Getting Started

Download RecursiveDescentJava.zip. Import it into your Eclipse workspace.

Your task

Modify the parser so that it supports parenthesized expressions.

Do so by adding the following production:

F → ( E )

You will need to modify the lexer so that it supports left and right parentheses as terminal symbols:

• Modify the definition of LEGAL in Lexer.java to include the ( and ) characters
• Modify Symbol.java to define new terminal symbols for left and right parentheses
• Modify the definition of the fromCharacter method in Symbol.java to handle ( and ) characters

You will also need to modify the parseF method in the parser class so that it applies the F → ( E ) production when appropriate.

Testing

Try running the program and entering the expression

(a + b) * 3

Solution

You can see a solution here: RecursiveDescentSoln.zip

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