Morning

måning

Morning

If somebody could contact the management and get them to turn up the thermostat for the UK that would be ace rn

morning

morning

Bore da

...and companionable morning shivers to you as well!

Morning

morning. re otform a cpl days ago: just got off my bike. wasn't that bad actually

what part of the world do you live in?

Well I got a strange not-sure-if-its-100%-true feedback from my Strictly blog post. Twas a comment on FB, “I’ve just bet my house on this.” Then a DM from a friend, “Chances are he’s bet the value, he’s the director of Aston Martin” 🤢

So glad I put that disclaimer in now.

only bet the houses that you can afford to lose

exactly

that is what I always do.

Monopoly houses don’t count @thomas

but those are the only houses I own!!!

lol

and the utilities as well.. I like those!

haha

Morning 🙂

Morning All 🙂

Anyone got a good recommendation for a primer on Java Interop with existing libraries..? I am not well versed in the Java ecosystem / toolchain but I want to figure out how to reference / depend on a library I've found and figure out how to use the bit I am interested in which is reasonably deep inside the object hierarchy

well ideally you’d only be using bits from the API layer of the library, if you’re rummaging in the internals then that might not end well

actual syntactic level Java interop is pretty straightforward (unless you want Java 8 lambdas or varargs method invocations) probably start here: https://clojure.org/reference/java_interop

are you just wanting to pull some data out from an object hierarchy @maleghast ? you can go a long way by hiding the java objects in a record or deftype and accessing with a protocol and a sensible clojurey api - converting to/from clojure structures to java structures in the protocol impl as required

@ben.hammond ldn

'exciting' place to cycle

@peterwestmacott @mccraigmccraig - I may be explaining badly (due to extreme Java ignorance) I want to be able to import the right bit of the library to use the following bits: http://icu-project.org/apiref/icu4c/classRuleBasedNumberFormat.html

There seems__ to my Java ignorant eye to be a lot of OO hierarchy “above” the bit I want, but I may be misunderstanding what I am seeing

uh, that doesn't look like java @maleghast?

Main page says C++/C

all those virtuals and & reference params would lead me to guess c++

yeah, the include kinda gives it away

#include <rbnf.h>

I appear to have gone down the wrong rabbit hole in my haste - there is a Java implementation - ICU4J

Hold on.

http://icu-project.org/apiref/icu4j/com/ibm/icu/number/NumberFormatter.html

Apols

ah 🙂 is that for internationalisation?

Amongst other things…

But mostly, aye

There is a specific use-case I am finding myself interested by right now__ but I am also thinking about I18n

🙂

so are you trying to use the NumberFormatter?

Sorry, this one

http://icu-project.org/apiref/icu4j/com/ibm/icu/text/RuleBasedNumberFormat.html

a subclass of NumberFormatter

@maleghast: that looks pretty straightforward from an interop perspective. The most exotic thing there are probably the multidimensional arrays for localisations

if you don’t care for the arrays just call seq on them

Yeah, that’s reassuring, thanks 🙂 Having next to no Java experience (and all of it being over 15 years old) I just don’t know my way around the Java ecosystem, so I get a bit “deer in the headlights” about how to interop and what I need etc.

@ben.hammond haha i was "trained" for city cycling in Budapest in the 90s and early 2000s. some drivers were explicitly hostile. ldn is an easy ride so far, touch wood.

@peterwestmacott has just done a very good job of demystifying it for me, so I think I know what I need to for now… 😉

some maybe helpful snippets:

(ns foo.bar 
  (:import [com.ibm.icu.text RuleBasedNumberFormat]))

;; creation probably something like

(RuleBasedNumberFormat. RuleBasedNumberFormat/SPELLOUT)

(btw I have no idea what that class does… haven’t read any of the text docs)

🙂

Thanks very much @rickmoynihan

@rickmoynihan @peterwestmacott - Thanks both very much - nailed it.

🙂

easy in the end then?

