here (because the assert didn't throw an error),
1084 -- return a nil and throw the error message on as a second arg
1085 return nil, error_message
1086
1087 end
1088end
1089
1090local function backslash_replacement_function(c)
1091 if c == "\n" then
1092 return "\\n"
1093 elseif c == "\r" then
1094 return "\\r"
1095 elseif c == "\t" then
1096 return "\\t"
1097 elseif c == "\b" then
1098 return "\\b"
1099 elseif c == "\f" then
1100 return "\\f"
1101 elseif c == '"' then
1102 return '\\"'
1103 elseif c == '\\' then
1104 return '\\\\'
1105 else
1106 return string.format("\\u%04x", c:byte())
1107 end
1108end
1109
1110local chars_to_be_escaped_in_JSON_string
1111 = '['
1112 .. '"' -- class sub-pattern to match a double quote
1113 .. '%\\' -- class sub-pattern to match a backslash
1114 .. '%z' -- class sub-pattern to match a null
1115 .. '\001' .. '-' .. '\031' -- class sub-pattern to match control characters
1116 .. ']'
1117
1118
1119local LINE_SEPARATOR_as_utf8 = unicode_codepoint_as_utf8(0x2028)
1120local PARAGRAPH_SEPARATOR_as_utf8 = unicode_codepoint_as_utf8(0x2029)
1121local function json_string_literal(value, options)
1122 local newval = value:gsub(chars_to_be_escaped_in_JSON_string, backslash_replacement_function)
1123 if options.stringsAreUtf8 then
1124 --
1125 -- This feels really ugly to just look into a string for the sequence of bytes that we know to be a particular utf8 character,
1126 -- but utf8 was designed purposefully to make this kind of thing possible. Still, feels dirty.
1127 -- I'd rather decode the byte stream into a character stream, but it's not technically needed so
1128 -- not technically worth it.
1129 --
1130 newval = newval:gsub(LINE_SEPARATOR_as_utf8, '\\u2028'):gsub(PARAGRAPH_SEPARATOR_as_utf8,'\\u2029')
1131 end
1132 return '"' .. newval .. '"'
1133end
1134
1135local function object_or_array(self, T, etc)
1136 --
1137 -- We need to inspect all the keys... if there are any strings, we'll convert to a JSON
1138 -- object. If there are only numbers, it's a JSON array.
1139 --
1140 -- If we'll be converting to a JSON object, we'll want to sort the keys so that the
1141 -- end result is deterministic.
1142 --
1143 local string_keys = { }
1144 local number_keys = { }
1145 local number_keys_must_be_strings = false
1146 local maximum_number_key
1147
1148 for key in pairs(T) do
1149 if type(key) == 'string' then
1150 table.insert(string_keys, key)
1151 elseif type(key) == 'number' then
1152 table.insert(number_keys, key)
1153 if key <= 0 or key >= math.huge then
1154 number_keys_must_be_strings = true
1155 elseif not maximum_number_key or key > maximum_number_key then
1156 maximum_number_key = key
1157 end
1158 else
1159 self:onEncodeError("can't encode table with a key of type " .. type(key), etc)
1160 end
1161 end
1162
1163 if #string_keys == 0 and not number_keys_must_be_strings then
1164 --
1165 -- An empty table, or a numeric-only array
1166 --
1167 if #number_keys > 0 then
1168 return nil, maximum_number_key -- an array
1169 elseif tostring(T) == "JSON array" then
1170 return nil
1171 elseif tostring(T) == "JSON object" then
1172 return { }
1173 else
1174 -- have to guess, so we'll pick array, since empty arrays are likely more common than empty objects
1175 return nil
1176 end
1177 end
1178
1179 table.sort(string_keys)
1180
1181 local map
1182 if #number_keys > 0 then
1183 --
1184 -- If we're here then we have either mixed string/number keys, or numbers inappropriate for a JSON array
1185 -- It's not ideal, but we'll turn the numbers into strings so that we can at least create a JSON object.
1186 --
1187
1188 if self.noKeyConversion then
1189 self:onEncodeError("a table with both numeric and string keys could be an object or array; aborting", etc)
1190 end
1191
1192 --
1193 -- Have to make a shallow copy of the source table so we can remap the numeric keys to be strings
1194 --
1195 map = { }
1196 for key, val in pairs(T) do
1197 map[key] = val
1198 end
1199
1200 table.sort(number_keys)
1201
1202 --
1203 -- Throw numeric keys in there as strings
1204 --
1205 for _, number_key in ipairs(number_keys) do
1206 local string_key = tostring(number_key)
1207 if map[string_key] == nil then
1208 table.insert(string_keys , string_key)
1209 map[string_key] = T[number_key]
1210 else
1211 self:onEncodeError("conflict converting table with mixed-type keys into a JSON object: key " .. number_key .. " exists both as a string and a number.", etc)
1212 end
1213 end
1214 end
1215
1216 return string_keys, nil, map
1217end
1218
1219--
1220-- Encode
1221--
1222-- 'options' is nil, or a table with possible keys:
1223--
1224-- pretty -- If true, return a pretty-printed version.
