I am trying to use a custom deps.edn in my ~/.clojure/ folder.

{
 :paths ["src"]
 :aliases
 {

  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;; Creating projects from templates

  ;; clj-new - 
  :new {:extra-deps {seancorfield/clj-new {:mvn/version "1.1.234"}}
        :exec-fn clj-new/create
        :exec-args {:template "app"}}}
}

Execution error (FileNotFoundException) at java.io.FileInputStream/open0 (FileInputStream.java:-2).
-X:new (No such file or directory)

that same command and same deps alias works fine for me. the error makes it seem like there might be an extra argument being passed

it looks like it's trying to open a file named "-X:new"

execution mode was added in https://clojure.org/releases/tools#v1.10.1.697

Aaah so i am running an older version 🙂

yes) update should fix that

Thanks!!! Was searching all over the place 🙂

Thanks a lot!!

@delaguardo It worked!!! Again thanks!

@marco.pasopas you may find this book useful when using Clojure with CLI tools http://practicalli.github.io/clojure/ I also have a well documented user-wide deps.edn configuration with a wide range of tools https://github.com/practicalli/clojure-deps-edn

so no free resources to learn re-frame or reagent

there are plenty documentation available for both )

also courses or tutorials where a site is build

I have done one which works wih on-click but I see also some of them which uses subscribe so confusing

I recommend the guides on http://purelyfunctional.tv

they are excellent

https://purelyfunctional.tv/guide/reagent/ https://purelyfunctional.tv/guide/re-frame-building-blocks/

Thanks, some study to do

Any suggestions on getting started and designing apps with Clojure and Kafka streams? I've ask this in #apache-kafka so appreciate answers there. https://clojurians.slack.com/archives/CDAA5T4KZ/p1611742901000200

@jr0cket Thanks for the pointer! I already found the deps.edn collection and surely they are usefull!!

An error has occured for me a couple of times the past days (Using Vs Code and Calva). Anyone know why this is happening?

Syntax error compiling at (src/clojure_functions/core.clj:22:1). Unable to resolve symbol: defn in this context

I’m getting this error when trying to jack-in using Cider

. Unhandled clojure.lang.Compiler$CompilerException
   Error compiling src/reader/snake.clj at (1:41)

             Compiler.java: 7526  clojure.lang.Compiler/load
                      REPL:    1  user/eval6049
                      REPL:    1  user/eval6049
             Compiler.java: 7062  clojure.lang.Compiler/eval
             Compiler.java: 7025  clojure.lang.Compiler/eval
                  core.clj: 3206  clojure.core/eval
                  core.clj: 3202  clojure.core/eval
    interruptible_eval.clj:   82  nrepl.middleware.interruptible-eval/evaluate/fn/fn
                  AFn.java:  152  clojure.lang.AFn/applyToHelper
                  AFn.java:  144  clojure.lang.AFn/applyTo
                  core.clj:  657  clojure.core/apply
                  core.clj: 1965  clojure.core/with-bindings*
                  core.clj: 1965  clojure.core/with-bindings*
               RestFn.java:  425  clojure.lang.RestFn/invoke
    interruptible_eval.clj:   82  nrepl.middleware.interruptible-eval/evaluate/fn
                  main.clj:  243  clojure.main/repl/read-eval-print/fn
                  main.clj:  243  clojure.main/repl/read-eval-print
                  main.clj:  261  clojure.main/repl/fn
                  main.clj:  261  clojure.main/repl
                  main.clj:  177  clojure.main/repl
               RestFn.java: 1523  clojure.lang.RestFn/invoke
    interruptible_eval.clj:   79  nrepl.middleware.interruptible-eval/evaluate
    interruptible_eval.clj:   56  nrepl.middleware.interruptible-eval/evaluate
    interruptible_eval.clj:  145  nrepl.middleware.interruptible-eval/interruptible-eval/fn/fn
                  AFn.java:   22  clojure.lang.AFn/run
               session.clj:  202  nrepl.middleware.session/session-exec/main-loop/fn
               session.clj:  201  nrepl.middleware.session/session-exec/main-loop
                  AFn.java:   22  clojure.lang.AFn/run
               Thread.java:  748  java.lang.Thread/run

1. Caused by java.lang.Exception
   No namespace: examples.import-static

I’m following an example for Programming Clojure This is the code so far

(ns reader.snake
  (:import (java.awt Color Dimension)
           (javax.swing JPanel JFrame Timer JOptionPane)
           (java.awt.event ActionListener KeyListener))
  (:refer examples.import-static :refer :all))
(import-static java.awt.event.KeyEvent VK_LEFT VK_RIGHT VK_UP VK_DOWN)

This is from the example file itself, so I haven’t actually changed anything.

got a link to where you got this from?

Its here @dpsutton https://media.pragprog.com/titles/shcloj3/code/shcloj3-code.zip

but the error seems straightforward : "No namespace: examples.import-static". relating to your (:refer examples.import-static :refer :all) (which seems quite strange to me

ooh

I think maybe I need to load the whole repo then?

instead of just this file?

yes. the examples.import-static is a reference to shcloj3-code/code/src/examples/import_static.clj

I see, thank you very much!

I'm trying to figure out how I can run tests for a namespace from the command line

I wonder why:

(map Integer/parseInt ["2011" "3" "21"]) ;this doesn't work

(Integer/parseInt "2011") ; but this is fine

It’s a Java method, not a Clojure function

Integer/parseInt is a Java method, not a clojure function. To use it with map and so on, you need to wrap it in an anonymous function like #(Integer/parseInt %)

@manutter51, I didnt know this limitation. I guess it is more general where else does it apply ?

