Spring 2024¶

Apr 26 Ellona Macmillan - MemDia: A JavaScript Library for Drawing Memory Diagrams

Abstract: A memory diagram is a picture that shows the contents of memory at a certain point in time while a program is running. Introductory CS courses (such as 149, 159, 240, and 261) use memory diagrams to teach subtle concepts about variables, objects, arrays, and references. Visualization tools like Python Tutor and Java Visualizer draw memory diagrams incrementally as the user steps through a program’s code. However, these tools are programming language specific and use a drawing format that is difficult for students to imitate. To address these limitations, we are developing a new library, named MemDia, for drawing memory diagrams in the browser. The user specifies a diagram in a plain text syntax, and the library draws the corresponding image in SVG format. MemDia is primarily designed for instructors and authors who wish to embed memory diagrams in classroom activities, lecture slides, and other materials.

Apr 26 Ben Saupp - Praxly: An Online IDE for the Praxis CS Test Pseudocode

Abstract: CodeVA offers a 15-week professional development course for Virginia K-12 teachers to prepare for the Praxis CS test. Teachers who pass this standardized test fulfill licensure requirements to teach advanced CS courses in public schools. The test uses a pseudocode language that is quite different from traditional programming languages. Previously, teachers have not had an easy way to trace the execution of pseudocode programs when learning and practicing. This talk will present Praxly, an online IDE for teachers to visualize, run, and debug Praxis pseudocode programs. We will demo Praxly's main features including a new step debugger. We will discuss Praxly’s layered architecture and implementation details. Finally, we will summarize experiences of an initial cohort of high school teachers who used Praxly during the past five months. Future revisions to the CodeVA course will embed Praxly into Canvas as the primary means for teaching pseudocode.

Apr 12 Dr. Chris Johnson - This is Knot Coding

Abstract: A knot is a path that meanders through space and returns to its start, usually crossing over itself many times. Knots have been studied by artists and mathematicians for centuries. You've seen knots in Roman, Celtic, and Islamic architecture and illuminated manuscripts. If you've ever used a Macintosh computer, you've touched one when you pressed the Command key. In this highly interactive workshop, you will learn to design your own custom knot as a mosaic of hexagonal tiles. Then you'll code it up in Twoville, a language written by Dr. Johnson for expressing shapes, and fabricate it as a vinyl sticker that you can take home. Bring a computer.

Mar 22 Dr. Siddharth Bhaskar - How do we run a program for an infinite number of steps?

Abstract: The finite world is just a tiny corner in our (mathematical) universe. Many natural algorithms extend smoothly to infinite data structures, where they typically require infinitely many steps to run. However, we have no way to formalize these algorithms with code, because we have no way to endow our code with a semantics that handles such transfinite computation. In this talk, I will construct a solution.