1225--
1226-- indent -- A string (usually of spaces) used to indent each nested level.
1227--
1228-- align_keys -- If true, align all the keys when formatting a table.
1229--
1230-- null -- If this exists with a string value, table elements with this value are output as JSON null.
1231--
1232-- stringsAreUtf8 -- If true, consider Lua strings not as a sequence of bytes, but as a sequence of UTF-8 characters.
1233-- (Currently, the only practical effect of setting this option is that Unicode LINE and PARAGRAPH
1234-- separators, if found in a string, are encoded with a JSON escape instead of as raw UTF-8.
1235-- The JSON is valid either way, but encoding this way, apparently, allows the resulting JSON
1236-- to also be valid Java.)
1237--
1238--
1239local encode_value -- must predeclare because it calls itself
1240function encode_value(self, value, parents, etc, options, indent, for_key)
1241
1242 --
1243 -- keys in a JSON object can never be null, so we don't even consider options.null when converting a key value
1244 --
1245 if value == nil or (not for_key and options and options.null and value == options.null) then
1246 return 'null'
1247
1248 elseif type(value) == 'string' then
1249 return json_string_literal(value, options)
1250
1251 elseif type(value) == 'number' then
1252 if value ~= value then
1253 --
1254 -- NaN (Not a Number).
1255 -- JSON has no NaN, so we have to fudge the best we can. This should really be a package option.
1256 --
1257 return "null"
1258 elseif value >= math.huge then
1259 --
1260 -- Positive infinity. JSON has no INF, so we have to fudge the best we can. This should
1261 -- really be a package option. Note: at least with some implementations, positive infinity
1262 -- is both ">= math.huge" and "<= -math.huge", which makes no sense but that's how it is.
1263 -- Negative infinity is properly "<= -math.huge". So, we must be sure to check the ">="
1264 -- case first.
1265 --
1266 return "1e+9999"
1267 elseif value <= -math.huge then
1268 --
1269 -- Negative infinity.
1270 -- JSON has no INF, so we have to fudge the best we can. This should really be a package option.
1271 --
1272 return "-1e+9999"
1273 else
1274 return tostring(value)
1275 end
1276
1277 elseif type(value) == 'boolean' then
1278 return tostring(value)
1279
1280 elseif type(value) ~= 'table' then
1281 self:onEncodeError("can't convert " .. type(value) .. " to JSON", etc)
1282
1283 elseif getmetatable(value) == isNumber then
1284 return tostring(value)
1285 else
1286 --
1287 -- A table to be converted to either a JSON object or array.
1288 --
1289 local T = value
1290
1291 if type(options) ~= 'table' then
1292 options = {}
1293 end
1294 if type(indent) ~= 'string' then
1295 indent = ""
1296 end
1297
1298 if parents[T] then
1299 self:onEncodeError("table " .. tostring(T) .. " is a child of itself", etc)
1300 else
1301 parents[T] = true
1302 end
1303
1304 local result_value
1305
1306 local object_keys, maximum_number_key, map = object_or_array(self, T, etc)
1307 if maximum_number_key then
1308 --
1309 -- An array...
