I would like to print the parameters based on the keyword selector

(defn shcomm [& comm printcommand]
 (when (= printcommand :print) (println (apply splitcomm comm)))  
  (apply sh (apply splitcomm comm)))

and use it like this: 

(shcomm "ls " "-a" :print)

In F# there is a method for calling server functions from the client called https://github.com/Zaid-Ajaj/Fable.Remoting. Is there a similar strategy for accessing server data from the client? What's your favored strategy? (trying to stay full clj/cljs)

Why does using a transient here doesn't make any difference in performance? It's similar to this example https://clojure.org/reference/transients#_example

(defn unrolled-2 [v2]
  (loop [idx 0 agg (transient [])]
    (if (< idx (- (count v2) 7))
      (recur (inc idx)
             (if (> 1000 (- (nth v2 (+ idx 7)) (nth v2 idx)))
               (conj! agg idx)
               agg))
      (persistent! agg))))

I'm passing this input FWIW (def times-v (into [] (take 1e6) (iterate #(+ % (rand-int 1000)) 0)))

maybe boxed math swamps the difference

a) how big is v2 and how did you test? (the jvm often requires some warmup to see improvement) b) you may be dominated by the boxed math here rather than by the collection batching. many of the math ops here will end up being boxed math, which is ~100x slower than primitive math. count and nth will return boxed numbers here. if you use long to cast the result of count and (set! *unchecked-math* true) , that may help a bit

heh, jinx

🥤

agg is a coll, so the final objects are going to be boxed regardless

you could also (set! *unchecked-math* :warn-on-boxed) to see additional warnings

the second - is going to be boxed math as well as the nth results will be boxed

thanks, is a example from a blog that I was trying to make fast without using arrays

well, you're never going to approach arrays, where the numbers can stay primitive without being boxed

you can use vector-of to store primitives, but the generic Clojure collection interfaces to get things in and out all require boxing and that's necessarily going to be a lot of overhead. transients helps a little, but I suspect the boxing/boxed math/unboxing costs are the worst of it.

some day (maybe Java 18?) we'll get https://openjdk.java.net/jeps/401 and that will open some new options

or I guess https://openjdk.java.net/jeps/402 is the part that will likely matter to us

could potentially be a huge boost to Clojure default performance

having connection issues... so that's something coming before valhalla?

anyway, now I'm curious to create a Java version with arraylist to see the overhead of the persistent collection

it's part of valhalla

if I understand correctly

if it is the unchecked math stuff, then you won't be measuring the "overhead" of a persistent collection, you'll be measuring the speed of math with and without having to do dispatch to determine the types of the operands

the point is, when you call a function like nth it returns an Object so when you do math on it there is extra code to execute (type tests boxing/unboxing. etc)

Hello everyone Is there a way to get the full name of a namespace from its alias?

(ns app.foo.bar
  (:require [app.x.y.z :as z]))

(? 'z)
;; => app.x.y.z
(type (? 'z))
;; => clojure.lang.Symbol