another problem, is prn-str always guaranteed to return valid EDN to be parsed by read-string? for some reason it is dropping double-quotes sometimes when printing maps, I’m not sure it this is not related to some repl stuff or printer configuration

Sounds like a print-dup issue?

@seancorfield: thanks, will try to tweak that setting, btw, I have switched that to transit and now it works without problems

Someone know what the difference between using defschema versus a plain def?. I couldn’t find an answer on the prismatic schema github page.

I read some tutorials in which the author used defschema, but in the prismatic website I only see schemas defined by def.

not much difference. It just adds some meta data.

docstring from the code itself "Convenience macro to make it clear to reader that body is meant to be used as a schema. The name of the schema is recorded in the metadata."

@roberto: Oh. I read that and I wasn’t sure if there was something else about it.

Thanks

Does anyone have an example use of this lein template? https://github.com/stuartsierra/reloaded

a web app perhaps, built using @stuartsierra’s workflow?

Hello! I only start studying Clojure. Prompt please about the conditional operators if. Where to find detailed information?

@billypiston: what do you think about this page : https://jafingerhut.github.io/cheatsheet/grimoire/cheatsheet-tiptip-cdocs-summary.html

here you can find info about all functions that you can use

Prompt please in the solution of a task. I have a clojure-project. I use a hiccup and Bootstrap styles. Everything works, but here only I don't understand as conditional operators work. Here my code: Project.clj file: (defproject yupppie "0.1.0-SNAPSHOT" :description "FIXME: write description" :url "http://example.com/FIXME" :license {: name "Eclipse Public License" :url "http://www .http://eclipse.org/legal/epl-v10.html" } :dependencies [[org.clojure/clojure "1.7.0"] [ring "1.4.0"] [compojure "1.4.0"] [hiccup "1.0.5"]] :plugins [[lein-ring "0.9.7"]] :ring {: handler yupppie.core/app }) Yupppie.core file: (ns yupppie.core require [compojure.core: refer: all] [compojure.route: as route] [ring.middleware.params: refer [wrap-params]] [clojure.pprint: refer: all] [hiccup.core: refer: all] [hiccup.page: refer [include-css include-js]])) (defn home [] (html [: head (include-css "/bootstrap-3.3.6-dist/css/bootstrap.min.css") (include-css "/styles.css") (include-css "https://fonts.googleapis.com/icon? family=Material+Icons") (include-js "/bootstrap-3.3.6-dist/js/bootstrap.min.js")] [: body [: div {: class "col-lg-6" } [: div {: class "input-group" } [: input {: type "text": class "form-control": placeholder "How old are you?" } [: span {: class "input-group-btn" } [: button {: class "btn btn-default": type = "button" } "Go, baby!"]]]]]])) ; (defroutes app (route/resources "/") (GET "/" [] (home)) (POST "/saveform" req (with-out-str (clojure.pprint/pprint params req))))) (def apps (wrap-params app)) I began to study it recently so so far not really I understand. I have a simple form. And at input in the field of figure less than 18 and pressing the button, it is necessary to make so that the picture was shown, and at input of figure 18 or more other picture. Here is how to me to use the conditional operator if that it earned?

oke, so you need to some sort of validate function

I think for these sort things you first need to learn the basics

Did you read a book about clojure or did exercises of 4clojure or did the clojure koans , @billypiston

I think you have to do some sort of if in the save form module

But you couldn't prompt to me as to solve this problem?

sorry I cannot , im also a beginner and I have not work on form and param of a form

and in this channel we like to learn people things and not just give answers

I think you have to look at the parameters or req to see how the contents of the form is stored

then you could do something like this (if (= (parameter which holds the number) 18) (print picture))

or use a cond if you have more then 1 possibility

but if you do not know the basics then you have a very hard time to finisch your programm

Thank you!

youre welcome

@billypiston: did you already figured out where and how to entered number is stored ?

No.

what does (with-out-str (clojure.pprint/pprint :simple_smile: params req))))) gives then

I thought it will print the params and the req ?

