Clojurians Log v2

sorry if this me failing to google before asking... anyone know if java-time can be used in closh?

/home/arthur» (cemerick.pomegranate/add-dependencies
         #_=>          :coordinates '[[clojure.java-time "0.3.2"]]
         #_=>          :repositories (merge cemerick.pomegranate.aether/maven-central
         #_=&gt;                               {"clojars" "<https://clojars.org/repo>"}))
{[clojure.java-time "0.3.2"] #{[clj-tuple "0.2.2"]}, [clj-tuple "0.2.2"] nil}
/home/arthur» (require '[java-time :as t])
Syntax error (IllegalAccessError) compiling at (java_time/temporal.clj:324:1).
tried to access field clojure.lang.APersistentVector._hash from class clojure.lang.PersistentUnrolledVector$Card1

@arthur That line in java-time.temporal in 0.3.2 is a comment so I'm wondering if closh itself already has an earlier version?

Hmm, doesn't look like it. But that does sort of feel like a compiled code/version conflict sort of issue. I've played with closh quite a bit -- but never try to add new dependencies while running -- and I did find it a bit crashy with some of the things I was doing 😐

I've been thinking about package dependencies and the issues happening in npm and Python world, where people name squat but also try to take advantage of typos and such to introduce vulnerabilities. Clojure recommends that you use org/package and uses namespaces, so name squatting isn't as easy, since you can't take over someone else's org, but you could still put packages of the same name in similar sounding orgs or different orgs and hope to introduce vulnerabilities by way of someone accidentally using the wrong package. Maven Central I learned does a manual verification for that purpose, where they validate that you own the domain of.your org for example. Now, in GitHub, you can verify your domain for a github organization as well, and that's actually automated. So I've been thinking, what if Clojars did something similar? It could ask to verify that you either own your domain, or your identity on some supported identity website like github. And the validation could be automated as well. For domain, do what github does, ask for a DNS TXT header secret to be there, assume your org in Clojars is the reverse domain name. Similarly, for github, could ask to create a gist that contains a secret, or a repo with a file that has the secret in it. And assume your org is your github username or org name. I don't feel this would add too much friction, and maybe if we want to be backwards compatible, Clojars could offer two repos, one verified one with such verification and one for free for all. Serious libs can do the extra work of being verified and people who need that level of trust can depend only on that repo. Thoughts? (Might post this to the reddit as well)

@didibus This is probably better suited to the #clojars channel -- there used to be a two-tier system with signed JARs and unsigned JARs but it was abandoned because so few people bothered to sign JARs 😐

We have so many groups on Clojars that are not either reverse domains or GitHub usernames that I don't think it would work... And Alex's blog post about qualified lib names suggested <provider>-<username>, e.g., github-seancorfield, which is not a pattern anyone uses right now but something like that would be required to avoid squatting on people's usernames on different services to sow confusion -- is seancorfield/some-lib from seancorfield on <http://github.com|github.com> (me!) or seancorfield on some other servicer provider? (potentially not me, but mostly I'm the only seancorfield everywhere as far as I know)

Also, there's no obvious connection between the domain I own <http://corfield.org|corfield.org> and the username I have on almost every service seancorfield so I'm not sure how domain verification would even work in that case?

Is it possible to add default implementation for protocol method?

I think you can by extending it for type Object

That's seems kinda nasty.

Is it possible to extend the type in record?

That would be better since I would not have to mess with Object.

Hum, I mean it's not any nastier than if there was a default. Though I guess Object would not work for nil, where a default would since protocols can extend nil.

You want it implemented for all record types?

I'm sure there's some similar parent that all record belongs too that you could use?

Wait, could it be you just want to use the same functions as the implementation for multiple record types?

If so you can use extend it takes a map from method name (as a keyword) to the function that implements it. So you can extend all your record and give them the same map

@didibus I would like to have some of the records to implement IEventSourceable interface and I don’t want to specify the same function implementation over and over again.

Ya you should be able to do that with extend. You'd still need to list out each record you want it for, but at least you won't have to type the implementation of the methods over and over

A bit like done here https://clojuredocs.org/clojure.core/extend#example-5be9f7e9e4b00ac801ed9ef3

Thank you @didibus. This is great! Do you know whether it's possible to get record function by keyword?

