On Sun, Jun 16, 2013 at 05:22:59PM -0700, briand@aracnet.com wrote:
Vertex3 takes three arguments, all of which must be of the same instance of VertexComponent. Specifying GLdoubles in the signature of wireframe specifies the types in the last three calls to Vertex3, but (0.0 :: GLdouble) is still requried on the first to fix the type there. How else could the compiler know that you mean 0.0 to be a GLdouble and not a GLfloat?
it's curious that
(0.0::GLdouble) 0.0 0.0
is good enough and that
(0.0::GLdouble) (0.0::GLdouble) (0.0::GLdouble)
is not required. I suspect that's because, as you point out, they all have to be the same argument and ghc is being smart and saying if the first arg _must_ be GLdouble (because I'm explicitly forcing the type), then the rest must be too.
That is exactly the reason. Tom