Something amazing has happened. After countless attempts to get a toehold on the glassy wall of structured Frame, I've suddenly managed to run up it as far as writing my first EDD – it works, it handles tables, I've successfully tried both ParagraphFormatting and ElementPgfFormatTag, and I still understood it the next day.
So now I'm happily experimenting with some very simple DITA files, prepared and validated elsewhere. I used a <ph conref="_ymvProductVariable.dita#terminal/product"/> construct in my DITA file to replicate the behaviour of a FrameMaker user variable. Opening the DITA file in FM and applying my EDD highlights the <ph> as an invalid element, which I can accept.
Question – to which I may not understand the answer, but I'll try: how do I define the <ph> element, so I can include it in a General rule like (<TEXT> | ph)+ and have it show the value of the variable?
My apologies for trying to run before I can walk, but after years feeling my feet were nailed to the ground it's irresistible.