Exercises:  Do these in order.  Do all of them.  I promise not to
	    waste your time.

0. There should be a directory named `Module' next to this one.
   Do all the exercises there first.  Then come back here.

1. Read the code in hello.pl and Hello.pm and try it out.  Run
   hello.pl and see what happens.

2. Look at the error message that the sample program produces.
   Change the `croak' to `die' in `Hello.pm' and see how the error
   message changes.  What is the difference?  When might you prefer
   `croak' to `die'?

3. What are the arguments to the `new' function?  Put a line into
   `new' that prints out the argument list, and rerun the test program.

   In `hello.pl', change the call to `new' to say

	new Hello ("Buenos Dias");

   What are the arguments now?

   Now change the call to say

	Hello->new("Guten Tag");

   What are the arguments now?

4. Change `new' to accept an optional argument which is used as an
   initial message for the greeting object.  If the optional argument
   is missing, the function should use "Hello, world" as it does at
   present.  Write a test program for this new feature.

5. What are the arguments to the `setmessage' function?  Put a line
   into `setmessage' that prints out the argument list.  Notice
   especially what `$self' looks like when you print it out.

6. Change `new' to set up a DEFAULT field instead of a MESSAGE field
   in the new object, and then fix `greet' to use the MESSAGE field if
   there is one, and the DEFAULT field otherwise.

   Then modify `setmessage' to make the argument optional.  If the
   argument is omitted, then instead of croaking, it should reset the
   message to the default.  Write a test program for this new feature.

7. Change the name of the module from `Hello' to `Greeting'.  Change
   the test program to use the new module.

8. Write to me with a suggestion about how the notes or exercises could be
   improved.  

	mjd-perl-modtut@plover.com