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clojurians | clojure | I can't think of anything that would cause people to switch to Clojure just to use it... | 2017-12-13T17:27:53.000016 | Daniell |
clojurians | clojure | (mind you, Akka and Play are both probably used more by Java devs now?) | 2017-12-13T17:28:11.000050 | Daniell |
clojurians | clojure | (fn [v n]
[(take n v) (drop n v)])
^-- is there a builtin for this? to 'split' a vector at a specified index | 2017-12-13T17:32:53.000426 | Berry |
clojurians | clojure | we have Datomic and Onyx, and of course ClojureScript, which has the obvious advantage of allowing you to avoid JS :stuck_out_tongue: | 2017-12-13T17:34:57.000234 | Leann |
clojurians | clojure | I would presume this kind of thing can only come in later in a project then, after the patterns have emerged. That would explain why our experiences differ. I've spent more time in the greenfield part of a project, and very little time in the stage where you're extending existing code.
We have a few places where we achieve something of a similar goal with data, e.g. defining schemas related to a graphql request, and allowing a small bit of code extract that.
I think the scariest part of what you said was "[building] an ad-hoc engine", I don't even know where I'd start really. Reading through odin, I find terms like "unification" and "tabling" quite intimidating. I should perhaps purchase your series where you build odin to try and learn more about Karen and such. | 2017-12-13T17:40:31.000476 | Jodie |
clojurians | clojure | <@Berry> clojure.core/split-at | 2017-12-13T17:43:58.000321 | Charity |
clojurians | clojure | Fwiw, I really like Odin so far. I'm trying to use it for querying REST apis. I've had to put a memoize in though (I want to replace this with a ctx cache), as Odin was "forking" (my term for the separate paths after doing an additional query) queries when I didn't expect it to, as there was no overlap in the inputs.
I'm not sure if I'm using it properly, or even if I'm benefiting from it.
I initially reached for datalog/datascript to do this, but being unable to make arbitrary rest queries made it difficult (having to commit to a db after doing part of the query I'm interested in probably doesn't give me much benefit. | 2017-12-13T17:48:15.000212 | Jodie |
clojurians | clojure | I'm struggling now with something in odin, which is something to the effect of:
- I've fetched all members from API
- I've fetched all tasks from API
- I want to find the assignee of a task
- I want to find the owners of a task
I seem to keep filtering all the members, instead of creating a list of members named "assignee". The closest way I came to achieving my goal was `(o/and (= (:assignee_id ?task) (:id ?member))`, which obviously doesn't involve any bindings. I wondered if I'd need to use `o/==` but I wasn't certain how I'd do that. | 2017-12-13T17:54:44.000023 | Jodie |
clojurians | clojure | also you could use subvec if you want a faster op that retains vectorness | 2017-12-13T17:55:41.000571 | Margaret |
clojurians | clojure | ```ser=> (let [v [1 2 3 4 5 6]] [(subvec v 0 3) (subvec v 3 (count v))])
[[1 2 3] [4 5 6]]``` | 2017-12-13T17:57:22.000058 | Margaret |
clojurians | clojure | Maybe I should be "re-fetching" a list of members for assignees. | 2017-12-13T18:07:46.000203 | Jodie |
clojurians | clojure | OK, probably a deep dark corner of Clojure functionality I haven't seen before, but can anyone explain what ('subset? ...) is doing in this line of code within the Clojure tests? <https://github.com/clojure/clojure/blob/master/test/clojure/test_clojure/rt.clj#L97> | 2017-12-13T20:30:25.000067 | Micha |
clojurians | clojure | map look up | 2017-12-13T20:31:13.000219 | Rebeca |
clojurians | clojure | looking up the symbol 'subset in the map returned by ns-publics | 2017-12-13T20:31:26.000332 | Rebeca |
clojurians | clojure | I just figured that out from REPL experimentation, which I probably should have done before asking. I knew that worked with a keyword as the first value in the form, but don't think I've ever used it with a symbol as the first value in the form. | 2017-12-13T20:32:40.000090 | Micha |
clojurians | clojure | <@Micha> `clojure.lang.Symbol` implements `clojure.lang.IFn` just like `clojure.lang.Keyword`, and seems to implement it in basically the same way, invoking `RT.get` on the argument passing itself as the lookup key | 2017-12-13T21:20:15.000158 | Buck |
clojurians | clojure | I will most likely forget this, and not miss the knowledge because I wouldn't want to see this in my code :slightly_smiling_face: | 2017-12-13T21:21:07.000002 | Micha |
clojurians | clojure | yeah it's a bit niche isn't it | 2017-12-13T21:21:42.000051 | Buck |
