Lab #6: Trees and More

Get the various points in this lab checked off by a TA by the last lab of 
Tuesday, 23 October.  It would be good, of course, to have them done the 
FIRST week!  

Part I: Some Progress on the Project.  We suggest you strive to get this
   done during the week of 15 October.

1. If you haven't worked on Assertion.java and Question.java yet, get the 
   NEW suggested templates from ~cs61b/hw/proj2, and fill them in.  
   The tricky part is reconstructing the question or answer from the 
   information in the Assertion or Question + the PuzzleParser it comes
   from (you need the latter to know what is a name, what is a color, 
   what is an occupation).  Really, the only one of the unfilled-in
   methods you are going to really is Question.formattedAnswer, but
   thinking about the others may be helpful. 

2. Implement PuzzleLineSet.  This just reads a bunch of words from a
   Reader, breaks them into groups that each end with a word that 
   ends with '.' or '?', and then stores each group as a single 
   String, with the words separated by single blanks (regardless of 
   the original whitespace between them).

3. Set up some test cases for your Project #2.

Part II: Tree manipulation.

4. On page 92 of the Data Structures book, there is a definition of
   eval on an expression tree.  You will find a modified version in 

 	~cs61b/hw/lab6/Expr0.java

   along with some supporting code.  The definitions of toString and
   read are incomplete.  Fill them in to make the code work (see the
   comment on the main program).

Now we'll create a re-implementation of Expr0 called Expr, but this we'll 
do it "the object-oriented way".

5. Copy over the template 
   
 	~cs61b/hw/lab6/Expr.java

   Modify it to do the same thing as Expr0.  You will have to add
   new classes (either in Expr.java or in separate files).
 
   HOWEVER, do NOT add any more 'if', 'while', 'for', or 'switch'
   statements or any more ?: operators; just use object-oriented
   stuff.

6. Show your TA what you have done for these parts to be checked off.