There are some examples of numbered capture groups using re-find on this page: https://clojuredocs.org/clojure.core/re-find

I tried with numbered but was not able to make it work the way i need it

I'll have a look at the examples

If you are trying to match things like "<some_string><other_thing><some_string>" where the second <some_string> is an identical sequence of characters as the first, that is a semi-special extension to regexes that some regex engines have, but others do not.

This is effectively what I'm looking for

It is not a regular expression in the computer science automata theory class sense of a regular expression, which is one of the reasons it is a semi-special extension. I do not recall if the Java regex engine can do that or not, as I never venture that far from automata theory regexes.

If you find that the Java regex engine cannot do it, a parser for a larger kind of languages can be parsed using other libraries, like Instaparse: https://github.com/Engelberg/instaparse

I'll have a look to that

According to the Java regex page https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html there is something called "Backreferences" that looks like it might be what you want.

Search on that page for both of "back references" and "backreferences" (with and without the space) to find all occurrences where it is mentioned

I have never used those before, so can't speak to their effectiveness in Java's regex engine.

And it looks like there are named capture groups

Which I have no idea what those do if you try to use one with Clojure's re-find

This is the page I was directed to when searching. I might have read it too fast...

From a quick experiment at the REPL, it seems like re-find returns the same thing on a match for named or unnamed capture groups:

user=> (re-find #"(?<foo>\S+)\s+(?<bar>\S+)" "the quick brown fox")
["the quick" "the" "quick"]

But the names might be nice if you have a complex enough regex that you want to use named back references and not have to keep count of them.

Ok, found a working regex: #"([a-z]).\1"

Many thanks for pointing me in the right direction 😉

Cool. Sounds like you are off to the races, then.

Yeah, once you get outside of concatenation, alternation/or using | , and + and * , not a whole lot is portable between different regex engines in different libraries/languages.

So true

but most of them support a whole lot more than that, if you are willing to write them non-portably.

I'm trying to use https://github.com/HCADatalab/powderkeg #powderkeg because I like the design of it a lot, but it hasn't been maintained in a while, and I'm struggling even to get a fork to compile. I'm kind of a beginner, so I may just be missing something. the issues are all concerning this module "ouroboros", and I'm getting everything from "namespace not found" to complicated errors involving (proxy) overriding things it apparently shouldn't be, as well as "illegal reflective access operation". I don't know enough about Java interop and (proxy) to figure it out. Has anyone here had any similar issues? Is there a gotcha that I'm hitting? I'd really like to use this library, I love the way it uses transducers so it doesn't have to reimplement all of Spark.

"illegal reflective access operation" might be something you can ignore, assuming you are using JDK 9 or later, if they are warning messages: https://clojure.org/guides/faq#illegal_access

Is there any kind of short circuit logic for comp ? e.g (comp int :number) that would return nil instead of throw NPE when number does not exist on object?

Like using some-> but with comp

What I’ve thought is to wrap the int coercer to allow & return nil in a custom int* fn

Why do I get two zeros in a vector here? Is it because of the spec/and?

hmm no because:

Is there a way to log an argument which is a function? Printing it gives something like #object[user$square 0x4f20a5e0 "[email protected]"]. I want the source instead.

In a REPL session, (source ) will show the source code, if it was loaded from a file (i.e. not entered in the REPL)

I haven't tried that for logging, but you could give it a go and see what happens in a small experiment.

The short answer to the question above is, no

If you have a function object, that’s an opaque compiled function instance that is invoke Le but not much else

It is possible to demunge the class name of the instance and make something readable (demunge will not working in every case, but most)

https://clojure.github.io/clojure/clojure.repl-api.html#clojure.repl/demunge

If you want the actual expression that was compiled into the function instance you have, you can’t get that

I need to prepare some JSON files for my clojure app. They're loaded when the app starts and used as a in-memory database of sorts. Currently I created a Bash script that downloads a csv, converts to json, handles it with jq and does a couple more things with the data in a folder I called scripts on my lein project root. If I change it to a clj script, still in the scripts folder i.e. not in the src path, can I run it as a script like clj myscript.clj or will my external libraries/dependencies not be loaded because I'm not using lein?

Wow. This whole, “We’re going to fix your editor so that you don’t have to think about matching parens anymore” thing takes a bit of getting used to, but then it’s pretty awesome.

Hi, what does this mean? Reflection warning: ... 87:7 all to java.lang.Integer ctor can't be resolved. ?

What's a good process for tracing/debugging code in a dependency? In Python, I could just go into my site-packages directory where pip installs packages and I could make edits to dependencies to add print s and breakpoints. Is there a similar way to hack around in dependencies in Clojure/ClojureScript?

@ericihli If you're running your code from inside the REPL, with your editor connected, then you can edit the code in the dependencies (assuming you've cloned them locally), and evaluate it into the running REPL, with your debugging changes in place.

> assuming you've cloned them locally Right now all my dependencies are as .jar files in an m2/repository directory. I'm trying to figure out how to point to a dependency that is a local directory, like a git repo.

In the scenario I described, you don't need the dependencies changed from the JARs. You just edit the source (elsewhere) and eval it into the running program.

Ah ah ah.

I see.

It's the same as editing code and eval'ing it into a live, running, production process 🙂 No need to restart the process or anything. The changes only hold while the process is running.