Bridging the GUI gap with reactive values and relations

Abstract

There are at present two ways to write GUIs for functional code. One is to use standard GUI toolkits, with all the benefits they bring in terms of feature completeness, choice of platform, conformance to platform-specific look-and-feel, long-term viability, etc. However, such GUI APIs mandate an imperative programming style for the GUI and related parts of the application. Alternatively, we can use a functional GUI toolkit. The GUI can then be written in a functional style, but at the cost of foregoing many advantages of standard toolkits that often will be of critical importance. This paper introduces a light-weight framework structured around the notions of reactive values and reactive relations. It allows standard toolkits to be used from functional code written in a functional style. We thus bridge the gap between the two worlds, bringing the advantages of both to the developer. Our framework is available on Hackage and has been been validated through the development of non-trivial applications in a commercial context, and with different standard GUI toolkits.

Runtime verification and validation of functional reactive systems

“…The remote debugger listens on the asynchronous channel and, when it detects an event, or when instructed by the user, uses the synchronous socket to send commands and obtain results. This lets us implement the remote debugger in a reactive way, with less knowledge of the internals of how SF execution is implemented, as described in Perez & Nilsson (2015). The FRP simulator runs locally on the device where we want to test the system, which can be a developer's computer, but also can be an external device.…”

Testing and debugging functional reactive programming

“…The remote debugger listens on the asynchronous channel and, when it detects an event, or when instructed by the user, uses the synchronous socket to send commands and obtain results. This lets us implement the remote debugger in a reactive way, with less knowledge of the internals of how reactimation work, as described in [Perez and Nilsson 2015].…”