1310 --
1311 local ITEMS = { }
1312 for i = 1, maximum_number_key do
1313 table.insert(ITEMS, encode_value(self, T[i], parents, etc, options, indent))
1314 end
1315
1316 if options.pretty then
1317 result_value = "[ " .. table.concat(ITEMS, ", ") .. " ]"
1318 else
1319 result_value = "[" .. table.concat(ITEMS, ",") .. "]"
1320 end
1321
1322 elseif object_keys then
1323 --
1324 -- An object
1325 --
1326 local TT = map or T
1327
1328 if options.pretty then
1329
1330 local KEYS = { }
1331 local max_key_length = 0
1332 for _, key in ipairs(object_keys) do
1333 local encoded = encode_value(self, tostring(key), parents, etc, options, indent, true)
1334 if options.align_keys then
1335 max_key_length = math.max(max_key_length, #encoded)
1336 end
1337 table.insert(KEYS, encoded)
1338 end
1339 local key_indent = indent .. tostring(options.indent or "")
1340 local subtable_indent = key_indent .. string.rep(" ", max_key_length) .. (options.align_keys and " " or "")
1341 local FORMAT = "%s%" .. string.format("%d", max_key_length) .. "s: %s"
1342
1343 local COMBINED_PARTS = { }
1344 for i, key in ipairs(object_keys) do
1345 local encoded_val = encode_value(self, TT[key], parents, etc, options, subtable_indent)
1346 table.insert(COMBINED_PARTS, string.format(FORMAT, key_indent, KEYS[i], encoded_val))
1347 end
1348 result_value = "{\n" .. table.concat(COMBINED_PARTS, ",\n") .. "\n" .. indent .. "}"
1349
1350 else
1351
1352 local PARTS = { }
1353 for _, key in ipairs(object_keys) do
1354 local encoded_val = encode_value(self, TT[key], parents, etc, options, indent)
1355 local encoded_key = encode_value(self, tostring(key), parents, etc, options, indent, true)
1356 table.insert(PARTS, string.format("%s:%s", encoded_key, encoded_val))
1357 end
1358 result_value = "{" .. table.concat(PARTS, ",") .. "}"
1359
1360 end
1361 else
1362 --
1363 -- An empty array/object... we'll treat it as an array, though it should really be an option
1364 --
1365 result_value = "[]"
1366 end
1367
1368 parents[T] = false
1369 return result_value
1370 end
1371end
1372
1373local function top_level_encode(self, value, etc, options)
1374 local val = encode_value(self, value, {}, etc, options)
1375 if val == nil then
1376 --PRIVATE("may need to revert to the previous public verison if I can't figure out what the guy wanted")
1377 return val
1378 else
1379 return val
1380 end
1381end
1382
1383function OBJDEF:encode(value, etc, options)
1384 if type(self) ~= 'table' or self.__index ~= OBJDEF then
1385 OBJDEF:onEncodeError("JSON:encode must be called in method format", etc)
1386 end
1387
1388 --
1389 -- If the user didn't pass in a table of decode options, make an empty one.
1390 --
1391 if type(options) ~= 'table' then
1392 options = {}
1393 end
1394
1395 return top_level_encode(self, value, etc, options)
1396end
1397
1398function OBJDEF:encode_pretty(value, etc, options)
1399 if type(self) ~= 'table' or self.__index ~= OBJDEF then
1400 OBJDEF:onEncodeError("JSON:encode_pretty must be called in method format", etc)
1401 end
1402
1403 --
1404 -- If the user didn't pass in a table of decode options, use the default pretty ones
1405 --
1406 if type(options) ~= 'table' then
1407 options = default_pretty_options
1408 end
1409
1410 return top_level_encode(self, value, etc, options)
1411end
1412
1413function OBJDEF.__tostring()
1414 return "JSON encode/decode package"
1415end
1416
1417OBJDEF.__index = OBJDEF
1418
1419function OBJDEF:new(args)
1420 local new = { }
1421
1422 if args then
1423 for key, val in pairs(args) do
1424 new[key] = val
1425 end
1426 end
1427
1428 return setmetatable(new, OBJDEF)
1429end
1430
1431return OBJDEF:new()
1432
1433--
1434-- Version history:
1435--
1436-- 20161109.21 Oops, had a small boo-boo in the previous update.
1437--
1438-- 20161103.20 Used to silently ignore trailing garbage when decoding. Now fails via JSON:onTrailingGarbage()
1439-- http://seriot.ch/parsing_json.php
1440--
1441-- Built-in error message about "expected comma or ']'" had mistakenly referred to '['
1442--
1443-- Updated the built-in error reporting to refer to bytes rather than characters.
1444--
1445-- The decode() method no longer assumes that error handlers abort.
1446--
1447-- Made the VERSION string a string instead of a number
1448--
1449
1450-- 20160916.19 Fixed the isNumber.__index assignment (thanks to Jack Taylor)
1451--
1452-- 20160730.18 Added JSON:forceString() and JSON:forceNumber()
1453--
1454-- 20160728.17 Added concatenation to the metatable for JSON:asNumber()
1455--
1456-- 20160709.16 Could crash if not passed an options table (thanks jarno heikkinen <jarnoh@capturemonkey.com>).
1457--
1458-- Made JSON:asNumber() a bit more resilient to being passed the results of itself.
1459--
1460-- 20160526.15 Added the ability to easily encode null values in JSON, via the new "null" encoding option.
1461-- (Thanks to Adam B for bringing up the issue.)
