CS 4536/CS 536 Homework Style Guidelines and Expectations

Coding Style

We are very serious about requiring you to write clean, well-documented code. 20% of your grade for programming assignments will depend on your design, style, and comments.

Not already knowing Scheme or having learned Scheme with a different style are not excuses for not following these requirements. We are using the coding style from How To Design Programs for this course (this is the same style used in the text and in class).

• All functions must have a purpose statement that fully explains, in a sentence or two, what the function does.
• All functions must have contracts (the comment summarizing the types).
• If you need to use a new type, define a new datatype to represent it. Do not overload lists. Understand the difference between lists and datatypes. Lists are homogenous collections of unlimited extent. In contrast, datatypes are heterogenous collections with a fixed number of members.
• As a general rule, all functions should be no longer than what fits on a screen. We will of course relax this for functions with a lot of pattern matching (parse comes to mind) and in that case recommend that each match case fits on a screen.
• Assume that your reader understands Scheme, so, in any inline comments, explain why you wrote the code, don’t explain what you wrote. We consider define-type to be self-documenting.

Test Cases

All functions must have tests that exercise non-trivial cases. We require this to encourage good software development skills, but, more importantly, to force you to show us that you know what your code is supposed to do and that you’re not getting a correct answer by guessing. Testing counts for 20% of your grade on all assignments unless stated otherwise. We will not give full credit to untested functionality, even if it is correct!

Good test cases:

• Test a single aspect of a single feature. Therefore, you will need multiple test cases per feature to ensure its correctness.
• Actually test the program. Testing means not only executing the program but also checking the output to ensure it is what you expected.
• Have a comment to explain their purpose.