Not sure what you mean?

hi! any way to mix expound's human-readable spec errors with orchestra instrumentation?

I tried setting s/*explain-out* to expound/printer , but when there's a spec error I'm still getting the normal explain output

Trying to grok when macroexpansion occurs in a dependency. We have a dynamic var that we wish to alter downstream. So that we can alter the behaviour of the macro dynamically.

What would be the best way to declare for a local dependency in deps.edn (`{:local/root "checkouts/project"`}} that it uses a certain alias that has extra source paths? Or is it customary to just add that source path directly to deps.edn directly?

I'd like to have the possibility to omit one source directory, that needs to be specified by the dependency user to include/not include it

The reason is that if you choose to have that directory, you must have add additional dependencies that not every project using the dependency needs at all

I think you are outside the bounds of what deps.edn supports

It happens whenever code using the macro is compiled. That could be at aot compile time, or load time.

Yeah, I thought so too – and it was trivial to just add the source path to :paths declaration in the project using the dependency (it's included as a submodule in checkouts)

I'm not sure if this is idiomatic, but works for our use case just fine!

http://clojure.com seems to be down

isn't it http://clojure.org, or does it have another domain i dont know

ohhh you're right. I think the dot com used to redirect somewhere at least? I clicked a dead link somewhere

.com has not existed for a long time

Hi everyone,

is there a way to parse timestamp with whatever format ?

Sure, what do you have in mind?

Clojure folks tend to rely on existing Java libraries for this, I believe.

what java libs you may suggest that helps here?

what do you mean?

Java, since version 8, has very good build-in time support, under the java.time package

Several different classes for different purposes, many with Java methods whose name contains "parse"

i think the most worth here is java.text.SimpleDateFormat

but that takes format

maybe i need to write another function to determine the date format at first

then parse it

anyway thanks guys

There are so many date/time formats in text, that saying "whatever" format is unlikely to produce a list that ends if you start writing it this year.

Any given application you have hopefully you can limit them to a small set of acceptable formats.

If your goal is "recognize dates/times in any way a human might recognize", then you are in AI/machine-learning territory.

yeah i got that, maybe you can use CRF model to do that, stanford NLP has that feature, but i'm not seeking dates extraction from text

i think i'll define some regexp for specific number of timestamp format, then search which regexp is right for it

after determine the format i'll parse it

Is the aim to parse any individual timestamp or to recognise a format given many date strings? Plenty of dates are ambiguous if you don't know the format, 01-01-2020T... could be day first or month first so very few programs would do anything beyond telling you which format to provide timestamps in

the ultimate goal is parsing timestamps, so the problem now as you addressed "the format", so i'll limit that to a set of formats then i'll need method to determine the format before the parse step

I'm wondering if there is a commonly adopted clojure framework used for building backend routes and services for a web app. Or is there a list that could help me know what one to use?

reitit

https://github.com/metosin/reitit

Thanks!

http://pedestal.io/

That's exactly what clj-time does - it tries to guess the format based on its own list of formats: https://github.com/clj-time/clj-time/blob/master/src/clj_time/format.clj#L156-L165

My lack of Java knowledge is really testing me right now, hopefully someone can point out the obvious for me. I instantiated a new com.googlecode.lanterna.gui2.MultiWindowTextGUI Object (https://github.com/mabe02/lanterna/blob/lanterna-3.0.3/src/main/java/com/googlecode/lanterna/gui2/MultiWindowTextGUI.java) using (new MultiWindowTextGUI screen wm x). I then want to tall the getFocusedInteractable method. When I check the source file https://github.com/mabe02/lanterna/blob/lanterna-3.0.3/src/main/java/com/googlecode/lanterna/gui2/MultiWindowTextGUI.java#L364 and also the API documentation https://mabe02.github.io/lanterna/apidocs/3.0/com/googlecode/lanterna/gui2/MultiWindowTextGUI.html#getFocusedInteractable-- then it looks like there should be a getFocusedInteractable method. However when I try to call it with (.getFocusedInteractable gui) I get the following error

