[Haskell-cafe] curious about sum

Don Stewart dons at galois.com
Tue Jun 16 11:36:41 EDT 2009

> On 16 Jun 2009, at 05:18, Don Stewart wrote:
>> keithshep:
>>> The answer is sometimes (only if you use an optimize flag):
>> You're turning on the strictness analyser. That's enabled with -O or
>> -O2.
>> But sum should be using a tail recursive foldl'. It's a bug in the H98
>> report, IMO.
> Not at all, as discussed, there are legitimate uses for a lazy sum, and 
> haskell is a lazy language by default.  The only change here needs to be 
> either claus' suggestion of generalizing functions over their  
> application operator, or providing a strict sum'.

Are the legitimate uses more common than the illegitimate uses?

-- Don

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