I concur with Timothy's assessment. Really well stated and illustrated use of reduce with a named reduce function.
On Fri, May 3, 2013 at 10:52 PM, Timothy Baldridge <[email protected]>wrote: > In general, loop/recur shouldn't be considered idiomatic, IMO. Instead, > try for a more functional style: > > > due = 100 > cards = cards.map do |card| > card.applied_balance = max(0, due - card.balance) > due -= card.applied_balance > > becomes (untested): > > (defn apply-balance-1 [{:keys [due] :as accum} [card-id balance]] > (let [applied (max (- due balance))] > (-> accum > (assoc-in [:applied card-id] applied) > (assoc-in [:due] due)))) > > > (reduce apply-balance-1 > {:due 100} > {:card-id-1 4404.00 > :card-id-2 3020.00 > ....etc....}) > > Often I have found that using reduce forces me to break functions into > several parts. If I used loop/recur, normally the function prelude, > postlude and loop block are all smashed into a single function. With reduce > + a do-step-1 function (as seen above) we can more easily reason about what > is happening. The code is then easier to test as well, as we can test the > calculations apart from the loop logic. > > When I'm performing Clojure code reviews, I often consider loop/recur to > be a code smell. > > Timothy > > > > On Fri, May 3, 2013 at 3:53 PM, Armando Blancas <[email protected]>wrote: > >> On Friday, May 3, 2013 1:15:24 PM UTC-7, Robert Pitts wrote: >>> >>> Armando was a good citizen and sent along a plain-text version as well – >>> https://groups.google.com/**group/clojure/msg/** >>> 6aae8287bc55d436?dmode=source&**output=gplain&noredirect<https://groups.google.com/group/clojure/msg/6aae8287bc55d436?dmode=source&output=gplain&noredirect> >> >> >> That must have been Google Groups doing the right thing... nice feature. >> >> -- >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to [email protected] >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> [email protected] >> For more options, visit this group at >> http://groups.google.com/group/clojure?hl=en >> --- >> You received this message because you are subscribed to the Google Groups >> "Clojure" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> > > > > -- > “One of the main causes of the fall of the Roman Empire was that–lacking > zero–they had no way to indicate successful termination of their C > programs.” > (Robert Firth) > > -- > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to [email protected] > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to [email protected] Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
