This post is a teaser for an article in my TiddlyWiki-based journal. The article illustrates an approach to separating logic and IO using the TV library. The TV approach clarifies the pure logic part and the IO part and is more conveniently composable than the mixed logic/IO formulation.
I’ve just released TV-0.2, which omits GUI functionality. That functionality is now present in the small new package GuiTV. The reason for this split is that the GUI support depends on wxHaskell, which currently can be difficult to install. Only TV (not GuiTV) is needed for this example.
See the article here.
Edit of Feb 13: If you tried the TiddlyWiki article in Opera and got an error, please try again. Problem fixed. (Slight difference in regexp handling in Opera vs FF & IE.)
Edit of March 5: This article was inspired by an example in Don Stewart’s “Programming Haskell” post.