@hackage / simple-observer

simple-observer

This is a Haskell implementation of the Observer design pattern [1,2], providing a typeclass and an example implementation (Synchronous) which is perfectly usable in its own right.

This package is based on Observable.hs by Bastiaan Heeren [3], originally published as part of an exercise [4] for his students. It has been modified, extended and packaged by Andy Gimblett [5,6].

TODO

• Implement a mechanism for removal of observers. Consider Tom Lokhorst's suggestion on haskell-cafe [7].

Changelog

2009.11.11 v0.0.1 - first release, renamed from observer to simple-observer in recognition that there are more sophisticated ways to skin this particular cat.

2009.10.30 v0.0.0 - first Cabalised version, unreleased.

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[1] Gamma et al: `Design Patterns: Elements of Reusable Object-Oriented Software', Addison-Wesley, 1994. [2] http://en.wikipedia.org/wiki/Observer_pattern [3] http://people.cs.uu.nl/bastiaan/ [4] http://www.cs.uu.nl/wiki/bin/view/Afp0607/ExerciseWXHaskell [5] http://www.cs.swan.ac.uk/~csandy/ [6] email:haskell@gimbo.org.uk [7] http://www.haskell.org/pipermail/haskell-cafe/2009-November/068915.html