The Nineteenth Byte

10:00 PM

@RedwolfPrograms M. Licinius Crassus impostor est -Graffiti found at Pompeii, probably

reminds me i have a class that made us use java beans event listener based model-view-controller architecture with models that are literally stateful wrappers around pure functions

user

I have no idea what any of that means lol

Unrelated String

i don't either

user

lol

Unrelated String

that whole thing just felt like a fever dream

user

10:01 PM

Why add stateful wrappers around pure functions?

Unrelated String

also we had to use a shit ton of... settable singleton factories

i feel like that defeats the point of a lot of things

like that's literally just a thunked global variable

the thunking wasn't even mandatory just encouraged

...is it a proper thunk if you have a hand implemented lazy initialization actually

probably not

user

If you want it lazyish, I think you can do something like:

Unrelated String

what we did was initialize a field to null then set it to what we actually want if you try accessing it while it's null

but then there's also a static method that lets you set it to something else which we actively used

the funny thing is this is a class about programming language concepts, where presumably we're looking at all this wacky java design pattern stuff to understand what motivates it, and the lectures are pretty good at exploring the motivations but the assignments... aren't

also i think the class is expected to not know that java has lambdas and method references because there's one place it seemed like we were supposed to use an enum or something to factor common logic out around processing data with two different methods and the assignment just said "you'll see a more elegant way to do this when we get to sml and lisp" like this literal 500 level class full of senior undergrads and actual graduate students has never heard of first-order functions before

user

class Singleton {
  private static class Holder { static Singleton INSTANCE = new Singleton(); }
  public Singleton getInstance() { return Holder.INSTANCE; }
}

DLosc

O_o

user

10:12 PM

@UnrelatedString :o

Unrelated String

i think i've seen that version before but i think it was when i was looking up singletons on wikipedia lol

user

@DLosc That was supposed to be a reply to my previous messages. If you don't care about laziness, then an enum should do:

enum Singleton {
  INSTANCE;
  //other stuff
}

DLosc

@user I must be reading it wrong, but it looks like a Singleton contains a Holder which contains a Singleton which contains a Holder which...

Unrelated String

i think we were just doing conceptual singletons as a shitty excuse to use factories when the problem as presented can't motivate factories

@DLosc the holder is static

er

user

@DLosc Singleton objects don't contain Holder objects, the static means that only one singleton instance is made, and Singleton doesn't have a Holder field at all

There is no instance of Holder ever created

Unrelated String

10:14 PM

actually i don't know what the fuck a static class does but the singleton is a static field of the holder

(which yeah is ofc never instantiated)

DLosc

I gotta say, I like Scala's object a lot better

user

A static nested class is the exact same as a non-static nested class for our purposes, it's just that it can be used in static methods

DLosc

(Assuming that accomplishes basically the same thing)

user

@DLosc Me too, although I like how Kotlin puts the companion object stuff inside the class itself

@DLosc Well, Scala creates an extra class for that companion object too, and that object is an actual object, unlike a static class that you can't really pass around. You can take that as an advantage or a disadvantage

@user *public static Singleton getInstance, not public Singleton

DLosc

Python can do singleton types, but you have to mess around with __new__ and it just feels hacky (assuming there isn't a better way to do it yet)

user

10:17 PM

It does have enums, right?

Redwolf Programs

My school tried to save money by using some really weird contrast settings when printing our student IDs

Unrelated String

@UnrelatedString oh yeah there was also some constraint on when we can initialize a scanner for reading stdin to cooperate with the unit tests but we actually weren't encouraged to use a singleton-enforcing factory for that, despite that being something that actually does motivate a singleton-enforcing factory

user

I kinda like how JS has really straightforward object literals

Redwolf Programs

@RedwolfPrograms It's not good

DLosc

@user Python? Not that I know of.

user

10:18 PM

Not built-in, but there's an enum class or smth

Redwolf Programs

@RedwolfPrograms Unfortunately I can't show y'all a picture, because that'd be a really efficient way to leak personal info :p

