dev-general

[prisma wave]

lmao

[old wyvern]

Maybe we can replace that with another symbol?

@?

[prisma wave]

yeah

hmmm

add : Add a @ a -> a -> a

[old wyvern]

hmm

[prisma wave]

@ could also be used for pattern matching if we're copying taking influence from haskell

[arctic juniper]

https://github.com/haskell/haskell-language-server
hls is this, right?

[old wyvern]

how do you mean?

yes vr

[prisma wave]

case x of -> 
  r@Record(a _ _ ) -> putStrLn (show r ++ a)

[old wyvern]

😮

yea thats lit

[arctic juniper]

stuff isn't in path

no it's pretty not lit

[old wyvern]

You'll need to add it to your path yourself

Theres instructions on the arch wiki

[prisma wave]

yeah ~/.ghcup/env needs to be added

[old wyvern]

https://wiki.archlinux.org/title/haskell

[prisma wave]

i think it offers to do that for you if you install it with the shell script, but not if you used the aur package

[old wyvern]

ah

[arctic juniper]

also ghc isn't in path

[prisma wave]

that will be in /env too

[arctic juniper]

and what do I put there

[prisma wave]

.

i presume you know how to add a directory to your path

[old wyvern]

export PATH="$HOME/.cabal/bin:$HOME/.ghcup/bin:$PATH"

[arctic juniper]

.ghcup/env doesn't exist

[old wyvern]

.

[arctic juniper]

ah, thanks

[prisma wave]

oh wait yeah

[old wyvern]

if you have stack as well
export PATH="$HOME/.local/bin:$PATH"

[arctic juniper]

I have neither yet

[old wyvern]

download both

[prisma wave]

my bad, it's env on my machine but it did weirdness

[arctic juniper]

well hold on

[old wyvern]

ghcup has cabal

stack is on a separate package

stack-static

[old wyvern]

ah

[prisma wave]

i usually use the shell script to isntall

which is slightly different it seems

[arctic juniper]

it just told me to upgrade ghc, jesus christ

[old wyvern]

lol

[arctic juniper]

time to download another 200mb

cya in a bit

[prisma wave]

🥲

what version are you on atm?

[arctic juniper]

was at 8.10.4

updating to 9.0.1

[prisma wave]

hmm

does vsc work with 9.0.1 yugi?

kali was having some issues with it the other day

although that was on windows

[old wyvern]

It should

It gives a warning in the main file tho

but that should be fine

[prisma wave]

ah okay

cool

[arctic juniper]

downloaded, installing

[prisma wave]

excellent

[arctic juniper]

[ Warn  ] This is an old-style command for installing GHC. Use 'ghcup install ghc' instead.
[ Error ] Unable to find a download for the requested version/distro.```

[prisma wave]

stack-static is an aur package

[arctic juniper]

ah

why am I installing it through aur?

[prisma wave]

idk the exact reason but i think it's because it's kind of 3rd party

[arctic juniper]

okay got them installed

[prisma wave]

awesome

[arctic juniper]

lemme just add to path

[prisma wave]

might have done that for you if it's on the aur

[arctic juniper]

okay I think I setup the language server

how do I start a project?

[prisma wave]

you using VSC?

[arctic juniper]

nvim

[old wyvern]

stack new <Project_name>

[prisma wave]

ah nice

uh

[arctic juniper]

it made a bunch of stuff

[prisma wave]

yeah tbh, you might want to steer clear of the build tools for the absolute basics

[old wyvern]

now run stack setup

yea true

[prisma wave]

kinda overkill if you just want a hello world

[old wyvern]

maybe just use ghci

[prisma wave]

yeah

[arctic juniper]

200mb fuuuuuu-

[old wyvern]

No

just run ghci

you have it with ghc

[prisma wave]

ghci is the jshell to java

[old wyvern]

lol

[arctic juniper]

after stack new or?

[old wyvern]

leave that project for now ig

[prisma wave]

or delete it, whatever. you can just use a single file for now

[arctic juniper]

do I install ghci

hold on, ghc isn't in path

[prisma wave]

it's part of ghc

ah

[old wyvern]

https://docs.haskellstack.org/en/stable/README/
Further instructions to use stack are here if you're interested

[prisma wave]

okay so anyway, in FP you often program at a REPL as it's usually more convenient for hacking together stuff

the official repl is ghci

[arctic juniper]

ah I see why it isn't in path

there's no ghci or ghc bin, there are bins with a version

ghci-9.0.1 is a command

[prisma wave]

ah that's an issue i was having a while ago

[old wyvern]

There should be a alias

oh wait

[arctic juniper]

there should be or I should alias?

[old wyvern]

I know whats wrong

You didnt set the version

[arctic juniper]

yep probably it

[prisma wave]

can you do ghcup tui and make sure you've set the versions you have installed

[arctic juniper]

okay ran ghcup set 9.0.1

[prisma wave]

that should make the aliases

nice

[old wyvern]

alright, now it should work

[arctic juniper]

does

[prisma wave]

awesome

[old wyvern]

lit

[prisma wave]

okay so uh

[arctic juniper]

I have a shell thing now

[prisma wave]

what now

yeah that's the repl

[arctic juniper]

oh my god 9 + 9 works

[prisma wave]

incredible

[arctic juniper]

says 18

amazing

[prisma wave]

try putStrLn "hello world"

i bet you can't guess what that does!

