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gadt-implementer

Implement Generalized Algebraic Data Types for type-safe data structures.

17|2|Updated Feb 16, 2026
Search Tags:#type safety#data structures#haskell#dsl#type theory#gadt
One-click install
npx skills add https://github.com/rainoftime/pl-skills --skill gadt-implementer
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: gadt-implementer
Source: https://github.com/rainoftime/pl-skills/tree/main/gadt-implementer
Command: npx skills add https://github.com/rainoftime/pl-skills --skill gadt-implementer

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires type-checker-generator, simply-typed-lambda-calculus, and includes references (resource) components.

What problem does it solve?

This Skill enables the creation of highly expressive and type-safe data structures by implementing Generalized Algebraic Data Types (GADTs), preventing common programming errors at compile time.

Core Features & Use Cases

  • GADT Declaration: Define data types with constructor-specific return types for precise type indexing.
  • Type Refinement: Leverage pattern matching to refine types within specific code branches.
  • Use Case: Build a type-safe embedded Domain-Specific Language (DSL) for a compiler, ensuring that only valid language constructs can be represented.

Quick Start

Define a GADT in Haskell to represent a typed abstract syntax tree.

Frequently Asked Questions about gadt-implementer

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I implement type-safe data structures using GADTs in Haskell?▼

You can implement type-safe data structures in Haskell by defining Generalized Algebraic Data Types (GADTs) with constructor-specific return types, ensuring precise type indexing and preventing common programming errors at compile time.

What are GADTs used for in type-safe embedded DSLs?▼

GADTs are used in type-safe embedded Domain-Specific Languages (DSLs) to represent typed abstract syntax trees, ensuring that only valid language constructs can be represented and preventing invalid states during compilation.

How does type refinement work during GADT pattern matching?▼

Type refinement in GADT pattern matching allows you to narrow types within specific code branches by matching constructors, leveraging type indexing to guarantee type safety without runtime checks.

Do I need to understand type theory to use GADTs for type-safe data structures?▼

Yes, implementing GADTs requires a foundational understanding of type theory, including pattern matching with type refinement and existential quantification, to define expressive and type-safe data structures correctly.

What is the best way to define constructor-specific return types in Haskell?▼

The best way to define constructor-specific return types in Haskell is by declaring GADTs, which allow each constructor to return a different specific type, enabling precise type indexing for advanced use cases.

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