I did it according to the instruction and still not really well I understand a code. I simply юы wanted that you prompted that I need to read to solve my task.

I attached all the code above and I don't know as where to enter that after input the picture was shown 18, and after input of number less than 18 another was shown.

sorry but when I ran your code in cursive it will not run. There is a missing :main in your project.clj

I hope some expert can and is willing to help you

I think you need something like firebug for Firefox to see what the form is sending exactly

Thanks. Everything works for me. Probably you didn't connect some files. And with my task I hope to me somebody will prompt.

I hope so. Which IDE do you use then

and luck with your project

I use IntelliJ.

oke, me too

Intelij with Cursive

still the best one

Yes.

sorry I can not help you. I hope a experts will help you soon

Ok. Thank you

YW

What is it?)

YW = Your Welcome

Ok)

@roelof: @billpiston - I am going to move my answer to this thread the #C053AK3F9 channel to keep down chatter in this channel.

Who has a good example of a clojure macro that shows how you can get rid of boilerplate that you would have in java?

(or other non-macro good is good also).

We chose the example from Programming Clojure: https://gist.github.com/borkdude/533beb1b833828092c35 But this is not entirely fair anymore since Java 1.8

@borkdude: How about any DTO / Factory and all the other x00 layers that are between one end and the others? I am serious here, the example might be a bit abstract, but it shows the strenghts of the data first approach IMO

yeah, but it has to fit inside a Java magazine on one page

and I want it to be a code example preferably

Ah ok

In Java 8 the example would be:

boolean allBlank(String str) {
        return str.chars().allMatch( c -> Character.isWhitespace(c));
 }

Wonder if @stuartsierra will use a different example in the next edition of the book

@borkdude: You still need to define an interface for the lambda, which kind of strips a lot of the benefits of using an anonymous function.

having trouble with bidi and cors requests

options method returns 404, although it's added to the route def

cors POST requests always send an options pre-flight, it's browser enforced

nvm, i had a typo in the cors middleware

<!here|@here> hi all

welcome!

hi!

hi!

hi!

Heya

@cored hi!

hi

@cored ehlo

Nice ping 😄

why would you...

hi

:-)

Hej!

hello

o/

wow this is a super welcoming community

LOL

Maybe I should turn off here and all pings 😛

looool)

Moin!

maayybeee

@cored Well you did ping everybody 😉

hahaha

@jano Hamburg?

yeap

@cored everbody

moin moin

@deas: jup

hey

I'm checking differnt languages to know which should be my next move, I'm a Ruby developer

Moin 😉

I thought in Clojure but don't know if from an job market point of view will be good option; I did some Racket in the past so I like it

Mahlzeit

been checking out Go lately too because of the market

@cored, don't find clojure job, create it! :)

rm: well, if only I could hehe

I work as a Ruby developer by day

I did too. Now we're slowly switching to clojure

but some stuffs about Ruby bothers me to be honest

at my current job we are building stuffs in Go

but Go doesn't feel that appealing I'm learning it because of my job not exactly because I like it that much

in some ways reminds of Java 1.4 which was what I was doing before moving to Ruby

but one of the advantages that I see of Go is the fact that is static linked after compiling a program, Clojure for intsance needs an investment in the JVM

Just pick a functional lang, any one.

also, one of the issues that I have with Ruby and teams is the lack of types not everybody knows how to write proper tests to take care of that but Clojure is a dynamic typed language

It's hard to gauge what is going to be successful in the long term anyway, unless you're willing to invest in all the major ones at once.

so wouldn't that mean the same issues in big teams?

sgerguri: well, base on that argument I could pick Haskell which I'm checking for academy purpose I don't think I'll find a job in it at least not in the mainstream

You're not going to find a 'mainstream' job in Clojure either.

I used to be probably one of the ~10 paid Erlang engineers in the country I come from, and I had to move to the UK to get a Clojure position.

