[Haskell-beginners] Existential data types

Brandon S. Allbery KF8NH allbery at ece.cmu.edu
Mon Dec 15 14:55:35 EST 2008

On 2008 Dec 15, at 12:49, Michael Snoyman wrote:
> I believe I have come to the conclusion that what I would like to do  
> is impossible, but I would like to have that confirmed. I would  
> basically like to be able to have a heterogeneous list without  
> boxing everything in a data type. Below is the sample code, with the  
> code I would like to use commented out. I'm I missing something, or  
> does Haskell simply not support what I am trying for?

It's possible but nontrivial.  Look at HList on http://hackage.haskell.org 
  for an implementation.

brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery at kf8nh.com
system administrator [openafs,heimdal,too many hats] allbery at ece.cmu.edu
electrical and computer engineering, carnegie mellon university    KF8NH

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.haskell.org/pipermail/beginners/attachments/20081215/3468c257/attachment-0001.htm

More information about the Beginners mailing list