Simplifying a Haskell Backend with GADTs: A Tale of Two Lambda Box Targets

This blog post details how the author used Generalized Algebraic Datatypes (GADTs) in Haskell to simplify the development of an Agda compiler backend. Facing the challenge of compiling to two different Lambda Box intermediate language targets (typed and untyped), the author leveraged GADTs and dependent types to elegantly avoid code duplication and enforce type safety. The type system prevents the omission of type information for the typed target. This practical example demonstrates the power of GADTs in everyday programming and showcases how dependent types can help prevent errors, resulting in cleaner, more maintainable code.