Ivan Lazar Miljenovic wrote:
Heinrich Apfelmus writes:
Ivan Lazar Miljenovic wrote:
Well, we'll provide a Map-based one that lets you specify the vertex type as a type parameter; this functionality (type parameter being ued for the vertex type) won't be required since not all graphs will be able to chop and choose which vertex type to use.
Ah, that would indeed make it easy. Maybe make the map based graph generic, so that it can be used with any primitive graph implementation?
data VertexGraph node gr a b = VG (gr a b) (BiMap node (Vertex gr))
instance (Ord node, Graph gr) => Graph VertexGraph node gr where
Not sure I understand what the point of the `gr' is there; what I meant was something like:
newtype MapGraph node a b = MG (Map node (Map node b, a, Map node b))
Yes; what I mean is that you can retrofit a custom vertex type to any graph implementation that uses a fixed vertex type. So, let's say that data Gr a b = .. -- graph with vertex type Vertex Gr = Int then type Gr' node a b = CustomVertex node Gr a b data CustomVertex node gr a b = CV (gr a b) (Map node (Vertex gr)) is a graph with custom vertex type node . Regards, Heinrich Apfelmus -- http://apfelmus.nfshost.com