CS200 Fall 2008 Homework 1: Constructing Grammars and Parsing Expressions - Prof. Adele E., Assignments of Computer Science

Download CS200 Fall 2008 Homework 1: Constructing Grammars and Parsing Expressions - Prof. Adele E. and more Assignments Computer Science in PDF only on Docsity! CS200 Fall 2008 HW 1 due 9/9/08 at 9:30AM Hand-in before start of lecture 1. Construct a grammar for the Java switch statement. Use <expr> (which denotes arbitrary Java expressions) as the starting non-terminal. You may also assume that some non-terminals have already been defined (i.e., <var> for variables, <expr>, and non-terminals for legal values of all basic types). [Note: your grammar is not responsible for checking type consistency.] 2. Construct a grammar for any length bit strings (alphabet is {0,1}) that start with 00 and end with one or more 1s. 3. Given the following grammar: <S> = ab<S> | bc<S>| bb<S> | a | cb 1. Is “bcbba” a legal sentence? 2. List all legal sentences of 5 characters or less. 4. Is “+ * 5 – 3 / 2 + + 6 1 – 8 7” a legal prefix expression? If yes, to what does it evaluate? If no, fix it, with as little change as possible, so that it is. 5. For the recursive descent parser provided in class (and on the website), a. will the code conclude that “* + a b – c / a b” is a legal expression? b. show how the execution stack will change as the code runs for the expression “* a + b c”. Every time a method is invoked, show a stack snapshot that includes the name of that method and its argument(s) at the top. [Note: The execution stack keeps track during program execution of what methods have been invoked from where in the code so that the program can return to the calling method when the called method returns.]