Re: [Haskell-cafe] Re: Write Haskell as fast as C.

Ketil Malde wrote:

Ketil Malde writes:

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data EvidenceCode = IAC | IUG | IFR | NAC | NR | ... deriving Show

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Could it be that this derived read instance is somehow very inefficient?

To answer my own question: this is exactly it, ghc derives less than optimal code in this case. Rather than reiterate the case here, I did a quick writeup at http://blog.malde.org/, and would be quite happy about any feedback or suggestions.

I think you'll find the code that GHC derives for a Read instance handles extra whitespace and all kinds of other whatnot that you don't actually need in this specific case. I suspect this is what's up - but I don't have any hard proof for that. ;-)