i’m having trouble with the brave book; specifically the reduce function

for example, what are these types of functions called so i can youtube videos about them?

The symmetrize-body-parts function (starting at ➊) employs a general strategy that is common in functional programming. Given a sequence (in this case, a vector of body parts and their sizes), the function continuously splits the sequence into a head and a tail. Then it processes the head, adds it to some result, and uses recursion to continue the process with the tail.

@tiotolstoy Search for "recursive functions"

(the other term to search for @tiotolstoy is "higher order functions")

Ok… me thusfar… • Visual Studio Code with Calve. • Went through Clojure for the Brave. • Did all Clojure Koans. (Icheated on the later ones by looking at the solutions. • Now planning on reading/going through “Web Development with Clojure, Third Edition” by Dmitri Sotnikov and Scot Brown ( http://pragprog.com ) Or are there other recommended paths for learning?

Write code. Haha. I did a lot of reading myself, but nothing beats working on your own project. At some point while studying I felt like I was just going through the motions and not paying as much attention. That never happens when you are trying to solve problems that you care about. Knowledge seems to stick better when you’ve earned it with sweat and blood, at least in my experience. Also, check out other people’s code repositories, or read the source for libraries that you use. You will wonder why people do things a certain way, and it teaches you a lot.

what would be the easiest way to go with any auto-complete tool on given data? (without integrating any search engine) fwould need to get some string and return some amount of relevant data (`starts_with` for example) simple start could be just to implement a "like_starts_with" SQL query with any clojure-jdbc. maybe there's some work with libraries on this? can't find much

how can I create an HTML string from hiccup? I would like to generate HTML and show it on a web page as part of a reagent app so that the user can copy the html and use it somewhere else

Hiccup has an html function which does what you want (I think) https://github.com/weavejester/hiccup#syntax

Not sure about reagent’s version though

Anyone interested in dependent types? There is “In Further Praise of Dependent Types” post on HN frontpage now that I didn’t understand at all, but the idea sort of maybe sounds interesting… It also led me to a comment mentioning Idris and how the author of Idris gave a talk about using it’s type system to define matrix transposition, and I found that video, and it’s so hard to folllow, and it’s lines and lines of type definitions for what is #(apply mapv vector %) in clojure, but still, all those static guarantees sound interesting, perhaps not very practical in currently existing statically typed languages…

Hello folks, I’m having an issue using the java.time package. It is definitely running Java 8. When running (java.time.LocalDate/of 2019 1 1) it throws IllegalArgumentException: No matching method of found taking 3 args.

I’ve confirmed that it works in a REPL as well as the java docs.

I know naming functions with ? when they return a boolean is idiomatic, but would you do the same for keywords like {:active? true} vs. {:active true} vs. {:is-active true}

So I have a bbb.clj file with ns myproject.bbb and defn bbx in it, when I test/execute bbx it works just fine I have core.clj with ns myproject.core and I include a require [myproject.bbb as abc] I then call in core.clj (abc/bbx) and it does not execute. Currently under the impression that by referencing bbx via require [myproject.bbb as abc] it should be working. Is this correct? Odd thing was that it was seemingly working previously

Do you have :as with a colon, or as with no colon? The latter is incorrect.

If it isn't too many lines, you are welcome to copy and paste your entire ns form into chat, so we can see what it looks like character-for-character

yes I have :as in place

It reports it cannot find bbx when executing the call from core

[myproject.bbb :as abc]

Is your project published anywhere? It is difficult to know what is going wrong without more information than you have given so far.

No it is not published - I am an early learner

Are you willing to copy and paste the entire (ns ...) form in the file that contains the [myproject.bbb :as abc] expression?

(ns myproject.core (:gen-class) ;;(:import (org.apache.logging.log4j Level LogManager)) (:require [cheshire.core :refer :all] [clj-http.client :as client] [clojure.data.json :as djson] [http://clojure.java.io :as io] [clojure.pprint :as pprint] [clojure.spec.alpha :as spec] [clojure.string :as string] [myproject.bbb :as abc] )) (abc/dispatch_fn "6738549661") (ns myproject.bbb (:gen-class) (:require [cheshire.core :refer :all] [clj-http.client :as client] [clojure.data.json :as djson] [http://clojure.java.io :as io] [clojure.pprint :as pprint] [clojure.spec.alpha :as spec] [clojure.string :as string]) (defn dispatch_fn [myval] (do something ..........) )

I had to truncate the code

I am under impression the code calling the defn in the referred file bbb.clj should execute When I call it within bbb.clj it works fine

and what is the error message?

