--- rexxpub: defaults: rony.yaml logo: oorexx --- . slide cover # JSON (JavaScript Object Notation) . cover-art . picture img/340_JSON_V08/p01-diagram-7.png # Overview . steps each=after - Introduction to **JSON** and the ooRexx package **json.cls** - The **json.cls** package got introduced with ooRexx 5.0.0 . click - ooRexx 5.1.0 improves it - Includes full JSON Boolean type support, handles all ooRexx collection classes - Adds the ability to create a legible (human friendly) rendering of JSON text - The 5.1.0 version can be used to replace deployed 5.0.0 versions - ooRexx 5.2.0 updates it to the latest standard and passes the official test suite . click - Nutshell examples - Roundup # JSON Encoded Data from Wikipedia . after steps - JSON got defined in the beginning of the 2000 to ease exchange of structured data via the Internet with JavaScript - **JSON** . after - Acronym for "JavaScript Object Notation" - JSON-Datatypes . after - *Object* – a collection of comma separated name-value pairs (a *Map*) in *curly* brackets - *Array* – an ordered list of comma separated values in *square* brackets - *String* – a quoted sequence of UTF-8 characters - *Boolean* – **true** or **false** - *Number* – any number - *null* (void) – **null** . after - See [https://www.json.org/](https://www.json.org/), [https://en.wikipedia.org/wiki/JSON](https://en.wikipedia.org/wiki/JSON) # The ooRexx package json.cls . after steps - Introduced with ooRexx 5.0.0, improved in ooRexx 5.1.0, and 5.2.0 - Needs to be required, such that its public class **.json** becomes accessible (`::requires "json.cls"`) - Explicitly supplies JSON Boolean values with **.json\~true** and **.json\~false** which behave like ooRexx **.true** and **.false** (can be used as ooRexx Booleans as well) - Class methods for reading/writing JSON data directly from/to file . after - **fromJsonFile(path2file)**, returns a Rexx object representing the JSON data - **toJsonFile path2file, rexxObject \[, legible\] )**, where **legible** is **.false** (default) or **.true** - Class (and instance) methods for turning an ooRexx object into a JSON string or a JSON string into an ooRexx object . after - **toJson(rexxObject \[, legible\])**, where **legible** is **.false** (default) or **.true** - **fromJson(jsonString)**, returns a Rexx collection object with the JSON data # Wikipedia JSON Encoded Data (Legible) See Wikipedia [https://en.wikipedia.org/wiki/JSON](https://en.wikipedia.org/wiki/JSON) (2026-10-18, "**wikipedia.json**") . after ```json { "first_name": "John", "last_name": "Smith", "is_alive": true, "age": 27, "address": { "street_address": "21 2nd Street", "city": "New York", "state": "NY", "postal_code": "10021-3100" }, "phone_numbers": [ { "type": "home", "number": "212 555-1234" }, { "type": "office", "number": "646 555-4567" } ], "children": [ "Catherine", "Thomas", "Trevor" ], "spouse": null } ``` . slide kicker=json_01.rex # Nutshell 1: Unencode and Encode JSON Data (1/3) . steps each=after - Read JSON encoded data from file - Use Wikipedia's example - JSON encoded sample data is broken up into lines and indented for better legibility - Usually JSON encoded data is "minimized", i.e. does not contain ignorable whitespace meant for easying legibility and comprehensibility for humans . click - Result is an ooRexx *directory* object that contains all imported data - JSON arrays are represented as ooRexx *array* objects - JSON objects (maps) get represented as ooRexx *directory* objects . click - At the end the generated ooRexx *directory* object will be used to create a legible and a minimal JSON rendering of it . slide kicker=json_01.rex # Nutshell 1: Unencode and Encode JSON Data (2/3) . after mark 3 pen=1 . click mark 5 pen=2 . after mark 7 pen=2 ```rexx -- ooRexx 5.1 or higher parse arg fn -- get file name o = .json~fromJsonFile(fn) -- reads and unencodes JSON file say .json~toJson(o,.true) -- encode as legible (human-friendly) JSON string say "---" say .json~toJson(o) -- encode as minimized (standard) JSON string ::requires "json.cls" -- get access to the JSON class ``` . slide kicker="“rexx json_01.rex wikipedia.json”" # Nutshell 1: Unencode and Encode JSON