Is it possible to write a macro that returns the qualified name of a symbol passed as parameter? Example:

(my-macro foo)
; => this-ns/foo

(my-macro other-ns/foo)
; => other-ns/foo

macros don't implicitly namespace symbols, but the ` reader-macro does

but it doesn't apply to your args

hm .. so I guess that I have to (in the macro) manually append the current ns to the symbol’s name when it is unqualified.

also "current ns" in a macro can be counterintuitive

Yeah, is it the namespace where the macro is defined, or where it is invoked?

And out of curiosity, what problem are you trying to solve?

Hi everyone. I'm just getting started with clojure...

Hey. I am debugging some code with a toplevel def and use something of the following form to try to monitor the changes.

(def ^:dynamic *a* (atom {}))

(add-watch *a* :watcher
           (fn [key atom old-state new-state]
             (prn "-- Atom Changed --")
             (prn "key" key)
             (prn "atom" atom)
             (prn "old-state" old-state)
             (prn "new-state" new-state)))

(reset! *a* {:foo "bar"})

Hi! Beginner question here, I'm trying to find my way through the options of serializing Clojure objects. I have a small ML model as an instance of a deftype that implements a bunch of protocols. Now that it's trained, I'd like to save it out to disk so that I can use it later on. In Python I'd either use TensorFlow's options to save to disk, or just use Pickle if it's an class I defined myself. I don't seem to find an equivalent to Pickle that works out of the box for custom objects in Clojure though. Am I missing something? A bit more background info: What I'm trying to save out is small neural net, implemented as a NeuralNetworkInference deftype as defined in Dragan Rocks' blogpost: https://dragan.rocks/articles/19/Deep-Learning-in-Clojure-From-Scratch-to-GPU-12-A-Simple-Neural-Network-Training-API. So it's basically a bunch of Neanderthal matrices and some function definitions wrapped in an interface. Thanks! 🙂

@frederikdieleman java comes with serialization, but for clojure data you can use transit and extend it for native types as needed

transit will pick up the custom data readers / writers for any defrecord / deftype

https://github.com/cognitect/transit-clj

careful with java serialization tho, it's a mess and leaky, better to avoid it

this is an example of using java's built in serialization, fwiw - I agree that it has serious problems

(import ( FileOutputStream
                 FileInputStream
                 ObjectOutputStream
                 ObjectInputStream
                 IOException))

(require '[ :as io])

(defn to-file
  [file-name & data]
  (with-open [file (FileOutputStream. file-name)
              stream (ObjectOutputStream. file)]
    (doseq [d data]
      (.writeObject stream d))))

(defn from-file
  [file-name]
  (with-open [file (FileInputStream. file-name)
              stream (ObjectInputStream. file)]
    (into []
          (take-while (complement #{::done}))
          (repeatedly
           #(try
             (.readObject stream)
             (catch IOException _ ::done))))))

I think the problems with java serialization are less severe with clojure (especially if you commit to reading and writing from the same clojure version) but transit is still more compact and it's human readable

I'm using nippy in my hobby project

it works out of the box with all Clojure standard types AFAIK, and serialises to bytes

As a Clojure beginner, I just discover condp and wow ! 😮 I updated my "Perfect number" exercism and now it's more concise than cond https://exercism.io/tracks/clojure/exercises/perfect-numbers/solutions/4e1654ede3b945518f1e0a4b0d18b0cf