[old wyvern]

sum [1..9]

[arctic juniper]

where are the parentheses

[prisma wave]

you don't write them

[old wyvern]

^

[arctic juniper]

is this ruby?

who stole them

[old wyvern]

Its used in multiple languages

lol

[arctic juniper]

sum [1..10000000] is slow

[old wyvern]

try sum [1,3..11]

[prisma wave]

in haskell (and other ML style languages) parentheses are to denote precedence, not for function application

[old wyvern]

well ofc xD

[arctic juniper]

my shell just crashed from doing this

[prisma wave]

lmao

rip

[arctic juniper]

okay it works now

[forest pecan]

prolly cause memory limits

idk

lmao

that is 10 million

[prisma wave]

you can probably identify all the parts in that, [1..n] is a list between 1 and n, and sum is a function that... sums a list

[arctic juniper]

36

[prisma wave]

simple

[arctic juniper]

yeah I see

[forest pecan]

(10million * (10 million + 1) )/2

[arctic juniper]

does .. only work in the [] thingies?

[prisma wave]

yeah

[old wyvern]

those are lists

[forest pecan]

or 5,000,000 * 10,000,001

lmao

[old wyvern]

sum takes a list as input

[arctic juniper]

gauss shit

[prisma wave]

they're list literals, you can also do stuff like [1, 2, 4, 8]

[arctic juniper]

does .. have a step?

[old wyvern]

sum :: Num a => [a] -> a

is the type

[prisma wave]

it can't do that unfortunately, sum has to be generalised for any summable type

or maybe it does do that

[forest pecan]

F

[old wyvern]

You can provide the step pattern in the list

[prisma wave]

idk

[forest pecan]

so it doesnt use a formula?

lmao

[prisma wave]

probably not

[arctic juniper]

okay now you lost me

[forest pecan]

L

it should

[prisma wave]

dw about that

[old wyvern]

Thats its type signature

oh oops

fixed

sum :: Num a => [a] -> a

[arctic juniper]

is that a named return value?

[old wyvern]

no

[prisma wave]

in java terms that's <A extends Num> A sum (List<A>)

[old wyvern]

Thats a constraint

[prisma wave]

but dw too much about that for now

[arctic juniper]

ah

[prisma wave]

let's keep it simple

[arctic juniper]

so a is a type

[prisma wave]

okay so

yes, a generic type

[arctic juniper]

well not a type

Num is the type

a is of type Num

[old wyvern]

No

[arctic juniper]

no?

[old wyvern]

a is the type

Num is a constraint

[prisma wave]

num is a type constraint, kinda like an interface except more powerful

[arctic juniper]

right

[prisma wave]

in other words "a can be any type that implements the Num type"

anyway

so

we know how to use functions

time to make a function

double x = x * 2

try this

or that

[old wyvern]

^

[prisma wave]

lol

[arctic juniper]

weird syntax

makes sense

[prisma wave]

you get used to it

[arctic juniper]

works

[prisma wave]

and then naturally you can do double 3 etc

[arctic juniper]

yay

[prisma wave]

awesome

[arctic juniper]

uh so

[old wyvern]

now define another function

[arctic juniper]

double 3 + 5 does what

[prisma wave]

that won't compile i don't think

[old wyvern]

(double 3) + 5

[prisma wave]

or maybe it will

ah yeah

[arctic juniper]

it compiles

and now you turned this into lisp

[prisma wave]

yeah function calling has the highest precedence

[old wyvern]

You will sometimes end up with lisp like syntax

lol

[prisma wave]

although not often

[arctic juniper]

5 + double 3

tada

[prisma wave]

nice

easy

[forest pecan]

are you guys converting someone to haskell?

😮

[prisma wave]

yep

[arctic juniper]

converting?

[forest pecan]

how dare u

[old wyvern]

😌

[old wyvern]

Its a cult here

[arctic juniper]

excuse me, I'm a catholic

[prisma wave]

also, cool bonus feature - when you're in ghci you can do :t x to find out the type of x

try :t double

[arctic juniper]

I am learning about your culture, not converting

[forest pecan]

lol

[prisma wave]

we'll see about that

[old wyvern]

You will convert soon dw

Once you have a bit, you cant have enough

[arctic juniper]

floats are fractionals?

[old wyvern]

Theres a distiction in haskell actually

[prisma wave]

yeah...

[old wyvern]

haskell has both fractional numbers and floating point numbers

[prisma wave]

decimal stuff is kinda messy sometimes

[arctic juniper]

pi is floating

[obtuse gale]

huh?

[arctic juniper]

my 6.9 is fractional

[obtuse gale]

how does that work

like

yeah okay I get it nvm

[arctic juniper]

is fractional so you don't lose precision?

[prisma wave]

if it's rational it will be Fractional*

yeah

[old wyvern]

Depends on the type you operate on and the functions you use fefo

[prisma wave]

it's a bit confusing

anyway, you'll probably know this from rust and kotlin but in haskell, functions are values

[arctic juniper]

what's next

[prisma wave]

meaning they're no different to any other "variable"

you can pass functions to functions, functions can return functions, etc

[arctic juniper]

right

[old wyvern]

Fractional is just anything dividable generally I think

[arctic juniper]

is pi not divisible

[old wyvern]

It can be

[prisma wave]

confusing stuff

okay what next

Strings

they're pretty similar

exactly the same even

and of course you have Chars too

exactly the same syntax as any other language for those

[arctic juniper]

'E' :: Char

mmyes

[prisma wave]

in other words "'E' is of type Char"

[obtuse gale]

so like.. it's a fraction basically lol it can be represented as a ratio of two numbers

right?

