Soloway's Rainfall problem, a classic benchmark in computing education research, has proven difficult for many CS1 students. Rainfall tests students' abilities at plan composition, the task of integrating code fragments that implement subparts of a problem into a single program. Nearly all prior studies of Rainfall have involved students who were learning imperative programming with arrays. In our recent multi-university study, students learning functional programming produced atypical profiles of compositions and errors on Rainfall.

What do these different results suggest about the problem of plan composition and programming education? This talk raises various questions about the relationships between programming languages, program design, curricula, and how students perceive code structure.

The talk assumes no experience with plan composition, functional programming, or having been rained upon. Please come equipped with pen and paper, because the talk will require you to write some programs.

Joint work primarily with Kathi Fisler.