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clojurians | clojure | all functions passed to f-> take a single arg (the stack) as input and produces a stack as output | 2017-12-08T19:01:06.000182 | Berry |
clojurians | clojure | <@Berry> right but you could imagine something like `[a b c ^{:argc 2} str]` as way to tell the compiler to take 2 args from the stack when applying str to it. | 2017-12-08T19:02:23.000049 | Deandrea |
clojurians | clojure | (f-> a b c (mod 2 str)), where mod :: int -> func -> func , specifies how many args to take and use | 2017-12-08T19:03:13.000070 | Berry |
clojurians | clojure | oh nice. i like that. | 2017-12-08T19:03:40.000183 | Deandrea |
clojurians | clojure | except instead of calling it mod, we should call it m! or something | 2017-12-08T19:03:40.000215 | Berry |
clojurians | clojure | heh, i sometimes wish clojure had that in core. when mapping over a list of lists (for example) i often want something that takes a number `n` and function `f` and pulls `n` many arguments from each list and applies them to the `f` rather than writing the function that unpacks the arguments by hand. it’s easy to write but i sometimes i wish i didn’t have to. :slightly_smiling_face: | 2017-12-08T19:05:23.000150 | Deandrea |
clojurians | clojure | <@Berry> `ap` might be a nice shorthand there. `[a b c str 2 ap]` | 2017-12-08T19:08:20.000144 | Deandrea |
clojurians | clojure | <@Deandrea>: how does 'str know to delay evaluation? | 2017-12-08T19:21:32.000174 | Berry |
clojurians | clojure | i'm assuming nothing but `ap` applies anything | 2017-12-08T19:22:16.000045 | Kareen |
clojurians | clojure | the model I had in mind was: if you get a constant, you push it, if you get a function, you eval it | 2017-12-08T19:23:50.000094 | Berry |
clojurians | clojure | but in this model, it appears to be "push until you hit ap" ? | 2017-12-08T19:24:01.000079 | Berry |
clojurians | clojure | how would you do HOF then? | 2017-12-08T19:24:09.000058 | Kareen |
clojurians | clojure | can you give me a concrete example you have in mind ? | 2017-12-08T19:24:29.000030 | Berry |
clojurians | clojure | write `(map inc [1 2 3])` | 2017-12-08T19:24:41.000063 | Kareen |
clojurians | clojure | is [1 2 3] a single arg on the stack, or is it a stack of 3 items ? | 2017-12-08T19:24:59.000026 | Berry |
clojurians | clojure | that's clojure | 2017-12-08T19:25:09.000139 | Kareen |
clojurians | clojure | write that in your stack based dialect | 2017-12-08T19:25:15.000258 | Kareen |
clojurians | clojure | if your semantics are "if the top element in my stack is a function, apply it", then you have no way of using a function as a value | 2017-12-08T19:25:49.000014 | Kareen |
clojurians | clojure | I was going to do all function combinators in clojure | 2017-12-08T19:26:44.000033 | Berry |
clojurians | clojure | the model I had in mind for `f->` is:
1. f-> gets a list of args
2. eval each arg
3. if arg is a constant, change it to a push
4. if it's a function, apply it | 2017-12-08T19:27:09.000176 | Berry |
clojurians | clojure | well good luck, keywords symbols vectors maps sets are functions too | 2017-12-08T19:27:47.000072 | Kareen |
clojurians | clojure | F--- | 2017-12-08T19:27:59.000202 | Berry |
clojurians | clojure | @qqq let me get back to you. :wink: I've gotta play with my kids right now. I will be back to meditate on this some more. :smile: | 2017-12-08T19:39:30.000039 | Deandrea |
clojurians | clojure | Hi, I just saw the changelog of Clojure 1.9. Do you know why the deps and cli tools were added to the language ? <https://clojure.org/guides/deps_and_cli> | 2017-12-09T01:25:50.000076 | Jami |
clojurians | clojure | as far as I understand, this is a new improvement on resolving dependencies, but what about building clojure apps ? | 2017-12-09T01:26:26.000001 | Jami |
clojurians | clojure | because clojure.core can't run without the clojure.spec.alpha library that is packaged separately | 2017-12-09T01:26:32.000016 | Margaret |
clojurians | clojure | will it replace or complement lein/boot ? | 2017-12-09T01:26:41.000004 | Jami |
clojurians | clojure | it's not a build tool, it just helps use deps | 2017-12-09T01:26:44.000019 | Margaret |
clojurians | clojure | the goal was that people should be able to run clojure directly using a simple tool from the clojure team - clj is designed for that, and just that | 2017-12-09T01:27:21.000046 | Margaret |
