Anyone have an easy way to get the namespace of a .cljs file? All I have is a string representation of the file contents. Or is my best shot to just resort to regex?

Oh I can just use edn/read-string haha

Amazing

Need some CSS help. Any specific channels?

#css exists as a channel but I have no idea how active it is @hindol.adhya

@kevin.van.rooijen something like https://github.com/clojure/tools.namespace/blob/8d632bfcd8ce4f872f9a9cdafb5245c9b10574a0/src/main/clojure/clojure/tools/namespace.clj#L57-L94 is probably most reliabel

hey, reading abit SICP and curious about streams and their impl in clojure as with LISP. what are streams in clojure then? I'm assuming 'seq' can be thought as a 'stream-like'? with it laziness? how can I think on streams with clojure? I see that delay, force are used as-well.

When I hear streams I think of core.async: https://github.com/clojure/core.async But I haven’t read SICP that far in, so I may be off in suggesting that

Stream = a channel, in this case

Streams in sicp are more like lazy seqs

Which are every where in clojure

https://sarabander.github.io/sicp/html/3_002e5.xhtml#g_t3_002e5_002e1

A scheme delay is more like a clojure promise

If I recall

A delay in clojure is not the same thing as a promise

> Our implementation of streams will be based on a special form called delay. Evaluating (delay ⟨exp⟩) does not evaluate the expression ⟨exp⟩, but rather returns a so-called delayed object, which we can think of as a “promise” to evaluate ⟨exp⟩ at some future time. As a companion to delay, there is a procedure called force that takes a delayed object as argument and performs the evaluation—in effect, forcing the delay to fulfill its promise. good memory

I think I got it reversed

The thing delay creates in scheme is a promise, which is like a clojure delay and not like a clojure promise

Ah. Receives a value versus has the thunk to compute it itself ?

I might be trying to much to create pure functions, possibly in places where it's hard to do so. To the more experienced Clojurians out there, is it normal that your DB layer functions are quite impure?

yes, my db layer functions are quite impure

I need to do some bitwise operations in Clojure; is there a way to work with 16-bit unsigned integers instead of the default 32-bit signed integers?

but they're also incredibly simple, often with one form inside

i.e. take the args, put them into the db function

If your app is basically doing CRUD, it's OK to have impure functions all over the place. It's worth trying to separate out any transformation as pure functions tho'.

(let [data (read-stuff db)
      new-data (pure-transform data)]
  (write-it db new-data))

Great, thanks

(that way you can test the transformation logic independently, perhaps generatively, for example)

yeah exactly. My business logic will be a lot of transformation, I had it in my head I'd be using (-> for these

and try to have them pure

I hope it's not rude, but since my question got covered up by the previous discussion, I'm going to repost it. > I need to do some bitwise operations in Clojure; is there a way to work with 16-bit unsigned integers instead of the default 32-bit signed integers?

Sorry @ordoflammae I've no idea.

Hello, I know less than John Snow, haven't written anything yet, but a quick search:

(->> 123
     (bit-and-not 16rFFFF))

I think Java doesn't have unsigned integers, and therefore Clojure as well

OK, that works.

What's the 2rstuff?

Or 16r.

a shift? I don't know

OK. Thanks @dolphinlink!

The radix (the base)

Oh, that makes sense

2r means binary. 16r means hex.

Hum... Seems that chars are 16bit unsigned

Maybe you could use that

Also, Java 8 has 32 bit unsigned support

Integer/divideUnsigned for example

That SO link has an answer from Alex Miller pointing at those Java 8 methods.

Thanks @seancorfield. Now the SO answer makes sense.

Hopefully the syntax isn't too obtuse...

If you liked 'Arrival': (->> 11111 (bit-and-not 7r66666)) => 16512

I think they dealt with a problem like this on this episode of Apropos: https://www.youtube.com/watch?v=parkWOdl8RU

I think you can actually use all bitwise operator on a char

In Java you can, so I'd assume Clojure as well

And char are 16bit unsigned

Not quite:

user=> (bit-and 5 \a)
Execution error (IllegalArgumentException) at user/eval1 (REPL:1).
bit operation not supported for: class java.lang.Character
user=> (bit-and 5 (int \a))
1

You won't be a le to use arithmetics though like +,-,*, etc. I believe

Hum

Nevermind then

> Java defines several bitwise operators, which can be applied to the integer types, long, int, short, char, and byte

Kinda sad that it's not the case for Clojure

char not Character

Oh ya, cast to (char) first

@didibus I think it's sort of a niche case, working with bitwise stuff, so it's probably not the best use of time for the Clojure developers.

There are bigger fish to be sad about 🙂

Although it would be interesting to have a library that allows manipulation of this kind of stuff.

(bit-and 5 (char \a)) ?

If you don't have a REPL, then how are you using Slack? 🙂

Phone :p

I only have Replete which is Cljs repl on my phone :(

So can't try those interop use cases

That explains lots of short messages rather than fewer longer tracts 🙂

Oh ya, I never realized that, it does ☺️

Clojure/JVM enables semi-straightforward use of values with types that are Java primitive long and double . I am not aware of any ways to make that semi-straightforward for other Java primitive types like char

It is straightforward to convert char or Character type values to integers, though.