Clojurians Log v2

Howdy y'all! Is there a formatter for edn files? one that adds indentation and line breaks?

Maybe this? https://github.com/kkinnear/zprint

What is the output of clojure -Sdescribe ?

It might be that you have an older version of the Clojure CLI tools than Sean was using when creating those files -- there have been changes in the last few months, especially around handling of the -X command line options.

if I have a regex, is there a way to get a match object that has indices of groups instead of the groups themselves?

e.g. if I have .(.)x or something I’d like the indices of where each part starts and ends

The underlying Java APIs used by Clojure/JVM to do regex matching should provide these indexes. IIRC using those indexes is exactly how Clojure determines the substrings of the input string to return for the match groups.

Look at the methods start and end for the class java.util.regex.Matcher : https://docs.oracle.com/javase/9/docs/api/java/util/regex/Matcher.html

Trying to do “Web Development with Clojure 3rd edition” and after creating the base app with luminus and h2 as suggested, still getting “No suitable driver” for database connection. H2 dependency is there. What the heck?

Thank you 🙂 that should do the trick

Hi team, please suggest a logging tool for Clojure application?

Everything is saved, and your REPL was restarted after adding the dependency?

@vnazaryan clojure.tools.logging

They asked this in #clj-new and it's because they have ... in deps.edn which causes the map literal error.

@twcrone I saw that you’d posted this same Q on StackOverflow so I’ve followed up there — I can’t repro the error based on the information you’ve provided so far (my answer shows the steps that work).

@vnazaryan Now I’m at my desk I can expand on my answer: using clojure.tools.logging, it will look for a Java logging library on your classpath. It looks for known libraries in a particular order, starting with slf4j. At work, we’ve decided to use log4j2, and we “bridge” all the other logging libraries over to log4j2 by having these dependencies in our project:

;; use log4j 2.x:
    org.apache.logging.log4j/log4j-api {:mvn/version "2.13.3"}
    ;; bridge into log4j:
    org.apache.logging.log4j/log4j-1.2-api {:mvn/version "2.13.3"}
    org.apache.logging.log4j/log4j-jcl {:mvn/version "2.13.3"}
    org.apache.logging.log4j/log4j-jul {:mvn/version "2.13.3"}
    org.apache.logging.log4j/log4j-slf4j-impl {:mvn/version "2.13.3"}

-Dclojure.tools.logging.factory=clojure.tools.logging.impl/log4j2-factory

Yeah it’s silly, I literally created and ran. Which by all accounts should just work. Figure I missed a step. I’ll look at more tonite. Didn’t spend much time since I figure was a stupid omission that is common

If you update your SO post with any new information, LMK, so I can update my answer.

Also if you’re confused about various Java logging libraries (as most of us are) here’s some background: https://lambdaisland.com/blog/2020-06-12-logging-in-clojure-making-sense-of-the-mess

>> (type (cons "asdf" [1 2 3]))
clojure.lang.Cons // expecting this to be persistentList

If that where so what would happen if you did (cons 1 (range))

and also from the docstring you should not have that expectation: > clojure.core/cons > ([x seq]) > Returns a new seq where x is the first element and seq is > the rest.

I think my understanding of seq is flawed, cons returns a seq but why does the type say clojure.lang.Cons?

(seq? (cons "asdf" [1 2 3])) ;; true

this guide is by far the most authoritative: https://clojure.org/reference/sequences

but the short and sweet is that, if you're familiar with other lisps, seq provides the "car" and "cdr" to many different types not just the two pointer cons cell