clojurians | clojure | so do you think there will be a need to create a new build tool ? | 2017-12-09T01:28:14.000040 | Jami |
clojurians | clojure | in other language, you usually have a compiler/interpreter and a build tool | 2017-12-09T01:28:32.000014 | Jami |
clojurians | clojure | clj isn't mandatory and isn't a build tool | 2017-12-09T01:28:44.000024 | Margaret |
clojurians | clojure | leiningen and boot are still build tools | 2017-12-09T01:28:57.000037 | Margaret |
clojurians | clojure | it doesn't replace leiningen or boot but there are plans to use it from boot at least | 2017-12-09T01:30:18.000022 | Margaret |
clojurians | clojure | I when I begin using clojure, I was confuse about boot and lein. I didn't know if these tool where the interpreter/compiler | 2017-12-09T01:30:23.000005 | Jami |
clojurians | clojure | that's a common problem | 2017-12-09T01:30:32.000025 | Margaret |
clojurians | clojure | ok, i see the picture | 2017-12-09T01:31:00.000040 | Jami |
clojurians | clojure | the goal is to have: 1) clj as the main interpreter, 2) deps.edn as a format to specify dependencies 3) boot/lein as build tool | 2017-12-09T01:31:31.000026 | Jami |
clojurians | clojure | but at the moment, boot and lein does everything | 2017-12-09T01:31:44.000039 | Jami |
clojurians | clojure | even if you run boot or lein clojure is still the compiler and runs the repl itself | 2017-12-09T01:32:13.000003 | Margaret |
clojurians | clojure | so they might just "wrap" (1) and (2) from boot/lein instead of providing them as they do now | 2017-12-09T01:32:26.000020 | Jami |
clojurians | clojure | they might - but you can run clojure 1.9 from lein or boot without clj | 2017-12-09T01:32:47.000015 | Margaret |
clojurians | clojure | I see, but I'm curious how the boot/lein team will address the overlap | 2017-12-09T01:35:59.000097 | Jami |
clojurians | clojure | they might find it useful, but they don't have to address it - everything still works the old way | 2017-12-09T01:36:55.000065 | Margaret |
clojurians | clojure | what's the best way to get the distinct by value of a collection. `(?? [[:a 1] [:b 1] [:c 2] [:d 1]]) => [:c 2]` | 2017-12-09T01:41:12.000077 | Willow |
clojurians | clojure | i've got some really gross partition by, filter, first, second, first threading going on | 2017-12-09T01:41:47.000016 | Willow |
clojurians | clojure | maybe group-by, then test which values are 1 element long? | 2017-12-09T01:42:46.000031 | Margaret |
clojurians | clojure | yeah but it ain't pretty
```
partitions (->> edges
(map (fn [kid] [(node-weight adjacency kid) kid]))
(group-by first))
[size distinct-edge] (->> partitions
(filter (fn [[p-size nodes]] (= 1 (count nodes))))
first
second
first)
``` | 2017-12-09T01:43:21.000007 | Willow |
clojurians | clojure | was hoping there was a better way | 2017-12-09T01:43:53.000028 | Willow |
clojurians | clojure | maybe some instead of filter but it's not much prettier | 2017-12-09T01:44:51.000050 | Willow |
clojurians | clojure | ```(->> [[:a 1] [:b 1] [:c 2] [:d 1]] (group-by second) (filter (comp #{1} count val)) (first) (val) (first))``` | 2017-12-09T01:47:41.000009 | Margaret |
clojurians | clojure | that's certainly better | 2017-12-09T01:48:21.000051 | Willow |
clojurians | clojure | i always forget about the #{1} style checking | 2017-12-09T01:48:44.000045 | Willow |
clojurians | clojure | it's more fun to write, but there's also `#(= 1 (count (val %)))` which performs better | 2017-12-09T01:49:41.000038 | Margaret |
clojurians | clojure | of course | 2017-12-09T01:49:45.000044 | Margaret |
clojurians | clojure | what about (->> [[:a 1] [:b 1] [:c 2] [:d 1]] (map reverse) (map vec) (into {})) => {1 :d, 2 :c} | 2017-12-09T03:05:11.000055 | Jami |
clojurians | clojure | or `(->> [[:a 1] [:b 1] [:c 2] [:d 1]] clojure.set/map-invert) => {1 :d, 2 :c}` | 2017-12-09T03:08:05.000018 | Jami |
clojurians | clojure | Thanks <@Margaret>, I did start with `file-seq` but noticed it was based on `.listFiles` and since the laziness didn't seem to be an advantage to me used that directly. I've also tried an nio based approach. There's 458GB of files in on my file system and DaisyDisk is scanning that in ~13s, my approach doesn't complete in less than 15 mins (at which point I abort it). | 2017-12-09T05:26:30.000076 | Kayleigh |
