Clojurians Log v2

Please avoid splitting your message into multiple messages - it's much better to edit the original message or start a thread. Helps with avoiding unnecessary notifications and fragmenting the discussion across multiple threads. is not an object, at least not in an OOP sense. It's just a function. You can check what it does with (doc ...) in your REPL:

user=> (doc )
-------------------------

([arg] [parent child] [parent child & more])
  Returns a java.io.File, passing each arg to as-file.  Multiple-arg
   versions treat the first argument as parent and subsequent args as
   children relative to the parent.
nil

user=> (doc javadoc)
-------------------------
clojure.java.javadoc/javadoc
([class-or-object])
  Opens a browser window displaying the javadoc for the argument.
  Tries *local-javadocs* first, then *remote-javadocs*.
nil
user=> (javadoc java.io.File)
true

I recommend https://github.com/babashka/fs for working with files, nicer than in my opinion.

Thanks for your swift and detailed reply! In my inital request I missed mentioning the function .listFiles which I need the return type of. Well, sry to say, I am stupid and still don't get it. In my REPL I tried (doc http://clojure.java.io/file) which is the officlal info which doesn't give me details on members. And (javadoc http://clojure.java.io/file) opens this page with Japanese snippets and no info at all: https://clojure-api-cn.readthedocs.io/en/latest/clojure.java.io/as-file.html So I took the link your system/REPL generated but this is just Javadoc not Clojure. How does the fact that the underlying Java File object's member .listFiles returns File[] help me in Clojure world where the return type seems to be a lazy seq? If you are too busy for this basic and franky stupid beginner's stuff I totally understand you dropping out of this, and I greatly appreciate your time and investment.

@teodorlu i have a look at this!

> which is the officlal info which doesn't give me details on members. Because c.j.i/file is not an object with members - it's a function that, when you call it properly, returns a java.io.File object. You're interested in that object, not in the function that creates it. So you need to get javadoc for the File class, not for the file function. > How does the fact that the underlying Java File object's member .listFiles returns File[] help me in Clojure world where the return type seems to be a lazy seq? I don't understand the question, could you rephrase it?

Sure. The clojure way of checking docs you gave me (Thanks!) points me to Javadoc. Here I see that the member .listFiles returns File[]. So do I work with File[] now in Clojure world? Well, I don't hitnk so. It's rather a lazy seq or something similar. But where is this documented? I need the precise return type. Knowing the underlying Java object is nice to have but doesn't help my stupid brain to proceed in Clojure world. The call (.listFiles my-file) returns what type?? (Sorry for my possibly comvoluted way of putting things - Suffering from a flu right now.)

Java interop forms return the same thing as their Java equivalents, so you'd indeed get a File[] if that's the case; for how you'd work with it, anything working on seqs works just fine on arrays, and generally Clojure can make sense of a lot of Java objects thrown its way

Does return File[] ?? Oooh, I see. Makes sense. I just vaguely remember that yesterday I saw an error message like "cannot do this on ....LazySeq ..." So I figurered .listFiles returns a lazy seq. MY MISTAKE. Sorry for making a big fuzz about it. Now I need to find out how to Java-interop with a File[] object. THANKS (to all three of you)!

Arrays can be turned into Clojure collections. Or used as is in some contexts. Plus, Clojure has a bunch of functions specifically for arrays.

clojure functions are inner classes of the namespace that creates them:

(ins)user=> (bean )
{:class $file, :requiredArity 2}

(ins)user=> (.invoke  ".")
#object[java.io.File 0x79ab34c1 "."]
(ins)user=> (.applyTo  '("."))
#object[java.io.File 0x28d79cba "."]

(ins)user=> (bean ( "."))
{:path ".", :freeSpace 521537241088, :parent nil, :directory true, :parentFile nil, :name ".", :file false, :canonicalFile #object[java.io.File 0x736f3e9e "/Users/justin"], :absolute false, :absoluteFile #object[java.io.File 0xbdc8014 "/Users/justin/."], :hidden true, :class java.io.File, :canonicalPath "/Users/justin", :usableSpace 521537241088, :totalSpace 994662584320, :absolutePath "/Users/justin/."}