clojurians | clojure | I've only ever written Clojure as a hobby, but a lot of hours have gone by without me seeing this in people's code. | 2017-12-13T21:22:03.000302 | Micha |
clojurians | clojure | would be interesting to mine crossclj for the most rarely used features. I don't think I've ever seen :strs or :syms destructuring in the wild, for instance | 2017-12-13T21:25:04.000073 | Buck |
clojurians | clojure | now I'm kind of sad that there's no clojure.lang.String that also implements IFn. Then we'd have three types you can both destructure and use to look themselves up. | 2017-12-13T21:26:40.000013 | Buck |
clojurians | clojure | <@Buck> We have `:strs` destructuring in our production code... :slightly_smiling_face: | 2017-12-13T21:42:48.000133 | Daniell |
clojurians | clojure | secretly I think I have this in my code too ... | 2017-12-13T21:45:53.000204 | Buck |
clojurians | clojure | but it's not "in the wild" so I think I escape on a technicality. `ag` reveals I actually have used it twice in just this one project I checked :flushed: | 2017-12-13T21:47:17.000148 | Buck |
clojurians | clojure | Spec question: If I have a function that takes a destructured map, what's the best way to spec that function, so that the values of the keys in my map are also specced? The best I've got right now is `(s/keys :req-un [::a ::b ::c])` given `(defn foo [{:keys [a b c]})` | 2017-12-13T22:05:36.000199 | Silas |
clojurians | clojure | But, I'd kind of want the names of the keys for my function to not match the spec name of their value. And I'd rather define the spec for them inline. Any easy way to do that? | 2017-12-13T22:06:05.000007 | Silas |
clojurians | clojure | Would be nice to have something like `(s/map :req [:a int? :b string? :c ::other-spec])` for this scenario | 2017-12-13T22:16:57.000139 | Silas |
clojurians | clojure | Is there a way to make this point free `#(assoc %2 :id %1)` | 2017-12-13T22:32:14.000228 | Eugenie |
clojurians | clojure | Clojure is the killer application. It sells itself, you don't really need anything else. For example, since you mentioned Akka, you'd probably be interested in core.async, though its just a part of Clojure. | 2017-12-13T22:37:17.000179 | Silas |
clojurians | clojure | lol, I don't think it'd be shorter in any point free style | 2017-12-13T22:42:39.000011 | Berry |
clojurians | clojure | I get that. This was a just a challenge based on a discussion we are having internally at my company. | 2017-12-13T22:48:57.000223 | Eugenie |
clojurians | clojure | In terms of things made in Clojure to be used as frameworks from other languages, I guess <@Leann> pointed to some: Datomic and Onyx. I'll add Apache Storm, Overtone, Cascalog, Riemann, Puppet, Metabase, Alda, Transit, Datascript and Quil to that list. | 2017-12-13T22:59:26.000035 | Silas |
clojurians | clojure | maybe something involving merge, apply, and reverse, and rotating | 2017-12-13T23:06:32.000059 | Berry |
clojurians | clojure | (apply assoc (reverse (interpose :id %))) | 2017-12-13T23:07:17.000175 | Berry |
clojurians | clojure | (->> args (interpose :id) reverse (apply assoc)) :slightly_smiling_face: | 2017-12-13T23:07:36.000070 | Berry |
clojurians | clojure | That's not point-free... | 2017-12-13T23:07:51.000024 | Daniell |
clojurians | clojure | What is point-free? I thought it merely meant "don't use variable names, and chain together functions" | 2017-12-13T23:08:26.000103 | Berry |
clojurians | clojure | But `args` and `%` are variables. | 2017-12-13T23:09:45.000141 | Daniell |
clojurians | clojure | right, so we need to get rid of the "args" field | 2017-12-13T23:10:18.000159 | Berry |
clojurians | clojure | the line before that was me working out intermediate steps | 2017-12-13T23:10:37.000112 | Berry |
clojurians | clojure | we need to removeargs from `(->> args (interpose :id) reverse (apply assoc))` and then we're good | 2017-12-13T23:11:05.000164 | Berry |
clojurians | clojure | Here's a point-free version: `(comp (partial apply assoc) reverse (partial interpose :id) vector)` | 2017-12-13T23:12:25.000051 | Daniell |
clojurians | clojure | ```boot.user=> ( (comp (partial apply assoc) reverse (partial interpose :id) vector) 123 {} )
{:id 123}``` | 2017-12-13T23:12:45.000031 | Daniell |
clojurians | clojure | <@Eugenie> ^ does that answer the challenge? | 2017-12-13T23:15:06.000098 | Daniell |
clojurians | clojure | <@Daniell> Sure does! Thanks! | 2017-12-13T23:17:56.000220 | Eugenie |
clojurians | clojure | The :clj: page on transients says that:
> In Clojure 1.6 and earlier, transients would detect any (read or write) use from a thread other than the one that created them and throw an exception. *That check was removed in 1.7* to allow for more flexible use in frameworks like core.async go blocks that enforce the single-threaded constraint via other means.
