"json.cls" as distributed with ooRexx 5.0.0 has one (actually two) limitation which can be regarded
to be a bug:
* It cannot handle JSON booleans properly: when reading a JSON file with
boolean values and
creating a JSON file from ooRexx the boolean values will not show up, rather
their ooRexx
numeric representations of "0" and "1".
In the past I came up with a solution for this problem which was not "liked" and was 30% slower than
json.cls (sounds dramatic, but in today's world with such power horses in the hands of end-users may
be negligeable, but still, one being made aware of this made it less attractive).
As the above limitation is really a problem if one wants to use ooRexx json.cls and exchange proper
JSON with other systems, e.g. via curl, I came up with a version (starting out with the current
json.cls) that does the following in addition:
* It adds support for JSON true and false: just send .json~true or
.json~false. The resulting
JsonBoolean objects behave like ooRexx .true and .false (both strings with
the numeric values
"0" and "1") and can be used interchangeably
o when reading a JSON file, JSON booleans will be represented with the
appropriate .json~true
or .json~false values
o when writing a JSON file, any JSON boolean value will be properly encoded with
"false" and
"true"
* It adds generic support for MapCollection and OrderedCollection instead of
restricting support
to Directory and Array,
* It uses StringTable instead of Directory for reading in JSON data,
* Although JSON is a string encoding, which could be read by humans, there are
two observable
properties that do not make it human-friendly:
o by default the encoding is "minimized" such that no ignorable whitespace
(usually used for
making JSON better legible e.g. cf. Wikipedia's JSON [1] sample) is
contained,
o there is no sorted order of name/value pairs (per specification no order
is implied, yet for
humans having a sorted order in the JSON encoded data makes it possible
to quickly check
whether certain name/values pairs exist or not without affecting any
JSON importer)
the replacement version will create by default minimized JSON encodings,
however it will sort
name/value pairs by name to ease reading by humans
* as this is Rexx/ooRexx it is made possible to create a "legible", a
"human-oriented" JSON
encoding in two ways: when creating a JSON instance or when sending the
toJson message one can
supply .true which causes the produced JSON encoding to be formatted with
ignorable whitespace
such that it will be easy to see the structure and spot name/value pairs
therein; yet, the
produced JSON is still JSON and can be processed without problems,
* two new convenience class methods for reading from and writing to files are
defined:
fromJsonFile(fileName) and toJsonFile(fileName, ooRexxObject [,
legible=.true])
Here the JSON sample given at [1]:
{
"firstName":"John",
"lastName":"Smith",
"isAlive":true,
"age":27,
"address":{
"streetAddress":"21 2nd Street",
"city":"New York",
"state":"NY",
"postalCode":"10021-3100"
},
"phoneNumbers":[
{
"type":"home",
"number":"212 555-1234"
},
{
"type":"office",
"number":"646 555-4567"
}
],
"children":[
"Catherine",
"Thomas",
"Trevor"
],
"spouse":null
}
Here the minimized rendering with the replacement version of json.cls:
{"address":{"city":"New York","postalCode":"10021-3100","state":"NY","streetAddress":"21 2nd
Street"},"age":27,"children":["Catherine","Thomas","Trevor"],"firstName":"John","isAlive":true,"lastName":"Smith","phoneNumbers":[{"number":"212 555-1234","type":"home"},{"number":"646
555-4567","type":"office"}],"spouse":null}
Here the legible rendering with the replacement version of json.cls:
{
"address": {
"city": "New York",
"postalCode": "10021-3100",
"state": "NY",
"streetAddress": "21 2nd Street"
},
"age": 27,
"children": [
"Catherine",
"Thomas",
"Trevor"
],
"firstName": "John",
"isAlive": true,
"lastName": "Smith",
"phoneNumbers": [
{
"number": "212 555-1234",
"type": "home"
},
{
"number": "646 555-4567",
"type": "office"
}
],
"spouse": null
}
---
Here an ooRexx program that creates a structure which will get encoded as
minimized and legible JSON:
-- create a Rexx structure
d=.directory~new
d["firstName"] = "Mary"
d["lastName" ] = "Doe"
d["children" ] = .list~of("Maribel", "John", "Annabel")
d["married" ] = .json~false
d["born" ] = "2001-02-02"
d["yearBorn" ] = 2001
d["bestMan" ] = .nil
j = .json~new
say j~toJson(d) -- write minimized JSON
say "---"
say j~toJson(d,.true) -- write legible JSON
::requires "json.cls" -- get access to the JSON class
Here the output of the above program:
{"bestMan":null,"born":"2001-02-02","children":["Maribel","John","Annabel"],"firstName":"Mary","lastName":"Doe","married":false,"yearBorn":2001}
---
{
"bestMan": null,
"born": "2001-02-02",
"children": [
"Maribel",
"John",
"Annabel"
],
"firstName": "Mary",
"lastName": "Doe",
"married": false,
"yearBorn": 2001
}
---
The replacement json.cls and the adjusted official json.tesgroup can be found in my sandbox at
<https://sourceforge.net/p/oorexx/code-0/HEAD/tree/sandbox/rony/json/>.
Performance when reading and writing is comparable to 5.0's json.cls.
---rony
[1] Wikipedia JSON: <https://en.wikipedia.org/wiki/JSON>
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