Re: [Haskell-cafe] Announcing OneTuple-0.1.0
G'day all. I asked: But more to the point: Can it send email? Quoting John Dorsey [EMAIL PROTECTED]: Can you give an example of a use case? I don't need one. It's not maximally flexible until it can send email. Cheers, Andrew Bromage ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
G'day all. Quoting Lennart Augustsson [EMAIL PROTECTED]: But I called it One. That's a _terrible_ name. One, surely is (), just as Zero is Void. While I'm at it, I really don't like the lexical syntax of comments. Someone should fix that. Cheers, Andrew Bromage ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
Jason Dagit [EMAIL PROTECTED] wrote: Jason Dusek [EMAIL PROTECTED] wrote: John Dorsey [EMAIL PROTECTED] wrote: Now you can: * Solve any of the software problems that cannot be solved without the singleton tuple ! What would those be? I'm still trying to figure out how a singelton tuple is really distinct from a plain value. Careful when making (or not making) this distinction. It could lead to infinite types such as, a = OneTuple a. Perhaps I am lacking in imagination, but I still can't see the value of one tuples. -- _jsn ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
RE: [Haskell-cafe] Announcing OneTuple-0.1.0
Quoting Lennart Augustsson [EMAIL PROTECTED]: But I called it One. I did a similar one for Yhc, and I think I called it Box. My guess was that boxing/unboxing wasn't an overloaded enough term :-) Thanks Neil == Please access the attached hyperlink for an important electronic communications disclaimer: http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html == ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
Let me pick one example. Let's make a class that can convert between tuples and lists. Of course there are restriction when this works, but it can still be useful. class TupleList t l | t - l where tupleToList :: t - l listToTuple :: l - t instance TupleList () [a] where tupleToList () = [] listToTuple [] = () -- XXX This doesn't work, and is just wrong. --instance TupleList (a) [a] where --tupleToList (a) = [a] --listToTuple [a] = (a) instance TupleList (a,a) [a] where tupleToList (a1,a2) = [a1, a2] listToTuple [a1,a2] = (a1, a2) instance TupleList (a,a,a) [a] where tupleToList (a1,a2,a3) = [a1, a2, a3] listToTuple [a1,a2,a3] = (a1, a2, a3) On Fri, Oct 3, 2008 at 8:17 AM, Jason Dusek [EMAIL PROTECTED] wrote: Jason Dagit [EMAIL PROTECTED] wrote: Perhaps I am lacking in imagination, but I still can't see the value of one tuples. -- _jsn ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
Lennart Augustsson [EMAIL PROTECTED] wrote: Let me pick one example. Let's make a class that can convert between tuples and lists. -- XXX This doesn't work, and is just wrong. -- instance TupleList (a) [a] where --tupleToList (a) = [a] --listToTuple [a] = (a) It's not clear to me what is so wrong about it. If the 1-ary tuple is the 1-ary product, it makes sense. -- _jsn ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
On Fri, Oct 3, 2008 at 3:17 AM, Jason Dusek [EMAIL PROTECTED] wrote: Perhaps I am lacking in imagination, but I still can't see the value of one tuples. You can use them to defeat seq. undefined `seq` x == undefined OneTuple undefined `seq` x == x That might be useful if a polymorphic function is using seq to force evaluation, and you don't want it to. But I can't imagine that coming up much in practice. -- Dave Menendez [EMAIL PROTECTED] http://www.eyrie.org/~zednenem/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
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. -- Lennart On Fri, Oct 3, 2008 at 6:07 PM, Jason Dusek [EMAIL PROTECTED] wrote: Lennart Augustsson [EMAIL PROTECTED] wrote: Let me pick one example. Let's make a class that can convert between tuples and lists. -- XXX This doesn't work, and is just wrong. -- instance TupleList (a) [a] where --tupleToList (a) = [a] --listToTuple [a] = (a) It's not clear to me what is so wrong about it. If the 1-ary tuple is the 1-ary product, it makes sense. -- _jsn ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
On Fri, 2008-10-03 at 15:38 -0400, David Menendez wrote: On Fri, Oct 3, 2008 at 3:17 AM, Jason Dusek [EMAIL PROTECTED] wrote: Perhaps I am lacking in imagination, but I still can't see the value of one tuples. You can use them to defeat seq. undefined `seq` x == undefined OneTuple undefined `seq` x == x That might be useful if a polymorphic function is using seq to force evaluation, and you don't want it to. But I can't imagine that coming up much in practice. Think element strict polymorphic containers, e.g. data HeadStrictList a = Nil | Cons !a (HeadStrictList a) then type LazyList a = HeadStrictList (OneTuple a) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
