How is this code to create a stateful lazy sequence?

Hi, Here's a function and a simple use of it. It works, but the code may not be good Clojure. I'm wondering how it might be better. (defn distinct-by "Returns a sequence with no repeats of (f item). A set is built up internally as the sequence is consumed, so don't use it on an infinite

Re: How is this code to create a stateful lazy sequence?

Yes, I find that much clearer too. Thanks! On Saturday, July 22, 2017 at 4:50:23 PM UTC-4, tbc++ wrote: > > If we think about what we're doing here is a stateful filter, then maybe > we could leverage a few more core Clojure functions: > > > (defn distinct-by [f coll] > (let [seen (atom #{})] >

printing self referential data?

I'm translating some code from an object oriented language to Clojure. I'm a little confused about a tree structure I had where tree nodes have parent and children properties, so the structure forms cycles. I used atoms for those properties, so I could wire it all up. The code is clean and simpl

Re: printing self referential data?

I think in my case here the easiest thing will be to remove the cycles, but still I'd like to understand a couple things... On Sunday, July 23, 2017 at 10:12:46 PM UTC-4, Didier wrote: > > I'm not sure I can fully help without you explaining more what you're > doing. It sounds like you've got a

tags or categories for tests?

Hi, The lein command `lein help test` explains that you can add metadata to tests and select subsets of tests to run. Is there a way to do something like that from the REPL (clojure.test/run-tests) without lein? Rob -- You received this message because you are subscribed to the Google Groups

Re: Help ship Clojure 1.9!

I get this when I switch from 1.8 to 1.9 beta, but maybe it's an issue with the `core.match` library? WARNING: boolean? already refers to: #'clojure.core/boolean? in namespace: clojure.tools.analyzer.utils, being replaced by: #'clojure.tools.analyzer.utils/boolean? Rob On Thursday, September

Updating repeated nested structures?

Hi, Say I have a map like this: (def m {:qs [{:nums [3 1 2]} {:nums [7 4]}]}) I want to transform each number with a function (say, `inc`). I imagine something like this: (update-in m [:qs * :cell-fns] #(map inc %)) ; or (update-in m [:qs * :cell-fns *] inc) But of cours

Re: Updating repeated nested structures?

Gah. I changed one name and not another. I meant: (update-in m [:qs * :nums] ...) On Tuesday, October 10, 2017 at 10:18:56 AM UTC-4, Rob Nikander wrote: > > Hi, > > Say I have a map like this: > > (def m {:qs [{:nums [3 1 2]} {:nums [7 4]}]}) > > I want to tran

form comment and meta data?

Hi, Why doesn't this compile? I tried to comment out the "private" metadata. (def #_^:private foo 1) CompilerException java.lang.RuntimeException: First argument to def must be a Symbol, compiling:(null:1:1) Rob -- You received this message because you are subscribed to the Google Grou

Re: form comment and meta data?

On Friday, October 13, 2017 at 2:55:51 PM UTC-4, Justin Smith wrote: > > what happens is that the metadata reader macro is applied before the > comment reader macro, so you comment out the name of the def (which also > had the metadata attached) > > user=> '(def #_ ^:private foo 1) > (def 1) >

core.async consumer + producer working by chunk?

Hi, I’m wondering if there is a core.async design idiom for this situation... - A buffered channel - One producer feeding it - A bunch of consumers pulling from it. - Producer should wake up and fill the channel only when it’s empty. In other words, the producer should work in chunks. My firs

Re: core.async consumer + producer working by chunk?

On Friday, January 5, 2018 at 2:03:00 PM UTC-5, Brian J. Rubinton wrote: > > > What is the buffered channel’s buffer used for? If that’s set to 1 and the > channel’s transducer is `(mapcat identity)` then the producer should be > able to continuously put chunks of work onto the channel with the

Re: core.async consumer + producer working by chunk?

Thanks for the explanation! This is very close to what I want. I see some confusing behavior though. See below. On Friday, January 5, 2018 at 2:40:14 PM UTC-5, Brian J. Rubinton wrote: > > > The work-queue channel has a fixed buffer size of 1. A collection (range > 50) is put on the channel. Whi

Re: core.async consumer + producer working by chunk?

On Friday, January 5, 2018 at 4:00:25 PM UTC-5, Moritz Ulrich wrote: > > > You have a channel with a buffer-size of one. You clear the buffer by > taking one item from it, making room for another one. Therefore the put > succeeds. Try just `(async/chan nil xform)` to create a channel without >

Re: core.async consumer + producer working by chunk?

On Jan 5, 2018, at 8:01 PM, Gary Verhaegen wrote: > What about simply having the producer put items one by one on the channel? I will do that. My current producer is doing too many other things, but if I break it up into separate threads or go blocks for each work queue, then that should wor

Loop causing OutOfMemoryError: GC overhead limit exceeded ?

I have some Clojure code that throws this, occasionally. Unfortunately I can’t paste my real function here, but it looks much like the one below. (Changed variable names and simplified some irrelevant - I hope - details). Anything jump out as a memory-leak? It queries a DB table to get a li

Re: Loop causing OutOfMemoryError: GC overhead limit exceeded ?

On Friday, March 2, 2018 at 12:48:28 AM UTC-5, Daniel wrote: > > How do you know this code is causing the error? Unless this is all your > code does, descriptions of the error suggest the memory leak might be > coming from anywhere. This tight loop might trigger too many successive GCs > thoug

Coordinating STM with database?

Hi, I see this was discussed before. Did it go anywhere? Basic idea: make a `dosync` transaction succeed or fail along with a database transaction. https://groups.google.com/forum/#!topic/clojure/qiKnCVAaZKw Rob -- You received this message because you are subscribed to the Google Groups "Clo

Re: Coordinating STM with database?

On Friday, March 23, 2018 at 4:26:37 PM UTC-4, Andy Fingerhut wrote: > > I do not know what the result of that discussion was, but I would guess it > did not turn into a change that was incorporated into Clojure. In the > discussion thread you linked to, Dave Griffith mentioned attaching a pat

spec with schema and select?

Hi, I just watched a chunk of this talk from a few months ago ("Maybe Not" [1]). Is there a pre-release version of spec available, that has `schema` and `select` in it? I have a project where I'm fine with using bleeding edge stuff that will change. Rob [1]: https://www.youtube.com/watch?v=YR

Re: spec with schema and select?

Thanks, I will do that. -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this g