Haskell Blog

GUI - Release of the threepenny-gui library, version 0.4.0.0

Sat, 21 Nov 2013 14:50:40 +0200

I am pleased to announce release of threepenny-gui version 0.4, a cheap and simple library to satisfy your immediate GUI needs in Haskell.

Want to write a small GUI thing but forgot to sacrifice to the giant rubber duck in the sky before trying to install wxHaskell or Gtk2Hs? Then this library is for you! Threepenny is easy to install because it uses the web browser as a display.

The library also has functional reactive programming (FRP) built-in, which makes it a lot easier to write GUI application without getting caught in spaghetti code. For an introduction to FRP, see for example my slides from a tutorial I gave in 2012. (The API is slightly different in Reactive.Threepenny.)

Version 0.4 is an incremental improvement over the previous version. A new UI monad has been introduced to simplify the JavaScript FFI and allow recursion for FRP. DOM elements are now subject to garbage collection. (Unfortunately, this also leads to a bug when using custom HTML files.)

To see Threepenny in action, have a look at the following applications:

Daniel Austin’s FNIStash
Editor for Torchlight 2 inventories.
Chaddai’s CurveProject
Plotting curves for math teachers.

Get the library here:

Note that the API is still in flux and is likely to change radically in the future. You’ll have to convert frequently or develop against a fixed version.

Many thanks to Daniel Austin and Daniel Mlot for their help with this project and to Chris Done for implementing the Ji library which is the basis for this effort.

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