cJson.ahk

The first and only AutoHotkey JSON library to use embedded compiled C for high performance.

Compatibility

This library is compatible with AutoHotkey v1.1 U64 and U32.

Now that AHKv2 is out of Alpha, it's likely that its object structures will not change significantly again in the future. Compatibility with AHKv2 will require modification to both the AHK wrapper and the C implementation. Support is planned, but may not be implemented any time soon.

Using cJson

Converting an AHK Object to JSON:

#Include <JSON>

; Create an object with every supported data type
obj := ["abc", 123, {"true": true, "false": false, "null": ""}, [JSON.true, JSON.false, JSON.null]]

; Convert to JSON
MsgBox, % JSON.Dump(obj) ; Expect: ["abc", 123, {"false": 0, "null": "", "true": 1}, [true, false, null]]

Converting JSON to an AHK Object:

#Include <JSON>

; Create some JSON
str = ["abc", 123, {"true": 1, "false": 0, "null": ""}, [true, false, null]]
obj := JSON.Load(str)

MsgBox, % obj[1] ; abc
MsgBox, % obj[2] ; 123

MsgBox, % obj[3].true ; 1
MsgBox, % obj[3].false ; 0
MsgBox, % obj[3].null ; *nothing*

MsgBox, % obj[4, 1] ; 1
MsgBox, % obj[4, 2] ; 0
MsgBox, % obj[4, 3] ; *nothing*

; If you set `JSON.BoolsAsInts := false` before calling JSON.Load
;MsgBox, % obj[4, 1] == JSON.True ; 1
;MsgBox, % obj[4, 2] == JSON.False ; 1

; If you set `JSON.NullsAsStrings := false` before calling JSON.Load
;MsgBox, % obj[4, 3] == JSON.Null ; 1

Notes

Data Types

AutoHotkey does not provide types that uniquely identify all the possible values that may be encoded or decoded. To work around this problem, cJson provides magic objects that give you greater control over how things are encoded. By default, cJson will behave according to the following table:

Value	Encodes as	Decodes as
true	1	1 *
false	0	0 *
null	N/A	"" *
0.5 †	"0.5"	0.500000
0.5+0 †	0.500000	N/A
JSON.True	true	N/A
JSON.False	false	N/A
JSON.Null	null	N/A

* To avoid type data loss when decoding true and false, the class property JSON.BoolsAsInts can be set := false. Once set, boolean true and false will decode to JSON.True and JSON.False respectively. Similarly, for Nulls JSON.NullsAsStrings can be set := false. Once set, null will decode to JSON.Null.

† Pure floats, as generated by an expression, will encode as floats. Hybrid floats that contain a string buffer will encode as strings. Floats hard-coded into a script are saved by AHK as hybrid floats. To force encoding as a float, perform some redundant operation like adding zero.

Array Detection

AutoHotkey makes no internal distinction between indexed-sequential arrays and keyed objects. As a result, this distinction must be chosen heuristically by the cJson library. If an object contains only sequential integer keys starting at 1, it will be rendered as an array. Otherwise, it will be rendered as an object.

Roadmap

• Allow changing the indent style for pretty print mode.
• Export differently packaged versions of the library (e.g. JSON, cJson, and Jxon) for better compatibility.
• Add methods to extract values from the JSON blob without loading the full object into memory.
• Add methods to replace values in the JSON blob without fully parsing and reformatting the blob.
• Add a special class to force encoding of indexed arrays as objects.
• Integrate with a future MCLib-hosted COM-based hash-table style object for even greater performance.
• AutoHotkey v2 support.

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