Exception in thread "async-dispatch-1" java.lang.IllegalArgumentException: No matching field found: getFocusedInteractable​ for class com.googlecode.lanterna.gui2.MultiWindowTextGUI
        at clojure.lang.Reflector.getInstanceField(Reflector.java:397)
        at clojure.lang.Reflector.invokeNoArgInstanceMember(Reflector.java:440)
        at trader.core$_main$fn__10988$state_machine__8040__auto____11009$fn__11011$fn__11013.invoke(core.clj:158)
        at trader.core$_main$fn__10988$state_machine__8040__auto____11009$fn__11011.invoke(core.clj:155)
        at trader.core$_main$fn__10988$state_machine__8040__auto____11009.invoke(core.clj:155)
        at clojure.core.async.impl.ioc_macros$run_state_machine.invokeStatic(ioc_macros.clj:978)
        at clojure.core.async.impl.ioc_macros$run_state_machine.invoke(ioc_macros.clj:977)
        at clojure.core.async.impl.ioc_macros$run_state_machine_wrapped.invokeStatic(ioc_macros.clj:982)
        at clojure.core.async.impl.ioc_macros$run_state_machine_wrapped.invoke(ioc_macros.clj:980)
        at trader.core$_main$fn__10988.invoke(core.clj:155)
        at clojure.lang.AFn.run(AFn.java:22)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at clojure.core.async.impl.concurrent$counted_thread_factory$reify__1811$fn__1812.invoke(concurrent.clj:29)
        at clojure.lang.AFn.run(AFn.java:22)
        at java.lang.Thread.run(Thread.java:748)

the only things I can think to try are: 1. trying the call in repl on a non async thread. 2. making the reflection call yourself to see what methods exist. maybe that can point to false assumption

based on your description, it seems like it should work

Indeed, it worked for me in REPL just fine:

(import com.googlecode.lanterna.terminal.DefaultTerminalFactory)
=> com.googlecode.lanterna.terminal.DefaultTerminalFactory
(def tf (DefaultTerminalFactory.))
=> #'user/tf
(def term (.createTerminal tf))
=> #'user/term
(import com.googlecode.lanterna.gui2.MultiWindowTextGUI)
=> com.googlecode.lanterna.gui2.MultiWindowTextGUI
(import com.googlecode.lanterna.screen.TerminalScreen)
=> com.googlecode.lanterna.screen.TerminalScreen
(def screen (TerminalScreen. term))
=> #'user/screen
(def gui (MultiWindowTextGUI. screen))
=> #'user/gui
(.startScreen screen)
=> nil
(.getFocusedInteractable gui)
=> nil

What does it mean to "make the reflection call yourself" ?

Something like this, only for MultiWindowTextGUI.

make the reflection call yourself

(require 'clojure.reflect)
(clojure.reflect/reflect com.googlecode.lanterna.gui2.MultiWindowTextGUI)

just to list what methods come up. it probably won't say anything too surprising, but it will at least let you know that the method does or doesn't exist

I would also check the class path to make sure that 3.0.3 is indeed the version that gets loaded.

one other thing that can happen if you're calling from weird threads is that thread's class loader isn't the right one. not sure if that applies here, but in your top level, you can do :

(def main-class-loader @clojure.lang.Compiler/LOADER)

(.setContextClassLoader (Thread/currentThread) main-class-loader)

I think clojure.core.aync handles a lot of those weird issues for you, but if nothing else is working, it's worth a shot

random shooting the breeze - I think as a community we under-utilize the fact that clojure code is data. Why spend so much time organizing code if code is data? Currently we view our (code/data) from only one perspective - file based. Maybe open multiple files. Jump around with stuff like `go-to-definition`.  But why do we constrain ourselves like that? Data science people have workflows designed around producing alternate views of the data. Maybe a tool that we are missing as programmers is a tool that looks at our code as data and re-formats it for our use based on the problem at hand? Does this even make sense? 😜

it makes sense, but there's a lot of inertia regarding text based source formats (editors, IDEs, version control, etc)

Interesting, I was also calling this within a go-loop, maybe that's the issue

Totally. Check out the end of @jimmy’s talk on Meander for a really inspired vision on this topic: https://www.youtube.com/watch?v=9fhnJpCgtUw&amp;m=7

ive not thought it through fully, but I don't think those are by necessity deal breakers. Storing code in the files is sensible (though unison may be an interesting alternative look - http://unisonweb.org). Perhaps it would be more clear if I put out an example... e.g.

