Efficient Memory Representation with GADTs in OCaml

This article explores using Generalized Algebraic Data Types (GADTs) in OCaml to optimize memory representation. The author first explains the limitations of OCaml's polymorphism, particularly the space inefficiency of List.iter when handling different data types due to uniform memory representation. Attempts to create a `Compact_array` type using ordinary variants and objects fail due to type inference and memory allocation issues. Finally, using GADTs, the author successfully creates a flexible and efficient memory representation for arrays of different data types, showcasing GADTs' usefulness beyond compiler writing—particularly in high-performance applications demanding fine-grained memory control.