The transformation has an additional signature for using jsonpath

Transformation.transform("JSONPATH",` "$.name", "{\"name\":\"test\"}");

Can you add that too?
I am not sure if it's the method from the TransformationHelper. I found another class org.openhab.core.transform.actions.Transformation, maybe that can help.

I think this looks good. Perhaps we should add some documentation as well?

I check the docu a little bit more and think you are right, this should work for jsonpath too. I just come from the jython rules and there its separated. Your syntax is more used in the items and sitemaps.

Some examples also for json would be good.

String value = Transformation.transform("JSONPATH($.name):%s", "{"name":"test"}");
String value = Transformation.transform("MAP(my.map):%s", event.getValue()");
vs.
String value = Transformation.transform("JSONPATH", "$.name", "{"name":"test"}");
String value = Transformation.transform("MAP", "my.map", event.getValue()");

Personally i find the second syntax better for programming. Either way its good to have the transformation in.

Great I will test it out and merge.

Sorry for the late review, been too busy but putting some work in now.
I'll look at the documentation as well