A Distributed Haskell for the Modern Web

Licentiate thesis, 2015

We present the design and implementation of a novel programming model and software development suite for interactive, distributed web applications using the Haskell programming language. The suite includes the JavaScript-targeting Haste Haskell compiler which improves on the current state of the art by producing smaller and leaner JavaScript code while preserving compatibility with standard Haskell as well as with the de facto standard GHC compiler. We also describe the Haste.Foreign lightweight, portable interface for interoperating with JavaScript code, which allows boilerplate-free incorporation of JavaScript libraries in Haskell programs and vice versa. Haste.Foreign is implementable as a client library, and does not require any compiler modifications. While designed for the Haste compiler, the interface is portable across a range of Haskell dialects and high level target platforms. Finally, we present the Haste.App programming model for distributed web applications, which abstracts over the separation of client and server to allow distributed applications to be written and type checked as a single program. The Haste.App model stands in stark contrast to the conventional way of developing web applications as separate client and server programs communicating explicitly over some network protocol. Haste.App reduces the amount of boilerplate code required to implement distributed web applications, and provides type safety across the network separating the client and server parts. This shortens development times and eliminates costly and embarrassing runtime failures at the boundaries between networked components. Like the foreign function interface, this programming model is implementable entirely as a library without any compiler modifications, and is thus similarly portable.