This repo contains a Haskell library (Data.Classy) for an enhanced version of classy deep embedding where some of the syntax and boilerplate burden is alleviated with advanced type system extensions. Furthermore, it shows some example applications: Expr: an expression language ExprGADT: a more type-safe expression language using GADTs Sharing: detection of sharing in expressions (modelled after: O. Kiselyov, ‘Implementing Explicit and Finding Implicit Sharing in Embedded DSLs’, Electronic Proceedings in Theoretical Computer Science, vol. 66, pp. 210–225, Sep. 2011, doi: 10.4204/eptcs.66.11.) SharingGADT: a GADT version of the above Region: a region DSL (modelled after: Y. Sun, U. Dhandhania, and B. C. d. S. Oliveira, ‘Compositional Embeddings of Domain-Specific Languages’, Proc. ACM Program. Lang., vol. 6, no. OOPSLA2, p. 34, 2022, doi: 10.1145/3563294.)