Homework assignment 8, due Monday, May 4, 2015.

Each problem is 10 points.

1. Exercise 91, page 338.
2. Exercise 92, page 338.
3. (a) Write an unambiguous grammar for regular expressions that are made up
from a, b, +, * (the asterisk operator), concatenation, and parentheses.  Your
grammar should reflect the idea that * has higher precedence than
concatentation, which has higher precedence than +.
Hint: compare the grammar for arithmetic expressions on page 188 with the
grammar on page 187.  
   (b)  Use the Cocke-Kasami-Younger algorithm with the grammar you wrote for
part (a) to parse the regular expression

                        (a+b)*+ab*a

and show how it produces only one parse for the whole expression.