@caumond on the vm / bytecode level, "methods" don't exist as real things, they are something an object knows how to do and only the objects are concrete

@caumond a clojure IFn is an object that only exists to carry a method (one which clojure calls if you put it in parens)

so, more concretely, you can't put something that isn't an Object on the stack, and IFn is an object, so you can put it on the stack, unlike a method

in order to pass something as an argument, it needs to end up on the stack

you can use method call interop syntax with IFn objects

user=> (.invoke str nil)
""

Yes. Very clear. Thanks. Im definitly not sure ive ever read something like that in the books I read.

(there's the potentially misleading fact that reflection api offers "method handles", which are Objects that allow you to manipulate / use the methods on another Object, but we'd be badly off if we needed to reflect and use method handles everywhere)

Hey Guys, I'm kind of stuck trying to get some data from a textfile. It already worked today but I destroyed it likely.

(map #(subs % (count prefix)(clojure.string/split-lines (slurp file-name))))
#object[clojure.core$map$fn__4781 0x5f20155b clojure.core$map$fn__4781@5f20155b]

(let [proef  (set/difference (set prae) (set post)) ]
             (println proef)
        ))

your map is only given a single argument here rather than two. i imagine you need to spit the split-lines form out of the subs form

single arg map arity strikes again

there are two distinct reifications of methods as objects java.lang.reflect.Method and java.lang.invoke.MethodHandle, reflect.Method is the older reflection api, MethodHandle is the new stuff built to work with (but possible to use independent of) invoke dynamic

😂 Ok this is the reason the first one worked earlier this day. First one solved.

@3samgal your second piece of code has an extra paren

On the 3rd line

yeah - I suggest taking some time to learn normal formatting / indentation conventions, they tend to make it easier to find and fix these sorts of bugs

indentation doesn't matter to the computer but properly indented code will make mistakes jump out at you

Thanks for the hint, but the parenthesis is part of the function ahead. Any other ideas?

It's gotta be a #{set} to use clojure.set/union, clojure.set/difference https://clojuredocs.org/clojure.set/union https://clojuredocs.org/clojure.set/difference I think you could do (into #{} (distinct -vals-) since a set must have unique values only

I solved it. Thank you so much.

Am I right that subcribe is re-frame where on-click is reagent and on both something happens ?

It's not possible to destructure in the arguments, right? Example might explain better:

(defn decomp-test [[a b c]]
  (+ a b c))

(decomp-test [[1 2 3]]) ; so this can be 6?

that would work, but with one more set of []

so:

(defn decomp-test [[[a b c]]]
  (+ a b c))

Nice.

why do I need the triple?

NB nested destructuring (or mix of map and sequential destructure) is usually better done in a let block

the first one is just the arguments that come in, the second one is the first vector, and the third one is the second vector

@christiaaan because you are passing a one element vector of vectors, so your destructure needs to match the shape

can I have named arguments?

destructure gives you named arguments

maybe I misunderstand that question

no, you are right. I was just stumbling over the [[[ thing, as it looks not that idiomatic

@christiaaan right, the part that is weird is that you'd define operations on single item vectors of vectors

well it’s not common you pass a vector in a vector

especially when it’s a 3 item vector in a 1 item vector.

oddly specific

Lemme see if I can give a nice example with the repl

my function gets a sorted list, and I wanted to avoid apply, I guess apply is prettier

Here you can run this and see all the stages of destructuring that you went through

(let [first [[1 2 3]]
      [second] first
      [[a b c]] first
      [a2 b2 c2] second]

  (prn (str "first=" first))
  (prn (str "second= " second))
  (prn (str "sum of a b c= " (+ a b c)))
  (prn (str "sum of a2 b2 c2= " (+ a2 b2 c2))))

also it’s an example of how to use let to test destructuring a bit easier

Thank you, that helps indeed

I would have had [a b c] second on that last binding line (same result)

that’s a good idea

I think it's easier to understand with the let

(defn is-valid? 
  "Checks the three sides of a would be triangle."
  [a b c]
  (let [[shortest short longest] (sort [a b c])] 
    (and (< 0 shortest)
         (> (+ shortest short) longest))))

@christiaaan also consider (< 0 shortest longest (+ shortest short))

Right! I had this thought but could not reconstruct it

that’s amazing

Beautiful

I guess that needs to be <= maybe...

0 length edges are not okay for a triangle

cool

@christiaaan my mental model for < is that it takes a series of numbers whose line graph rises like the top half of the symbol 😄

it's like a stonks emoji

😂

at this point we shoud probably not make fun about wsb stonks

I remember why I ditched the idea. That would eliminate equilateral triangles

right, shortest and longest could be equal

of course you could have (< 0 shortest (inc longest) (+ 1 shortest short)) but that's weird

Hi! I finally made fast binary exponentiation algorithm. Could you review it? https://github.com/reflechant/binary-pow/blob/main/src/binary_pow/core.clj

so powers isn't the powers of x, it's x, square x, square(square x) etc?

I don't know this algorithm off the top of my head, but with a name like powers I expected powers of x

ins)user=> (take 10 (iterate #(*' % %) 2))
(2 4 16 256 65536 4294967296 18446744073709551616N 340282366920938463463374607431768211456N 115792089237316195423570985008687907853269984665640564039457584007913129639936N 13407807929942597099574024998205846127479365820592393377723561443721764030073546976801874298166903427690031858186486050853753882811946569946433649006084096N)
(ins)user=> (take 10 (iterate #(* % 2) 2))
(2 4 8 16 32 64 128 256 512 1024)

@noisesmith it depends on whether the power is even or odd

I was using this description: https://cp-algorithms.com/algebra/binary-exp.html

was trying to write a tail-recursive version and failed

oh, it is a sequence of squares, super surprising but I see