This is rad, I want to try it out @sritchie09

Is there a way I can grab items from a list, one at time - like generators/yield in js?

the common way to do that is wrap the code in a context that traverses (like map or reduce), but you can also do this with core.async or interop

though I don't know off hand what the raw interop looks like without the js syntax

That’s cool, thanks :thumbsup:

if this isn't out of date, it looks like generators are intentionally not available in cljs https://observablehq.com/@shaunlebron/proposal-generators-and-async-functions-in-clojurescript so you'd need to write at least a stub of js

if I'm reading it correctly

quoting (likely from this very same channel)

await/async is just sugar over functions that return Promise. You can always use the Promise API on the result of async function. If you need to provide async function in your cljs public API, just return Promise. Generators are sugar for generating stateful Iterators and way to add some kind of laziness to JS. Cljs structures are lazy and implement Iterator for long time. Cljs is ahead in this. 

Hrm I see Iterator, that might be the way

iterator, or even just a lazy seq, sure

I think iterator might be the way to go. It specifically has next - giving me the next value, as opposed to lazy seq which gives me the entire seq up to a point?

a lazy-seq is more idiomatic, but requires a rearrangement of the code, so that instead of a stateful object providing new values, a function inside a comprehension consumes those values

but for every solution that stores a state and reuses it, there's another that reifies that state into position on a lazy-seq and runs inside a map or reduce

and I think it's provable that (given some sort of async driver) both can do what the other does

iterator might be most direct for your usage, but code that's reshaped to use laziness instead tends to be better clojure code

When doing JS interop, is there an idiomatic way to propagate down nested obejcts without null-checking? In ES, there is this ? operator. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Optional_chaining

@timrichardt you mean with null-checking? (some-> obj .-foo .-bar) would work

Can someone please suggest a simple data visualisation library in Clojurescript. The use case is to plot simple graphs like simple line plots/bar chart with smoothing option.

can someone point me in the direction of an auto documentation tool or library that has support for clojure.spec

and obviously supports clojure and clojurescript

something ala codox (but with support for clojure.spec)

@bones https://clojurescript.org/guides/promise-interop

while this isn't exactly what you're talking about, you can generators work with core.async same as Promises

Just to have asked: Is it possible to get the contents of an edn-file into clojurescript? The file contains some generated lookup data that I need in my frontend code. Currently I copy the contents into a var in a cljs-file, but it would be nice to instead just consume the edn-file directly (e.g. using (:require [“lookup.edn” :as lookup])) as that would pick up any updates to it. Is this possible without e.g. an AJAX request or having the backend inject it into the HTML page, … Thinking about it I might as well just generate a cljs instead of edn, but I would still be interested in an EDN solution.

Hey all - does anyone have tips on how to get a list of all vars declared in a namespace, from cljs?

(keys (ns-publics 'clojure.set))

I'm looking to write a function or macro that can do the equivalent of the evil :refer :all, just for a repl session

nice, trying

use ?

or is that not a thing in cljs

not a thing

super strange... I 'm seeing this error:

Invalid :refer, macro sicmutils.env/literal-function does not exist in file
   <cljs repl>

the macros seem to be getting treated as functions

(ns sicmutils.examples.pendulum
  (:refer-clojure :exclude [+ - * / zero? partial ref])
  (:require [sicmutils.env :refer-macros [literal-function]]))

(sending code link)

https://github.com/littleredcomputer/sicmutils/blob/sritchie/convert_env/src/sicmutils/env.cljc#L59

all of these macros seem affected

oh, I might have an idea... I may have left a .clj file around, doing the importing

nope, not that. has anyone seen this, where macros simply aren't seen?

I don’t have enough information to diagnose the error

well if you're in cljs, there are no macros right?

sorry, my bad, let me summarize - I've got sicmutils.env, which declares three macros

(and I've done this in a few spots around the library)

@alexmiller it's a cljc file, so we should be good here

https://github.com/littleredcomputer/sicmutils/blob/sritchie/convert_env/src/sicmutils/env.cljc#L63

here's the env file with macros:

then, when I try to evaluate this new namespace form that pulls in that namespace and refers macros: https://github.com/littleredcomputer/sicmutils/blob/sritchie/convert_env/src/sicmutils/examples/pendulum.cljc#L23

I see

Unexpected error (ExceptionInfo) compiling at (REPL:1).
Invalid :refer, macro sicmutils.env/with-literal-functions does not exist in file <cljs repl>

(ns sicmutils.examples.pendulum
  (:refer-clojure :exclude [+ - * / zero? partial ref])
  (:require [sicmutils.env :as e :include-macros true])
  (:require [sicmutils.function :as f :include-macros true]))

(f/with-literal-functions [x y z]) works great at the repl, referencing this macro

https://github.com/littleredcomputer/sicmutils/blob/sritchie/convert_env/src/sicmutils/function.cljc#L336

(e/with-literal-functions [x y z]) fails

meaning, it doesn't act as a macro, so I see

WARNING: Use of undeclared Var sicmutils.examples.pendulum/x at line 1 <cljs repl>
WARNING: Use of undeclared Var sicmutils.examples.pendulum/y at line 1 <cljs repl>
WARNING: Use of undeclared Var sicmutils.examples.pendulum/z at line 1 <cljs repl>

I'll try to slim the ns way down and get a small repro

but thought someone might be able to pattern match on that strange error /behavior

try adding to sicmutils.env ’s ns form:

(:require-macros [sicmutils.env])

ah but you have :include-macros in the consuming ns

hm

are there any errors at macro time? e.g. a parse or compiler error in your Clojure REPL

let me try adding that line

no errors that I can see

@lilactown the macros seem to be acting as functions

that return their form?

this looks like the output you get when using bootstrapped clojurescript

this is cider, with the node repl

okay! we may have a winner

wrapping the macro definitions in a reader conditional worked, here

boooom thanks all!