Remove Num instance for Angle #150
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Data.VectorSpace provides correct operators for addition and scalar multiplication. Multiplication of angles is meaningless, and allowing numeric literals as Angles leaks the internal representation.
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Looks good to me. Relatedly, there is also the further question of whether we want to make separate |
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Interesting. I'll have to think more about a possible |
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I think this should have been part of #140. In that PR I introduced a bunch of bugs which @byorgey had to fix. (abff596, 174f7b4, 10cae4c) With the changes in this PR, such buggy code will not type check.
With the old Angle class, we used the Num instance for the
1/2 :: Turnsyntax. We don't need that now, so it leaks the internal representation:rotate (1/2)is the same asrotate (1/2 @@ rad), but we shouldn't ever do that. Multiplication of Angles was always a bad idea.If this looks good to folks, I'll make the corresponding changes in other packages.