Unhandled clojure.lang.Compiler$CompilerException Error compiling src/myproject/core.clj at (45:1) #:clojure.error{:phase :compile-syntax-check, :line 45, :column 1, :source "/Users/xxxxxx/Google Drive/development/projects/myproject/src/myproject/core.clj"} Compiler.java: 6808 clojure.lang.Compiler/analyze Compiler.java: 6745 clojure.lang.Compiler/analyze Compiler.java: 3820 clojure.lang.Compiler$InvokeExpr/parse Caused by java.lang.RuntimeException No such namespace: abc Util.java: 221 clojure.lang.Util/runtimeException Compiler.java: 7384 clojure.lang.Compiler/resolveIn Compiler.java: 7358 clojure.lang.Compiler/resolve Compiler.java: 7319 clojure.lang.Compiler/analyzeSymbol Compiler.java: 6768 clojure.lang.Compiler/analyze Compiler.java: 6745 clojure.lang.Compiler/analyze

Is there a way to get all keywords in a map that match a pattern? I have many keywords that start with :subnet_ or :pool_ like ':subnet_id :pool_id :subnet_name :pool_name', etc How can I pull out all the :subnet_* entries?

you can use filter across (keys m) , inside the filter you can use name to get a string form a key, and starts-with or re-matches to find a given prefix

@michael819

scratch=> (filter (fn [k] (clojure.string/starts-with? (name k) "foo_")) (keys {:foo_a 0 :foo_b 1 :bar_a 2}))
(:foo_a :foo_b)

ns:myproject.core ns:myproject.scope I I :require [project.scope :as s] (defn abc [] ,,,) I I (s/abc 123) ;; it works!! ;; (abc 123) ;; it works!! actually it is (abc somenumber) actually it is (abc somenumber) ns: myproject.scope.test I (deftest qwerty (abc 123)) ;; does not work Question---------- for myproject.scope.test do I require [project.scope :as s] thus: (deftest qwerty (s/abc 123)) -OR- do I require [project.scopecore :as c] thus: (deftest qwerty (c/abc 123)) -OR- both?? to make my test execute

at the top - myproject.core should not be able to use abc directly

and no user of myproject.core should be able to use abc as if it were in core - require is not transitive like that

OK so how do access abc. Do I use '(require.... statements? from core

right, if you have :require [myproject.scope :as s] you should use s/abc

I added that in

and this should be done in every ns that wants to call abc directly

I updated my question to reflect that in the interim

c/abc doesn't work, you can only get abc from the ns that defines it

Nevertheless, so whereever I want to access abc I need to state :require [myproject.scope :as s]

right, you can use a different alias of course, but that's the concept

So I have to have :require [myproject.scope :as s] in myproject.test as well

right, usually what we do is pair a test ns to a code ns, and only test one ns per test

What is interesting is that I did include :require [myproject.scope :as s] in myproject.scope.test as well but it does not execute - I get no such namespace

that should be working, you might have some broken state that needs to be reset / restarted

I ran the "test" call in the code ns and it still works. Same with core

Not in the test, yet all have [myproject.scope :as s]

any file that has a valid require should be able to use definitions in myproject.scope, if there's something else wrong you need to describe the specific error because I can't see what the problem is from what you've shared so far

I am learning clojure.testing so it must be my deftest is incorrect. I will have to investigate (deftest aaa ((is (= 0 (s/abc "123")))) fails to work

😁 Now it works!! I give up Thx @noisesmith

you have too many parens around is there btw - remember that clojure doesn't have "free parens" - they change the meaning of something

(x) in clojure is like x() in other programming languages - it means you want to call x

,Funny ting is (deftest azz (is (= 1 1) )) works (deftest aaa ((is (= 0 (s/myproject.scope "123")))))

does not

like I said, (x) means call x

so ((x)) means call x, then call the thing it returns

yes - (s/myproject.scope "123") returns a value

is returns nil, so ((is ...)) is an npe it will probably error, unless the thing you put inside is directly returns a function you can call

so it becomes (is (= - result))

