CWI: A Lightweight, Expressive Approach to Generic Programming in Haskell

Title: CWI: A Lightweight, Expressive Approach to Generic Programming in Haskell

Abstract: This research explores the concept of CWI (Composition with Type-Specific Instructions), a lightweight, expressive approach to generic programming in Haskell. The primary goal of this research is to create a concise, yet powerful method for traversing and processing trees, while maintaining type safety and flexibility. CWI achieves this by reconstructing functional strategies as an amalgamation of certain forms of polymorphism, type case, polytypism, and overloading.

Research Question: How can we create a lightweight, expressive, and type-safe approach to generic programming in Haskell that allows for flexible traversal and processing of trees?

Methodology: The research is based on the development of a new approach to generic programming called CWI. This approach is built upon the principles of functional strategies, which are first-class generic functions that can traverse into terms while mixing uniform and type-specific behavior. The methodology involves the following steps:

1. Definition of the CWI type: The first step is to define the CWI type, which models functional strategies and allows for the composition of type-specific instructions. 2. Implementation of nulla: The nulla function is implemented as a placeholder for the type-specific instructions. This allows for the creation of a null tree that can be used in the composition of strategies. 3. Development of combinators: The research involves the development of combinators that allow for the manipulation and composition of CWI strategies. These combinators include higher-order functions that can be used to create, update, and apply strategies. 4. Illustration of expressiveness and conciseness: The research demonstrates the expressiveness and conciseness of the CWI approach by providing highly parameterized definitions of traversal schemes.

Results: The main result of this research is the development of the CWI approach, which provides a lightweight, expressive, and type-safe method for generic programming in Haskell. The research also shows that the CWI approach is more concise and easier to use than other existing methods, such as XSLT.

Implications: The implications of this research are significant for the field of functional programming. The CWI approach provides a new and improved method for generic programming that is more expressive, concise, and type-safe than existing methods. This can lead to more efficient and maintainable code, as well as new possibilities for the development of generic programming techniques in Haskell and other functional programming languages.

Link to Article: https://arxiv.org/abs/0204013v1 Authors: arXiv ID: 0204013v1