@cored: I don't think issues in large teams are caused by the choice of programming language.

sgerguri:gotcha

jannis: well, what I'm saying is that we as developers need to have a very good communication skill to share stuffs but if the language has some quirks then it will be even harder

There's a limit to how far you can take a lang - and the typing is just one part of it. The other is practices, how the code is structured etc.

I always say that dynamic languages require a better type of developer to work on

if you have intermidate developers working on those type of platforms it will be harder to manage a big code base

Erlang is dynamically typed and our platform backbone had 30k+ lines of it. It was also massively concurrent and distributed, but you could still wrap your head around it.

I see

What I'm writing in Clojure now is just a bunch of (micro)services so each one tends to be relatively small, in the hundreds to low thousands of lines of code.

I think Clojure use is higher in the USA which is where I'm living right now

make sense

what do you think about Go ?

is getting a lot of momentum lately

I wouldn't learn a tech just because there's demand for it. Learn it because it teaches you something new.

Clojure for the whole data-first, transformation approach. And for it being a lisp.

Erlang for its concurrency model/distribution and approach to failover.

Haskell for the type system and purity.

@cored: Judging from the large number of C projects and the awfulness I've seen there, I'm not sure I agree. I would agree however that the language can make aspects such as maintainability harder. One example would be the ten different ways to write a simple loop in Ruby - everyone does it differently, so unless you enforce a specific style, your code can end up a mess. I'd argue that typing is only a small factor in this.

sgerguri: was thinking in Elixir instead of Erlang

sgerguri: but I see your point

jannis: so, I'm right on that part it's a matter of communication skills

I'm not a big fan of learning hosted langs first. Learn the underlying tech before you go for what's built on top of it.

sgerguri: the downside for me is that for the fact that Go programs are easy to deploy at my current job are starting to use it to rebuild/build part of the application as micro services

sgerguri: make sense

@cored: Yes, communication, code review, discipline... it takes a good developer to write good, maintainable software, in any language.

gotcha

I have interest in Clojure because of what can teach me as a Lisp and as mention I did some racket which was fun

and as with Ruby at the time I started with it I just did for fun, ended up finding a lot of jobs and quitting Java

are any of you going to the software craftmanship meeting tomorrow?

could be good to see an expert doing some problems in Clojure

Here's a question to the wider Clojure community - do you do top-down (i.e., from the api interfaces/main logic loop towards the data structure manipulation functions that you'll need) or bottom up (data structures first, then main logic flow/API level)?

I have a colleague who's very much into the bottom-up style, which I find usually leads to weird design unless you have very clear idea in your head as to where you are going. Interestingly, he seems to be the only one around who is so rigid about it, everyone else usually switches between the two as needed (myself included).

I do a mix usually

@sgerguri I really like to start with the data structures and then go back to top-down and revise them based on what the overall API tells me about what’s happening.

Thinking about the api I want usually leads me directly to consider the data structures I want the fns to operate on

The bottom up stuff is useful if I don’t know what the algorithm is going to be. Makes small tests and incremental experimentation easy

I’d call it top-down more often than not: write the code I want, then write the code I need in order to make it work

@donaldball True, looking at the function level helps for both. If you keep functions small it is easy to revise the structure.

And sometimes you end up realizing that the “big picture” needs to change once you’ve worked on the low-level view for a bit

the big problem with bottom-up is that it’s very easy to lose sight of the actual intended final product. so you can end up chasing down a rabbit hole that leads to the wrong solution

at least if you have a brain like mine ;D

Thanks for chipping in, guys.

@sgerguri: There is a video of a talk about bottom up and top down from last clojure conj

@abp: I've seen it. The trouble with cases like these is that you naturally have a reasonably big program state which you need to transition.

