using pipeline-blocking, do I have reasonable expectation the functions will be started in message order ? more specifically if my xf does calling a network service in normal operation the network calls will start in message order ?

no

results will come out the order data when in, but pipeline runs your xf in parallel according to the number you give it

I suspect the degree out of out of orderness that can happen is bounded, by n (the parallelism number you pass to pipeline-blocking), but I am not sure

(require '[clojure.core.async :as async])

(def counter (atom 0))

(def to (async/chan))

(def from (async/chan))

(async/pipeline 8 to (map (fn [value] [value  (swap! counter inc)])) from)

(async/go
  (dotimes [i 1000]
    (async/>! from i))
  (async/close! from))

(count (for [[x y] (async/<!! (async/into [] to))
             :when (not= x y)]
         true))
;;=> 980

no proof, but it would appear that the max out of order it gets is n+2, which I think matches other n+2 behaviors pipeline has

http://dev.clojure.org/jira/browse/ASYNC-163

hum

that’s pipeline, not pipeline-blocking

right

I don't mean that issue is directly applicable

it is another instance of n+2 popping up from one of the pipeline functions

pipeline go-loops over a channel with n buffer, -blocking spawns threads

oh async/thread

the only difference in implementation between pipeline and pipeline-blocking is the use of async/go or async/thread

pipeline-async diverges more from those two

i’m not sure i understand how pipeline-blocking provides parallelization

that issue up above is a result of pipeline-async's "parallelism" being related to the buffering behavior of the pipeline as a whole(n+2), and less directly to the number of "workers" (n)

oh (dotimes n)

which relates to what you are asking about, because I suspect the max out of order you will see using pipeline and pipeline-blocking is dependent on the buffering behavior of the pipeline, which is some how 2+n

yeah there is no guarantee those threads won’t preempt each other

correct, the threads introduce out of orderness, but the size of the output buffer (which is n) limits how far ahead a thread can get

the +2 is some how added in the copying machinery

tkx!

in my use i need to do parallelism 1 then manage the side effects

I am not sure what the point of using 1 with pipeline would be

yeah, at that point it’s just go-loop

i was going with the pipeline thing

Last day for ClojureRemote tickets!

https://t.co/eF8iVWUWx8

Is anyone else having issues deploying to clojars? It just keeps telling me 401 unauthorized but I know I have the proper credentials.

is there a built-in fn / more idomatic way of doing (cons :new-1 (rest '(:1 :2 :3)))

@yedi: can it be a vector?

=> (assoc [:1 :2 :3] 0 :new-1)
[:new-1 :2 :3]

unfortuantely its a seq

but no biggie

another q: is there a standard variable name for a boolean returning function you might send to another function

pred?

word ty

Are there any 3d modeling tools written in clojure (or cljs)? Something where I can model in OpenGL, then render it with a ray tracer.

@eslachance if you're still having trouble, pop in to #clojars and we can help

Based on a very quick test I see that using partial is somewhat faster than using the #() notation. Anyone can enlighten me on why that would be?

Maybe because with partial there is only 1 function call, and with #() - two

@achesnais Normally #() is faster, can you post code?

You are right – my initial test was with the time macro, but using criterium I see #() is faster. What’s the explanation though?

Maybe because partial returns a variadic function?

hi there is clojure.data.xml/parse lazy ??? because i'm trying to load an 400mb large file and in the repl it takes damn long to write it into a variable.

m3tti https://clojure.github.io/data.xml/#clojure.data.xml/parse

anyone here ever had any luck getting pedestal and sente to work together?

is it possible to create an anonymous multimethod?

not using the normal api for multimethods

I wrote up a blog post on debugging a memory leak in production (it turns out it was a badly memoized fn): https://techblog.roomkey.com/posts/memory-leak.html

nice read!

when I log something with clojure/tools.logging, I see a couple of lines in the console:

Feb 09, 2017 6:09:22 PM my.ns invoke
INFO: my log message

What does the #' macro do? as in: (jetty/run-jetty #'app {:port port :join? false})

@sineer it's the var-quote reader macro, equivalent to (var app) https://clojure.org/reference/reader

Thanks!