[old wyvern]

http://zvon.org/other/haskell/Outputprelude/Floating_c.html

[obtuse gale]

well numbers idk what you can do in haskell but hopefully you get what I'm trying to say

[prisma wave]

lol

[arctic juniper]

so what do I use when I want to deal with decimals?

[prisma wave]

generally i think you'd just let the compiler figure it out

[arctic juniper]

Rational?

[prisma wave]

i guess Floating is the "traditional" way, but im not sure what's conventional tbh

[obtuse gale]

classic native languages

[old wyvern]

Seems like it also consists of irrationals? not sure tbh

[arctic juniper]

so how would I make a multiline function?

[old wyvern]

do blocks

[prisma wave]

good question

[old wyvern]

But

[prisma wave]

this is where ghci gets a bit annoying

[old wyvern]

Warning

[prisma wave]

you can't do multiple line stuff very well

[old wyvern]

those are syntax sugar, anything not part of the final result either as a value or as a bind will NOT be evaluated

[prisma wave]

lol

okay you might wanna switch over to an actual editor now, and make a new file

we'll have a look at do blocks

[eternal flare]

Minecraft on java 1.16 😶

[ocean quartz]

Yasss

[arctic juniper]

initializing languageserver.haskell

[prisma wave]

👀

[old wyvern]

https://tenor.com/view/dababy-lets-go-gif-21336342

[prisma wave]

🥲

[eternal flare]

https://www.minecraft.net/da-dk/article/minecraft-snapshot-21w19a

[old wyvern]

Ok mockito is just trolling now

Why does it say cglib is not on the classpath when its right damn there

🥲

[prisma wave]

classic

[arctic juniper]

Cannot find any haskell-language-server exe, looked for: haskell-language-server-9.0.1, haskell-language-server-9.0, haskell-language-server

f

[prisma wave]

f

wait

[arctic juniper]

I don't have it installed for 9.0.1

[prisma wave]

did you do ghcup set hls?

[old wyvern]

its

right

there

[ocean quartz]

🥲

[old wyvern]

ok screw this

[prisma wave]

ima keep typing while you try and figure it out - i could never get vim working but i also suck at vim so that might be why

[arctic juniper]

the problem is that hls doesn't support ver 9

[prisma wave]

ah

[old wyvern]

is there any other framework that can mock with proxies?

[ocean quartz]

Wouldn't happen unit testing Haskell!

[arctic juniper]

I guess I'll just go back to 8.10.4

[prisma wave]

that's similar to the problem kaliber was having a while ago

[old wyvern]

ikr

[prisma wave]

yeah that's probably best

you're not gonna be missing much

okay so, in haskell every function is a single expression. there are no "blocks", just expressions.
however as you might expect this can get a bit annoying, so there's a syntax sugar called "do blocks" that replicate an imperative {} block

[arctic juniper]

okay it loaded in like a second

[prisma wave]

great

all working now?

[arctic juniper]

waited for 2 minutes straight before

coc didn't tell me anything was wrong

[prisma wave]

good enough

[ocean quartz]

Seems like Ktor uses Mockk for it

[arctic juniper]

okay yep works

[prisma wave]

okay so let's start with the main function actually, you've already seen putStrLn "hello world", but that only evaluated in the repl

[arctic juniper]

yes

[prisma wave]

like most languages we have a main function

[arctic juniper]

main =
    putStrLn "hello"```

dis?

[prisma wave]

yup

[arctic juniper]

yay I guessed it

[prisma wave]

conventionally you'd put that on the same line

but sure

[arctic juniper]

what if I want more lines?

[old wyvern]

Does that work outside kotlin? the 2 kks make me feel like its for kotlin

[prisma wave]

that's when do blocks come into play

[arctic juniper]

how do I close a do?

[prisma wave]

try this: ```hs
main = do
putStrLn "hello"
putStrLn "world"

[ocean quartz]

Ah, probably not yeah 😦

[old wyvern]

welp

[arctic juniper]

okay it compiles

but what's the point of do if I don't close it?

[obtuse gale]

klassik kotlin adding K's everywhere 🌝

[prisma wave]

it's indentation based

[arctic juniper]

ah

[old wyvern]

🥲

[ocean quartz]

Lmao yes, i actually hate that xD

[prisma wave]

you can technically use braces if you want, it's just not generally done

main = do {
  putStrLn "hello";
  putStrLn "world";
}

this is also valid

[arctic juniper]

  { haCharBuffer :: IORef (...something...)
  , haBuffers :: IORef (...something...)
  , haBufferMode :: BufferMode
  }```commas before the line??