Yeah. Your help and Peter’s basically demystified the “what’s the magical incantation” aspect of my Java-n00b paralysis and then it was easy-peasy. Thanks very much indeed

Great… I can appreciate its a bit daunting if you’ve not done java, but there wasn’t much in that class that was exotic in terms of interop… main things were the multi-dim arrays (but you may not need to use those), the class level constants, and probably the difference between string and StringBuffer… FYI str on a StringBuffer will convert it back into a string.

more difficult things to interop with are java 8 lambdas, java vararg methods, and libraries that require you to subclass existing classes. Most of those are also perfectly doable too… just require a bit of boilerplate… the problem comes when you have to do a lot of the more exotic interop; in which case you might just be better doing it in java; and presenting a cleaner java interface for the clojure code.

Anyway I’ve done a lot of quite complex interop over the years; and I think there’s only once when I bothered myself to write 408 lines of java.

though IIRC the IDE wrote about 350 of those for me

@maleghast I always look at the Clojure library for anything first, if I see it’s just wrapping a lot of Java code then I’ll make the decision to just interop the part I need. If it’s a convoluted API (naming no names Google Analytics and Google Search Console) I’m happy to shiv the whole thing in to the project in a java-src folder and call it from Clojure.

@jasonbell - The first bit of what you just said definitely makes sense and I did have a more than brief look around for a complete Clojure implementation / wrap-up of ICU4J, but I couldn’t find one… The second bit of what you said there has plunged me back into n00b-space / imposter syndrome territory as I wonder what the hell what you are saying would actually entail… 😞

Must go hunt lunch…

@maleghast I can show you at ClojureX

it’s easier to explain that way

Sounds good - thx @jasonbell 🙂

A pleasure

@jasonbell do you mean copying the whole library source into java-src or putting a thin wrapper of your own in there?

usually putting a thin wrapper of my own in there

😌

Depends on the project, time, budget etc

yeah that’s what I meant above.

I don’t want to spend three days trying to figure something out when I can spend two hours shivving it instead 🙂

Agreed. lein is remarkably good at building java code too… the only disadvantage with that approach is that to write that java you can often end up forgoing java IDE tooling… which is fine if its a few lines, but if its bigger your IDE may want its own project files etc… though you can to some extent mitigate those issues by creating a pom.xml from lein and pointing the IDE at that.

@rickmoynihan Oh if it’s all going to hell then I’ll crack open an IDE and do the Java bits first, then copy the source and the maven repo locations. 🙂

Though I’ve seen myself to that less and less now.

ditto

eitherway I think the tools actually work quite well here… i.e. you can make do with less tools when its small… and when its a bigger (going to hell) you can scale up - but take on the extra cross project pain.

basically you have enough options to manage it sanely.

Agreed. Never had any really big issues. Lein has done most things I needed it to without any fuss at all.

We've got a number of shims wrapping Java stuff for ease of use

Mostly Kafka and AWS SDKs

I caught myself using as-> where I would have previously used a partial today

(it is always a bit scary that everyone can see into the guts of what we do every day in the sausage factory https://github.com/MastodonC/witan.send/pull/114/files )

@carr0t - You don't use Amazonica?

(For AWS SDKs I mean)

We do. We wrap it to provide nice core/shell, compositional structures etc for the bits we want to use, so that people don’t have to know the internals of a dynamodb request to build one, for example. Or the response to get the objects from it. And we do lazy sequences under the hood where pagination is required, so our apps don’t have to worry about it etc etc

But Amazonica is big. Really we should just pull in the bits we need, but we pull in the whole thing in our dynamo lib, which is far more than we actually want

Now that I think about it more, we probably don’t have any Java interop in there, just in lib-kafka

Having the Kafka required bits in shims makes sense

Amazonica is black magic though. It seems to auto generate everything. I wonder how fast it’ll be able to support the 2.0 SDK

The most of Amazonica I use is mainly for S3 things.

A question for everyone - who would you like to see as a keynote at ClojureX 2019. Please add suggestions as a thread.