Home
Reading
Searching
Subscribe
Sponsors
Statistics
Posting
Contact
Spam
Lists
Links
About
Hosting
Filtering
Features Download
Marketing
Archives
FAQ
Blog
 
Gmane
From: Sittampalam, Ganesh <ganesh.sittampalam <at> credit-suisse.com>
Subject: RE: #2532: Add Typeable instance to Data.Unique
Newsgroups: gmane.comp.lang.haskell.libraries
Date: Friday 5th September 2008 12:23:35 UTC (over 9 years ago)
Jim Apple wrote:

> http://hackage.haskell.org/trac/ghc/ticket/2532
>
> Discussion deadline: Sept 7

I believe that the combination of this instance, the behaviour of
Data.Unique, and the behaviour of hs-plugins is broken.

In particular, as I understand the behaviour of hs-plugins, it is already
possible to generate Unique values inside a plugin that conflict with
Unique values generated in the main program, and this instance will allow
those values to be passed across the plugin boundary.

It's not clear to me what is to blame here. hs-plugins does something
dodgy, in that it hacks the behaviour of Data.Typeable instances so that
the same types get identical instances on both sides of the plugin
boundary. Data.Unique is doing something dodgy by using a global variable.
(There's a long discussion about this on haskell-café at the moment.) The
combination is what leads to the brokenness.

I will test this to confirm as soon as I can, but as the deadline is
approaching I thought I should raise the issue immediately.

Cheers,

Ganesh

==============================================================================
Please access the attached hyperlink for an important electronic
communications disclaimer: 

http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html
==============================================================================
 
CD: 3ms