On Oct 14, 11:16 pm, Sean Corfield <seancorfi...@gmail.com> wrote: > On Fri, Oct 14, 2011 at 5:50 PM, Alan Malloy <a...@malloys.org> wrote: > > I really liked this one too, though my first draft of it was more like > > (defn pipe [test f] > > (fn [value] > > (...))) > ... > > fix is basically your pipe, except it takes a series of test/f pairs, > > and to-fix is my original version, returning a function of x instead > > of computing on x immediately (this is handy as you can map (to-fix > > string? read-string) over a collection, for example). > > Out of curiosity, why wouldn't you define pipe to take [test f value] > and then you can map (partial pipe string? read-string) over a > collection?
As you notice lower, I like this argument-order so that I can chain operations on values better: (swap! some-atom update-in [:kind] fix string? keyword) flows very nicely: "Change this atom, updating its :kind value by converting a string to a keyword if necessary". But, that map is handy, so we have (to-fix), which is basically a partial setting all *but* the first arg (tying nicely into what you ask for in the next paragraph). > > > Given accepts only one clause and is "shaped" right for use in -> > > thread chains, like: > > > (-> x > > inc > > (given even? / 2)) > > So it's given [value test f & args] yes? Yeah, mirroring update-in and friends. At the moment given is a macro, so that args don't have to be evaluated unless the test passes, but I'm not really happy with that choice: it means you can't use it in update-in chains like you can use fix. I'd love input about these sorts of decisions, whether or not it ever gets into clojure proper. > I'm finding quite often I want a function that's a bit like partial > but puts the deferred arguments at the beginning of the argument list, > let's call it impartial (j/k) so you could do: > > ((comp (impartial given even? / 2) inc) x) > > I know that's contrived but I'm finding #(f % args) common enough that > something like "impartial" (with a better name, please!) would be > useful in some sort of contrib library of higher-order functions. Yeah, I've heard this from a few people. Myself, I don't think I run into this need very often, but maybe I just have a blind spot for it. > > If nothing else, I recommend you change the argument order to your > > pipe function: (defn pipe [value test f]) is clearly the "correct" > > signature, since it means that (like fix) you can use it in update-in/ > > alter/swap!/-> chains. > > Ah, that answers my question above. Interesting point. Argument order > choices are still something I'm learning new things about all the > time! > -- > Sean A Corfield -- (904) 302-SEAN > An Architect's View --http://corfield.org/ > World Singles, LLC. --http://worldsingles.com/ > Railo Technologies, Inc. --http://www.getrailo.com/ > > "Perfection is the enemy of the good." > -- Gustave Flaubert, French realist novelist (1821-1880) -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
