A programming language and model of computation that matches the optimal λ-calculus reduction algorithm perfectly.
Browse cluster: Functional Programming & Type Theory →Interaction Calculus is a minimal term rewriting system and programming language designed as an alternative to Lambda Calculus that achieves optimal reduction comparable to Lamping's optimal λ-calculus evaluator. Built in portable C99, the system introduces affine (single-use) and global variables, along with first-class superpositions and duplications, enabling efficient computation and expressiveness for concepts like continuations and linear higher-order abstract syntax. The repository includes a reference implementation in C (IC32, a 32-bit runtime), a Haskell implementation for learning, and a complete formal specification with interaction rules for term reduction to weak head normal form and full normal form.