I love this channel, I learn so much from other people's questions

Hey guys, am looking for a clojure library to access elasticsearch. Am using latest version of elasticsearch (7.16.1) and already tried https://github.com/clojurewerkz/elastisch, but it looks like it does not support elasticsearch version 7. For example when I create an index I get 405 error message and it looks like elastich uses POST for creating index and since elasticsearch version 6, index is created using PUT and not POST. If anyone knows any other library that can be used with elasticsearch version 7, please let me know 🙂

you can always use the java library for elasticsearch

I'm going through book Clojure for the brave and true, and they mention this is operation

are operators something that only a language can specify, or can a macro make a new operator?

you can make new operators

via macro?

or via functions

operators are just functions/macros

so what i considered a function, is really just an operator?

https://www.tutorialspoint.com/clojure/clojure_operators.htm

assuming this is what they mean

@filip.strajnar https://github.com/clojure/clojure/blob/master/src/clj/clojure/core.clj#L986-L996

I don't think that's the same, because in the book, they mention branching constructs as operators too

ah, well, then it's all functions and macros then

Any form (rator rand ...) The first element is the operator. It can be a function which means it will be evaluated at run time, or a macro which will be evaluated at compile time

Generic term to mean either function or macro

or a built in operator? or is in built operator just a function?

i think it's fine if i just assume in built operator is just a functions really

Some are directly compiled, special forms. They include def fn* let* loop*, if, do

There are a few

https://clojure.org/reference/special_forms

"Operators" are not a thing in Clojure - that tutorial is wrong (or trying to give you a story that might relate from another language)

what is a thing then

Cora recommended that book

in other languages, there are syntactic operators defined in the language syntax

in Clojure the first element in a parenthesized expression is "a thing that can be invoked". if you want to call that position the "operator" that's ok, but it's important that it's not a fixed set of things in the syntax

so, if we decide to call the first position operator, operator is either a function or a macro, either pre-defined or in built in the language?

generally the things to be invoked are either functions (almost everything) or special forms (defined by the language)

things like + are just functions provided in clojure.core

it's also safe to assume that every time i use (), i'm invoking / evaluating an expression?

except for '(), which is un evaluated list?

lists are evaluated by invoking the first element with the rest of the elements as args

'() is special only because of the quote, which says to read, but not evaluate

but other than that, when i see (), clojure is evaluating?

you might find https://clojure.org/guides/learn/syntax a helpful starting point on the basics

it covers most of this

oooh

i already read this, but coming back to it, i understand it better

thanks

On a pedagogical note, it’s also generally beneficial to get a basic working model that is not comprehensive, and let your understanding and complexity of your model increase with time. Chemistry, math, physics, economics, probably everything, all work like this when we learn. Understanding that image you just posted is probably a great starting point for a good while

I have a vector of words and I want to remove the empty ones, which of the following would you use?

(remove empty? words) ;; close to the semantics of the goal but uses a double negative

(filter seq words) ;; common idiom but not sure if the intent is as clear to the casual reader

(def x {:a 1 :b 2})

#:foo {:a 1 :b 2}

an important thing to note is that the map is not qualified, that is just a syntax that can be used when all keys (or symbols) share the same namespace

the map is {:foo/a 1 :foo/b 2}

Good point. Is there any sugar to qualify each key in the map to the same namespace or do I need to reduce it?

there is no core function that can magically do this ( update-keys is coming in 1.11 though) so you would need to transform the starting map into a target map

(reduce-kv #(assoc %1 (keyword "foo" (name %2)) %3) {} x) is one option

Sounds like 1.11 has some nice stuff in it. Thanks as always @alexmiller.

This is something I still struggle with, how to represent as edn a mixed map using the literal for the namespace.

