[PPL-Lang] PPL support json_set, json_extend functions

[acarbonetto]

Is your feature request related to a problem?

As follow-up to #780, continue Supporting the PPL Json grammar with adding the next functions:

• json_set(object, [(path key, value) list])

Inserts or updates one or more keys and their corresponding values from the specified JSON object: 

objects: the Json object is the field being evaluated
[path key, value]: the list of key-value pairs to add/update in the document

• json_extend(object, [(path key, value) list])

Appends values to a JSON array element with provided values and returns the updated JSON object.

objects: the Json object is the field being evaluated
[path key, value]: the list of key-value pairs to extend arrays with values in the document.

What solution would you like?

Support the following json_set

Example:

    os> source=people | eval updated = json_set('{"a":[{"b":1},{"b":2}]}', '$.a[*].b', 3) | head 1 | fields updated 
    fetched rows / total rows = 1/1
    +-------------------------+
    | updated                 |
    +-------------------------+
    | {"a":[{"b":3},{"b":3}]} |
    +-------------------------+

Support the following json_extend

Note that json_extend is identical to json_append function except that it flattens the arrays before appending them to the json value at path.

Example:

    os> source=people | eval extend = json_extend(`{"teacher":["Alice"],"student":[{"name":"Bob","rank":1},{"name":"Charlie","rank":2}]}`, 'student', '{"name":"Tommy","rank":5}') | head 1 | fields extend
    fetched rows / total rows = 1/1
    +-----------------------------------------------------------------------------------------------------------------------------------+
    | extend                                                                                                                            |
    +-----------------------------------------------------------------------------------------------------------------------------------+
    |{"teacher":["Alice"],"student":[{"name":"Bob","rank":1},{"name":"Charlie","rank":2},{"name":"Tommy","rank":5}]}                     |
    +-----------------------------------------------------------------------------------------------------------------------------------+

    os> source=people | eval extend = json_extend(`{"teacher":["Alice"],"student":[{"name":"Bob","rank":1},{"name":"Charlie","rank":2}]}`, 'teacher', array('Tom', 'Walt')) | head 1 | fields extend
    fetched rows / total rows = 1/1
    +-----------------------------------------------------------------------------------------------------------------------------------+
    | extend                                                                                                                            |
    +-----------------------------------------------------------------------------------------------------------------------------------+
    |{"teacher":["Alice","Tom","Walt"],"student":[{"name":"Bob","rank":1},{"name":"Charlie","rank":2}]}                                 |
    +-----------------------------------------------------------------------------------------------------------------------------------+


    os> source=people | eval extend = json_extend(`{"school":{"teacher":["Alice"],"student":[{"name":"Bob","rank":1},{"name":"Charlie","rank":2}]}}`, 'school.teacher', array('Tom', 'Walt')) | head 1 | fields extend
    fetched rows / total rows = 1/1
    +-------------------------------------------------------------------------------------------------------------------------+
    | extend                                                                                                                  |
    +-------------------------------------------------------------------------------------------------------------------------+
    |{"school":{"teacher":["Alice","Tom","Walt"],"student":[{"name":"Bob","rank":1},{"name":"Charlie","rank":2}]}}            |
    +-------------------------------------------------------------------------------------------------------------------------+

What alternatives have you considered?

N/A

Do you have any additional context?

• json_append was added as part of [PPL-Lang]PPL support json_delete,json_append functions #970
• Feature request: [FEATURE]Add PPL JSON extended functions support #667