proptotype of make style dep stuff

Thomas Schilling nominolo at googlemail.com
Tue Oct 30 19:23:37 EDT 2007


On Tue, 2007-10-30 at 16:04 -0700, Stefan O'Rear wrote:
> On Tue, Oct 30, 2007 at 10:45:34PM +0000, Duncan Coutts wrote:
> > On Fri, 2007-10-26 at 10:48 +0000, Duncan Coutts wrote:
> > 
> > > So what's next...
> > > 
> > > We want to write some specifications
> > 
> > Spencer, Lennart, Thomas and I had a joint hacking session in which we
> > made some progress on this issue today. Specifically we can now generate
> > random dep graphs for use in QuickCheck tests. For example:
> > 
> > http://haskell.org/~duncan/cabal/foo.svg
> > 
> > 
> > We can tune the size and 'density' of these graphs. As you can see we
> > get cycles in the graphs. We'll have to filter out cycles. Any
> > suggestions on a simple way to do that? It's ok to depend on Data.Graph
> > for this kind of test code.
> 
> It is a well known result in the theory of graphs that any directed
> graph admits a topological ordering.  Thus, you could simply arrange to
> only generate edges from nodes to previously-created nodes.  Although
> this would change the distribution of shapes somewhat.

Wouldn't that mean we can only get trees (instead of DAGs)?



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