Unrelated String

like
he literally told us that we have to initialize it after some other thing
and that we have to not initialize multiple scanners
but then gave some example code that uses a static variable in a method or something
like why

user

A static Scanner? They need to build a tenth circle of hell for him

DLosc

@user TIL

I wonder if it's worthwhile to use that in any of my code

rak1507

no

dictionaries are just as good

Unrelated String

10:22 PM

@rak1507 it's just a completely orthogonal use case

a dictionary is for if you need to get values from names
an enum is for if you need names that just so happen to have values

Redwolf Programs

Dictionaries, objects, enums, arrays, numbers, dogs, cats, all the same thing

user

@rak1507 I prefer thesauruses, I can instantly ~~make~~ cause ~~myself~~ I personally ~~sound~~ flawless ~~more~~ also ~~smart~~ agile

4

Redwolf Programs

We should be more like JS

rak1507

@UnrelatedString d['name'] vs enum.name

DLosc

Like for example in Pip, operators have an associativity, which right now is one of the three strings "L", "R", and "C". That seems like a classic use case for an enum. I'm just not sure it's worth the effort to switch.

Unrelated String

10:26 PM

it at least feels cleaner to pretend you're using c or haskell style enum types regardless of whatever python jank is actually happening

user

I would say it is, because enum names can be resolved by a linter, whereas strings can be mistyped

Also ^^

Unrelated String

^^^

user

But if you're using a dynamically typed language, you're a masochist anyway, so feel free to screw yourself over and use dicts instead

(/s)

Unrelated String

/hj

DLosc

@user Huh, TIL :P

Unrelated String

10:28 PM

i hate how no matter how much i'm continually growing to dislike python it's still the language i default to using

user

Well, it's really nice for small stuff

Unrelated String

that is true

(usually)

Aaroneous Miller

Switch to PHP, I hear it's fantastic.

Unrelated String

true

user

If someone told me to write a quick thingy to parse HTML, I'm not going to bother cracking out Java or even Scala

DLosc

10:29 PM

s/ for small stuff//

user

Eh, for people like me who make lots of mistakes and are bad at testing, statically typed languages (with actually good type systems) are much easier when you have bigger projects

Unrelated String

reminds me i really need to get on that making a language to do advent of code in project i kind of forgot it's already october

Redwolf Programs

I feel the same way with JS, although I mostly grew to hate parts of it all at once and now it's just sort of been the same level of okayness for the last two or three years

user

Redwolf has Stockholm Syndrome

Aaroneous Miller

@user yeah, it's much easier to just pull out some regex.

Unrelated String

10:30 PM

even if you're good at testing and don't make many mistakes it just feels good to statically know how little you've fucked up

user

@AaroneousMiller ikr. import re; re.match(... ftw

Redwolf Programs

JS is bad, but once you know how it works it just...works. There's not too much jankiness, compared to languages like Python.

It's not great for the first few years, but once you're used to it you get pretty fast at working around its issues. That's true for any language I guess, but JS's are just a bit less of an obstacle I think.

user

But 0.00000001% jankiness is better than 0.001% jankiness. Even something to transpile from a statically typed lang like TS is nice

Aaroneous Miller

May 27 at 14:42, by Redwolf Programs

Python takes you on a date, talks to you for a while, and its issues slowly start to show up. JS shakes your hand, punches you in the face, and then is fairly normal from then on.

user

@RedwolfPrograms Taking a few years to get around jankiness does not make for an okay language imo

@AaroneousMiller That's somewhat accurate, except JS continues punching you after that from time to time, just when you least expect it

Redwolf Programs

10:33 PM

Idk about that

DLosc

@user I have really come to appreciate the way that a statically typed language like Scala lets the IDE tell you exactly what type any variable is and what member functions it has. I just can't get over how much darn setup there is before you can run a simple Hello World program! (And how long sbt takes to start up each time.)

Unrelated String

reminds me i have never actually used typescript but on paper i like the idea a lot more than type-hinted python

user

@DLosc Oh yeah, that is annoying

Unrelated String

like type-hinted python just feels wrong

user

@RedwolfPrograms My nose is bloody

Although you seem to have faired better

@UnrelatedString Cython looks weirder

Redwolf Programs

10:35 PM

Tbf JS is my native language, so its jankiness is just sort of the default for me

DLosc

@RedwolfPrograms See, I would've said JS is way jankier than Python.

user

Mmm, I wonder if Java's jankiness is just the default for me and I'm missing obvious flaws

Redwolf Programs

Well, not as much subtle jankiness

@user You are you are you are you are

user

What am I missing?!

