---
title: "SU-CS242 OCT172024"
source: https://www.jemoka.com/posts/kbhsu_cs242_oct172024/
date: 2024-10-17
---

Lambda calculus, now with sums:
\begin{equation} e \to (x | \lambda \lambda x.e | e e | i | e+e) \end{equation}
explicit evaluation order write \(e + e&rsquo;\) as&hellip;.
\(( \lambda x . ((\lambda y . (\lambda z.z) (x + y)) e&rsquo;)) e\)
in a call by value world, this would explicitly specify the order that we add \(x\) and \(y\) together.
Notice! We can also write this with let notation:
two good things about this
the order of evaluation is explicit every intermediate result is now named