[prisma wave]

o_O

yes generally

[arctic juniper]

w- what

[old wyvern]

Except thats not the convention 🥲
Prepare to be horrified

main = do 
  { putStrLn "hello"
  ; putStrLn "world"
  ; }

[prisma wave]

the conventions for spacing and things are definitely a little different

[old wyvern]

yea

[prisma wave]

yes 🥲

[arctic juniper]

[prisma wave]

but im not sure it can be considered a convention if nobody actually writes it like that

[ocean quartz]

Who created that convention? i need to have a talk with them

[old wyvern]

They do use that I think

[prisma wave]

i mean usually you're not using braces or semicolons

but anyway

[arctic juniper]

thank fuck

[prisma wave]

@arctic juniper try putStrLn 3

in a repl if you want

[old wyvern]

ah

[arctic juniper]

not working

[prisma wave]

yup

[old wyvern]

Because Int is not a ...

String!

[prisma wave]

indeed

[old wyvern]

Anything the derives Show provides a show function

[obtuse gale]

OH MY GOD

[old wyvern]

Which can "Stringify" it

[obtuse gale]

gradle 7 for fabric mods UJFDSUOJSDNBJLOS

[arctic juniper]

is that ! a part of the type?

[prisma wave]

putStrLn :: String -> IO () this is the signature of putStrLn - it takes a String, and returns an IO () (which we'll get to in a minute)

[old wyvern]

no

xD

putStrLn (show 3)

try that ^

[arctic juniper]

what the

[prisma wave]

show is roughly analogous to toString

[old wyvern]

we'll remove the paren soon

dw

[arctic juniper]

works

[old wyvern]

ok

now

[arctic juniper]

I removed the parentheses, it doesn't work

[old wyvern]

to save yourself from parenthesis hell

We have custom operators

Haskell has one defined in the base class to apply an argument

[prisma wave]

yeah, that's because of precedence. without the parentheses it would be interpreted as putStrLn(show, 3) in C-style function calling

[old wyvern]

This is for a single argument and so can only be used for the last argument

[prisma wave]

whereas what we want is putStrLn(show(3))

[old wyvern]

its the $ operator

so you have
putStrLn $ show 1

try that

[arctic juniper]

shows a warning

[old wyvern]

It simply takes whats on its right, and applys its to the function on the left

[arctic juniper]

tells me to use print 1

[prisma wave]

indeed

[old wyvern]

Yea, thats a function that prints with show

This was an example to use $

[prisma wave]

that's kinda verbose so there's print which is a combination of putStrLn and show

[old wyvern]

brb

[arctic juniper]

how do multiple args work?

[prisma wave]

just spaces

add x y = x + y

add 3 4

[arctic juniper]

add $ add 1 2 $ add 3 4```

would this do what I think it would?

[prisma wave]

i dont think so, this is where it can get a bit confusing

actually maybe

try it

i don't think it will

[arctic juniper]

add(add(1, 2), add(3, 4))```

[prisma wave]

add (add 1 2) (add 3 4) this will work

we can't use commas

they are for tuples

[arctic juniper]

add x y doesn't compile

[prisma wave]

you need the body

[arctic juniper]

I have it

[prisma wave]

oh?

what have you got rn

[arctic juniper]

oh do I put the add outside of main?

yeah the thing doesn't compile

lemme try parentheses

[prisma wave]

yeah outside of main

you can nest functions, but that has a slightly different syntax

[arctic juniper]

    print $ add (add 1 2) (add 3 4)

[prisma wave]

that should work

[arctic juniper]

it does

[prisma wave]

awesome

[obtuse gale]

what kind of chain rule is that lol

[arctic juniper]

weird and confusing

[prisma wave]

heh

okay

now for the real mind-blow

go into ghci, define add again and then check the type of add

[arctic juniper]

fuck

a -> a -> a

[prisma wave]

it should be something like (Num a) -> a -> a -> a rigth?

okay

[arctic juniper]

add :: Num a => a -> a -> a

[obtuse gale]

loll

[prisma wave]

that looks a little intimidating

but

[arctic juniper]

looks very intimidating

[prisma wave]

it's actually quite simple

[arctic juniper]

I want to kill it

[prisma wave]

in haskell functions only have 1 parameter

[arctic juniper]

they what

[prisma wave]

if you have functions with multiple, that's just a function that returns a function

and so on

[arctic juniper]

oh makes sense

hold on

so

add(1)(2)```

in a normal language

[prisma wave]

precisely

are you familiar with the concept of "currying"?

[arctic juniper]

I know what curry is

[prisma wave]

also known as "partial application"

🥲

[arctic juniper]

currying is the process of applying curry to food?

[prisma wave]

close enough

anyway, what this funky parameter stuff means is that we don't need to provide all of the parameters to a function

so for example, we can do add 3

[arctic juniper]

oh

[prisma wave]

which in turn returns another function

[arctic juniper]

so that returns a function we can use later

[prisma wave]

exactly!

[arctic juniper]

similar to julia

[prisma wave]

oh does julia do that too?

[arctic juniper]

yeah some functions return a function if you don't supply all params

[prisma wave]

ah cool

yeah, super common pattern in FP

i was gonna explain where it might be useful but im guessing you already know

[arctic juniper]

julia> ==("69", "69")
true

julia> ==("69")
(::Base.Fix2{typeof(==), String}) (generic function with 1 method)

I have no clue where that could be useful

[prisma wave]

ah yeah exactly the same thing

okay

well

you're familiar with map and filter right?