clojurians | clojure | I'm sure DD must be using something but cannot yet see how it might be the spotlight cache since my researches so far suggest that it doesn't contain a complete list of files on the file-system | 2017-12-09T05:34:25.000040 | Kayleigh |
clojurians | clojure | I'm having a strange problem. I'm working on a problem from the advent of code, and I need to copy an input string from the webpage, and transform it into a data structure. A basic `(#{:a :b} :a)` comparison was returning nil, which prompted me to take a closer look at the result of the transformation. If I call `(transform raw-input-string)`, the printed result looks fine (and in fact, works fine!), but if I compare the printed result to the value returned by the function call `(= (transform raw-input-string) <previous result>)` I get `false`! | 2017-12-09T07:08:51.000002 | Mark |
clojurians | clojure | I'm guessing there's some hidden special characters in there, that get dropped when the output is printed into the repl | 2017-12-09T07:09:14.000058 | Mark |
clojurians | clojure | Is there a way to remove them..? I'm already removing non-breaking spaces, and using trim (which doesn't really do much I guess) | 2017-12-09T07:09:43.000019 | Mark |
clojurians | clojure | I've tested this in cursive's repl inside Idea, lein's repl, and planck | 2017-12-09T07:10:08.000025 | Mark |
clojurians | clojure | Eh, I `spit` the data structure into a file, and then `(-> file slurp read-string)` | 2017-12-09T07:25:26.000037 | Mark |
clojurians | clojure | And apparently the special characters are gone | 2017-12-09T07:25:34.000041 | Mark |
clojurians | clojure | <@Mark> `(clojure.string/replace "your string" #"[^\p{Print}]" "")` | 2017-12-09T07:26:36.000030 | Heriberto |
clojurians | clojure | or `(clojure.string/replace "your string" #"[^\x00-\x00]" "")` with range of characters (replace `00` with proper values) | 2017-12-09T07:28:37.000025 | Heriberto |
clojurians | clojure | I tried the first one, I don't think it did anything. I'm probably not going to bother with the second one for now, since I got it working with that hacky file workaround. Appreciate the help though :slightly_smiling_face: | 2017-12-09T07:30:22.000027 | Mark |
clojurians | clojure | I've never "installed Clojure" before (always used lein) but I was curious - is there an update for MacPorts rather than Brew ? | 2017-12-09T07:46:21.000039 | Beulah |
clojurians | clojure | <@Beulah> <https://github.com/macports/macports-ports/blob/master/lang/clojure/Portfile> | 2017-12-09T07:48:56.000120 | Heriberto |
clojurians | clojure | ```
version 1.8.0
maintainers nomaintainer
``` | 2017-12-09T07:49:10.000034 | Heriberto |
clojurians | clojure | <@Heriberto> yeh I was thinking of Clojure 1.9 the latest | 2017-12-09T07:50:57.000034 | Beulah |
clojurians | clojure | oh I see | 2017-12-09T07:51:06.000170 | Beulah |
clojurians | clojure | I’m not sure what that is in MacPorts, but it’s not published by the Clojure core team | 2017-12-09T08:04:28.000007 | Sonny |
clojurians | clojure | Hi, Clojurians! I have a question about Java Interop.
I'm trying to translate some of the examples from [web3j](<https://docs.web3j.io/getting_started.html#start-sending-requests>) into Clojure.
The synchronous requests work fine:
```
// Java
Web3j web3 = Web3j.build(new HttpService());
Web3ClientVersion web3ClientVersion = web3.web3ClientVersion().send();
String clientVersion = web3ClientVersion.getWeb3ClientVersion();
```
```
; Clojure
(def http (new HttpService))
(def web3j (Web3j/build http))
(-> web3j
(.web3ClientVersion)
(.send)
(.getWeb3ClientVersion))
; "Geth/v1.7.3-stable-4bb3c89d/linux-amd64/go1.7.3"
```
But my asychronous requests aren't working, and I think it has something to do with the Java 8 lambdas:
```
// Java
Web3j web3 = Web3j.build(new HttpService());
web3.web3ClientVersion().observable().subscribe(x -> {
String clientVersion = x.getWeb3ClientVersion();
...
});
```
```
; Clojure
(def http (new HttpService))
(def web3j (Web3j/build http))
(defn callback [x]
(println "received value:" x))
(-> web3j
(.web3ClientVersion)
(.observable)
(.subscribe callback))
; CompilerException java.lang.IllegalArgumentException: No matching method found: subscribe for class rx.Observable
```
The [rx.Observable docs](<http://reactivex.io/RxJava/javadoc/index.html?rx/Observable.html>) say the subscribe method takes an argument of type Action1, which extends the Action interface, which extends the Function interface.