(def d {:blah/name "my blah name" :id 1})

{#:blah{:name "my blah name"} :id 1}

well that particular outer map only has 3 elements in it

those two things are not the same - you've introduced a nesting level

#:blah{:name "my blah name" :_/id 1} can be used for this

although I can pretty confidently say almost no one is even aware that exists

Hey team, I’m trying to convert a curl request, into a clj-http call:

curl '' \
  -H 'pragma: no-cache' \
  -H 'cache-control: no-cache' \
  -H 'sec-ch-ua: "Not A;Brand";v="99", "Chromium";v="96", "Google Chrome";v="96"' \
  -H 'sec-ch-ua-mobile: ?0' \
  -H 'sec-ch-ua-platform: "macOS"' \
  -H 'upgrade-insecure-requests: 1' \
  -H 'user-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.93 Safari/537.36' \
  -H 'accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9' \
  -H 'sec-fetch-site: none' \
  -H 'sec-fetch-mode: navigate' \
  -H 'sec-fetch-user: ?1' \
  -H 'sec-fetch-dest: document' \
  -H 'accept-language: en-US,en;q=0.9,fr;q=0.8,ka;q=0.7' \
  -H 'cookie: ajs_anonymous_id=...; notice_behavior=...; <redacted>' \
  --compressed

ajs_anonymous_id=...; notice_behavior=...; <redacted> converted to a ClientCookie. 

(clj-http.cookies/decode-cookie (slurp (io/resource "mfp_cookie.txt")))                                                                                                             

split on semicolon and decode each separately?

I mean you can more or less split on semicolon and then split each on the first =, taking into account that some cookie values aren't key=val

here's one I used for decoding cookies in an app

or it looks like you could split on ; and pass that to the plural function? https://github.com/dakrone/clj-http/blob/3.12.1/src/clj_http/cookies.clj#L79-L83

is there parhaps a tool that'd auto suggest possible namespaces/ classes to import?

and methods of specific instance of object?

(interop with java libraries)

i can imagine chances of this existing being slim but i figured i'd ask

@filip.strajnar do you mean in the context of an editor/IDE? If so, I believe IntelliJ/Cursive does that and so does VS Code/Calva to some extent (with LSP support).

Thanks @corasaurus-hex! Worked like a charm. For future reference, here’s what I did:

(clj-http/get
   (str ""
        username "?from=" from-date-str "&to=" to-date-str)
   {:throw-entire-message? true
    :headers mfp-headers
    :cookies (->> (-> (slurp (io/resource "mfp_cookie.txt"))
                      (string/split #";"))
                  (map cookies/decode-cookie))})

#beginners

Can someone please tell me where exactly I should start to get my hands on clojure, I'm a beginner

@jabeen2699 Welcome! Are you a beginner to programming as a whole or just to Clojure? Also, are you on Windows or Linux/macOS?

Just to clojure, and I'm on macOS

Cool. So https://www.clojure.org/guides/getting_started should get you up and running with the basics.

And then https://www.clojure.org/guides/learn/syntax (linked from that page).

A lot of folks also recommend https://www.braveclojure.com/ but it introduces Emacs which can be a bit daunting (you can ignore the Emacs stuff if you have an alternative editor with Clojure integration).

What editor/IDE do you use today, and what language(s) are you normally working with?

I've just installed intellij

And worked on c,c++ and python

You'll probably want to join the #cursive channel -- the maintainer of that IntelliJ plugin is very responsive, as are other users there.

@jabeen2699 , I’ve created an interactive guide for that. Would love to know if you think it does the job: https://calva.io/get-started-with-clojure/

on macos you can install clojure through homebrew, fwiw

the getting started repl in calva it's fantastic to get a feeling for the language 🙂

sort of a loaded question, but should I use lein or the clojure cli tools? Does one offer some functionality that the other does not?

should use them for what ? :)

Really the main thing I guess is dependency management for me atm - not necessarily packaging

I think the clojure cli really shines at that

packaging is a bit more configuration and often a small script with clojure cli. But so are the lein based versions, they are just baked in for you and are very difficult to diagnose or change. It is nice when they just work™ but very annoying if their defaults about what to include in a jar aren’t what you need

Personally: lein is batteries included for a lot of things, but the moment you try doing something a bit more complicated you’ll usually start hitting walls. clj has very little magic to it, which sometimes means doing a bit more work than its lein counterpart, but anything more difficult becomes far simpler. I started with lein, and moved over because of this. But also note I moved over because I started doing things that didn’t need batteries included. As a beginner, either will serve you pretty well.