Design Goals

You should try to design your programs so that they satisfy the following overall design goals.

Programs should be:

Correct: Above all, programs should do what they are meant to do. The simpler and clearer both the design and specification are, the more likely this goal is to be achieved. The use of standard program types can help simplify the specification of the design and reduce the likelihood of errors in the logic. More formally, programs should generally follow structured principles, for example, be made up of constructs which can be transparently replaced with prime structures.
Transparent: Programs should be as readable and as understandable as possible. This requires that you structure programs sensibly, avoid tricky programming, document properly, and use helpful names, notations, and standard techniques.
Modular: Programs should be as modular as possible, so that changes to any one part have a minimal effect on other parts. You should also design to be independent of any system specific facilities.
Robust: Programs should handle any routine errors sensibly without crashing. If a serious error occurs, they should preserve the integrity of the database and collapse in a tidy manner; for example, not leave objects allocated or locked.
Efficient: Programs should perform their function in a way that uses as little machine resource as possible.