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 <abm221...@gmail.com> 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.
>
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