Allow "any kind of letter from any language" instead of [a-zA-Z] in jsonata expressions.

[trzye]

Hi,

First of all I would love to say that I'm big fan of this library and I'm using it's extensively, thank you for all the hard work put into JSONata4Java! :)

Today I was trying to migrate our old jsonata processes from nodejs implementation to yours, and I have found that some of our expressions aren't working because they're using special polish diacritics like [żółćśęą] for example:

json:
{ "żółw": { "Tytuł": "Pan Tadeusz" } }

with expression:
{ "Title": żółw.Tytuł }

will throw

com.api.jsonata4java.expressions.ParseException with message token recognition error at: 'Ż'

When using try.jsonata this expression is perfectly fine:

https://try.jsonata.org/kNopHVcxh

and will return

{
  "Title": "Pan Tadeusz"
}

I've actually prepared the patch and tests for this case. Link in the next comment :)

I hope that you can review this and include in some release.

Thanks in advance,

Michał Jereczek

[trzye]

Here's my forked solution:

trzye@b82b27a

and pull request:

#201

[wnm3]

Thank you for adding this extension. I have merged the code and will make a new release soon. I'm trying to address an issue #199 before creating a new release.