Hello Mark. Could you give a link to the "specification of Shen", that is, is there a battery of test that for a fork of Shen certifies that the fork is a conforming with the specification fork?, is the "official standard documentation web page of Shen the text of the specification alluded in the license?
After searching for the official specification (a term used formally in the license), the only thing I could find is the web page for the documentation that is called the official shen standard doc, http://www.shenlanguage.org/learn-shen/shendoc.htm, so I suppose the official specification is the content of this page. As I don't have the book of Shen I can't tell if there is further documentation about the "specification of the language".
The author in the license page claims that he is not going to make a fork illegal by changing the standard in such a way as to make the fork retrospectively illegal.
There was one author who made a close source port of Shen in java but then there were big problems. Perhaps he could give a lot of information of what kind of problems are you to encounter when you try to develop a close source product using Shen. The last think I can remember was that he bought the book of Shen for her 16 years old daughter and he was emotionally very interested in Shen but then all went down. [By the way, I apologize for not putting the 's i the third person )). in my other posts.
I seem to remember that the author only require that the forked Shen satisfies a number of published tests, that is to guarantee that the forked program function like the original Shen in the basis case. A forked program could extended the original one with new capabilities, libraries and ideas. I think that the author of Shen believe that free sofware should not be free as in beer, now he earn some money selling the Shen book. Only my two cents.
Thanks for you work in Shen.