Data (3/3) . columns 4 8 . click ```output rexx json_01.rxj wikipedia.json ``` . next column . after label Output (note attributes are sorted by name to ease locating them): . end columns . columns 4 4 4 tight . with label wikipedia.json . with ```json { "first_name": "John", "last_name": "Smith", "is_alive": true, "age": 27, "address": { "street_address": "21 2nd Street", "city": "New York", "state": "NY", "postal_code": "10021-3100" }, "phone_numbers": [ { "type": "home", "number": "212 555-1234" }, { "type": "office", "number": "646 555-4567" } ], "children": [ "Catherine", "Thomas", "Trevor" ], "spouse": null } ``` . next column . after ```json { "address": { "city": "New York", "postal_code": "10021-3100", "state": "NY", "street_address": "21 2nd Street" }, "age": 27, "children": [ "Catherine", "Thomas", "Trevor" ], "first_name": "John", "is_alive": true, "last_name": "Smith", "phone_numbers": [ { "number": "212 555-1234", "type": "home" }, { "number": "646 555-4567", "type": "office" } ], "spouse": null } ``` . next column . click id=#mini ```output --- {"address":{"city":"New York","postal_code":"10021-3100","state":"N Y","street_address":"21 2nd Street"},"age":27,"children":["Catherine"," Thomas","Trevor"],"first_name":"John","is_a live":true,"last_name":"Smith","phone_numbe rs":[{"number":"212 555-1234","type":"home"},{"number":"646 555-4567","type":"office"}],"spouse":null} ``` . after callout --> #mini at=below Minimal (standard):\ – no white space characters\ – no carriage-return characters\ – no line-feed characters . end columns . slide kicker=json_02.rex # Example 2: JSON Encoding from ooRexx Data (1/2) . after steps - The **toJSON** class method takes an ooRexx object to encode - The example creates an ooRexx structure using an ooRexx relation object, an ooRexx array and an ooRexx list and demonstrates how to encode that data . after - Encoding to JSON demonstrates how a JSON Boolean value gets employed - The **toJSON** class method creates minimized encodings by default - An instance of the JSON class encodes for humans if **toJSON**'s optional **legible** argument is set to **.true** . slide kicker=json_02.rex # Example 2: JSON Encoding from ooRexx Data (2/2) . columns 6 6 . after . click mark 6 pen=1 . click mark 9 pen=2 . click mark 11 pen=3 ```rexx rel = .relation~new -- create a relation (allows duplicates) rel["WU"]="Vienna Business University" rel["Wien"]= ("Vienna", "Vienne") -- English, French rel["historical districts"] = .list~of(1190, 1090, 1020) rel["currently in district"] = 1020 rel["is older than Harvard"] = .json~false -- a JSON false value say .json~toJson(rel) -- encode as minimized JSON (standard) say "---" say .json~toJson(rel,.true)-- encode as legible JSON (human friendly) ::requires "json.cls" -- get access to the JSON class ``` . next column . after group . numbered steps=2,3,4,5,6,7,8,9,10,11,12,13,14,15,16-18 each=after ```json {"WU":"Vienna Business University","Wien":["Vienna","Vienne"], "currently in district":1020,"historical districts":[1190,1090, 1020],"is older than Harvard":false} --- { "WU": "Vienna Business University", "Wien": [ "Vienna", "Vienne" ], "currently in district": 1020, "historical districts": [ 1190, 1090, 1020 ], "is older than Harvard": false } ``` . end group . end columns # Roundup . steps each=after - ooRexx 5.0 introduced the Rexx package **json.cls** - Implements a public ooRexx class named **.json** - The **fromJSON** class and instance methods allow for turning JSON encoded string data into an ooRexx structure (collection) - The **toJSON** class and instance methods allow for encoding any ooRexx structure (collection) into a JSON string . click - ooRexx 5.1, and ooRexx 5.2 improve "**json.cls**" - Compatible with ooRexx 5.0 "**json.cls**" (hence no need to change programs) - Adds explicit support for JSON Boolean values - The attribute **legible**, if set to **.true** will encode JSON in a human friendly form - Adds utility class methods to directly read (**fromJsonFile(fileName)**) from or write to files (**toJsonFile(fileName, rexxObject\[, isLegible=.false\])**) - Complies to the latest JSON standards . slide card logo=none # Contact