derek.a.elkins: On Fri, 2008-10-03 at 15:38 -0400, David Menendez wrote: On Fri, Oct 3, 2008 at 3:17 AM, Jason Dusek [EMAIL PROTECTED] wrote: Perhaps I am lacking in imagination, but I still can't see the value of one tuples. You can use them to defeat seq. undefined `seq` x == undefined OneTuple undefined `seq` x == x That might be useful if a polymorphic function is using seq to force evaluation, and you don't want it to. But I can't imagine that coming up much in practice. Think element strict polymorphic containers, e.g. data HeadStrictList a = Nil | Cons !a (HeadStrictList a) then type LazyList a = HeadStrictList (OneTuple a) Used in practice to prevent strict state components in list fusion leaking into user's lazy code, dataL a = L a -- lazy / lifted newtype S a = S a -- strict / unlifted class Unlifted a where instance Unlifted (L a) where expose (L _) s = s instance Unlifted (S a) where expose (S a) s = seq a s data Stream a = forall s. Unlifted s = Stream !(s - Step a s) -- ^ a stepper function !s-- ^ an initial state So we can then ensure stream :: [a] - Stream a stream xs0 = Stream next (L xs0) where next (L []) = Done next (L (x:xs)) = Yield x (L xs) Has the appropriate strictness properties. -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
Lennart Augustsson [EMAIL PROTECTED] wrote: 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? At present, tupling doesn't lift values into anything, since we don't have generic operations on tuples. The last two messages in this thread suggests this has more to do with the internals of Haskell than they do with consistent semantics -- so I am perhaps missing the point. -- _jsn ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
On Fri, Oct 3, 2008 at 2:29 PM, Jason Dusek [EMAIL PROTECTED] wrote: Lennart Augustsson [EMAIL PROTECTED] wrote: 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. The last two messages in this thread suggests this has more to do with the internals of Haskell than they do with consistent semantics -- so I am perhaps missing the point. I think most Haskellers try their best to keep the first subservient to the second. Cheers, Tim -- Tim Chevalier * http://cs.pdx.edu/~tjc * Often in error, never in doubt If you don't understand the causes, it is impossible to come up with a solution. -- Joe Biden ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
On Fri, Oct 3, 2008 at 7:26 PM, Tim Chevalier [EMAIL PROTECTED] wrote: On Fri, Oct 3, 2008 at 2:29 PM, Jason Dusek [EMAIL PROTECTED] wrote: Lennart Augustsson [EMAIL PROTECTED] wrote: 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 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
On Fri, Oct 3, 2008 at 7:24 PM, Luke Palmer [EMAIL PROTECTED] wrote: Well, unboxed tuples are not really lifted nor unlifed, since you can't even pass one to a function. It's true that unboxed tuples are not first-class. But what I mean by unlifted is that the type (# Int, Int #), when interpreted as a set, does not contain _|_ as an element (and I'm purposely conflating the unlifted/liftedness distinction with the unboxed/boxness distinction here). Is that what you mean, or do you mean something else? I like to pretend tuples are unlifted. Here's how I do it: Sure. But the compiler won't check that assumption for you. I don't know whether that has anything to do with the original question, though :-) Cheers, Tim -- Tim Chevalier * http://cs.pdx.edu/~tjc * Often in error, never in doubt If you don't understand the causes, it is impossible to come up with a solution. -- Joe Biden ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
On Fri, Oct 3, 2008 at 8:32 PM, Tim Chevalier [EMAIL PROTECTED] wrote: On Fri, Oct 3, 2008 at 7:24 PM, Luke Palmer [EMAIL PROTECTED] wrote: Well, unboxed tuples are not really lifted nor unlifed, since you can't even pass one to a function. It's true that unboxed tuples are not first-class. But what I mean by unlifted is that the type (# Int, Int #), when interpreted as a set, does not contain _|_ as an element (and I'm purposely conflating the unlifted/liftedness distinction with the unboxed/boxness distinction here). Is that what you mean, or do you mean something else? Yeah kind of, because if it doesn't contain _|_ as an element, then it's not even a domain! :-) I like to pretend tuples are unlifted. Here's how I do it: Sure. But the compiler won't check that assumption for you. I don't know whether that has anything to do with the original question, though :-) Nobody's questions are original. Luke ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
G'day all. Quoting John Dorsey [EMAIL PROTECTED]: Contributions are welcome. The project could use a tutorial, and a decent test suite. Strict singleton tuples are planned for the next version. I hope it has a Monad instance. But more to the point: Can it send email? Cheers, Andrew Bromage ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
On 10/2/08, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: G'day all. Quoting John Dorsey [EMAIL PROTECTED]: Contributions are welcome. The project could use a tutorial, and a decent test suite. Strict singleton tuples are planned for the next version. I hope it has a Monad instance. You could always use this one-tuple instead and get Functor, Monad and MonadFix for free: http://hackage.haskell.org/packages/archive/mtl/1.1.0.1/doc/html/Control-Monad-Identity.html ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
On Thu, Oct 2, 2008 at 1:17 AM, Simon Brenner [EMAIL PROTECTED] wrote:
On 10/2/08, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote:
G'day all.
