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Last updated at 7:22 pm UTC on 5 November 2018

JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write. It is easy for machines to parse and generate. It is based on a subset of the JavaScript Programming Language, Standard ECMA-262 3rd Edition - December 1999. JSON is a text format that is completely language independent but uses conventions that are familiar to programmers of the C-family of languages, including C, C++, C#, Java, JavaScript, Perl, Python, and many others. These properties make JSON an ideal data-interchange language.

JSON is built on two structures:

JSON serialization


    location: 'http://www.squeaksource.com/JSON'
    user: ''
    password: ''

For version http://www.squeaksource.com/JSON/JSON-tonyg.39.mcz
all tests green in Squeak 5.1. The main object is JsonObject.

see also STON

Notes 2010


Author: Hannes Hirzel

Ancestors: JSON-rh.31

In the project SCouchDB a copy of JSON is maintained by Igor Stasenko
and Radoslav Hodnicak.

This merges part of the changes back, in particular

SCouchDB project


Main changes

1. JsonObject is now a subclass of Dictionary instead of Object. So
there is no need to implement the Dictionary interface.
2. Fix for converting Unicode characters to \uNNNN format (missing
padding to 4 characters)

No further changes

The SCouchDB project contains more changes in the copy of the JSON package.

I did not go further in merging because in SCouchDB / JSON-rh.32
Radoslav Hodnicak introduces an instance variable 'converter'

which is initialized to

 converter := UTF8TextConverter new

Igor Stasenko, Levente Uzonyi and Hannes Hirzel agreed that the UTF8
conversion does not belong into the JSON package


Levente Uzonyi:

You only need to convert the characters to UTF-8, because you're
sending them over the network to a server, and Unicode characters have
to be converted to bytes someway. So the JSON printer shouldn't do any
conversion by default except for escaping. The only problem is that
escaping is not done as the spec requires it, but that's easy to fix.


A string is a collection of zero or more Unicode characters, wrapped
in double quotes, using backslash escapes. A character is represented
as a single character string. A string is very much like a C or Java
About escaping Unicode characters

Actually escaping Unicode characters to


is not necessary for characters with codes >127 in case of an upload
to a CouchDB. But this version does it.

In case you want to patch this change method

  Json class escapeForCharacter: c

Test case see WebClient, JSON and couchDB

ToDo add example using the rijksmuseum API.