Parallel list comprehensions

John Meacham john at
Thu Feb 16 04:13:55 EST 2006

On Thu, Feb 16, 2006 at 09:06:24AM +0000, Ross Paterson wrote:
> On Sat, Feb 04, 2006 at 03:11:10PM +0100, John Hughes wrote:
> > I noticed ticket #55--add parallel list comprehensions--which according to
> > the ticket, will probably be adopted. I would argue against.
> As there are many voices against and only John M speaking for these,
> it seems reasonable at least to move them from "probably yes" to "maybe".

I really like them, partially because it gives list comprehensions more
power than plain old do notation.

> > My opinion may be coloured by the fact that I never use the things.
> > However, I think it's a mistake to add rarely used features with
> > a small payoff to the language. It just makes the language larger,
> > harder to learn, and harder to read for all but the expert, without
> > much corresponding benefit.
> I agree, but then I feel the same way about pattern guards.  I've used
> them only recently, and that was modifying code (GHC) that already had
> lots of Maybe-returning functions designed for use with pattern guards.

Oh golly, I can't live without pattern guards. they are the best thing
since sliced bread. :) I don't know how people can write concise code
without them. 


John Meacham - ⑆⑆john⑈

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