Coalton

Provides compile-time type checking with beautiful error messages that catch bugs early, as shown in the differentiation example where type mismatches are clearly flagged.

Embeds directly into Common Lisp codebases, allowing mixed usage and leveraging existing Lisp tooling and the REPL, demonstrated by the interactive code snippets.

Supports algebraic data types, pattern matching, and parametric polymorphism for safe, expressive code, evident in the Expr type definition and diff function implementation.

Used in real-world applications like defense and quantum computing software, indicating robustness and performance in critical domains.