Quoting John Dorsey [EMAIL PROTECTED]:
Contributions are welcome. The project could use a tutorial, and a
decent test suite. Strict singleton tuples are planned for the next
version.
I hope it has a Monad instance.
You could always use this one-tuple instead and get Functor, Monad and
MonadFix for free:
http://hackage.haskell.org/packages/archive/mtl/1.1.0.1/doc/html/Control-Monad-Identity.html
But that one is different:
newtype Identity a = Identity { runIdentity :: a }
data OneTuple a = OneTuple { only :: a }
So OneTuple has one more value than Identity (Identity Int has
Identity _|_ and Identity n for each n, whereas OneTuple Int has _|_,
OneTuple _|_, and OneTuple n for each n)
Luke
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Re: [Haskell-cafe] Announcing OneTuple-0.1.0
Hmm, it looks like you forgot to write a Traversable instance. I don't believe: sequenceA (OneTuple [1,2,3,4]) = _|_ is correct. Here is my contribution! instance Traversable OneTuple where sequenceA (OneTuple x) = fmap OneTuple x Luke On Thu, Oct 2, 2008 at 12:56 AM, John Dorsey [EMAIL PROTECTED] wrote: Fellow Haskellers, Much attention has been paid over the years to the regrettable omission of singleton tuples from Haskell. I am pleased to announce OneTuple, a humble implementation of the singleton tuple for Haskell. Now you can: * Wrap a single value of any type in a OneTuple ! * Pattern match to retrieve your value ! * Solve any of the software problems that cannot be solved without the singleton tuple ! * Enjoy instances for all the classes normal tuples have, plus more ! * Proclaim feature parity with Python ! Note: the singleton tuple does not support tuple syntax. Contributions are welcome. The project could use a tutorial, and a decent test suite. Strict singleton tuples are planned for the next version. Enjoy! Regards, John Dorsey ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
All, I'm bundling responses to save paper. [EMAIL PROTECTED] wrote: I hope it has a Monad instance. Naturally! But more to the point: Can it send email? Can you give an example of a use case? Do the Haskell-98 standard tuples have a correspondence feature? I wasn't able to find one with Hoogle. Simon Brenner wrote: You could always use this one-tuple instead and get Functor, Monad and MonadFix for free: As Luke pointed out, that one seems to be too strict. It may simplify the strict implementation, though. The initial release did have Monad and Functor instances... I'll look into MonadFix (thanks!). Luke Palmer wrote: Hmm, it looks like you forgot to write a Traversable instance. Oops... I included the instance statement but retained the default, mutually recursive methods. Too bad GHC didn't warn me. (Pesky halting problem.) Your change is in 0.1.1 -- thanks! Benjamin L.Russell wrote: Wonderful! I'm intrigued Thank you. What is the syntax for the singleton tuple? [...] What is your solution? Haskell has no such syntax, of course. '(x)' is no good due to ambiguity with parens' usual associative use. '(x,)' has been discussed, I think. It's ugly; it's inconsistent with other tuples, which don't share its final comma; it looks a bit like a tuple section, which could cause confusion. My solution was to use a normal Algebraic Data Type: data OneTuple a = OneTuple a I think the need for singleton tuples is rare enough that the syntactic inconsistency is tolerable. Jon Fairbairn suggests using unicode 0x27e8 and 0x27e0 in place of parentheses for tuples. I like the idea, especially as an alternate syntax for the same tuple types, permitting the singleton. minh thu writes: I thought to this idea in another way : parenthesis could be used for s-expressions and [unicode 0x27e8 and 0x27e0] could be used for regular grouping. This would allow to switch in the same code between infix and s-expr (e.g. enabling SXML)... I don't think I fully understand your proposal, although it sounds interesting. Regards, John Dorsey ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
On Thu, Oct 02, 2008 at 03:58:12PM -0400, John Dorsey wrote: All, I'm bundling responses to save paper. [EMAIL PROTECTED] wrote: I hope it has a Monad instance. Naturally! But more to the point: Can it send email? Can you give an example of a use case? Do the Haskell-98 standard tuples have a correspondence feature? I wasn't able to find one with Hoogle. Pfft, that kind of thinking never stopped Emacs! :-) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
