For that matter, I could do this:
(defmacro andp
([] true)
([x p] `(~p ~x))
([x p & next]
`(let [and# (~p ~x)]
(if and# (andp ~x ~...@next) and#))))
On Jul 23, 5:33 pm, ataggart <alex.tagg...@gmail.com> wrote:
> Not that preserves the short-circuiting behavior of 'and. This works
> though:
>
> (defmacro andf [& fns]
> (let [x# (gensym)]
> `(fn [~x#] (and ~@(map #(list % x#) fns)))))
>
> user=> (filter (andf integer? odd?) [1 2 3.1])
> (1)
>
> On Jul 23, 2:27 pm, ".Bill Smith" <william.m.sm...@gmail.com> wrote:
>
> > I want to filter a list based on the logical AND of a set of
> > predicates. For example, let's say I have single-argument functions
> > f, g, and h (without side-effects), and I want those items x in the
> > list such that (f x), (g x) and (h x) are all true. I know I can do
> > this:
>
> > (filter #(and (f %) (g %) (h %)) my-list)
>
> > Is there a more terse way to express the same thing? I suspect there
> > is a mechanism similar to (or perhaps a generalization of) composition
> > for that, but I couldn't find it in the API docs.
>
> > Bill Smith
> > Austin, TX
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