Redwolf Programs

It's so baaaaaaaaaad

user

10:36 PM

Oh this is just the "JAVA bad" meme

Unrelated String

type-hinted python is just a dynamically typed language larping as a statically-typed language, ultimately combining the problems with both for marginal benefit

Redwolf Programs

@RedwolfPrograms Well, half of that might just be OOP

I'm really not a fan of OOP :p

Unrelated String

java's approach to oop is crufty but honestly not a problem once you've written enough code that the boilerplate is proportionally small

user

@UnrelatedString The worst is when you have a type hint referring to the class you're defining it in, so you have to say class Foo: def bar(baz: "Foo") ... to avoid it crashing

@RedwolfPrograms I think OOP is a very nice and intuitive paradigm, although I don't like that Java forces you to put everything in a class

Unrelated String

i do hate some stuff about java typing but it's honestly not a bad language

yeah

user

10:38 PM

Static methods and variables feel like odd workarounds to ^^^

@UnrelatedString I like how regular it is - it's a really easy language to teach beginners despite the static typing

Unrelated String

yeah

DLosc

@user Definitely. I don't know if it's a flaw or not, but any time y'all mention "factories" my eyes glaze over. I don't even know what that is, but every other language I've learned gets along fine without it, so to me it just sounds like jargon for the sake of jargon.

@user And that

Unrelated String

i feel like java doesn't deserve its place as The Language To Teach People but it's still good for teaching

user

@DLosc ¯\_(ツ)_/¯ fwiw, I don't understand design patterns either, I assume it's the kind of thing you get used to after some professional experience, similar to Haskell programmers being unfazed by functors and gonads and stuff

@UnrelatedString Yes, it should be Scala.

Unrelated String

i feel like design patterns probably make sense in context

true

user

10:41 PM

I agree, I just haven't used them much (well, not knowingly), and I get mildly uncomfortable around them

DLosc

@UnrelatedString I agree. There's no reason to use type hints in a perfectly good dynamically typed language. :P

Unrelated String

...i think that time i was looking singletons up it was because i was wondering if there's some particular reason they actually need to exist and i think i did actually find that there are arguments against them

DLosc

Now, I will say that if Python had type-based function overloading like Julia does, that would be cool.

user

Groovy

has type-based method overloading at runtime, I mean. Multimethods or something, they're called

Unrelated String

neat

user

10:43 PM

Why am I speaking like half grammatically correct Yoda?

DLosc

Mysterious, the Force is

Redwolf Programs

I'm mostly not a fan of teaching Java to new programmers because, at least to me, it feels like it's a language that died long ago and is only still being used in corporations, like Fortran or COBOL. Plus, it's still a little low level compared to JS or Python, and I could see that getting in the way of learning.

Aaroneous Miller

@user It's "Vyxal Bad" but without making us Vyxalers sad

DLosc

The things I ended up disliking about Julia were 1) it puts all those overloaded functions in the global namespace together, so it becomes nearly impossible to sort through the 138 different definitions of + to find the one you want, and 2) you can write code at the top scope but it's way less efficient or something? I don't remember the details.

user

@RedwolfPrograms I wouldn't call Java low level at all, and it certainly isn't dying, although there are more modern languages out there

Besides, programmers work for corporations, and there are probably more jobs for Java programmers than there are for Fortran or COBOL programmers

DLosc

10:48 PM

@RedwolfPrograms Fun fact: Java is four years younger than Python

Unrelated String

@DLosc i feel like with stuff like arithmetic operators especially there's something wrong if you're actually overloading them instead of making them work with some kind of interface or typeclass

user

What's wrong with (static) overloading?

Redwolf Programs

@user Well sure, because Java's newer. But it seems like it's very clearly going down the same path. And sure, it's not low level compared to C, but having to deal with types and C/Java sort of arrays seems like something that would just get in the way of learning.

user

CMP: Best language to teach new programmers?