[arctic juniper]

yes

ohh

yep

[prisma wave]

hehe

[arctic juniper]

I see

[prisma wave]

yup

[arctic juniper]

filter(==("69"), arr)

[prisma wave]

exactly

[arctic juniper]

in julia

[prisma wave]

in haskell that would be filter (== "69") arr

[arctic juniper]

is equivalent to filter(x -> x == "69", arr)

[prisma wave]

so almost exactly the same

[arctic juniper]

nice

well anyway

thanks for the help

[prisma wave]

lol no problem

[arctic juniper]

it's getting late and I haven't showered in 3 days

[prisma wave]

🥶

fair enough

if you decide to carry this on feel free to ping me if you have any questions

[arctic juniper]

actually gonna go a bit later

[prisma wave]

this is just the tip of the iceberg of all the fancy stuff haskell has

👀

[arctic juniper]

so you told me all about functions and all that fancy stuff

[prisma wave]

yup

[arctic juniper]

but what about if statements

[prisma wave]

no statements, only expressions

[arctic juniper]

right

[prisma wave]

the difference being that an if requires an else

[arctic juniper]

it what

[prisma wave]

so it can evaluate to some value

[arctic juniper]

right

why does it evaluate to a value

[prisma wave]

because everything in haskell is an expression

and the definition of an expression is something that evaluates to a value

[arctic juniper]

does haskell have no void type?

[prisma wave]

it does

[arctic juniper]

do functions with 0 params exist?

[prisma wave]

kind of

values are functions with 0 params

[arctic juniper]

eh?

[prisma wave]

because haskell does lazy evaluation

[arctic juniper]

ah

[prisma wave]

so you can do blah = print 3 and that won't actually print anything until you try and get the value of blah

[arctic juniper]

wait

yeah that's weird

[prisma wave]

it is a bit weird

[arctic juniper]

and it evaluates how many times?

how do I define a var?

[prisma wave]

that is an interesting question

technically it just evaluates once

[prisma wave]

name = value

[arctic juniper]

in main

[prisma wave]

ah

let name = value

[arctic juniper]

