[Haskell-cafe] ANN: convertible (first release)

John Goerzen jgoerzen at complete.org
Wed Jan 28 17:50:52 EST 2009

wren ng thornton wrote:

> [1] The Ord instance for Float and Double is also wrong, since NaN means 
> there's no total ordering (and the existence of NaN is necessitated by 
> the existence of Infinity). In addition to the fact that partial 
> orderings are more common than total orderings, this means we should 
> have a partial ordering class anyways.

Putting aside whether or not we should have a partial ordering class,
you may be technically correct but practically quite wrong.  To say that
we ought not to be able to use <= on a Double or < on a Float is crazy.
 To say that I can't detect, with <= and the like, that 2.5 is between
2.0 and 5.0, just because I can't detect its relationship to NaN,
strikes me as absurd.

Let's not poison the well for 99% of uses because 1% of users have a
leaky bucket.

-- John

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