Hello! In coordination with the original authors, I am writing a Clojure Version of the legendary "Structure and Interpretation of Computer Programs" (SICP) since about one year. I expect to finish the first draft in a few months. Is anyone willing to review early versions? / Where should I ask this question? 🙂

Hey guys, I want to extend a protocol I have for some classes in case the person who loaded my library loaded also some other library

I used (Class/forName ... to check if the other library is present

but the problem is that my (extend-protocol sentence has direct references to the classes

which fails to compile

@roklenarcic you'll need to use a macro, clojure.core has examples of doing this.

ok

it's called "when-class" and is private, but you could copy the implementation yourself.

I've noticed that generally (not= (class (reify)), (class (reify))). I find this desirable behavior. However, certain contrived reify returned by a defn always returns the same class. It's as if the underlying reify's class was cached. Wondering what triggers this and how to control it?

Verified that my assumption was wrong, thanks @hiredman 🙂

is the ^int type tag deprecated in favor of ^long?

user=> (defn foo [^int x])
Syntax error (IllegalArgumentException) compiling fn* at (REPL:1:1).
Only long and double primitives are supported

It is still mentioned here: https://clojure.org/reference/java_interop#TypeAliases

It is complicated

You can only use long or double on function arguments

ok

and as primitive return types.

and although the docs are a little lacking on this minor detail, you can only get in compiled code long or double primitives for loop-bound symbols. If you try to make it int, you get long instead. If you try to make it float, you get double instead.

Are there any big gotchas with aot nowadays?

The same as there always have been @emccue 🙂

It's "OK" to do AOT on everything as the last step when building an uberjar if you want the startup time improvement it can bring, but most other cases can introduce problems so it's best avoided unless you must do some AOT (`gen-class` for example).

And even for gen-class, the advice I seem to hear most is "use a Java shim instead" if you can (and use Clojure's "Java API" from that shim to load Clojure code).

I have one project that relies on gen-class for one namespace and that has no dependencies outside clojure.core and clojure.string, and my deps.edn file looks like this

{:deps {org.clojure/clojure {:mvn/version "1.8.0"}}
 :paths ["classes" "src"]
 :aliases
 {:compile {:main-opts ["-e" "(compile,'cfml.struct)"]}
  :test {:extra-paths ["test"]
         :extra-deps {expectations/clojure-test {:mvn/version "1.1.1"}
                      org.clojure/test.check {:mvn/version "0.10.0-RC1"}}}
  :runner {:extra-deps {com.cognitect/test-runner
                        {:git/url ""
                         :sha "3cb0a9daf1cb746259dc8309b218f9211ad3b33b"}}
           :main-opts ["-e" "(compile,'cfml.struct)"
                       "-m" "cognitect.test-runner"
                       "-d" "test"]}
  :build {:extra-deps {seancorfield/depstar {:mvn/version "0.2.3"}}
          :main-opts ["-e" "(compile,'cfml.struct)"
                      "-m" "hf.depstar.jar" "cfml-interop.jar"]}}}

(it's an implementation of clojure.lang.APersistentMap that has case-insensitive keys... because CFML...)

Yeah, just considering it for making the uberjar for my class

I talked the strangers I need to work with into using clojure so I'm pumped