1:00 AM
Sandbox posts last active a week ago: Same number list shape?, Polyglot quiz

1:29 AM
tfw school wifi blocks stuff by using http

1 hour later…
2:58 AM
That moment when a math question asks you to prove a statement true, but you end up proving it false instead.

bruh

the question is: show that there are no 3 prime numbers (`p1`, `p2`, `p3`) such that `p2 = p1 + 2` and `p3 = p2 + 2`
and unless I'm mistaken `3, 5, 7` are 3 prime numbers where `5 = 3 + 2` and `7 = 5 + 2`

lmao
That's the only case, but it's kinda funny

lowkey wondering if it's a trick question or if they forgot to add a range of numbers or if there's a typo somewhere
or if they genuinely forgot 3, 5 and 7 exist

For full marks I'd suggest proving that there are no others but pointing that out as an edgecase

3:06 AM
but if there's an edge case, that means that the statement is false overall
I'mma ask someone about it on wednesday

3:51 AM
0

Print or return the following string: R******* *R****** **R***** ***R**** ****R*** *****R** ******R* *******R *....... .*...... ..*..... ...*.... ....*... .....*.. ......*. .......* *....... .*...... ..*..... ...*.... ....*... .....*.. ......*. .......* *....... .*...... ..*..... ...*.... ....*.....

1 hour later…
5:17 AM
Just accepted an answer and now I feel I have done something bad
@lyxal there may be an infinite set of triples like that!

2 hours ago, by emanresu A
That's the only case, but it's kinda funny

@lyxal I am so wrong
"one of every three sequential odd numbers is a multiple of three, and hence not prime (except for 3 itself)"
We can have the smallest and largest differ by 6 though in a prime triplet
Eg 881, 883, 887
There are also prime quintuplets
And "sexy prime quadruplets"
:)

8 hours later…
1:10 PM
was thinking of a challenge idea; sort of a pascal's triangle sort of situation, you're given a triangle of numbers and are asked to verify that each number (besides ones on the top row) are the sum of any two of the numbers above* them
*above is a little weird to define but basically like, any of what would be that number's "parents", not any of the ones that could never contribute to that number in a regular pascal triangle
more importantly though im just not sure whether it should be;
a) verify that this property holds for each number
b) verify that this property does *not* hold for *any* number
a) would mean that once youve found at least one eligible pair you can stop searching (probably) but b) is less edge casey since the top would have no eligible pairs no matter what
also with a) theres room to make the requirement stricter / potentially more interesting if this isnt cool enough lolol

1 hour later…
2:17 PM
0

Program a parser compiler Write a program, function, or likewise that takes in a BNF-like grammar specification(see below) and outputs a program or function in a language of your choice that takes strings as input and returns truthy if that string is parseable with the specified grammar, and fals...

2:43 PM
Hello all!

Hello

Hi!

3:00 PM
oh boy a new Raspberry Pi kernel

3:16 PM
Actually posting today in case anyone wants to feed me back:
2

Polyglot quiz code-golfcops-and-robberspolyglot In this challenge as a cop you will choose two programming languages A and B, as well as a non-empty string S. You are then going to write 4 programs: A program which outputs exactly S when run in both A and B. A program which outputs S in A but n...

@emanresuA As in, forcibly downgrades to HTTP?

@emanresuA Do they allow websockets?

@emanresuA they do what now

> blocks stuff by using http
You're welcome

wow
that's a new level of evil bodge

3:28 PM
I'm not really sure what "blocking [with HTTP]" is even supposed to mean

@NoHaxJustRadvylf I assume it means they downgrade connections to HTTP, then read the content and block based on that

That won't work really anymore

Oh nice
Is HTTP secure now?

HSTS and browsers caching HTTPS status means only really old sites you've also never visited before will allow downgrading

Oh ok

3:38 PM
Presumably they have a locally trusted CA so everything is reupgraded to HTTPS

And you don't really need to try to force a downgrade to block stuff anyway, at least until DoH/DoT and eSNI/ECH become common

@pxeger Unless there's certificate pinning, this would work

@pxeger Depends on if it's emanresu's device or not. My school district only has root certs on their own devices, but lets you get away malware-free if you bring your own
IMO mainstream browsers just shouldn't let you trust your own certs.

It would be nice if there were some way to trust your own cert only for certain subdomains

Since, without a doubt, as soon as ECH rolls out in FF/Chrome, every school and (malicious) workplace will force everyone to install root certs, ultimately reducing security in a lot of cases

3:42 PM
@pxeger Actually that's such a good idea I'd be surprised if it doesn't already exist

@pxeger That wouldn't really help with schools/other places requiring root certs though, right?

Well I have my own root cert installed to access my locally-hosted network services without exposing even their existence to any external CA (and thus the public, because of certificate transparency)

@NoHaxJustRadvylf *HSTS preload, forgot there's both that and plain old HSTS

that's a legitimate use case for custom roots
so if browsers could only allow those (and probably only for non-Publix Suffixes) then I'd be happy
but until then I'd rather keep the ability to have custom roots

Yeah, definitely. Or maybe you need to like, compile in support. But something that schools can't really expect their students to do themselves.

