Prompts for “On Understanding Types…”

Due on Monday, November 19 by 10pm

Read pp. 3–4 from “On Understanding Types, Data Abstraction, and Polymorphism” by Luca Cardelli and Peter Wegner.

Commit your response as a PDF to your short responses repository. You are encouraged (but not required) to use LaTeX to typeset your response.

1. Cardelli and Wegner argue that types are a natural consequence of organization, and that such features in a programming context are helpful. If types are helpful as they claim, why do you think that many people use languages without strong or static types?
2. The plus + operator is clearly polymorphic in some languages, like Java. For instance, you can “add two numbers,” as in 1 + 1, and you can “add two strings,” as in "hello " + "world". Based on what little we know about polymorphism at the end of page 4, do you think that + uses parametric polymorphism or ad-hoc polymorphism?
3. How do you feel about your project? Are you excited to work on it or do you dread working on it? E.g., would you prefer taking a final exam instead? Don’t tell me here. Please use the anonymous feedback form for this class. Since I won’t be able to tell if you actually did this question, we will simply be on the honor system. I value your opinion and I hope that you will take a few minutes to tell me what you think.