I finally found some time to upgrade the PatternDispatch <https://github.com/toivoh/PatternDispatch.jl>package to support Julia 0.4 (and 0.3). The package allows to overload functions based on patterns which can be more fine granular than matching argument types for each argument (as Julia's multiple dispatch does). A simple example is
@pattern f(x) = x @pattern f(2) = 42 where the second method matches only if the argument === 2.