So if I understand the use of it in (jetty/-jetty #'app {:port port :join? false}), it means if app is undefined then the fn will be called with a single arg arity correct?

@sineer So let's back up and look at (jetty/-jetty app ...) This will work, but the problem is that if you redefine app it won't show up without a server restart. This is because every use of a var implies a deref of the var ((.deref jetty/-jetty) (.deref app) ...)

However, if you use the var itself, via #'app that implied deref is disabled, and so you're passing in the direct var itself. Which means that jetty will invoke the var #'app on every incoming request. So now your changes to #'app show up without needing a server restart.

It's a way of moving the point of .deref from setup-time to run-time.

wow!

Awesome 🙂 Thank you very much! I'm surprized I didn't know about this one yet... very clever!

How to make sure only given keys are in spec? I have (s/def ::good-state (s/keys :req-un [::name ::active-panel])) and it doesn’t complain when the state also has :whatever true.

spec does not allow this through using s/keys — what you can do, if you must, is add an additional predicate to ensure that only the keys you want are in the map. however, the question to ask is, what does it hurt, if :whatever is present in the map?

spec says, “validate what is there”, not “validate what is there, and ensure that nothing else is there"

@joshjones, it doens’t hurt, I’m just exploring what can be done

a simple example to ensure that the map has only 1 key:

(s/def ::a string?)
(s/def ::mymap (s/and (s/keys :req [::a])
                      #(= 1 (count (keys %)))))
(s/explain ::mymap {::a "abc" ::b 2})
;; val: #:sandbox.spec{:a "abc", :b 2} fails spec: :sandbox.spec/mymap predicate: (= 1 (count (keys %)))

so, you can use the additional custom predicate to perform whatever test you want on the given map

@joshjones, got it, thanks

@negaduck The idea about maps in general is that they are open. Leaving the possibility to add what you need and every function picks what it needs

on the second thought, it can hurt when there is a typo in code that updates a key, e.g., in re-frame event handler

You mean a typo that updates the wrong key?

simple :req doesn’t catch :active-panel :hmoe-pane

:req-un would ensure that you have both :active-panel and :hmoe-pane — what is the specific case that is problematic?

yes, wrong example.

here is a solution

that is one solution, as is the one above, but I don’t think you’ve given a problem that this solves yet?

specifically, when does the presence of a key in a map present a problem that ignoring it won’t solve?

joshjones,

(re-frame/reg-event-db
 :set-active-panel
 [check-spec-interceptor]
 (fn [db [_ active-panel]]
   (assoc db :actiev-pneal active-panel)))

now db has both :active-panel and this one with typo

so, it feels dirty because it shouldn’t be there, but no one will ever know .. right?

a user clicks a button and nothing happens

is there something more that spec should be checking about the :active-panel key itself that would inform you that it should have been set differently? (sorry, not a re-frame guy)

What if a man, says something deep in the woods and no one can hear him. Is he still wrong?

Weird stuff: I'm catching TimeoutException, but I get uncatched CheckedOperationTimeoutException in logs. This one subclasses TimeoutException. I have no idea what is going on here, but maybe someone can enlighten me? Should catching parent exception type catch all children?

are you using the go macro from core.async?

yeah, catching a superclass should catch all subclasses, so you should check to see if the exception is actually being thrown where you think it is

joshjones, yes, here spec checks if the :active-panel is exactly one of two options: (s/def ::active-panel #{:home-panel :about-panel}), this is straightforward.

I think the question here is not, if the map contains a key you did not expect. The question is more or less, if there is a bug in your code that adds this key and the value. So it could be useful as a measure to find a very rare species of bugs.

Is there any reference to the function that clojure uses to look up reader literals? I have a need to do it dynamically, I've implemented something that follows the docstring, but wanted to know if I could kill the work altogether.

@hiredman no, I'm not using go macro, it's a pretty regular code

so the usual possibilities, the exception isn't being thrown where you think it is, or it is being caught before it gets to your handler and logged

why after expansion it tries to use current-namespace/any? instead of cljs.core/any? here: (macro whatever [] (any? 1))?

@negaduck i’m guessing quote vs syntax quote?

http://stackoverflow.com/questions/26485514/clojure-difference-between-quote-and-syntax-quote

probably. Thank you.

np