Emphasis mine. But under summary it still says:
> Thread isolation - enforced
I tried the following in :clj: 1.8:
```
(dotimes [_ 5]
(def tv (let [tv (transient [])]
(future (Thread/sleep (rand-int 3))
(conj! tv 1))
(future (Thread/sleep (rand-int 3))
(conj! tv 2))
tv))
(Thread/sleep 3)
(println (persistent! tv)))
;; =>
;; [2 1]
;; [2 1]
;; [2 1]
;; [2 1]
;; [1 2]
```
So it clearly _is_ possible to modify a transient from different threads. What, then, does "thread-isolation--enforced" mean?
<https://clojure.org/reference/transients> | 2017-12-13T23:54:10.000150 | Andra |
clojurians | clojure | [just guessing] perhaps it means that with respect to a transient, conj! pop! push! are all atomic -- i.e. if you run them from different threads, its as if they're beintg run from the same thread in some order - they won't 'trample' on each other due to race conditions | 2017-12-14T00:22:38.000124 | Berry |
clojurians | clojure | also, the above example confuses me, as I thought you were supposed to look at the return value of conj! ... instead of printing the 'original transient' | 2017-12-14T00:23:16.000007 | Berry |
clojurians | clojure | IIUC `conj!` modifies in place but returns the modified value. | 2017-12-14T00:29:41.000157 | Andra |
clojurians | clojure | quoting: <https://clojuredocs.org/clojure.core/assoc>!
```
;; The key concept to understand here is that transients are
;; not meant to be `bashed in place`; always use the value
;; returned by either assoc! or other functions that operate
;; on transients.
```
not sure if "other functions" includes conj! | 2017-12-14T00:32:09.000152 | Berry |
clojurians | clojure | I'm looking for a clojure DSL that lets me output C code.
Is <https://github.com/aaronc/c-in-clj> (5 years since last commit?) the best we've got ?
Pre-emptive: why not just use C?: C's macro system is lacking. I want to use the full power of Clojure amcros for my macro system. | 2017-12-14T00:37:13.000034 | Berry |
clojurians | clojure | There are several cases where conj! May not change the input, and instead may return a new collection | 2017-12-14T01:25:00.000218 | Sandy |
clojurians | clojure | So yes, treat transients like persistent collections. | 2017-12-14T01:25:11.000173 | Sandy |
clojurians | clojure | Not that I know of, it’s not really a easy thing to pull off since C lacks almost everything Clojure would need | 2017-12-14T01:26:18.000123 | Sandy |
clojurians | clojure | But writing a AST to C layer wouldn’t be *that* hard. I know of several projects that do that | 2017-12-14T01:26:41.000186 | Sandy |
clojurians | clojure | Carp? It transpiles to c so I guess it would fit | 2017-12-14T01:55:34.000041 | Weston |
clojurians | clojure | Not sure how mature it is tho | 2017-12-14T01:55:56.000096 | Weston |
clojurians | clojure | <@Sandy>: I'm not trying to do Clojure -> C . I'm trying to do "Clojure data representing a program -> C". | 2017-12-14T03:17:34.000094 | Berry |
clojurians | clojure | I have some code which deals with nothing but tensors of floats -- no other data structure, no gc-ing, nothing else
and I want to represent this code as 'clojure data', and then generate C from it (which will let me hit both WebAssembly and Cuda afterwards) | 2017-12-14T03:18:30.000308 | Berry |
clojurians | clojure | if I'm dealing with a java class that extends a HashMap, is there an easy way to cast a map into it? ```public class RowData extends HashMap<String, Object> {
}
``` | 2017-12-14T03:26:08.000338 | Debby |
clojurians | clojure | would love to do `(cast RowData (java.util.HashMap. {:a 1}))` but that raises a `ClassCastException` | 2017-12-14T03:26:28.000361 | Debby |
clojurians | clojure | I'm playing with function specs and I wondered if one could use it to emulate type checking, during compile time, something like this:
```
(s/fdef divide
:args (s/cat :x integer? :y integer?)