DLosc

@UnrelatedString I'm not 100% sure what that means... example?

@user QBasic /ohj

user

10:50 PM

@RedwolfPrograms That's the fault of Java courses - real life Java (afaict) doesn't involve that kind of low level stuff

Redwolf Programs

Types and arrays?

user

Arrays

Redwolf Programs

Please don't say ArrayList (shudders)

user

I'm on a robotics team, and even when for the math-intensive methods, we rarely have to do anything "low-level"

DLosc

@user But in all seriousness, probably Scratch (though I haven't tried it myself).

user

10:51 PM

@RedwolfPrograms Why not? They're perfectly good

Redwolf Programs

hahahahahahahahahhahahahahahahahahhaha

hahahahahahahahahahahahahaha

user

@DLosc Ooh yeah I heard it had some new features

Unrelated String

@DLosc like, you could have an Addable interface/typeclass for things you can add and actually no that would restrict the kinds of addition you can define so yeah overloading is fine lol

Redwolf Programs

hahahahahahahahahahahahahahahahahahahahahahah

user

You've convinced me with those arguments, imma turn all my Java into JS now :P

@UnrelatedString Isn't that kinda overloading?

Redwolf Programs

10:52 PM

Having to use .get/.set to access into all of your arrays is horrible

rak1507

@DLosc definitely disagree

Unrelated String

it's polymorphism without overloading

rak1507

JS/python/basically anything are sufficiently beginner friendly

and not completely unrealistic + shit

user

@RedwolfPrograms So? You don't have to do it that often

Most of the time, you just iterate over it

Redwolf Programs

Yeah you do...that's literally what you do with arrays

user

10:53 PM

Not really

Redwolf Programs

Does Java seriously not have a way to customize that sort of thing?

user

A lot of our code that does use arrays/ArrayLists looks something like this:

Unrelated String

yeah it sucks that java doesn't let you use square braces for containers that aren't arrays when you do not want to use arrays

Redwolf Programs

If it lets you make 2+2==5 it should really let you do something as simple and useful as that

user

for (var subsystem : subsystems) {
  doTheThing(subsystem);
  asdfasf;
}

Operator overloading would be amazing, but the Java people thought it'd be abused ¯\_(ツ)_/¯

Unrelated String

10:54 PM

and == is reference equality so you have to use a .equals() method which just leads to drowning in parentheses

that is true

user

I really wish I could use Kotlin or Scala for everything, but apparently Kotlin is considered a difficult language to teach so that idea got shot down :(

Unrelated String

:(

Redwolf Programs

But when you're teaching someone a programming language, you can't do everything the easy, nice looking way at first

You have to .get and .set and do weird stuff all the time

user

True

DLosc

@user I'll add that to my list of reasons not to like Java, then. Operator overloading is the best part of OOP.

Unrelated String

10:55 PM

...i'd say i have no idea how kotlin could be difficult to teach but i actually haven't seen anything it has outside what i learned in the koans a month or two ago lol

user

@RedwolfPrograms How often do you need to index into arrays/ArrayLists and mutate them?

Redwolf Programs

All...the...time

user

@UnrelatedString I assume the explicit null checking might be a problem for some, but the flow typing and type inference is glorious

Redwolf Programs

At least in JS, I probably average a couple of array indexings per line

user

@RedwolfPrograms ???

You're serious?

Redwolf Programs

10:56 PM

Yes

user

Oh wow

Unrelated String

i do feel like you can mitigate the need for overloading if you just make it easy to have new operators

user

I guess web development just requires different stuff then?

Unrelated String

and/or general infix function syntax

DLosc

@UnrelatedString Does Kotlin do that? That's a cool feature I've often thought about, but not one that's in any language I know.

user

10:57 PM

I'd like to point out that Java has amazing IDE support in IntelliJ (I know JS does too, but static typing gives Java an edge here) so a lot of stuff is auto completed

@DLosc No, but Scala does :)

Redwolf Programs

If you have to rely on your text editor to write and understand your code for you the language is bad

user

Kotlin does have operator overloading

@RedwolfPrograms Why?