I'd go with it depends - more often than not building up function from simple manipulations towards more complex routines is the most sensible route, but sometimes you know what sort of toplevel structure you want. For example right now I'm writing a scaffolding for event sourcing and I do a bit of both - I understand what general shape would components in the system have and do a bit of bottom-up shaping exact methods that work on the events that I attach on those components.

is anyone aware of any reason not to set jetty's response header size limit to essentially unlimited in dev?

we use liberator and want to have liberator trace headers on all the time

So it naturally leads to a data-manipulation-approach-first, since the majority of logic is going to be pure. Living in the AWS as a microservice talking to Kafka and Dynamo means large chunks are impure, however.

that very quickly exhausts 8192

I'm not sure which direction I work. I tend to be the user of the api for the libraries I create so I usually have some capability in mind that I want to have and I rework things as much as necessary until it gets to the point that I can do what I want with a minimum of fuss.

@sgerguri: take datomic as an example, is big state transition really bad? Sorry in mobile, so terse

Said colleague of mine has taken this data approach to the extreme, we have reifications of atom interfaces so that Dynamo items can be treated as any other atom, with atomic CAS swaps.

Just have to say - floats are the work of the devil himself - what a royal pain in the ...

Trying to figure out why I'm sometimes ending up with a messed up polygon mesh. 😞

I don't know - like @joost-diepenmaat said, I find it fairly easy to lose sight of your destination when doing bottom up. It's fine if you can treat everything like pure data, but I find it easier to just flesh out the main logic and fill in the pure stuff once I have a skeleton ready than the other way around.

Hm but those are different problems @sgerguri dont conflate

From my experience clear data based approaches slim the design, so yea there is potential for mistakes but also great oppurtunities

@abp I suppose they are, but they are related - this (along with a few other things) basically allows you to treat external storage almost like the local one, and in such scenario you can really write the entire program logic using simple data manipulation functions. And in those situations doing pure bottom-up kind of makes sense.

do you use breakpoints in your code and code execution stops there when calling that code from the REPL inside Cursive? I tried that and it's not working.

Anyway, thanks to everyone who chipped in, I appreciate hearing your opinion.

Is there a way to represent an empty string as a keyword?

not using the reader

@bronsa: ok, thank you

you can always do that, but it's a really terrible idea

Yea, I just tried (first [:]) and it throws an exception

@sgerguri For the dynamo atoms, what’s the behavior when a dynamo request errors or times out?

which is the clojure way to extract "clojure" out of this string? "highlight highlight-source-clojure"

@donaldball: Off the top of my head, not exactly sure - I think there's an error thrown. Check out https://github.com/mixradio/multi-atom for the implementation.

@jjconti: what do you mean by extract? return a string without clojure, just the rest?

I feel like I'm missing something fundamental here, can someone explain to me why this assertion is being checked?

user> (binding [*assert* false] (assert (= 1 2)))
AssertionError Assert failed: (= 1 2)  user/eval76726 (form-init2864370576484743983.clj:1)

Any ideas why my project is not deleting resources/public/js when I run lein clean? This is my configuration: https://github.com/carouselapps/ninjatools/blob/master/project.clj#L60

@pupeno: no, return only 'clojure'. I'm doing

(clojure.string/replace "highlight highlight-source-clojure" "highlight highlight-source-" "")

What do you want to happen if clojure is not present?

Hi - I’m using timbre for logging and am curious about how it handles lazy sequences. I’m basically just doing (timbre/info “some keys” (keys a-map). My question is; is this a bad idea and should I be calling (doall (keys a-map))

"clojure" can be not present. It can say "ruby" instead

danmidwood: not sure you can set assert this way, it's a compile time thing

danmidwood: there you go: http://stackoverflow.com/questions/4874517/how-to-make-clojure-respect-assert-variable

jjconti: maybe

(re-seq #"highlight highlight-source-(.*)” "highlight highlight-source-clojure")

@mpenet: Ah, of course. That makes a lot of sense, thanks

pupeno: thanks

danmidwood: would be nice to have a property to toggle it ex: -Dclojure.compiler.assert=false

sgerguri: docker containers is the way to try new languages/environment at any job :-) talking about our last conversation

like I can build a clojure service put it inside a container and test things out in there

Whatever you do, just don't ask for permission.

Unless you're working at an enlightened place chances are you're not gonna get it.

hm

like not saying that I'm going to build this?