:ret number?)
(defn divide [x y] (/ x y))
;; should throw when compiled?
(defmacro divide-by-foo []
(eval `(divide 6 :foo)))
```
yet this namespace doesn't throw, why? | 2017-12-14T05:27:57.000188 | Deneen |
clojurians | clojure | Interesting Idea, but probably needs some time to become doable. For example if? in the future Kotlin can compile to web-assembly it will become easier. | 2017-12-14T05:48:09.000356 | Daine |
clojurians | clojure | Actually not that far away, <https://blog.jetbrains.com/kotlin/2017/11/kotlinnative-v0-4-released-objective-c-interop-webassembly-and-more/> | 2017-12-14T05:49:05.000070 | Daine |
clojurians | clojure | hi guys | 2017-12-14T05:55:29.000243 | Mallory |
clojurians | clojure | why this work in second case and not work in the first | 2017-12-14T05:56:00.000091 | Mallory |
clojurians | clojure | ? | 2017-12-14T05:56:02.000205 | Mallory |
clojurians | clojure | <@Deneen> you need to have instrumentation enabled to have it throw | 2017-12-14T06:01:12.000254 | Retta |
clojurians | clojure | <@Deneen> something like <https://github.com/jeaye/orchestra> | 2017-12-14T06:02:02.000584 | Retta |
clojurians | clojure | <@Deneen> by default, clojure spec doesn't circumvent evaluation to perform spec analysis, you need to tell it to check your specs | 2017-12-14T06:03:34.000103 | Retta |
clojurians | clojure | so just `(:require [clojure.spec.test.alpha :as st])` and `(st/instrument 'divide)` ? | 2017-12-14T06:04:37.000034 | Deneen |
clojurians | clojure | you'll have to read over the docs, and mess around with it | 2017-12-14T06:08:11.000371 | Retta |
clojurians | clojure | think it's after you define your specs, but before you evaluate your function that you want spec analysis for | 2017-12-14T06:08:43.000317 | Retta |
clojurians | clojure | hmm | 2017-12-14T06:09:31.000009 | Retta |
clojurians | clojure | your defmacro is never going to throw a spec error until it's been evaluated | 2017-12-14T06:09:55.000198 | Retta |
clojurians | clojure | note that instrumentation was turned on after the specs have been introduced and evaluated | 2017-12-14T06:12:46.000415 | Retta |
clojurians | clojure | (into (new RowData) my-map)?
Into uses conj | 2017-12-14T06:12:51.000301 | Jutta |
clojurians | clojure | I could have put it at line 7 or 9 | 2017-12-14T06:13:04.000349 | Retta |
clojurians | clojure | the divide-by-foo case should probably fail, none of this has been tested | 2017-12-14T06:13:47.000160 | Retta |
clojurians | clojure | <@Daine>: I think we are discussing different problems. What problem do you think I am trying to solve? | 2017-12-14T06:20:52.000483 | Berry |
clojurians | clojure | this is my problem - I don't understand why at compile-time the macro doesn't become `(eval (/ 6 :foo))`, which should still throw. The divide-by-foo will fail for sure (with an exception or spec validation error depending on whether instrumentation is turned on), like you say. | 2017-12-14T06:21:28.000099 | Deneen |
clojurians | clojure | if i want to display some quick charts from the repl, is incanter the best option? | 2017-12-14T06:26:45.000468 | Jena |
clojurians | clojure | i just want to quickly visualize some line charts, no fancy processing is needed | 2017-12-14T06:27:15.000203 | Jena |
clojurians | clojure | Does either "lein repl" or "boot repl" have a web interface?