DLosc

@user =) Well I am looking forward to reading about that!

Redwolf Programs

@user We might as well write directly in machine code...

user

This is 2021, you expect people to use ed now? :P

@RedwolfPrograms wut

Unrelated String

10:58 PM

@user i feel like most people should be much happier with explicit null checking and nullable types than with getting the infamous java nullpointerexceptions out of nowhere when they probably don't even know what a pointer is

DLosc

@user No, vim, of course :P

Redwolf Programs

The whole point of programming languages is to represent code in a way that's human readable

user

@UnrelatedString Yes, but it's a hindrance to beginners. Rust's borrow checker is nice, but I keep fighting it

Redwolf Programs

If you need an IDE to do that for you, the programming language has failed its #1 task

Unrelated String

lol

i need to get around to learning rust

DLosc

10:59 PM

@UnrelatedString I don't remember much C#, but I remember really liking the nullable types and the ?? operator

user

@RedwolfPrograms And Java is readable

Unrelated String

maybe i'm just open to nullable types because i spent some time playing with haskell's Maybe

Redwolf Programs

@user I'm going to stop arguing this because I've just realized how entirely subjective this is :p

user

A language isn't just its syntax, it's also the libraries, the IDE support, the community

@RedwolfPrograms So many things are subjective that it's just pointless to argue anything :(

DLosc

@RedwolfPrograms [insert astronaut meme] Always has been

Redwolf Programs

11:00 PM

@user Yeah, but I have a feeling if I'd started with Java and you'd started with JS, we'd be arguing for the oppposite positions :p

user

@UnrelatedString Oh yeah, I just looove foo.flatMap(_.fold("")(_.toString).find(asdf))

@RedwolfPrograms I started with JS :P

Redwolf Programs

D:

Traitor

DLosc

Uh oh X^D

user

Just a really crappy subset of JS in a crappy editor (Khan Academy)

Or maybe it was just an older version of JS

Redwolf Programs

Oh, I need to go do some math homework that's a month late. See y'all o/

Unrelated String

11:01 PM

i think i started with js on fucking w3schools lmao

user

I tried moving the JS from the editor into an HTML file and literally nothing worked because Khan Academy was just weird

DLosc

@user It is true that JS has gotten way more usable over the past 10-15 years.

Redwolf Programs

JS has improved massively in the last decade, keep that in mind

ninaj;d

user

Yeah, as has editor support

Unrelated String

ninaj;d

user

11:02 PM

I still much prefer Scala or Kotlin, though

Redwolf Programs

I was trying not to get my ninaj ninja'd

So I typed a little fast and...

DLosc

;d

Unrelated String

truew

i make so many speed typos i just found ninaj;d especially funny

likje one time i was typing lmao and it came out as lampo

user

@DLosc docs.scala-lang.org/tour/operators.html btw (and Kotlin)

Unrelated String

it's been my nickname on a discord server ever since

DLosc

11:04 PM

@UnrelatedString The little-known fifth Marx brother

@user Scala syntax >> Kotlin syntax, IMO

user

:P

Perhaps you mean Scala syntax >>>>>>>>>>>>>>>>>>>>>>>>> Kotlin syntax

DLosc

I much prefer being able to define a function + (or maybe operator+) instead of a function with some name that doesn't contain the operator symbol that I then have to remember. That's one thing I dislike about Python's operator overloading.

user

^

Unrelated String

wait do you not have to actually declare new operators
and fixity is just like implicitly derived from the symbols you use
thjat's neat

Redwolf Programs

^^^

Unrelated String

11:09 PM

@DLosc i can NEVER remember the name of python's dunder for indexing

i hate it

user

Even Scala does this, to some extent: the apply method just automatically overrides the "function application operator" (if you can call it that). I wish you had an annotation or something like @thisFunctionOverrides() or smth

Unrelated String

is apply not from a callable interface or something

DLosc

@UnrelatedString Uhhh.... X^D I want to say it's __get__ and then __set__ for when it's an LHS, but I'm not 100% confident

user

@DLosc otoh you can just look it up, since you probably don't need it too often

Redwolf Programs

JS does operator overloading in a very peculiar way

Proxy

it's scary

Unrelated String

11:10 PM

@DLosc i feel like the word item is in there... probably

DLosc

Oh, right

Wheat Witch

@UnrelatedString Neat, but also horrifying.

