On Sat, 01 May 2010 01:01:47 -0700, Sebastian Fischer
On May 1, 2010, at 8:08 AM, Ivan Lazar Miljenovic wrote:
* I can't redefine the Graph methods to introduce the (Cls a) constraint [reasonable]
Not sure if you can.
I think Kevin means that he cannot change the signature of the methods in the Graph class because those are defined in the FGL package.
Mostly. If I was able to redefine the method to add the class constraint in *my* code, that would be "what I wanted" but clearly wrong from the general type perspective: once defined it should not be possible to redefine. I was more trying to indicate that I'd been flailing around and trying everything, even things that make me look stupid. :-)
You're putting the constraint in the wrong places: put the "(Cls a) => " in the actual functions where you need it.
Those seem to be the methods of the Graph class, where he can't place the constraints. Kevin may have a version of makeGraph with additional constraints but cannot use it to to define a Graph instance.
Exactly. I posted a separate response with more details, but this is my problem. Actually, I'm even struggling defining the "empty" method of Graph. -- -KQ