1462--
1463-- Added some support for very large numbers and precise floats via
1464-- JSON.decodeNumbersAsObjects
1465-- JSON.decodeIntegerStringificationLength
1466-- JSON.decodeDecimalStringificationLength
1467--
1468-- Added the "stringsAreUtf8" encoding option. (Hat tip to http://lua-users.org/wiki/JsonModules )
1469--
1470-- 20141223.14 The encode_pretty() routine produced fine results for small datasets, but isn't really
1471-- appropriate for anything large, so with help from Alex Aulbach I've made the encode routines
1472-- more flexible, and changed the default encode_pretty() to be more generally useful.
1473--
1474-- Added a third 'options' argument to the encode() and encode_pretty() routines, to control
1475-- how the encoding takes place.
1476--
1477-- Updated docs to add assert() call to the loadfile() line, just as good practice so that
1478-- if there is a problem loading JSON.lua, the appropriate error message will percolate up.
1479--
1480-- 20140920.13 Put back (in a way that doesn't cause warnings about unused variables) the author string,
1481-- so that the source of the package, and its version number, are visible in compiled copies.
1482--
1483-- 20140911.12 Minor lua cleanup.
1484-- Fixed internal reference to 'JSON.noKeyConversion' to reference 'self' instead of 'JSON'.
1485-- (Thanks to SmugMug's David Parry for these.)
1486--
1487-- 20140418.11 JSON nulls embedded within an array were being ignored, such that
1488-- ["1",null,null,null,null,null,"seven"],
1489-- would return
1490-- {1,"seven"}
1491-- It's now fixed to properly return
1492-- {1, nil, nil, nil, nil, nil, "seven"}
1493-- Thanks to "haddock" for catching the error.
1494--
1495-- 20140116.10 The user's JSON.assert() wasn't always being used. Thanks to "blue" for the heads up.
1496--
1497-- 20131118.9 Update for Lua 5.3... it seems that tostring(2/1) produces "2.0" instead of "2",
1498-- and this caused some problems.
1499--
1500-- 20131031.8 Unified the code for encode() and encode_pretty(); they had been stupidly separate,
1501-- and had of course diverged (encode_pretty didn't get the fixes that encode got, so
1502-- sometimes produced incorrect results; thanks to Mattie for the heads up).
1503--
1504-- Handle encoding tables with non-positive numeric keys (unlikely, but possible).
1505--
1506-- If a table has both numeric and string keys, or its numeric keys are inappropriate
1507-- (such as being non-positive or infinite), the numeric keys are turned into
1508-- string keys appropriate for a JSON object. So, as before,
1509-- JSON:encode({ "one", "two", "three" })
1510-- produces the array
1511-- ["one","two","three"]
1512-- but now something with mixed key types like
1513-- JSON:encode({ "one", "two", "three", SOMESTRING = "some string" }))
1514-- instead of throwing an error produces an object:
1515-- {"1":"one","2":"two","3":"three","SOMESTRING":"some string"}
1516--
1517-- To maintain the prior throw-an-error semantics, set
1518-- JSON.noKeyConversion = true
1519--
1520-- 20131004.7 Release under a Creative Commons CC-BY license, which I should have done from day one, sorry.
1521--
1522-- 20130120.6 Comment update: added a link to the specific page on my blog where this code can
1523-- be found, so that folks who come across the code outside of my blog can find updates
1524-- more easily.
1525--
1526-- 20111207.5 Added support for the 'etc' arguments, for better error reporting.
1527--
1528-- 20110731.4 More feedback from David Kolf on how to make the tests for Nan/Infinity system independent.
1529--
1530-- 20110730.3 Incorporated feedback from David Kolf at http://lua-users.org/wiki/JsonModules:
1531--
1532-- * When encoding lua for JSON, Sparse numeric arrays are now handled by
1533-- spitting out full arrays, such that
1534-- JSON:encode({"one", "two", [10] = "ten"})
1535-- returns
1536-- ["one","two",null,null,null,null,null,null,null,"ten"]
1537--
1538-- In 20100810.2 and earlier, only up to the first non-null value would have been retained.
1539--
1540-- * When encoding lua for JSON, numeric value NaN gets spit out as null, and infinity as "1+e9999".
1541-- Version 20100810.2 and earlier created invalid JSON in both cases.
1542--
1543-- * Unicode surrogate pairs are now detected when decoding JSON.
1544--
1545-- 20100810.2 added some checking to ensure that an invalid Unicode character couldn't leak in to the UTF-8 encoding
1546--
1547-- 20100731.1 initial public release
1548--