(defattr :a {:t1 value
             :t2 value
             ...}

(defattr :b {:t1 value
             :t2 value
             ...}

maybe you want to see only :t1 for each attr. could be done by creating a view of the code

@goomba oo, I've seen that before. Forgot that he talked about this though 🙂

Ok, that seems to be the issue. So I can't call this method within a different thread?

you just need to set the thread's context class loader to match the clojure compiler's class loader

So within the go-loop call (.setContextClassLoader (Thread/currentThread) main-class-loader) ?

right

although, I thought clojure.core.async did that for you

which thread are you starting the go-loop from?

The main thread

But this doesn't seem to resolve it. I'll try creating a new thread normally

There have been many attempts to create something along those words. I believe some ideas originated from Engelbart and some things were even implemented in Xerox Alto. But it never had any serious traction. There are still undergoing attempts though, I know of http://www.andrewbragdon.com/codebubbles_site.asp and https://github.com/JJ-Atkinson/Fisher

oh, lol, that's my repo

I'm actually thinking about this as a feature for Fisher

not quite the same as code bubbles

Oh, oops. :D

Yeah, I get that. I just mentioned that because the overall concept is the same - being able to focus on something in particular, no matter what the "lens" looks like.

true. I guess I've been thinking along these lines for a while 🙂

IntelliJ IDEA has some interesting features as well that are somewhat relevant. Namely, analyzing data flow: https://www.jetbrains.com/help/idea/analyzing-data-flow.html But all such focusing/lensing/analysis goes out of the window as soon as there's anything dynamic going on. Even a simple (keyword n) would mess things up.

that's really cool

I am so lost, I had it working in the main thread, now this doesn't work anymore

(defn -main [& _args]
  (let [terminal (.createTerminal (DefaultTerminalFactory.))
        screen (TerminalScreen. terminal)
        gui (MultiWindowTextGUI. screen)]
    (.startScreen screen)
    (.getFocusedInteractable​ gui)))

Reminds me of https://futureofcoding.org/essays/dctp#d-is-for-denotative

how are you running it?

can you add:

(prn "thread: " (Thread/currentThread) )

The problem is also that not everything in a Clojure sourcecode file is data. ;; comments are not. Empty lines for separation are not. Neither is formatting.

@jatkin I guess. And you can go all the way to the pure lambda calculus. :) The issue is that any useful program written using lambda calculus would almost certainly be incomprehensible. So far it seems that practicality demands sacrifices that, in turn, beget other, indirect, sacrifices.

well... I found the issue

@zilti 3 possibilities. make comments data (metadata even?), enforce a standard formatting rule, and re-implement the original use of custom formatting by creating custom views of the code ... though if you are breaking a formatting rule it's typically a boutique case and maybe not possible to create general rules for

@p-himik yup

So I think there's some kind of special character in 1 of my example codes

I have 2, one works, the other doesn't, and they are literally equal

doh!

This is so stupid 😕

Thanks for helping out though. Can't believe I spent so much time with this

Yeah, a common case of "those two bytes just cost me 8 hours", quite frustrating.

I think I copied @p-himik code, which was pretty much the same as what I did, but his actually worked. Then later I must've copied back the bad text and it broke again

:bananadance:

I can't believe this 😂

Hidden space, great stuff. I guess copied from API docs or something. I have no idea

Thanks again, friends!

@jatkin What would you do when you want to, e.g. have a long map where the entries are aligned such that the values all start in the same column? Do you add metadata to the map?

I don't think formatting is that big a deal. gofmt let's go users not have to worry about formatting which seems like a good thing

I dunno. I kind of think formatting is a moot point most of the time. I'd like to see the editor try to maintain formatting rules to show to the programmer, and maybe when saving the file to git put the file back in the default formatting. Would allow each programmer to see code how they want, and not have tons of formatting clashes on the way out

I think the tougher challenges are around all the other tooling that expects files: packaging, making jars, version control, code editors, grep, etc.

When you require in a macro to a ns is that classified as load time?

right. I'm just wondering if it's possible (or, more accurately if it's useful), to use transformations to create views of our code for debugging or project exploration.

