Hi all ! I must admit, if there is anything serious in this, I don't understand it. A crosscompiler from Haskell to J ? Why would it be useful ?
Cheers, Erling -----Original Message----- From: [email protected] [mailto:[email protected]]on Behalf Of Oleg Kobchenko Sent: den 2 oktober 2009 23:26 To: Chat forum Subject: Re: [Jchat] Haskell > Put differently, if I were to implement J in Haskell, I would This is only one way to approach it. Quite another, which I think is more interesting: is to implement Haskell in J. (Haskel is just another Lisp even more so than Smalltalk, the similarity with which is the use bytecode in some Haskells.) J can act as a backend. Here's JavaScript acting as a backend in the a browser: http://haskell.org/haskellwiki/Haskell_in_web_browser > From: Raul Miller <[email protected]> > > On Fri, Oct 2, 2009 at 9:36 AM, Erling Hellenäs > wrote: > > I think the J notation is shorter than the Haskell notation. If you see J as > > a "homogenous algebra", I'm interested in how a Haskell implementation or a > > compiled language written in Haskell that uses something similar to this > > algera would look. The type information in Haskell is impressive, and I > > didn't mean to say it could be shorter. > > Well... > > From my point of view, J's functions have domains which > do not map well onto types. In the general case, every > function's domain can be independent of any other function's > domain. And, when the result of one function is used as > the argument for another, the derived function may have > some yet different domain. > > For example, the domain of i.@,~@(^&1r2) is square numbers. > > Types, from my point of view, are an attempt at characterizing > domains, but with constraints on what can be represented > to avoid issues with the halting problem. And, I believe that > if you work around those constraints, I think you lose a lot of > the power of the type system. > > Put differently, if I were to implement J in Haskell, I would > build myself an array type, which contained a list of > dimensions and a sequence of lists of primary data (each > sequence would be a different primitive type -- character, integer, > float, etc, and.only one of them could be non-empty). I would also > want an efficient way of determining which of those types > was present. I think this would let me implement any J operation > in Haskell, but I do not think Haskell's type system would give me > much traction on functions which use this data type. (But I could > be wrong, maybe Haskell's type system can make meaningful > and significant inferences in this context? Mostly, though, I think > it would be telling you when you were passing "non-J-like" data to > "J-like functions" which is an issue which you do not even have > to consider when you work directly in J.) > > Does my point of view make sense to you? > > If so, do you agree or disagree with me? > > If not, where does what I wrote start descending into nonsense > for you? > > Thanks, > > -- > Raul > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
