Discussion: name for reversing fromList in Data.Sequence

David Feuer david.feuer at gmail.com
Thu Sep 1 19:57:19 UTC 2016

My concern is for what happens when such rules don't fire. If someone
converts a large list to a sequence only to reverse it, then the
badly-ordered sequence will end up being evacuated by the garbage collector
unnecessarily, pushing up the next major collection.

In contrast, I've used rewrite rules to fuse map with reverse; the worst
case there is some extra churn in the nursery.

That said, if others don't consider it important enough, or have enough
faith that rules will fire in this case (which may very well be), I can go
the rules route.

On Sep 1, 2016 3:51 PM, "John Wiegley" <johnw at newartisans.com> wrote:

>>>>> "DF" == David Feuer <david.feuer at gmail.com> writes:

FD> I'd like to add a function
DF> fromListReversing :: [a] -> Seq a

Hi David,

Perhaps rather than proliferating the libraries with fused compositions that
are faster than their composites via (.), we could defer things like this to
REWRITE rules.

John Wiegley                  GPG fingerprint = 4710 CF98 AF9B 327B B80F
http://newartisans.com                          60E1 46C4 BD1A 7AC1 4BA2
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