[Haskell-cafe] Byte Histogram

[Erik de Castro Lopo]

Daniel Fischer wrote:

> On Thursday 03 February 2011 23:19:31, Johan Tibell wrote:
> > Hi,
> >
> > For what it's worth I saw the problems in your counting examples right
> > away, without reading the explanatory text below.
> 
> Yes, they were pretty obvious with enough experience. For beginners I 
> expect it to be a rather insidious trap.
> 
> > Hopefully that means
> > that it's possibly to learn how to spot such things without resorting
> > to e.g. running the program or reading Core *gasp*.
> 
> Within limits. Detrimental laziness or strictness can be arbitrarily well 
> hidden.

I am a relative newcomer to Haskell, but I think I have a reasonable
understanding of the executaion model. Enough to fix performance
issues in simple code like the example given.

However, one of the Haskell projects I work on is Ben Lippmeier's
DDC compiler. Thats about 50000 lines of Haskell code and finding
performance issues there is really difficult. 

Erik
-- 
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Erik de Castro Lopo
http://www.mega-nerd.com/