Simplifying transformation in State Description metadata

[scatterthought]

The problem

As discussed in this Community thread, implementing a transformation in State Description metadata via Main UI requires the user to type in the location of the transformation pattern. This requires that the user know the required syntax. For example (from the linked thread):

SCALE(config:scale:compass_direction):%s

While this is not difficult if you know the syntax, it is not intuitive for a new user.

Per the thread, the topic of storing patterns in Main UI and then referencing them in profiles or state transformations is not covered in the documentation. I'm considering a PR to address this, but the topic may go beyond my expertise.

Your suggestion

To simplify the process of applying transformation in state descriptions, I suggest that we add fields to select the type of transformation and the location of the transformation pattern (when required). It would be similar to how a transformation profile can be applied to a channel link, which allows a pattern to be selected in the profile configuration. For State Descrption metadata, only the available transformation services would be shown as options.

This would enable the user to define the transformation pattern in Main UI, then select it from a list. They wouldn't need to know the syntax.

Your environment

openHAB 4.1.1