This issue with the REPL not breaking on Ctrl-C/Ctrl-D while evaluating an infinite lazy sequence is sort of getting in my way.

which repl?

(my guess is it isn't evaluating but printing)

@dpsutton off my lein repl which is the default. So repl-y I guess?

@hiredman - possible.

lein repl and i evaluated (range) and it just sat there and spun. it obeyed a control c and gave me the prompt back. (prn (range)) and it was time to kill 🙂

check (set! *print-length* 100) and then try (prn (range 1e5))

@dpsutton thanks. That certainly helps

Is there a good use case for with-redefs

in actual code that is, not tests.

(defmulti foo class)
(defmethod foo ::collection [c] :a-collection)
(defmethod foo String [s] :a-string)

that’s an example given on the Clojure site

It says that if I execute a (foo []) then I ought to get :a-collection

Earlier on it derived a bunch of things from :a-collection

Ah, ignore. I did something wrong

@dpsutton The repl thing works when its just a print, but here’s where it breaks (drop-while (partial <= 0) (range))

And I distinctly remember that working earlier

Hi, everyone I was wondering If I could write a macro to turn a map into a function defintion that resolves the keys in that map into its corresponding value using case form ... but couldnt quite get it right. (This is as far as I got ....) How is it possible (or am I getting something terribly wrong ?)

Not sure if you were aware, but you can "call" a map value in Clojure, like a function, passing a first argument that is some value, and it will look up that value in the map, and return the corresponding value, e.g.

user=> (def my-map {:a 1 :b -2 "c" 42})
#'user/my-map
user=> (my-map "c")
42

Hi everyone, I’m working on gRPC server running in Clojure. This is an example of simple method creating server:

(defn build-server [config info-service]
  (let [port (:port config)
        server (-> (ServerBuilder/forPort port)
                   (.addService ^BindableService info-service)
                   (.build)
                   (.start))]
    (println "gRPC server started listening on port" port)
    server))

(defn build-server [config handlers]
  (let [port (:port config)
        server (-> (ServerBuilder/forPort port)
                   (as-> builder
                         (do (doseq [h handlers]
                               (.addService builder ^BindableService h))
                             builder))
                   (.build)
                   (.start))]
    (println "gRPC server started listening on port" port)
    server))

(as-> builder
      (do (doseq [h handlers]
            (.addService builder ^BindableService h))
          builder))

check out doto

all this looks fine to me btw, but doto can help when doing a lot of java factory stuff

Thanks @alexmiller, I know doto but in this piece is not going to help very much as I can’t use it with doseq. If there were a doseq returning a result of last execution :thinking_face:

Howdy, I am trying to send a pdf ( as ByteArrayOutputStream ) back to front end in the body of the http response. In our middle wear stack >> Transit << is barfing on that ( NullPointer ) so I am wondering if there is something I am missing. Do i have to make custom handler for transit or something?

my response looks like this {:status 200 :body pdf-output-stream :headers {"Content-Type" content-type}}

where pdf-output-stream is the byte array output stream

What would be an idiomatic way to return the keys of a map for which the values match some predicate?

e.g. (map first (filter #(predicate? %2) my-map)); is there a more idiomatic way?

return the keys or key/value pairs?

(for [[k v] my-map :when (p? v)] k) ??

@dpsutton keys only

(filter predicate? (keys my-map))?

Hi! random question 😛 why metadata impact on equality for functions?

(let [f (fn [])
        m {}]
                  (println "fn withMeta == fn"  (= (with-meta f {1 1}) f))
                  (println "m  withMeta ==  m" (= (with-meta m {1 1}) m))) 

fn withMeta == fn  false
m  withMeta ==  m true

Functions have identity equality semantics. Generally you shouldn’t be comparing them for equality in the first place.

ok 😔, thanks!!

Function equivalence is reducible to the halting problem which cannot be solved: https://stackoverflow.com/a/1132167/6264

Where "cannot be solved" is the general case, for an arbitrary pair of functions. There are special cases that are decidable, but Clojure's = makes no attempt to help you find those. But I agree that point is getting fairly far from the original question 🙂

functions have reference equality, but implement the value metadata interface, and implement it by wrapping

How can I analyze a directory of files using tools.analyzer?

Answering my previous question (https://clojurians.slack.com/archives/C03S1KBA2/p1551018489292000) I found a more elegant approach of expressing the same:

(defn build-server [config handlers]
  (let [port (:port config)
        server (-> (ServerBuilder/forPort port)
                   (as-> builder (reduce #(.addService %1 %2) builder handlers))
                   (.build)
                   (.start))]
    (println "gRPC server started listening on port" port)
    server))