Three Stabs at a Typed Schema DSL in Kotlin

Short summary

The post explores three progressive Kotlin design patterns for typed schema DSLs: classical constraint solver APIs, type-safe builder DSLs with lambda receivers, and product-type approaches. Each trades off flexibility for compile-time type safety, but practical limitations emerge: positional field access, trait extension ambiguities, and the need to thread typed references through function signatures. The author concludes that languages with higher-kinded or dependent types may be necessary for fully composable, name-based schemas without leaky abstractions.

• •Compares three Kotlin DSL patterns for constraint solvers and streaming statistics libraries
• •Shows how type safety prevents runtime errors but creates positional-access brittleness at scale
• •Identifies limits of Kotlin's type system for fully composable, name-based schema access

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