[Haskell-cafe] Examples of useful functions of order >= 3?
haskell at steffen-mazanek.de
Fri Dec 14 06:28:46 EST 2007
Do you mean Okasakis "Even higher-order functions for parsing or Why would
anyone ever want to use a sixth-order function?"?
2007/12/14, Ben Lippmeier <Ben.Lippmeier at anu.edu.au>:
> Hi all,
> I'm working on a type-based side effect analysis for a Haskell-like
> language, and need to test it against some more higher order functions.
> The situation is a bit icky because it uses bounded quantification
> and various related issues (ie covariance vs contravariance) only
> come into play when dealing with functions of order >= 3.
> Trouble is, the vast majority of useful higher order functions
> that I can think of are of order 2. Oh, I can certainly invent toys
> order3 f = f succ
> order4 b f = if b then f else order3
> .. and so on, but I'm left feeling unsatisfied.
> I vaguely remember a paper called something like "Is there any use
> for a seventh order function?", but I forget why they were used, and
> I can't find it on Google, or ACM or any of the other likely places.
> Does anyone have any examples of code (in whatever language) which
> usefully uses functions of order >= 3?? Preferably up to 5?
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> Haskell-Cafe at haskell.org
Dipl.-Inform. Steffen Mazanek
Institut für Softwaretechnologie
Universität der Bundeswehr München
Tel: +49 (0)89 6004-2505
Fax: +49 (0)89 6004-4447
E-Mail: steffen.mazanek at unibw.de
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