qed allowed naming of regular expressions using `e' and their recursive invocation using \E, with results suggested earlier.
http://cm.bell-labs.com/cm/cs/who/dmr/qedman.html http://cm.bell-labs.com/cm/cs/who/dmr/qedman.pdf ``It should be noted that the ability to define regular expressions recursively makes the term "regular expression" a misnomer: it is not hard to see that expressions can be constructed to match exactly the members of any given context-free language.''