Like not saying you're going to write it in "x" if you can get all the support tooling ready to deploy and monitor it.

Or build a prototype and showcase it afterwards, with a focus on the advantages this gives you.

Trying to write a test that will stub out the lambda/get-function ... trying this ...

(deftest test-exception-throw-invalid-function
  (with-redefs-fn {#'lambda/get-function (fn [c f n] "yikes")}
    (let [result (handler/get-policy-link "foobar")]
      (is (= result "blah")))))

ERROR in (test-exception-throw-invalid-function) (core.clj:7209)
Uncaught exception, not in assertion.
expected: nil
  actual: java.lang.ClassCastException: java.lang.Boolean cannot be cast to clojure.lang.IFn

i expect a failing test. like blah is not yikes or something 😉

@clojuregeek: with-redefs-fn takes an anonymous function as its body

(with-redefs-fn {..} (fn [] ..))

it's a function, not a macro. if you want to avoid the (fn [] ..) and the vars that you're redeffing are known at compile time, you can use with-redefs instead

sgerguri: gotcha

the -fn suffix is about with-redefs-fn being the function variant of with-redefs, not about the kind of vars that it can redef

ok let me try some more.. thanks ... but in theory, its possible to redefine the function in the lambda namespace when its used in the function i want to test?

yes

try this:

(deftest test-exception-throw-invalid-function
  (with-redefs [lambda/get-function (fn [c f n] "yikes")]
    (let [result (handler/get-policy-link "foobar")]
      (is (= result "blah")))))

@clojuregeek: you can also try conjure

https://github.com/amitrathore/conjure

cool, i'll take a look .. but I think i want to just have one simple test right now.. trying example from @bronsa

is there an up to date web programming book for clojure?

The newest I'm aware of is a year behind.

https://www.packtpub.com/application-development/clojure-web-development-essentials

This one

There's supposed to be a new edition of https://pragprog.com/book/dswdcloj/web-development-with-clojure but it's not out yet.

@jaen: thank you

@jaen perhaps I can contact the author and get an early sample

@yogthos: any chance I can get a preview ?

@tesseract: I don't actually have any control over that, the publisher figures out everything related to distribution

good news is that the beta is scheduled for Jan 13th, so not a long wait

@yogsototh: that is good news

thank you

yeah I’m holding my breath for that book

@yogthos: in the new book light table is also used or can I follow it when I want to use cursive ?

I dropped anything editor specific in the new edition actually

nice

and I use cursive myself, so the workflow in the projects is definitely cursive friendly

that is good news

at this moment, my focus is on learning clojure with the help of 4clojure

@bronsa sorry got sidetracked, yes that works great thanks!

somewhere in 2016 I want to make my first website in clojure

@borkdude: That's Stuart Halloway's book, not mine

@yogthos: any tips for learning now or just the luminus docs?

the luminus docs are probably a good place to start

I've tried to aggregate all the common examples for typical web apps there

@stuartsierra: oops sorry

oke, and that docs are up-to-date. I tried the web Essentials book about luminus but I got the idea that some things were changed already

@roelof: yes currently it is out of date

that is why I put my tries to make a simple web app on hold

I hope I can find docs for things like login and authorisation

@roelof: luminus has some documentation around that

I am just reading the READMEs of the underlying libraries

like immutant/compojure/ring and also luminus’ doc

@yogthos: perhaps someone has a working basic web app with authorization built in so we could examine the source code?

just in case you happened to know

@tesseract: hmm not sure of any off top of my head, the ClojureCup entries for this year might be a place to look actually

thank you!

