[Haskell-cafe] Impredicative Types
simonpj at microsoft.com
Fri Nov 19 14:45:30 EST 2010
Yes, impredicative types are still in, but in a simpler form than before, along the lines of QML
I have been too busy with getting the new type checker working to describe or document it. Notably, I have not yet added syntax for QML's rigid type annotations, which leads to a loss of expressive power.
too much to do!
Bottom line: if you are interested in impredicative polymorphism, let me know. A good way to do so would be to register your interest on
Just add your email address to the cc list, *and* write a comment giving an example of how you are using impredicative poly, and pointing to any further info. That'll help motivate me to do the remaining work!
| -----Original Message-----
| From: haskell-cafe-bounces at haskell.org [mailto:haskell-cafe-bounces at haskell.org]
| On Behalf Of Gregory Crosswhite
| Sent: 19 November 2010 19:23
| To: Haskell Cafe
| Subject: [Haskell-cafe] Impredicative Types
| Hey everyone! I haven't had a chance to try out GHC 7 myself, but I saw
| in the documentation that Impredicative Types are still supported. Is
| this true? I thought that they were on their way out because they
| overcomplicated type checking; has this plan been changed?
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| Haskell-Cafe at haskell.org
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