Re: [Haskell-cafe] Announcing OneTuple-0.1.0

On Fri, Oct 3, 2008 at 7:26 PM, Tim Chevalier wrote:

On Fri, Oct 3, 2008 at 2:29 PM, Jason Dusek wrote:

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Lennart Augustsson wrote:

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But (a) is not a lifted version of a, whereas (a,b) is a lifted version of the a b product. So it's not consistent, and thereby wrong.

Well, we can't represent the unlifted product in Haskell, right? You have to use some constructor. So if we just say we are using tuples to represent unlifted products, what's so bad about that?

Unless I'm confused, unboxed tuples represent unlifted products. In a sense this is "[using] some constructor", but in a sense not, since an unboxed tuple constructor has no runtime representation.

Well, unboxed tuples are not really lifted nor unlifed, since you can't even pass one to a function. I like to pretend tuples are unlifted. Here's how I do it: * Never use seq on tuples (or functions). I could make this precise by putting seq in a typeclass (like it used to be - like it should be), and not having instances for tuples. * Never do a strict pattern match on a tuple. I.e. instead of writing f (x,y) = ..., I will write f ~(x,y) =... everywhere. Then (_|_,_|_) might as well be _|_, we have no way to tell them apart. I like to pretend functions are unlifed the same way; i.e. const _|_ = _|_. There are apparently occasions where lazily matching on a tuple will introduce a space leak. I am not 1337 enough to recognize them yet. Luke