Thanks! clojure.zip is convinient but slow, I used clojure.walk and it
turned to be several times faster in my case.
On Wednesday, December 3, 2014 10:48:18 PM UTC+2, Jony Hudson wrote:
>
> If I understand right, I think you might be able to use the existing
> replace functions in clojure.walk. I find that this is about twice as fast:
>
> (time
> (dotimes
> [_ 100000]
> (walk/postwalk-replace
> {"exp_1" 100 "exp_2" 20 "exp_3" 5}
> [:DIV [:ADD [:ID "P1" "exp_1"] [:ID "P2" "exp_2"] "exp_2419"] [:ID
> "P3" "exp_3"] "exp_2418"])))
>
>
> Jony
>
> On Wednesday, 3 December 2014 18:49:01 UTC, Dmitriy Morozov wrote:
>>
>> Hi, guys!
>>
>> I have an issue with my function where I use zippers to modify data
>> structure. The function modifies a tree (parsed grammar tree) to replace
>> expressions with values from a given map. Sadly, the algorithm I came up
>> with is pretty slow. I would appreciate if anyone can give me a hint on
>> what would be the right approach to do what I'm trying to accomplish.
>> Thanks!
>>
>> (defn- transform-values [parse-tree values-map]
>> "Replaces all expressions in parsed tree with values from a given map."
>> (loop [loc (zip/vector-zip parse-tree)]
>> (if (zip/end? loc)
>> (zip/root loc)
>> (if (zip/branch? loc)
>> (let [id (last (zip/children loc))]
>> (if (contains? values-map id)
>> (recur (zip/next (zip/replace loc (zip/node [(get
>> values-map id)]))))
>> (recur (zip/next (zip/edit loc #(into [] (butlast %)))))))
>> (recur (zip/next loc)))
>> )))
>> (time
>> (dotimes
>> [_ 100000]
>> (transform-values
>> [:DIV [:ADD [:ID "P1" "exp_1"] [:ID "P2" "exp_2"] "exp_2419"] [:ID "P3"
>> "exp_3"] "exp_2418"]
>> {"exp_1" 100 "exp_2" 20 "exp_3" 5})))
>>
>> "Elapsed time: 2317.491 msecs"
>>
>>
>>
>>
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