Mostly done coding!

I go that little join engine working, put it on the right under semantic processor. It will traverse and join any arbitrary pair of finite graphs having a JSON style plain text, outputting their matched intersection. Output is in JSON as that is the only attachment I have for now,. Still testing it. Added the wildcard character asterisk. The attachment must support three methods, at a minimum:  

enum CursorMethods{ 
 Fetch, 
 Step, 
 Append
 };

The attachment has two entry point, one for match evaluation and one for executing the graph methods above.   It recurses the Dots and increments the Commas. 

The join does inner product  via recursion:
(a.b.c)  join (d.e.f)

And outer product in the loop:
(a,b,c)  join  (d,e,f)

The loop itself is  30 lines of code, most of the work being done in the attachments.