Class 10: Pause for Breath

Held Wednesday, February 7, 2001

Summary

Today we pause for a day to consider issues in the design of Scheme procedures and to help resolve any confusions you may have over past labs.

Assignments

• Read Characters and Strings.

Notes

• I wasn't able to get all of the references done for the reading on strings.
  • Keep your eyes posted for more.

Overview

• Program design
  • Indentation
  • Comments (at least two types!)
• Problems?
  • Two digits after decimal
  • Others?

Program Design

Using Whitespace

• Computers don't care.
• Humans do.
• So set up your code in a way that humans can more easily read it (and trace parantheses).

Comments

• Computers don't care.
• Humans do.
• So try to explain things to those who must use your code.
• Who will use your code?
  • Folks who want to take advantage of your procedures without paying attention to how you implement them.
  • Folks who have to fix your procedures when you get things wrong.
  • Folks who want to do something similar.
• While you may understand your code perfectly now, you'll soon forget what you've done (even if you program regularly) and will eventually fall into many of these categories.
• So write lots of comments.

Problems

• Two digits after decimal
• snoc