[Haskell-cafe] Re: The Worker/Wrapper Transformation

Ben Franksen ben.franksen at online.de
Sat Jan 5 18:08:46 EST 2008


Isaac Dupree wrote:
> Achim Schneider wrote:
>> http://www.cs.nott.ac.uk/~gmh/wrapper.pdf
>> 
> on page 6, stronger vs weaker seemed backwards to me... isn't (wrap ◦
> unwrap = idA) a stronger condition than (wrap ◦ unwrap ◦ body = body),
> because it tells you more, and is true in fewer cases? (which is also
> why you want to assume (wrap ◦ unwrap = idA) when you can, because it's
> the most useful one for subsequent program transformation)

Ah, thanks you say that, I have been asking myself if that was just me,
having things backward. In my book, stronger => weaker, too.

Cheers
Ben



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