Re: ShEx negation of edge path

What is your opinion about the case 4 I described earler:

4) accept any combination except  when two a's and one b
<XXX>{
 .... ,
 (:a xsd:string*, :b xsd:string*) ^ (:a xsd:string{2}, :b xsd:string),
 ....
}

(note that  there is no , to separate the two statements).

This case is the (quite usual) include/exclude case that can be found
a lot in declarative statements, such as Ant's fileset, .gitignore...
This is tricky to read, but very useful to modelize some tricky cases.
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