((is ...)) for any ... is an npe as is returns nil

doesn't matter what is inside

oh wait - it returns the thing you check, my bad

so if = returns true, it will blow up because true isnt' a function

is https://clojuredocs.org/clojure.core.logic • (is u v op)

Set the value of a var to value of another var with the operation
 applied. Non-relational.

we want clojure.test/is not clojure.core.logic/is

yes

(ins)scratch=> (doc clojure.test/is)
-------------------------
clojure.test/is
([form] [form msg])
Macro
  Generic assertion macro.  'form' is any predicate test.
  'msg' is an optional message to attach to the assertion.

  Example: (is (= 4 (+ 2 2)) "Two plus two should be 4")

  Special forms:

  (is (thrown? c body)) checks that an instance of c is thrown from
  body, fails if not; then returns the thing thrown.

  (is (thrown-with-msg? c re body)) checks that an instance of c is
  thrown AND that the message on the exception matches (with
  re-find) the regular expression re.
nil

So (deftest azz   (is (= 1 1) ))

right, that's a correct usage of test/is

(deftest aaa   ((is (= 0 (s/myproject.scope "123")))))

that fails because neither true nor false are functions

the extra parens announce that you want to call the return value of is

and = can only return true or false

so = result in (is (true OR false)) which is not allowed

in the context of invocation, neither true or false is valid, correct

the fix is to not use extra parens

parens request invocation

how do you mean

using my example

(f) => true

((f)) error, true isn't a function

yes it is an outcome

"outcome" doesn't mean anything in clojure, it's a boolean

how do i then get is to apply to the state

t/f

(=1 1 ) is true

just change ((is ...)) to (is ...) the extra parentheses cause your error

that is a type there is only one set () on outside of is (deftest aaa   ((s (= 0 (s/myproject.scope "123")))) how it got here I dont know

This fails

(deftest aaa   (is (= 0 (s/myproject.scope "123")))) how it got here I dont know

fat fingers 😉

if you just evaluate (s/myproject.scope "123") what does that return?

fail cannot find namespace s

no such namespace

yet I have it in the ns

s/myproject.scope looks weird - I don't think it's even possible to have a var with that name

Unable to resolve symbol: scope in this context when I remove the s/

well myproject.scope isn't a var, it's potentially a namespace

what you want is something like s/abc

Guys I have been working on my stuff since 8 a,m BST. I am now whacked and perhaps I am making mistakes now. I appreciate your assistance but I think I need to call it a day and have a kip With a clearer mind Thanks @noisesmith

So i have a deps.edn project I am trying to use cljfmt to format. When I run

clojure -Sdeps '{:deps {cljfmt {:mvn/version "0.6.4"}}}' \
  -m cljfmt.main check

it puts "project.clj" into its default-paths, which can be changed by providing more args after check / fix https://github.com/weavejester/cljfmt/blob/c9f94c0d426230d0fb696af4eb53b00cc5002035/cljfmt/src/cljfmt/main.clj#L196

so you could try cljfmt.main fix src test deps.edn

++ that did seem to work

anything after fix or check, if present, should be used instead of the default which contains project.clj - for bonus points one could make a PR on the project that doesn't try to access project.clj if it doesn't exist (at least not fail over it...)

Looks like there is an open PR that addresses the issue: https://github.com/weavejester/cljfmt/pull/193

wow, nrepl versions 0.7.0 and 0.8.0-SNAPSHOT both crash on ::foo/bar keywords claiming they are invalid

Like repo is to eval just that keyword. Blows up in >0.7.0?

https://github.com/nrepl/nrepl/issues/182 - might be tty specific

@dpsutton right, but that keyword ::foo/bar is only valid if foo is aliased in the current ns. Regardless, it shouldn't crash the client though.

it's just a syntax error / unable to resolve

Right. The fix sounds difficult. And there’s something similar in piggieback as well. How to read input

if I use lein repl :connect instead of using nrepl directly via clj it works just fine

I thought the ticket said it was only tty

The bencode transport was unaffected

maybe I found a second issue, or maybe clj is somehow using the tty transport the way I invoked it

I problably should have brought this up in #clojure rather than #beginners, but at least I have my workaround