Deepseq proposed patch

Lennart Augustsson lennart at
Fri Jun 11 14:19:37 EDT 2010

Yes, gmapQ is very slow.  This might not matter for forcing mostly
unevaluated data, but for evaluated data it would really hurt.

On Fri, Jun 11, 2010 at 8:20 AM, Stephen Tetley
<stephen.tetley at> wrote:
> On 10 June 2010 22:15, Julian Blake Kongslie <jblake at> wrote:
> [SNIP]
>> The point of my email was more that I'm not sure it
>> makes sense to have a "NFData" class, where "Data" would appear to suffice
>> and be easier for programmers to work with.
> Don't Data.Data and traversals through gmapQ etc have a reputation for
> being particularly slow? (most newer generics libraries benchmark
> against it to show their swiftness).
> That seems one good reason against this broad instance.
> Best wishes
> Stephen
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