Screaming Penguin

In honor of Ada Day: So easy. Those of you who read the "Quote" box will see some of my favorite Hopper quotes, but women in tech is one of those things that I think gets overlooked. Well, OK, "People in Tech" get overlooked. But that is a different rant. I am going to punt on being clever, and just honor our 2008 Turing Award winner (BTW, ask me about Turing re: IHG :P) However, one of the most important aspects of object oriented computing is the Liskov Substitution Principle, named for Barbara Liskov In common nerd parlance, we might call this Duck Typing. It states that:

If for each object o1 of type S there is an object o2 of type T such that for all programs P defined in terms of T, the behavior of P is unchanged when o1 is substituted for o2, then S is a subtype of T.

This in abstract terms breaks the ontological "Is A" for "Acts Like A" in terms of proving program correctness. Personally I have always liked the idea of calling this "Quixotic" typing. It reminds me of a line from the movie Quiz Show re:Don Quixote, "If you want to be a knight, act like a knight." The shift in meaning from "Looks like a duck; quacks like a duck; is a duck," is subtle but meaningful. It doesn't redefine ontological types, but it implies that there is little difference between acting like that, and being that. Anyway, in the interest of laziness, Dr. Liskov's bio from Wikipedia:

Barbara Liskov, (born Barbara Jane Huberman in 1939), is a computer scientist. She is currently the Ford Professor of Engineering in the MIT School of Engineering's Electrical Engineering and Computer Science department and an Institute Professor at the Massachusetts Institute of Technology. She earned her BA in mathematics at the University of California, Berkeley in 1961, and became the first woman in the United States to be awarded a Ph.D. from a computer science department, in 1968 from Stanford University.[2] The topic of her Ph.D. thesis was a computer program to play chess end games.[3] Liskov has led many significant projects, including the Venus operating system, a small, low-cost and interactive timesharing system; the design and implementation of CLU, the first programming language to support data abstraction; Argus, the first high-level language to support implementation of distributed programs; and Thor, an object-oriented database system. With Jeannette Wing, she developed a particular definition of subtyping, commonly known as the Liskov substitution principle. She leads the Programming Methodology Group at MIT, with a current research focus in Byzantine Fault Tolerance and distributed computing. Liskov is a member of the National Academy of Engineering and a fellow of the American Academy of Arts and Sciences and of the Association for Computing Machinery (ACM). In 2004 she won the John von Neumann Medal for "fundamental contributions to programming languages, programming methodology, and distributed systems". She is the author of three books and over a hundred technical papers. Liskov received the 2008 Turing Award from the ACM[4] for her work in the design of programming languages and software methodology that led to the development of object-oriented programming.[5] Specifically, Liskov developed two programming languages, CLU in the 1970s and Argus in the 1980s.[5] The ACM cited her contributions to the practical and theoretical foundations of "programming language and system design, especially related to data abstraction, fault tolerance, and distributed computing."[6]