I want something like "boot web-repl" or "lein web-repl" to
1. open up a webserver on port 8081
2. I can go to <localhost://8081> and interact with the repl
3. have certain forms of output render nicely into HTML tables / SVG diagrams / ... | 2017-12-14T06:32:27.000121 | Berry |
clojurians | clojure | You want some way to go from clojure to WebAssembly right? | 2017-12-14T06:34:07.000355 | Daine |
clojurians | clojure | You can do a plug-in with it
<https://github.com/yudai/gotty> | 2017-12-14T06:36:31.000100 | Jutta |
clojurians | clojure | <@Berry> gorilla repl can do that | 2017-12-14T06:37:30.000094 | Angela |
clojurians | clojure | <http://gorilla-repl.org/start.html> | 2017-12-14T06:37:43.000011 | Angela |
clojurians | clojure | or to CUDA which kinda makes it invalid approach to go for Kotlin | 2017-12-14T07:01:26.000397 | Cecilia |
clojurians | clojure | Can you run CUDA in the browser? | 2017-12-14T07:22:07.000085 | Daine |
clojurians | clojure | is there a tool for formatting end files? | 2017-12-14T07:22:24.000099 | Danille |
clojurians | clojure | <https://github.com/weavejester/cljfmt> | 2017-12-14T07:48:48.000208 | Maggie |
clojurians | clojure | .. why did I not just try running cljfmt on it earlier. I keep running it on my .clj files | 2017-12-14T07:49:52.000190 | Danille |
clojurians | clojure | thanks :slightly_smiling_face: | 2017-12-14T07:49:54.000432 | Danille |
clojurians | clojure | Hi, I am transducing over a lazy sequence that reads from a file (hurray). However I am having some trouble figuring efficient ways to debug or any plausible way to debug at all. Maybe you can comment?
Here's code:
```
(ns cleanser.dictionary-test
(:require
[clojure.pprint :refer [pprint]]
[puget.printer :refer [cprint]]
[clojure.inspector :as inspect :refer [inspect-tree]]
[cleanser.dictionary-search :refer :all]
[<http://clojure.java.io|clojure.java.io> :as io]
[clojure.set :refer :all]
[clojure.math.combinatorics :refer [cartesian-product]]
[clojure.test :refer :all]
[<http://clojure.java.io|clojure.java.io> :as io]
[clojure.string :refer [split]]))
(defn text-file-reader [filepath reader]
" return a lazy sequence for streaming through the file contents "
(with-open
[file-reader (reader filepath)]
(line-seq file-reader)))
(deftest names-dictionary
(let
[text (slurp "resources/names/hebrew-wikipedia-content.txt")
names-dump-filter (remove #(re-matches #"# < > \[ \] \{ \} / @ \*" %))
names-dump-breaker (mapcat #(split % #"\|"))
names
(sequence
(comp names-dump-breaker names-dump-filter)
(text-file-reader "resources/names/user-names-unique.txt" <http://clojure.java.io/reader|clojure.java.io/reader>))
dictionary (build-dictionary names)]
(println (search text dictionary))
(println (type names) ; a lazy stream
(println names)))) ; java.io.IOException: Stream closed
```
printing `names` seems futile, the stream has been expended by then. Any suggestion for a better design for stream-processing file contents with transducers?
Any best practice for debugging within the transduction itself is very welcome as well
Many thanks! | 2017-12-14T08:19:00.000070 | Kalyn |
clojurians | clojure | <@Kalyn> you could use trace to monitor the input/output of your transducer functions <https://github.com/clojure/tools.trace> | 2017-12-14T08:23:17.000223 | Jami |
clojurians | clojure | actually, I am not very sure how I'd `trace` very elegantly in transducing code like above | 2017-12-14T08:30:36.000337 | Kalyn |
clojurians | clojure | <@Kalyn> I though it would be easy with trace, but it doesn't work as expected in my case | 2017-12-14T09:25:12.000773 | Jami |
clojurians | clojure | instead, you could define your own transducer for logging purpose | 2017-12-14T09:25:29.000325 | Jami |
clojurians | clojure | ```
(defn xflog []
(fn [rf]
(fn
([] (rf))
([res] (rf result))
([res input] (println input) (rf res input)))))
``` | 2017-12-14T09:26:09.000134 | Jami |
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