Object-Oriented Design Frequently Asked Questions

Python

Where do I find answers to questions about Python ?

Tutorials, references, and links kan be found at http://www.python.org.

An excellent starting point is the Python Tutorial by Guido van Rossum.

How does one check whether an object `c` is of "type" `C` ?

For builtin types, one can use the operator type(). For example:

     >>> type(2)
     <type 'int'>

If we declare a class C and create an instance c as shown below, type() will give rather general information:

    >>> class C:
        pass
    >>> c=C()
    >>> type(C)
    <type 'classobj'>
    >>> type(c)
    <type 'instance'>

If we want to check whether c is an instance of class C, we can use the test
```
    >>> isinstance(c, C)
    True
    
```
This will evaluate to True if c is an instance of class C or any of C's sub-classes.
In recent versions of Python, it is possible to test for basic types with isinstance as in isinstance(1,int), isinstance(1.2,float), isinstance((2,3),tuple), isinstance([3,4],list) and isinstance([1,2],list).

How do I generate nice HTML from Python source code ?

Colorized pretty-printing for file code.py can be done with
```
enscript -Whtml -Epython --color code.py -o code.html
```
An API document for file code.py can be generated with
```
pydoc -w code
```
The more advanced Epydoc allows one to generate API documentation for Python modules, based on their docstrings and in addition supports a lightweight markup language called Epytext to format docstrings, and to add information about specific fields, such as parameters and instance variables.

Which tool do we use to draw UML diagrams ?

A plethora of tools is available. In COMP 304 we focus on the "essence" of OO design and build only relatively small designs. For these reasons, using a huge, sophisticated tools may (1) take a long time to learn and (2) distract from the "essence" of the problem. Some useful tools (installed on the Trottier machines):

Dia is a very lightweight drawing tool with support for UML.
MagicDraw is a commercial product with support for UML 2.0. A community edition is available.

Assignments

MUST we work in teams of 2 ?

You must work in a team of exactly two people. Previous experience has shown that after the initial transient chaos of finding a partner, this works really well. Try to find a team partner after class or by sending a message to the entire class on WebCT. Remember that "pair programming" requires you to actually work together (same place, same time). You may form different teams for different assignments.