Date: Sun, 15 Sep 2002 21:41:11 -0400
To: lliao@mail.eecis.udel.edu
Subject: questions on the homework


1.I don't really see a big difference beteween canBeEmpty and valid functions(ex1). They both
check whether Repeat is present or not in the string.What is the difference then?
2. could you give  more examples of what prematch function should be doing?The instructions say it
"returns a list of suffixes, one for each prematched prefix" and there is only one example that
doesn't give a very good description(ex2)
3.What does it mean when you say "concatenation and alternation are right associative" and "left
recursion free"? Could you give an example?(ex3)