[Haskell] Annoying naming clashes

John Meacham john at repetae.net
Thu Jun 17 18:33:46 EDT 2004


On Thu, Jun 17, 2004 at 06:03:31PM -0400, David Menendez wrote:
> Stefan Holdermans writes:
> 
> > Well, you've just identified the well-known trade-off between
> > abstraction and induction. A language extension involving 'views' [4,
> > 1, 3] has been proposed [2] to deal with this issue.
> 
> That proposal for views is eight years old. Has there been any movement
> towards implementing it? Did some technical obsticle arise, or have
> people simply been busy elsewhere?

I think it was a couple things, Pattern guards were introduced which
were conceptually a whole lot simpler and provided a way to do many of
the things views did. 
http://research.microsoft.com/~simonpj/Haskell/guards.html

The other thing is that it is unclear whether they are a good idea, I
mean, they would probably be useful to some, but as extensions go, they
would be a pretty radical change to the language. Many consider the
simplicity and consistancy of pattern matching a virtue. Also, the views
proposal is 8 years old, I don't know if anyone has thought much about
how they would interact with all the other generally accepted language
extensions that have happened in the meantime.

I think the moral is, don't hold your breath. and learn pattern guards,
they are a really really useful and universal extension to the language. 

        John

-- 
John Meacham - ⑆repetae.net⑆john⑈ 


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