user

@UnrelatedString Nope, so that you can define your own "polymorphic functions" in Scala 2 and stuff

Unrelated String

wack

user

@WheatWitch idk about horrifying, but it is annoying for DSLs and stuff. Does make parsing easier, though

@UnrelatedString ¯\_(ツ)_/¯ It's quite handy when you want to define a constructor-like method, I just don't like the way you "override" that "operator"

Redwolf Programs

11:12 PM

One thing I dislike about operator overloading is the people who use it when it really shouldn't be used

user

Oh yeah

But you could say that of a ton of features that can also be handy

Unrelated String

@user sometimes you want to just pass indexing as a function and it's hard to want to just write a lambda that uses the square brackets syntax when you know there's a method you can use directly and it'll only take five minutes to look it up

Redwolf Programs

Unless you're making something that replaces or upgrades a built-in class that uses that operator, I don't think you should use overloaded operators

Unless it just really makes sense

user

@UnrelatedString Oh right, Python lambdas are kinda annoying, right?

Redwolf Programs

Looking at you, cin/cout.

Unrelated String

11:13 PM

i'm not sure how they compare to other lambdas but i don't love having to write out the word lambda

user

@RedwolfPrograms They can make life easier (although cin << and cout << are weird, they could've been methods/functions/whatever)

Redwolf Programs

It just feels so unnatural and arbitrary

user

Wouldn't it be cool if every concept in every language had to be accompanied by the longest and most unintuitive mathematical name for it one could find? /s

Redwolf Programs

Why not just input() and print()

Unrelated String

i like how the c++ stream syntax encourages chaining but it still feels kinda superfluous

user

11:14 PM

Oh, that kinda makes sense

Wheat Witch

List a is just the free monoids generated by a.

Isn't that so much clearer!

Unrelated String

i really need to learn actual category theory

DLosc

@user So wait, how does the Scala parser know that some random identifier that I defined somewhere is now an operator?

user

It doesn't?

It determines the fixity solely based on the first character (and if the last character is :, it's right-associative). That makes life easier for the parser because it doesn't have to resolve other stuff first

Unrelated String

i'm in a semantics class and i keep thinking about how a category-theoretical semantics might handle context and quantifiers and then i realize i don't know category theory

Wheat Witch

11:17 PM

(monoids aren't strictly a ct concept btw, they are originally from abstract algebra, but they fit neatly in with ct)

user

@UnrelatedString Just mumble something about "a monad of A is just a monoid in the category of endofunctors of A with product replaced by composition" and you'll be fine

Unrelated String

@user it also makes it easier for a human to read an expression with user-defined operators if they can intuit the precedence and associativity without having to know what the operators do or reference their declarations

DLosc

@user Maybe the page you linked isn't giving all the details, but it says "You can use any legal identifier as an operator," and then it gives an example where and is defined as a method of a class and immediately used as an infix operator...?

user

@UnrelatedString True

@DLosc The parser doesn't need you to define and at all, though, it'll still parse it correctly. The compilation error will just come later when it can't resolve and

DLosc

So if I write an expression x y z, the parser will assume y is a binary operator?

Unrelated String

11:21 PM

compare haskell operators where you can usually guess precedence within a class of related operators based on what's most useful but then you want to use >>= and <$> together and sit for a minute wondering how that works

user

@DLosc Yup. It treats that as equivalent to x.y(z)

DLosc

Interesting. Does that just work for binary operators, then? Because if it also works for unary operators, then w x y z would be ambiguous

user

@UnrelatedString >>=<$>, easy. You got any harder ones? :P

Unrelated String

true

user

@DLosc You can't define unary operators like that, they're special. They have the same problem you dislike about Python: you have to define methods called unary_!, unary_~, etc. You can't make any identifier a unary operator, which I think is a good thing

I kinda dislike unary operators in general, despite their usefulness

Unrelated String

11:24 PM

yeah

Wheat Witch

Are y'all familiar with how Agda does operators?

