A Block Design for Introductory Functional Programming in Haskell

Abstract

This paper describes the visual design of blocks for editing code in the functional language Haskell. The aim of the proposed blocks-based environment is to support students' initial steps in learning functional programming. Expression blocks and slots are shaped to ensure constructed code is both syntactically correct and preserves conventional use of whitespace. The design aims to help students learn Haskell's sophisticated type system which is often regarded as challenging for novice functional programmers. Types are represented using text, color and shape, and empty slots indicate valid argument types in order to ensure that constructed code is well-typed.