In this project I provide a set of interfaces for spam classifiers, classification runners (normal, k-fold cross validation...), results formatters, etc. and some implementations for them (random and Graham classifier, normal and cross-validation runner, default formatter...) which can be used to test a set of classifiers against the same test data with the same training data for comparison.
I've had spam issues in comments in my blog and I'd like to try a few different content-based classifiers and see how they perform with my data. I thought it would be cool to be able to compare a wider range of messages (some user may want to include additional metadata in the classifier computations) so I will code it with some degree of genericity or polymorphism. To do that, I have decided to represent the result of a given classification with a simple boolean type: true for positive, false for negative.
My goal is that, if you already have your classes for representing messages and classifiers, you can build a simple Adapter for your classifier and plug both along with a pair of training set and test set and see the numbers pop out. Thus I have to make it simple so you don't need to modify the internals of the classifier.
The Classifier interface will probably change soon, because with the current implementation of the Cross-Validation runner it is not possible to change the default parameters of the classifier under test (except through inheritance, but it would be unfeasible to create an inherited class for all the combinations of parameters one may want to try).
Right now it can only be used through scripts like the ones shown in CVExampleComparator.php and ExampleComparator.php. The DefaultFormatter class returns a simple representation of the results, but you can create a formatter that implements the ResultsFormatter interface (or not) to give the RunnerResults any format.