@tesseract: if you find one. Could you send me a link

I will do the same to you

@roelof: this one uses oauth https://github.com/split-brain/poetree

There's this http://rundis.github.io/blog/2015/buddy_auth_part1.html

But it uses JWT

So it's a bit different than your usual multi-page webapp

@roelof: http://clojurecup.com/teams

most of them have no auth and if they do it seems to be oauth

pity

maybe look at buddy or Friend then

@tesseract: the buddy tutorial looks very good at first sight

@roelof: thanks, I am learning the same stuff as you

Yeah, buddy is pretty approachable compared to friend

and the buddy tutorial is quite good to understand

Then I have to make a decesion. Make first a sample app with hiccup or wait on Om next

and try to learn some react in the meantime

first try some more challenges from 4clojure

I have almost of the easy challenges ready. I think some 10 to go

If I were you I wouldn't wait on Om.next. It solves problems you won't appreciate it solving until you encounter them. It will just feel needlessly complex. I'd rather try writing with reagent and re-frame first and after you get your bearings in that, only then try Om.next.

Or you can just keep writing multi-page applications first

That's even easier than React.

oke, I like to make a sort of ecommerce site and I like the idea that the shopping card is updated without a browser needs to load everything again

Reagent can do that

and are there tutorials about re-frame and reagent

re-frame has a brilliant readme

And very good wiki

Including documents explaining various reagent topics - https://github.com/Day8/re-frame/wiki#reagent-tutorials

That's probably all you need to get started with reagent.

Thanks, I will read them all and look if it's fit for me

@roelof: You should also take a look at http://hoplon.io and http://boot-clj.com/. Hoplon is an alternative to the react-based front-ends and is VERY approachable for those new to clojure. The #C08BDAPRA channel is active and the folks there very helpful.

https://github.com/exicon/homepage uses hoplon - and they published their front-end - as well as https://github.com/exicon/webapp-skeleton (which may be dated).

@donmullen: thanks

I will also take a look at that

The more I read about the reactive frameworks the more I think I like the style of quiescent

Its small, it does one thing, and it isn't reinventing the atom wheel (insert usual caveat: I'm a noob and probably don't know what I'm talking back)

@rantingbob: I’ve found https://github.com/hoplon/javelin fairly compelling - easy for people to understand the spreadsheet model of cells / formula cells.

@tesseract: @roelof closp has authorization and authentication built in using buddy: https://github.com/sveri/closp

@sveri: thanks!

@tesseract: np, if you have questions, just go ahead

@sveri: why does this part -n foo.bar in the lein new command

@roelof @tesseract is delegating authZ authN an option?

@roelof: it creates a default namespace like foo.bar.core.clj, you can omit that

oke

@oli: no, local with DB is preffered

sveri if I want to run your showcase the logindata is provided are not working

@sveri ^^^^

but the idea looks good

nice material to study how things like login and roles can work

@sveri can I use it and adapt it to my own needs

@oli: for someone getting started is it worth looking at boot or should I just use lein ?

I like to use datomic later on in the project because I think I need a lot of joins

I call it a day. See you all tommorrow

@sveri : one question, Where can I find out how I can tell which user has which role

@roelof: you mean the one at http://sveri.de? could be someone changed it, there is no reset job. Apart from thatlein repl

Sry, did not want to send this

Yes, I mean at http://sveri.de

but no sweat

I am setting this up again, I think someone just changed the passwords

I will use this on my own computer

Regarding the auth question. look here: https://github.com/sveri/closp/blob/master/resources/leiningen/new/closp/clj/service/auth.clj roles are "hand baked" and currently there is only a difference between a not loggedin user a logged in user and an admin

oke, so the user admin is the admin and the other user are only registered

Thanks for clearing this

May I use this and adapt to my own needs ?

of course

that's what it's there for

oke, I hope I can learn from it

as how login works

Take it step by step, my template is pretty exhaustive and picking single parts from it is difficult if you are new to clojure / the webstack

thanks, I will also read things like the buddy and so on

and im in no hurry because this is at this moment a hobby project

sounds good

@sveri: I am watching the component talk from Sierra to see how your stuff differs Also I need to figure out ring and the like first, but your template looks great.

Step by step like you said

I am using system: https://github.com/danielsz/system/ which sits on top of component, offering some readymade ones. It is component just with a thin wrapper around it

@tesseract: i've never had an itch that i needed boot to scratch but i'm just a hobbyist YMMV

@roelof: the showcase is working again