Lab: Statement and Recursion

Objective

In this lab you will practice manipulating Statement values by implementing and testing the static method countOfPrimitiveCalls.

Setup

To get started, import the project for this lab, StatementCountPrimitiveCalls, from the StatementCountPrimitiveCalls.zip file available at this link. If you don't remember how to do this, see the Setup instructions in an earlier lab.

Method

1. Open the file CountPrimitiveCalls.java in the src folder and complete the body of the static method countOfPrimitiveCalls by pasting the code you wrote for the homework into the skeleton provided.
2. Open the CountPrimitiveCallsTest.java JUnit test fixture in the test folder and carefully review the createFromArgs method and its contract. One sample test case is provided as an example of how to test countOfPrimitiveCalls (note that it uses the input file test1.bl in the data folder). If you have questions about the test fixture, make sure to ask an instructor.
3. Run the test fixture. If your implementation of countOfPrimitiveCalls does not pass the test case provided, you need to debug your code. It might be helpful to create new (smaller) test cases that allow you to test each individual branch in the switch statement. Add the new test cases to the test fixture and test/debug your code until you believe it to be correct.

Additional Activities

1. Implement and test the following static method. You can copy and paste countOfPrimitiveCalls and then update the contract and modify the header and the body.

   /**
    * Reports the number of calls to a given instruction, {@code instr},
    * in a given {@code Statement}.
    * 
    * @param s
    *            the {@code Statement}
    * @param instr
    *            the instruction name
    * @return the number of calls to {@code instr} in {@code s}
    * @ensures countOfInstructionCalls = [number of calls to instr in s]
    */
   public static int countOfInstructionCalls(Statement s, String instr) {...}
   

2. Implement and test the following static method. You can copy and paste countOfInstructionCalls and then update the contract and modify the header and the body.

   /**
    * Refactors the given {@code Statement} by renaming every occurrence of
    * instruction {@code oldName} to {@code newName}. Every other statement is
    * left unmodified.
    * 
    * @param s
    *            the {@code Statement}
    * @param oldName
    *            the name of the instruction to be renamed
    * @param newName
    *            the new name of the renamed instruction
    * @updates s
    * @requires [newName is a valid IDENTIFIER]
    * @ensures <pre>
    * s = [#s refactored so that every occurrence of oldName is
    *   replaced by newName]
    * </pre>
    */
   public static void renameInstruction(Statement s, String oldName,
           String newName) {...}