3:46 PM
It also kinda breaks the transparent principles of the internet, in that theoretically you should be able to make your own completely isolated internet all by yourself
which wouldn't be possible if you were beholden to verisign or whatever

Wow--all new starboard in the past day. This should be interesting reading.

things happened

I don't know what's wrong with my SE chat but I had an all-old, not all-new, starboard, so I reloaded and now it's the same messages but with different timestamps

I don't think anything is wrong, I think it's Just Like Thatâ„¢

@pxeger something something Mandela effect

4:15 PM
@WheatWizard What is your rationale for wanting languages to run on FreeBSD?
I understand wanting them to run on some freely-available OS, but choosing FreeBSD (and I guess for that matter Linux) specifically is a bit annoying

@pxeger The goal is to force it to be reasonably cross platform. So I chose the two largest Free OSes.
Maybe it should be or instead of and.

That would be nice
And anyway, even if the language is cross-platform, can't I just say my program nonetheless requires a specific environment?
Or does that count as making a new "language" subject to that environment

4:32 PM

1 hour later…
6:01 PM
0

Solve the Greek Computer Puzzle Toy There is a small toy of a series of stacked dials -- loosely inspired by the Antikythera Device. The puzzle, made by Project Genius, has a series of dials that must be arranged in a particular configuration to win. In this challenge, you will write a function/p...

6:13 PM
@pxeger I mean, that wouldn't really need HTTPS, would it?
And while you sacrifice some of the ease of making your own little internet, right now tons of people are sacrificing any privacy at all thanks to root certs

7:10 PM
knight lang to solve a knight challenge lolol: codegolf.stackexchange.com/questions/251050/…

@NoHaxJustRadvylf Why wouldn't it need HTTPS?

@user If it's completely isolated, it wouidn't (well, if it was completely isolated and only used by you)

But what if "you" is the entire country of codegolfland?
what if I want to make my own internet for all my citizens once I become president

I guess if it was an isolated internet with a bunch of people maybe, but DNS seems like more of a threat to decentralization than HTTPS with the current CAs

7:26 PM
@pxeger Or if you want a more realistic example, a big company
@NoHaxJustRadvylf A better solution would be to make laws to stop companies from being able to force people to install root certs (possibly also harder though)
Hey @forest! Thanks for recommending Gentoo btw, my old laptop's come back to life (for the third time)

@user I'm glad you like it!

@NoHaxJustRadvylf It's not that stupid, no. It blocks banned websites by downgrading to HTTP so modern browsers won't support it

7:50 PM
Yeah, that's what I meant
If they don't tamper with the content, just force a downgrade, can't you just use `curl` to get around it?

Perhaps? I don't know if they tamper with the content tho

I'm like 90% certain that they're actually injecting their own block page
And it gives you the downgrade error because they try to downgrade in order to show it

Ah, makes sense

8:07 PM
i just jumped in on a lecture on models of computation and it was actually kind of hard to sit through 20 minutes of the rest of the class sk
somehow failing to understand dfas

'morning, 'afternoon, 'evening

'night

'time

@WheatWizard oh hi!

'noon

8:17 PM
hey guys
@AidenChow it's technically always either 'afternoon or 'beforenoon
@AviFS and since 'beforenoon='morning, i was right :p

8:31 PM
@AviFS Hmm, depends how technically you want to take it. Technically, there is a time called noon, which by definition is neither before noon nor after noon. On the other hand, when the clock says 12:00 pm, it's usually more like 12:00:14 pm, which is technically after noon.

1 hour later…
9:52 PM
@DLosc I guess it's a dartboard paradox sort of thing
There is a time that's exactly 12:00:00, but the probability of this being it is 0

10:32 PM
you might say its almost surely either 'beforenoon or 'afternoon

@DLosc Good point, I guess it depends whether "technically" means "technically, in practice" or "technically, in theory."
@thejonymyster Wait, that's actually super cool, and entirely perfect! Also, it's really neat how it just sounds like normal English, so the technical correctness could totally go over your head. On the other hand, you can be a prick without sounding like a prick, which is always convenient :p
(ie without sounding pretentious)
@thejonymyster But I actually totally forgot there was a name for that concept. Thanks a mill!

"Good Morning!" said Bilbo, and he meant it. The sun was shining, and the grass was very green. But Gandalf looked at him from under long bushy eyebrows that stuck out further than the brim of his shady hat.
"What do you mean?" he said. "Do you wish me a good morning, or mean that it is a good morning whether I want it or not; or that you feel good this morning; or that it is a morning to be good on?"

Does anyone care to clarify whether that's measure theoretic or probabilistic. And please don't say both! Like, when is something strictly measure-theoretic, but not probabilistic again? (Ie what level of abstraction does that take?)
@DLosc Ah yes, good one.
I feel like that tells you a lot about what kinda man JRR Tolkien was, haha

@AviFS it really is a top tier technical term

11:25 PM
@DLosc ...all of them at once, I suppose