-- |
-- Takes a string naming a 'Colour' (must be all lowercase) and returns it. Fails if
-- the name is not recognized.
readColourName :: MonadFail m => String -> m (Colour Double)
readColourName "rebeccapurple" = return rebeccapurple
readColourName :: MonadFail m => String -> m (Colour Double)
readColourName "rebeccapurple" = return rebeccapurple
readColourName "rebeccapurple" = return rebeccapurple