    let test = print 69
```this doesn't work until I access test

[prisma wave]

yeah

that line alone won't print anything

because it doesn't evaluate until it's forced to

[arctic juniper]

    let test = print 69
    test
    test```this prints twice

[prisma wave]

ah yes

there is a reason for that

it's just kinda hard to explain

[arctic juniper]

it's like a weird ass macro

[prisma wave]

basically, to keep functions pure, stuff like print don't actually print anything, they just return a value that describes some IO.
so it's returning the same value every time, but the do block is executing the IO twice

print doesn't actually print anything, it returns a value that's sort of like a list of instructions on what IO to do in order to print that value

[arctic juniper]

why is it executing the value?

[prisma wave]

because the do block assumes you want to execute it

[arctic juniper]

oh is test like a 0 param function now?

[prisma wave]

kind of

this is quite a tricky concept

but it will make sense

it's probably best not to worry about that for now

for all intents and purposes, it's a 0 param function

[arctic juniper]

no no

it's nothing for now

[prisma wave]

lol

¯_(ツ)_/¯

basically, haskell wants every function to be pure, so it doesn't actually do any IO, it just describes the IO to do, and then the compiler bundles that up and does evil wizardry to perform that IO

the language stays pure, but it can still do IO

[cinder flare]

might as well rename this channel to #intro-to-haskell

[prisma wave]

yes

do it

[arctic juniper]

Tomorrow at 00:00

[cinder flare]

im kinda diggin it though

just following along after

makes actually a bit of sense

hey do you know how to do infinite lists BM

[prisma wave]

yes

[cinder flare]

what's up with those

[prisma wave]

wdym

[cinder flare]

what are they used for

[prisma wave]

hmm

they are somewhat niche

[cinder flare]

but super cool!

[prisma wave]

but usually number generating stuff

[arctic juniper]

how do you get all odd numbers

[cinder flare]

oh I see like a number generator is just an infinite list of all possible numbers generated?

[prisma wave]

yeah

if you wanted to generate a list of all primes, a naive but functional implementation would be filter isPrime [1..n]

[cinder flare]

2N+1

[prisma wave]

[1,3..]

[cinder flare]

lol

[arctic juniper]

OH

I just realized

.. continues the whole thing, not just the last element

[prisma wave]

yup

[arctic juniper]

damn

what if I...

[1, 1, 2, 3, 5, 8..]

[prisma wave]

sadly it's not that sophisticated

it can do arithmetic progressions

not much more than that

[arctic juniper]

ah

sad

[cinder flare]

{2n − 1 | n ∈ N}

now that's set theory baby

[arctic juniper]

is that valid haskell

[cinder flare]

no

that's set theory

[prisma wave]

probably valid julia lol

[arctic juniper]

well ∈ is a thing in julia

and 2n is a thing in julia

[cinder flare]

∈ means is an element of in set theory

[prisma wave]

you could do an infinite list of all fibonnacci numbers with some recursion magic

[cinder flare]

2n is just multiplying n by two lol

[arctic juniper]

but | is just binary or

[cinder flare]

| means such that

[prisma wave]

shame

[cinder flare]

you read that statement as: 2n -1 such that n is an element of all natural numbers

so basically every odd number

[arctic juniper]

main :: IO somethingwat

[prisma wave]

Ah you've discovered the IO monad

[cinder flare]

haha monads go brrr

[prisma wave]

Now we're cooking with gas

[arctic juniper]

I haven't discovered shit, I just googled how print works

[cinder flare]

gas

[prisma wave]

Lol

[arctic juniper]

btw, what's haskell used for?

[prisma wave]

Quite a lot

It's definitely traditionally used for academia

But Facebook uses it for spam detection, GitHub uses it for language parsing

[cinder flare]

yeah as I said it's really good at expressing set theory and category theory lol

type theory too

[prisma wave]

It's gaining more adoption

But yes the original use case was definitely just for nerdy professors to experiment with complicated mathematical ideas

Which sounds pretty fun tbh

[arctic juniper]

it's gaining more adoption? isn't it half a century old?

[cinder flare]

hey im a nerdy normal person, not a professor

[cinder flare]

python was made in the 90's and it's still gaining more adoption

[prisma wave]

Nah Haskell came out in 1991 iirc

Or around that time

93 maybe

[cinder flare]

yea a lot of langs came out early 90's

[arctic juniper]

ah it is 1990

thought it was older

[prisma wave]

Ah close enough

FP is definitely older

[cinder flare]

ML go brrrr

[prisma wave]

I mean lisp was like 1958 or something

[arctic juniper]

ml is what

[prisma wave]

Maybe 61

[cinder flare]

ML is the precursor to Haskell

[arctic juniper]

what does ml stand for

[cinder flare]

1973 phew

Meta Language

technically OCaml, Standard ML, and F# are all ML bois

[prisma wave]

There were quite a few functional languages in the 70s and 80s, until they realised that there were too many languages to learn so they all sat down and made Haskell

That's not a joke

Pretty much what happened

[cinder flare]

ooh ML influenced Kotlin and Rust!

and C++

and Coq, nice

[prisma wave]

ML was pretty influential afaik

That and Lisp were like

The big 2

Back in the day

[arctic juniper]

how do you read that

[cinder flare]

awe man what a time to be alive

[prisma wave]

Not that I'd know

[cinder flare]

try spelling it out, with a ck instead of a q

[arctic juniper]

hmm

[obtuse gale]

u horny ass

[cinder flare]

oy

[obtuse gale]

lmao

[cinder flare]

is it cause I mentioned C++

[arctic juniper]

blyat

[cinder flare]

it summoned you out of your cave

[arctic juniper]

tf2 guy

you alive?

[obtuse gale]

lol not because of that, no

[prisma wave]

Ofc

[cinder flare]

tf2 guy

my hero

[obtuse gale]

I was laughing about this tbh

[prisma wave]

lmao

That's not even an exaggeration

[arctic juniper]

so we stopped at the io thing

what's next

[prisma wave]

Ah yeah

Uh

[arctic juniper]

monads?

[cinder flare]

woah have you guys heard of Cyclone

it's like C but they made it harder to fuck yourself

[prisma wave]

Oh that's gonna take a while to explain

[prisma wave]

Pretty low bar

[cinder flare]

yeah

[arctic juniper]

I don't like when they make it hard to fuck yourself

[cinder flare]

bro go back to writing ASM then

