Just do it while compiling!: Fast extensible records in Haskell

摘要

Almost all programming languages have some kind of record data structure. While the theory is fairly well understood (they are labeled products, which can be considered open or closed depending on one's typing rules), the pragmatics are still hotly debated. This is especially apparent in Haskell, where the community generally agrees that its record system is poor while emphatically disagreeing on a better solution. Exploring this design space through concrete implementations is thus quite important.