Any ideas as to what I should be passing to a Java function that expects to receive a lambda?
Thanks! | 2017-12-09T10:30:51.000014 | Alexander |
clojurians | clojure | You need to use `reify` but I'm not sure which interface it's needed to implement here | 2017-12-09T10:42:37.000006 | Heriberto |
clojurians | clojure | java lambdas are just syntactic sugar, at the bytecode level they're equivalent to anonymous classes
there's no way to infer a conversion between clojure functions and Rx functions so you have to explicitly pass an instance of Rx expected type Action1 | 2017-12-09T10:43:51.000017 | Rosia |
clojurians | clojure | ```
(def callback
(reify Action1
(call [_ x] (println "received value:" x))))
``` | 2017-12-09T10:44:40.000029 | Rosia |
clojurians | clojure | <@Rosia> <@Heriberto> Thanks! I will try this out and report back :thumbsup: | 2017-12-09T10:48:31.000062 | Alexander |
clojurians | clojure | no, they are not anonymous classes
<https://softwareengineering.stackexchange.com/questions/177879/type-inference-in-java-8/181743#181743> | 2017-12-09T10:48:32.000104 | Heriberto |
clojurians | clojure | <@Rosia> After figuring out which class to import (it was `rx.functions Action1`), it worked flawlessly! Going to write up a blog post with my adventures when I have something a bit more substantial, and I will give you the credit for helping me out with this one. Thanks for the lesson! | 2017-12-09T10:56:01.000120 | Alexander |
clojurians | clojure | thanks, I was unaware of that | 2017-12-09T11:02:51.000004 | Rosia |
clojurians | clojure | <@Alexander> np but have look at <@Heriberto>’s link in the thread, my comment is inaccurate | 2017-12-09T11:04:49.000044 | Rosia |
clojurians | clojure | I have a question;
```clojure
(list? (cons 'do '((identity x) bla-bla)))
=> false | In Clojure
=> true | In Clojurescript
``` | 2017-12-09T11:14:37.000019 | Olen |
clojurians | clojure | What makes the difference ? | 2017-12-09T11:15:11.000151 | Olen |
clojurians | clojure | I am sorry if it’s a newbie question or it’s obvious. But I really wondering, why… | 2017-12-09T11:15:42.000060 | Olen |
clojurians | clojure | I always found it sneaky that a `cons` returns something that isn’t a `list?` in clj. It can trick you in situations like macros. Especially involving syntax quote because you don’t always know when it might return a `cons`. So really I end up just avoiding using `list?` for these sorts of things (so mostly just never use it) | 2017-12-09T11:36:45.000044 | Petronila |
clojurians | clojure | It’s odd that cljs would be different though. I didn’t know that | 2017-12-09T11:37:08.000137 | Petronila |
clojurians | clojure | Yea it did. | 2017-12-09T11:37:12.000063 | Olen |
clojurians | clojure | So what are you using as a pred ? | 2017-12-09T11:37:56.000120 | Olen |
clojurians | clojure | <@Petronila> often when you think you want `list?` the right predicate is `sequential?` | 2017-12-09T11:38:16.000043 | Margaret |
clojurians | clojure | though that is true for vectors | 2017-12-09T11:38:32.000040 | Margaret |
clojurians | clojure | Typically `sequential?` | 2017-12-09T11:38:37.000024 | Petronila |
clojurians | clojure | Yeah if you don’t want vectors perhaps just `not` `vector?` | 2017-12-09T11:39:14.000078 | Petronila |
clojurians | clojure | Oh, I did it right. :innocent: | 2017-12-09T11:39:15.000039 | Olen |
clojurians | clojure | Yeah, I think that's a holdover from lisp? <@Petronila> | 2017-12-09T11:39:36.000034 | Sandy |
clojurians | clojure | Seems like the real predicate is `seq?`, and sometimes `sequential?` | 2017-12-09T11:39:55.000044 | Sandy |
clojurians | clojure | Often, outside of lisps, `list?` implies something that has O(1) counting. | 2017-12-09T11:40:17.000098 | Sandy |
clojurians | clojure | you rock !
it's definitely a huge win for me, my benchmarks are almost on par with java with your patch. | 2017-12-09T11:40:40.000143 | Rosia |
clojurians | clojure | <@Sandy> interesting. I’d have to check out something like Common Lisp to compare on that one. | 2017-12-09T11:41:22.000024 | Petronila |
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