[arctic juniper]

if I want to fuck myself I will do it and nobody will stop me

[prisma wave]

Damn right

[arctic juniper]

I actually did do some a few days ago

[cinder flare]

oooh that's cool

x86 I presume?

[arctic juniper]

nasm

[cinder flare]

https://i.imgur.com/9UG7Kor.png

nice

[prisma wave]

Okay I am gonna go to bed pretty shortly but I will try and briefly explain the IO monad (or at least the idea behind it)

[arctic juniper]

network assembly I think is what it stands for

[cinder flare]

Netwide Assembler apparently

[arctic juniper]

close enough

[cinder flare]

so this is... portable ASM?

that's kinda weird

[old wyvern]

back

[arctic juniper]

but anyways, I tried making a simple tcp server

then it decided to not work

[old wyvern]

how far did you get vr?

[cinder flare]

in ASM? holy cow

[arctic juniper]

the literal equivalent in c did work

so I was left confused

it didn't error, it just returned

weird stuff

well not returned, ran the whole thing

without error

also debugging assembly is a pain in the ass

especially without libc

[old wyvern]

Seems like human anatomy

[prisma wave]

this is what I was talking about earlier where we have an abstraction that describes some IO to do. The main function says "this is a list of the IO I would like to do", and the compiler turns that into evil unsafe code.
This is expressed through the type IO a which basically represents some IO operation that returns an a

So print and putStrLn are IO () because they're an IO operation that returns no meaningful value (() is the void type, known as "unit")

[old wyvern]

Dont forget Elm 😌

[cinder flare]

yugi really going back through the message history and commenting

[prisma wave]

similarly we have other IO functions like getLine (gets a line from standard input), this returns an IO String

[old wyvern]

Yea

[cinder flare]

also Wikipedia does not list Elm as an ML boi

[old wyvern]

Elm is afaik

[cinder flare]

it was influenced by

but it's not a dialect

https://i.imgur.com/8dMiY38.png

[arctic juniper]

hmm well it is kind of confusing

[cinder flare]

yeah influenced

[old wyvern]

Even haskell was "influenced by"

[cinder flare]

not part of

ofc haskell was influenced by

ML was the baby version of haskell

[old wyvern]

Its literally the same syntax as haskell

[arctic juniper]

can you print inside another function?

[old wyvern]

It only lacks custom monads

[prisma wave]

Yes, but that function has to return an IO value

[old wyvern]

Elm is actually pure

[arctic juniper]

oh

[cinder flare]

yeah ML isn't 100% pure

[arctic juniper]

what if I want to return another value?

[cinder flare]

it allows unsafe stuff

[old wyvern]

Ofc, Elm isnt a complete ML ripoff

I just meant it shares the same elements haskell does from ML

[prisma wave]

Example?

[old wyvern]

or atleast most of it

[arctic juniper]

if I have a function that prints 69 and returns 420

[cinder flare]

nice

[prisma wave]

So something like ```hs
funny = do
print 69
return 420

[arctic juniper]

yes

that works

[prisma wave]

This would have to return an IO Int

[arctic juniper]

IO Int?

[old wyvern]

Yes

[cinder flare]

combo types!!!!

[prisma wave]

Because it's an IO operation that eventually returns an Int (420)

[old wyvern]

IO is also a constraint

imagine it similar to how a Future works

[cinder flare]

what if I don't know how a Future works either 🥲

[arctic juniper]

wait can I run any function that doesn't return IO in main?

[old wyvern]

Haskell itself does not read or write anything, so it needs to compose IO Actions to create the sideeffects

[prisma wave]

Yes

[old wyvern]

yes

BUT

[arctic juniper]

I can't run add

[old wyvern]

IO functions can only eb called in IO functions

Except a few cases wher eyou can lift em with transformers

but the general rule stands

[prisma wave]

That is because you're not doing anything with the result I'm guessing

[old wyvern]

You need an instance of MonadIO

^

[prisma wave]

yugi you might be overcomplicating this a little

[old wyvern]

#dev-general message

[arctic juniper]

yes

[old wyvern]

🥲

[prisma wave]

Yeah you have to bind it with a let binding, or not call it at all

[arctic juniper]

doesn't binding just not run it at all?

[cinder flare]

oh snap he's got a point

[prisma wave]

It will run it if you force it to evaluate

[cinder flare]

lazy evaluation biting oyu

[old wyvern]

Wait

What exactly were you running vr?

[prisma wave]

main = do
   let res = add 3 4
   print res

This works as you might expect

[arctic juniper]

so say I got this

add x y = x + y

main = do
    let poo = add 69 420

    print "ha"```

this works fine

but add will never actually be called

[old wyvern]

Mhm

[prisma wave]

right

[cinder flare]

print poo

[old wyvern]

Everything is evaluted only when it needs to be

[arctic juniper]

and I can't just put poo on the next line, it won't work unless I print it

[prisma wave]

the thing is, because add is pure you won't actually know that it doesn't get called

there's no noticeable difference

[arctic juniper]

well yes, but I will know

[prisma wave]

Indeed

[obtuse gale]

sounds like a functor to me 🌚

[arctic juniper]

a what now

[prisma wave]

[old wyvern]

lol

functor is just fancy for function

dw

[arctic juniper]

do you call a functor or is there a fancier word?

[obtuse gale]

an object that can be treated as a function

or smth

[prisma wave]

is it really

[cinder flare]

this is why we stay in haskell land

[old wyvern]

Well you could say "A mapping between 2 categories"

[cinder flare]

no weird C++ shit

[old wyvern]

But

Assuming you are sane

And havent started circlejerking

lets just go with function

[prisma wave]

I would never do that

[old wyvern]

ofc, same

🥲

[prisma wave]

anyway, Vr the reason you can't just do poo is because of what do blocks compile to

[obtuse gale]

cough http://learnyouahaskell.com/functors-applicative-functors-and-monoids

[arctic juniper]

what do do blocks compile to?

[prisma wave]

main = do
    print 3
    print 4

This gets translated to ```hs
main = print 3 >> print 4

[arctic juniper]

?

[prisma wave]

Yeah

[arctic juniper]

well yeah

what is >>

[prisma wave]

It basically takes 2 IO actions and turns them into 1

[cinder flare]

oh I didn't know you actually knew haskell lol i thought that was a C++ thing

[prisma wave]

it's like .thenRun with a CompletableFuture or something

