Create LuaJSON json.util documentation

[agladysh]

ORIGINALLY: json.util.merge stopped working as expected

LuaJSON lacks useful documentation of utilities, even though it recommends the usage of them for customization. Documentation is a required attribute of useful software tools, and as such, LuaJSON needs it.

https://github.com/agladysh/json2lua/blob/master/json2lua#L171-L179

 decode_options = json_util.merge(
    {
      object =
      {
        setObjectKey = json_decode_util.setObjectKeyForceNumber;
      };
    },
    decode_options
  )

This code does not work (option is ignored) with 1.3, and it did work with 1.2. I did not find anything related in release notes, so I assume that this is a regression.

[harningt]

Hm, it looks like the merge logic may be inverted in the code.

It would have worked in 1.2 since object.setObjectKey was not defined in the 'simple' table. In 1.3, you can lookup what the actual options are now, but this has the side effect that it overwrites your option.

Example output for each version for json.decode.simple:

1.2 == just has the options that took the "defaults" to be the simple state

json.decode.simple = {
  others = {
    null = false,
    undefined = false
  }
}

1.3 == has a fully independent option state that will not be merged later with the "defaults"

json.decode.simple = {
  number = {
    hex = false,
     .....
   }
}

What you'd want there is the following construct to merge, I think:

merge({}, decode_options, {object = setObjectKey......})

That way you merge onto an empty table, first filling with options from decode_options, then filling from your {object = ...} one.

[agladysh]

Hmm, OK, thanks. Shouldn't this be documented somewhere?

[harningt]

Yes indeed, reworking this ticket as a documentation one.

[harningt]

Fixed as of release 1.3.2 - specifically commit 3883db4b5f24cb685af7998dbe38e18ca7ff54ff