[Haskell-cafe] 'Associative' order of calling

Francesco Ariis fa-ml at ariis.it
Fri Oct 23 15:21:57 UTC 2015

On Fri, Oct 23, 2015 at 10:26:08AM -0400, Charles Durham wrote:
> Is there a name for a fold that promises to call a function such that only
> an associative function will always return the same result. Or in other
> words, it has the property that it promises to call a function
> "associatively" on a set of data?

I am not sure I am understanding the question correctly. Every Monoid has a
single binary operation which happens to be associative and one of
the basic fold functions has signature

    foldMap :: (Foldable t, Monoid m) => (a -> m) -> t a -> m

(which does what you expect). Does that answer your question? If not,
I'd be grateful if you would provide an example.

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