On 2014-06-08, 2:44 AM, Neil wrote:
Benoit Jacob wrote:Strawman class diagram: Transformation / | \ / | \ / | \ / | \ Identity Matrix Other transform types e.g. Translation In such a world, the class containing the word "Matrix" in its name would not have a isIdentity() method; and for use cases where having a "variant type" that can avoid being a full blown matrix is meaningful, we would have such a variant type, like "Transformation" in the above diagram, and the isIdentity() method there would be merely asking the variant type for its type field.I think roc suggested the possibility of something similar i.e. Transformation / | \ / | \ / | \ / | \ Identity 2DMatrix 3DMatrix Then from JS you would just write (matrix instanceof Identity). I don't know whether this would make the implementation unduly complex though.
I worked a good deal on Sage [1], a general algebra computation platform, and one lesson we learned again and again is that baking mathematical properties into the type hierarchy directly caused more problems than it solved. I'd like to avoid properties encoded as instance types if we possibly can. (Exposing isIdentity as an internal instanceof is fine.)
Nick [1] http://sagemath.org/ _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