Does anyone have experience using Jib https://cloud.google.com/java/getting-started/jib to build Clojure containers for GCP? There's very little info online and the only example I have is for a lein project and none with CLI and deps.edn

These challenges have been solved basically. There have been languages in the past that didn't use files, but instead an "image". The one language today doing that I am aware of is Pharo. The code you see there is merely a serialization of the image / VM state.

Sometimes I wonder where we'll stop. At how many levels deep. After packing a VM into a pseudo-VM into a VM using a config file that's been generated by a config file plus a tool, in turn generated from another config file plus tool...

The original proof of concept for LightTable was focused on functions and call trees but when they tried it with focus groups, folks complained it was too hard/unfamiliar and wanted something more file-based... so really only the auto-eval/inline-results survived from that early concept.

When you load the ns that does the require, yes

Well, I guess some of the ideas of visualizing data in the editor did too (something that ProtoREPL offered for Atom -- but that's no longer maintained). Now folks are using REBL and Reveal alongside "regular editors" as a way to do that sort of visualization and data navigation.

I like the idea. I think all of the problems people have brought up so far (except for the text editor) could be solved by just saving all the code into 1 file. I think having multiple views is useful. These days even the worst editors, like one one in visual studio supports more than one "vertical view" (like emacs), and this sounds like it would be even better. Having project scaffolding with default view definitions that people can commit to the codebase would help with the on-boarding. One challenge is what properties should you automatically assign to a function/class/etc based on the view it is typed into? Could probably think of something reasonable, though.

As soon as we finally implement "Turtles all the way down". :)

I think what Pharo does is that you actively have to add a property/method/whatever to a class

Another challenge would be how to deal with imports/requires. You would need something way better than the stuff in Clojure, for example. I guess imports/requires would need to be global, and the way "`rf/dispatch`" expands to re-frame.core/dispatch being controlled by another view-like definition.

@zilti Hmm, wouldn't that mean your functions could disappear on you from your view if you forgot something? Seems like an easy mistake

Meanwhile, for our company, I've just created a short Ansible script that deploys the server. And all the CI pipeline for our project does is to build the project, scp it to that server, and send an ssh command to restart the service. I hope I can stay away from Docker for as long as possible

I was very excited about the early LT concepts -- I would have loved to try it out. It would have been interesting to see how it would scale to a really large code base. I think Clojure definitely could be a good target for an editor that treated every top-level form as a "thing" to be edited but there would need to be a huge amount of semantic support (ordering of definitions for the purpose of feeding them to the compiler/REPL for starters).

Well, there are just two ways to write code in Pharo, you either write and evaluate something on the "scratch pad" which just alters the image you are running; or if you want permanent code, you choose a class, then write the code inside it

@seancorfield That's the goal of Fisher. I've run out of time to work on it short term (startup is starting to get into sell mode :P). I plan to possibly monetize it and get a team together. Dunno, would need a proof of concept though before I do all that.

just looking over the readme sounds very cool (and a lot of work 🙂 ).

yes 🙂

Hey guys, weird error happening here: I've got a ring based app, deployed as a datomic ion behind an AWS API Gateway that acts as lambda proxy as described here: https://docs.datomic.com/cloud/ions/ions-tutorial.html#lambda-proxy It works so far, but when i enable ring/ring-defaults with the following config {:session true} the AWS Api Gateway (not the app itself) crashes with: Execution failed due to configuration error: Malformed Lambda proxy response However, I double-checked and my ring-reponse seems still valid. Any ideas on how to tackle this problem?

What would be the closest thing to Scala futures in Clojure? Core async? Is it as performant?

how can i import a nested enum? https://github.com/apache/mina-sshd/blob/master/sshd-common/src/main/java/org/apache/sshd/common/session/SessionHeartbeatController.java#L36 i'm trying [org.apache.sshd.common.session.SessionHeartbeatController $HeartbeatType] but its not finding a class there

its an enum of an interface

[org.apache.sshd.common.session SessionHeartbeatController$HeartbeatType] is apparently it. I thought we could import nested classes but i guess we can't

you can, that is the name of the class

[org.apache.sshd.common.session.SessionHeartbeatController $HeartbeatType]?

Someone mentioned Pharo in the thread, thought you’d like this: https://gtoolkit.com/ I think this app may give you some ides @jatkin

yup, thanks

@joservarelaf It's actually really really cool. I'm gonna have to dig into this a bit 😉