2008/10/2 John Dorsey [EMAIL PROTECTED]: All, I'm bundling responses to save paper. [EMAIL PROTECTED] wrote: I hope it has a Monad instance. Naturally! But more to the point: Can it send email? Can you give an example of a use case? Do the Haskell-98 standard tuples have a correspondence feature? I wasn't able to find one with Hoogle. Simon Brenner wrote: You could always use this one-tuple instead and get Functor, Monad and MonadFix for free: As Luke pointed out, that one seems to be too strict. It may simplify the strict implementation, though. The initial release did have Monad and Functor instances... I'll look into MonadFix (thanks!). Luke Palmer wrote: Hmm, it looks like you forgot to write a Traversable instance. Oops... I included the instance statement but retained the default, mutually recursive methods. Too bad GHC didn't warn me. (Pesky halting problem.) Your change is in 0.1.1 -- thanks! Benjamin L.Russell wrote: Wonderful! I'm intrigued Thank you. What is the syntax for the singleton tuple? [...] What is your solution? Haskell has no such syntax, of course. '(x)' is no good due to ambiguity with parens' usual associative use. '(x,)' has been discussed, I think. It's ugly; it's inconsistent with other tuples, which don't share its final comma; it looks a bit like a tuple section, which could cause confusion. My solution was to use a normal Algebraic Data Type: data OneTuple a = OneTuple a I think the need for singleton tuples is rare enough that the syntactic inconsistency is tolerable. Jon Fairbairn suggests using unicode 0x27e8 and 0x27e0 in place of parentheses for tuples. I like the idea, especially as an alternate syntax for the same tuple types, permitting the singleton. minh thu writes: I thought to this idea in another way : parenthesis could be used for s-expressions and [unicode 0x27e8 and 0x27e0] could be used for regular grouping. This would allow to switch in the same code between infix and s-expr (e.g. enabling SXML)... I don't think I fully understand your proposal, although it sounds interesting. (It's not related to your tuple) Here is an example, quite contrived: With angle bracket: f a b c d = a + (+ b ⟨c + d⟩) -- the + before the b is in prefix position is equivalent to Normal Haskell: f a b c d = a + (b + (c + d)) With angle brackets, parenthesis mean this is an s-expr and angle brackets mean this is an standard (infix) expression. In the s-expr, there is no precedence rules while they are kept in the top level or in angle brackets. Hope it's clearer, Thu ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
John Dorsey [EMAIL PROTECTED] wrote: Now you can: * Solve any of the software problems that cannot be solved without the singleton tuple ! What would those be? I'm still trying to figure out how a singelton tuple is really distinct from a plain value. -- _jsn ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
On Thu, Oct 2, 2008 at 2:46 PM, Jason Dusek [EMAIL PROTECTED] wrote: John Dorsey [EMAIL PROTECTED] wrote: Now you can: * Solve any of the software problems that cannot be solved without the singleton tuple ! What would those be? I'm still trying to figure out how a singelton tuple is really distinct from a plain value. Careful when making (or not making) this distinction. It could lead to infinite types such as, a = OneTuple a. Jason ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
Just FYI, at Credit Suisse I wrote a 1-tuple type a few years ago. It was the only way to get a consistent way of dealing with certain things. But I called it One. I think the OneTuple should be in the base library, I mean, ask an 8 year old what number is missing in this sequence 0,2,3,4,5,6,7,8,9,... -- Lennart On Thu, Oct 2, 2008 at 7:56 AM, John Dorsey [EMAIL PROTECTED] wrote: Fellow Haskellers, Much attention has been paid over the years to the regrettable omission of singleton tuples from Haskell. I am pleased to announce OneTuple, a humble implementation of the singleton tuple for Haskell. Now you can: * Wrap a single value of any type in a OneTuple ! * Pattern match to retrieve your value ! * Solve any of the software problems that cannot be solved without the singleton tuple ! * Enjoy instances for all the classes normal tuples have, plus more ! * Proclaim feature parity with Python ! Note: the singleton tuple does not support tuple syntax. Contributions are welcome. The project could use a tutorial, and a decent test suite. Strict singleton tuples are planned for the next version. Enjoy! Regards, John Dorsey ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announcing OneTuple-0.1.0
On 2008 Oct 2, at 19:00, Jason Dagit wrote: On Thu, Oct 2, 2008 at 2:46 PM, Jason Dusek [EMAIL PROTECTED] wrote: John Dorsey [EMAIL PROTECTED] wrote: Now you can: * Solve any of the software problems that cannot be solved without the singleton tuple ! What would those be? I'm still trying to figure out how a singelton tuple is really distinct from a plain value. Careful when making (or not making) this distinction. It could lead to infinite types such as, a = OneTuple a. As for the difference, doesn't the tuple have an additional _|_ compared to a direct value? _|_, (_|_,), (value,). -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED] system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED] electrical and computer engineering, carnegie mellon universityKF8NH ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
