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DSL Builders only accept primitives, and are somewhat difficult to "build"

See original GitHub issue

Building JSON is a bit difficult with Klaxon, since the DSL for building them uses nesting to create complex objects. While that’s fine for Java, it would be more idiomatic to use a more “builder” style for creating JsonObjects.

This is how you make a JsonObject in Klaxon:

json {
  obj("colors" to 
      "grey" to "#333",
      "red" to array(255, 0, 0), 
      "green" to array(0, 255, 0),
      "others" to obj(
        "white" to "#fff"

This results in:

  "colors": {
    "grey": "#333",
    "red": [255, 0, 0],
    "green": [0, 255, 0],
    "others": {
      "white": "#fff"

The current method does not allow for any custom serialization (as far as I know?), and nests obj calls inside of parenthesis to create it’s own DSL. All of the builder code must be included on adjacent lines, and you can’t insert your own code between each line. This assumes that you have all of the information you need to build the JSON object before you decide to build it.

It might be beneficial to create a DSL that looks more like this:

json {
  obj("colors") {
    put("grey", "#333")
    putArray("red", listOf(255, 0, 0))
    putArray("green", listOf(0, 255, 0))
    obj("others") {
      put("white", "#fff")

This format allows arbitrary code to be ran between each call and lets you “build” a JSON object more programmatically. You can insert code between each line, making this a bit more Kotlin friendly.

Also, the ability to convert arbitrary object within the tree would also be great: Supplying a value outside of the range of primitive values could be converted to it’s JSON equivalent.

Thank you, Klaxon is great! ❤️

Issue Analytics

  • State:open
  • Created 3 years ago
  • Comments:6 (3 by maintainers)

github_iconTop GitHub Comments

cbeustcommented, Aug 4, 2020

Fair point. I just implemented this, take a look and let me know if this addresses your suggestion:

Totaluscommented, Apr 6, 2022

Could we also allow to use the obj() function without specifying a key so that we can populate the root fields of the object ?

This way the following expression could work:

json {
  obj {
    put("hello", "world")

Resulting in:

   "hello": "world"

Currently there seem to be no easy way to do that. (See #316)

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