Unrelated String

nope

user

It scares me

DLosc

@user Proposal: replace all unary operators with a single binary operator that performs different operations on its right operand depending on the value of its left operand /s

Wheat Witch

You define them with slots, so you basically can just make new syntax.

DLosc

11:25 PM

@user Well that's too bad

Unrelated String

neat

Wheat Witch

Syntax like if x then y else z is user definable in Agda.

The one issue is that this method requires separating tokens by spaces.

user

@DLosc However, since it has been previously established that you are masochist, you will have -language:postfixOps enabled, which means that w x y z will be parsed as w.x(y).z. But! If the next line has another a, it will be parsed as w.x(y).z(a). But! If there is another blank line or ; between w x y z and a, it will be parsed as w.x(y).z and then a, separately. I swear, Martin Odersky must've been drunk when he put that feature in

@WheatWitch That doesn't sound terrible, though

The fact that you have this much power is kinda scary. How is a human to remember so many fixities and stuff?

Wheat Witch

Yeah, it sucks a bit for code golf, but really it's quite reasonable.

DLosc

@user I may be a masochist, but I'm a picky masochist. That doesn't sound like my type of fun. :P

@WheatWitch I don't know much about Rebol, but I think it has some capabilities along those lines (and also requires space-separation).

user

11:29 PM

@WheatWitch How exactly do you define if without if? Pattern matching?

Wheat Witch

Yeah pattern matching, case switching etc.

user

Interesting

Wheat Witch

Agda doesn't really have if in the way other programming languages do. It's just a part of the standard library.

user

nvm I'm not making any sense

DLosc

@WheatWitch I love it when a language has a tiny core and can implement everything else as library functions. ^_^

I guess it's a bit like building up mathematics from a small set of axioms, isn't it?

user

11:32 PM

@WheatWitch btw, may I ask why?

Wheat Witch

I am not a fan of it's eager evaluation, I like type erasure, and I don't really like it's universe model.

user

Does Agda have type erasure?

Unrelated String

oh yeah i forgot how much i love type erasure

user

Java's type erasure is different, isn't it? It doesn't do monomorphization or whatever so you can't have two methods with one taking a list of strings and another a list of Files

Wheat Witch

Java doesn't really have type erasure.

user

11:38 PM

Does Idris have a different definition of type erasure?

Unrelated String

yeah i had no idea java even had something resembling it
i'm pretty sure java has all kinds of type at runtime

Wheat Witch

You can get type errors at run time in Java.

user

Oh, you mean like not having any type checking at runtime?

Yeah that sucks (getting ClassCastExceptions, I mean)

Wheat Witch

I've had an issue where Java would erase my type signatures, then infer the wrong type and have a type error.

user

Also the fact that arrays are covariant-ish in the type system but invariant at runtime so everything crashes and burns

Unrelated String

11:40 PM

@WheatWitch what

user

@WheatWitch I think you mentioned this once before

Wheat Witch

2

Q: Can I give a generic function the correct type information?

I have a bunch of class properties that are initialized in a somewhat complicated but very uniform way. Since it is both error prone and a pain to maintain about 10 copies of this code I would like to abstract this. Here is what the code looks like for setting one property: if ( userConfigMapPat...

user

ninja'd

Wheat Witch

I believe that Agda can be type erased, I don't know if the most popular instance is.

But sort of oddly the possibility of being type erased is more important to me than the practice.

Unrelated String

yeah

user

11:44 PM

@WheatWitch May I ask if there's some reflection magic going on behind the scenes?

Are you using some kind of compiler plugin?

Because if there's a cast to some type parameter in there, then that should just be erased, and you can't instantiate something with a type parameter either, so you'd need a Class object or something, right?

Wheat Witch

No compiler plugins.

user

If you're using Jackson, could this help (if you're still using that code)?

Wheat Witch

This is not like an intentional thing where I want to show off how to break Java. It was something I actually encountered at work.

I am (fortunately) no longer on a team using Java.

user

:)

It's so bizarre that UserConfig and other types aren't erased when you use them directly but are when you give them as type arguments

And this isn't even some obscure library, it's a popular one that should just work

Transcript for