[arctic juniper]

what happens to bindings?

[prisma wave]

they get inlined I believe

So your poo example becomes ```hs
main = print (add 69 420)

[arctic juniper]

wouldn't that call the function multiple times?

[prisma wave]

potentially

Potentially not

It's up to the compiler

[arctic juniper]

what now

[obtuse gale]

yeah a functor is also a thing in C++, although I think it's different

and no I don't know haskell lol

[cinder flare]

ah nice

[prisma wave]

We generally don't worry about it, because the compiler can determine whether it's worth caching or not

this kinda what yugi was saying earlier, how you don't need to think about performance much

because the compiler is able to do a lot of the optimisations for you

[arctic juniper]

so can I think of bindings as kind of #define?

[prisma wave]

they usually act in a similar way yeah

But they might not, as far as I know that's an implementation detail

[arctic juniper]

ya know

I thought the g in ghc was gnu

[prisma wave]

lol

it uses bsd I think

[arctic juniper]

so, what's a monad?

[gusty glen]

functor + map, or just flatmap

[prisma wave]

😱

[arctic juniper]

uh

[prisma wave]

It is getting pretty late so I don't think I can explain that now

[arctic juniper]

you mean early

[prisma wave]

But an oversimplified explanation would be "an abstraction over a value"

[prisma wave]

Not quite

11:35 pm for me

[arctic juniper]

ah

I'm an hour ahead

[prisma wave]

Ah nice

Okay I should probably be heading off

[obtuse gale]

LMAO classic

[prisma wave]

Adios

[obtuse gale]

chao

[arctic juniper]

cya

you free tomorrow?

[gusty glen]

I just call monad a thing that has flatmap, which is just lazy operations over the wrapped object, plus flattening the object later (if I'm not mistaken here)

[prisma wave]

Absolutely

The only thing stopping me from talking about Haskell 24/7 is school and "sleep"

Quite unfair imo

[arctic juniper]

okay I just realised I forgot to do something I should've done 3 hours ago

[prisma wave]

uh oh

[arctic juniper]

no, not 3, 5 hours ago

[prisma wave]

🥶

[arctic juniper]

meh fuck it I'll do it tomorrow

well today

[distant sun]

A global mute will also stop you :)

[prisma wave]

WHAT

[arctic juniper]

why do I have to bring papers physically

I have a phone with a camera

I want to die

cya

gn

[obtuse gale]

same

[ocean quartz]

Oh boy

[steel heart]

arguably newer versions are more optimized. then we have better switch expressions, records, sealed classes, the java std lib gets better and better also for every version

[forest pecan]

new gc

[obtuse gale]

List.of() 🙂

[forest pecan]

lol

[distant sun]

Basically everything

[obtuse gale]

CMS yeah boy

[dense dew]

ty

[ocean quartz]

Enjoy

https://piotrminkowski.com/2021/02/01/new-developer-friendly-features-after-java-8/

TIL Java 13 added text block 😮

[obtuse gale]

yeah lol

[distant sun]

sealed thing looks interesting

Does kotlin have that?

[ocean quartz]

Yup, it had for some time, 1.5 added sealed interfaces though
Actually just used it for the first time today

[obtuse gale]

Private Methods in Interfaces
I genuinely don't see the point in this though

[ocean quartz]

me neither

[distant sun]

Who cares about you two 🤷

[obtuse gale]

I do

to some extent

it's not like I'm loving my life to the fullest

[cinder flare]

wait holy shit I just realized how awesome Java 16 will be for plugins

this solves my oldest woe of everyone using JDK 8

[distant sun]

so you dont specify which classes can extend that but define them inside the sealed class itself? @ocean quartz

[ocean quartz]

You know what would be awesome

[obtuse gale]

huh?

[ocean quartz]

Valhalla 🥺

[old wyvern]

what specifically? or do you just mean the new features in general?

[cinder flare]

what is there not to understand

i hate how everyone uses old java versions

and this fixes it

[distant sun]

tldr for valhalla?

[old wyvern]

Probably not

[obtuse gale]

oh I misread

[ocean quartz]

You can even define them outside, as long as they are in the same file

[cinder flare]

oh yeah i mean just everything

[distant sun]

Ah nice

[old wyvern]

ah ok

[cinder flare]

i am usually very sad that we don't get to use anything cool

but now we get like switch expressions and record classes or whatever

[old wyvern]

Yea happens when you dont use haskell

[cinder flare]

i gotta read up on new features babyyy

[obtuse gale]

I came just by reading List<int>

[old wyvern]

c# being ahead of its time 😌

[ocean quartz]

For Kotlin it means full support for value classes and a few other features I don't remember much

[distant sun]

Ic

[cinder flare]

no its just java being behind its time

[old wyvern]

maybe

maybe not

Just

Nothing

IO

error

[cinder flare]

nullpointerexception

[old wyvern]

ew

[obtuse gale]

I'm sure you've read this one before cuz I've shared it before but for a more detailed list of things that whatever Matt shared 🙄 https://advancedweb.hu/a-categorized-list-of-all-java-and-jvm-features-since-jdk-8-to-16/

[cinder flare]

yeah I skimmed it once but it just made me sad cause I thought I would never use them

[obtuse gale]

now read it joyfully

[old wyvern]

Why not?

[cinder flare]

because this is the only reason people will upgrade java versions

have you seen the graph

70% or something of people are still on java 8

[old wyvern]

I assume you plan to make stuff outside of the minecraft community as well

[cinder flare]

not with java probably

[old wyvern]

ah I c

[cinder flare]

that's what Rust is for 😉

[old wyvern]

eh

personally Ill probably main java, atleast for a while

[cinder flare]

there's really not too much you can do with Java

[obtuse gale]

Did you know that 33 percent of obese men have a low sperm count?

[cinder flare]

i don't see many projects besides Minecraft stuff written in java

[old wyvern]

What is this "too much"?

[obtuse gale]

And one of them could be you

[cinder flare]

bruh

[old wyvern]

There are lots of applications written in java

[obtuse gale]

lmaoo

[cinder flare]

such as?

[old wyvern]

Google it up my guy

[cinder flare]

wow great point proving

[ocean quartz]

The amount of web servers using Java is insane

[cinder flare]

moral of the story, I don't see a lot of stuff I'd like to work in written in java

[old wyvern]

A lot of people using spring

[quiet depot]

google uses java

my government uses java