The Nineteenth Byte

Dannyu NDos

00:13

I've heard that eval tends to produce malicious codes. I presume it holds especially for Ruby?

user

Produce?

Dannyu NDos

Err

user

Using eval can possibly lead to ACE exploits, but I haven't heard of eval making code, malicious or otherwise

Dannyu NDos

I dunno much about computer viruses tho.

Oh, actually it's not about eval. It's Ruby being able to parse strings to functions.

Bbrk24

...yes, that's what eval is

same thing in JS

Dannyu NDos

00:20

D:

Bbrk24

Though JS has other ways of doing it, like Function and setTimeout

lyxal

@user cries in Sympy

Dannyu NDos

As a wise man once said, Do not ever use scanf. Use fgets and sscanf instead.

Bbrk24

Wait why?

Like I get why %s but surely %d is safe?

Dannyu NDos

Dunno the explicit reason, but maybe because scanf tends to forget to parse newlines?

The wise man is Steve Oualline, btw.

lyxal

00:36

10

A: How to use sscanf correctly and safely

The scanf family of function cannot be used safely, especially when dealing with integers. The first case you mentioned is particularly troublesome. The standard says this: If this object does not have an appropriate type, or if the result of the conversion cannot be represented in the obje...

Bbrk24

okay but surely like

int32_t i = -1;

while (!(feof(stdin) || scanf("%" SCNi32, &i))) {
    DISCARD getchar();
}

is safe right?

Dannyu NDos

I wasn't regarding whether it's safe tho. More like whether it's cumbersome.

Bbrk24

It's easier than cin in this case because I don't have to clear it on error

Dannyu NDos

And that's why imperative languages should consider adopting parser combinators.

ReadP and ReadPrec FTW!

Bbrk24

(DISCARD is a macro for either [[maybe_unused]] auto _ = or (void) depending on the language version)

lyxal

00:40

> I strongly recommend the combination of fgets() and sscanf(), because that way you can prevent buffer overflows. Using scanf() only, you'll get a buffer overflow if the actual input is longer than the buffer you reserved for it, because there is no length check (AFAIK even scanf("%10s", ...) isn't safe, but I'm not absolutely sure about that). The result can be anything from unpredictable behavior to a segmentation fault.

linuxquestions.org/questions/programming-9/…

Bbrk24

7 mins ago, by Bbrk24

Like I get why %s but surely %d is safe?

lyxal

> You might think of %5d tricks and such but you'll find they're not reliable. Or maybe someone will think of errno. The scanf functions aren't required to set errno.

6 mins ago, by lyxal

10

A: How to use sscanf correctly and safely

The scanf family of function cannot be used safely, especially when dealing with integers. The first case you mentioned is particularly troublesome. The standard says this: If this object does not have an appropriate type, or if the result of the conversion cannot be represented in the obje...

Bbrk24

Also I'm okay with UB for too-big inputs

:P

lyxal

then I guess it's safe for your purposes :p

Bbrk24

Like I already read it into a 32-bit number and then truncate it to 24 bits

OldSandboxPosts

01:00

Sandbox posts last active a week ago: Complexity of a binary matrix

lyxal

@OldSandboxPosts probably O(n)

Idk probably depends on the binary matrix

Bbrk24

01:16

$ clang-format --version
clang-format NPM version 1.8.0 at C:\Users\bbrk2\AppData\Roaming\npm\node_modules\clang-format\index.js

Darren Smith

03:42

Hey @lyxal, did you want to continue that discussion from yesterday by any chance? I joined the room

lyxal

Maybe another time - I have some uni work to do

and I'm already procrastinating enough here :p

Darren Smith

Ok cool, talk to you later

Very late already here anyway, are you in Australia by any chance?

lyxal

I am

Darren Smith

Cool cool, colorado here, have a good day ;)

Sandbox Posts

06:13

0

A: Sandbox for Proposed Challenges

Generate a naïve isEven() We've all seen the memes of a beginner programmer writing an isEven() function that looks something like this: def isEven(num): if (num == 0): return True elif (num == 1): return False # and so on You and I know this is tedious to do by hand,...

PlaceReporter99

08:11

@SandboxPosts doesnt seem like a good fit for the site

Number Basher

10:26

hopefully will finish my script today

PlaceReporter99

11:28

Tip: prepend view-source: to a url to see the source code of the web page!

hyper-neutrino

13:23

or just press Ctrl+U

lyxal

ctrl+s also works

just takes a few extra steps :p

hyper-neutrino

lol

lyxal

there's also ¨U (or ŒG if you're more gluten minded)

or gelatin

Sandbox Posts

0

A: Sandbox for Proposed Challenges

How are you doing, PLDI? In this challenge, you must write a full programme that gets the Area 51 stats of the PLDI site and prints the numbers to STDOUT along with their labels without any HTML tags. To assist in the creation of your answer, here is the HTML source code. Remember, this is a code...

lyxal

one of those two

idk

Bbrk24

13:37

Since when is NaN ** 0 == 1? I thought anything to do with NaN is NaN

lyxal

what language?

Bbrk24

C#

so it’s spelled Math.Pow, not **, but whatever

lyxal

fwiw js does it too

PlaceReporter99

@SandboxPosts how is my sandbox post?

Bbrk24

yeah I imagine it’s part of the IEEE standard. I don’t know why C# would deviate from it

lyxal

13:39

@Bbrk24 shouldn't be doing that

PlaceReporter99

@Bbrk24 EVERYTHING to the power of 0 is 1, even 0.

lyxal

source

Ginger

math

Bbrk24

mɐth

Ginger

meth

lyxal

13:41

jesse

Ginger

jesse we need to cook more NaNs

Bbrk24

Oh you know what it might be

Rydwolf Programs

readies move to DBA

Ginger

readies cakes

lyxal

@Bbrk24 as a matter of fact, no

I don't :p

Bbrk24

13:42

It’s a custom function with nullable arguments, and it treats null like zero. I just said that if arg2 is null it returns 1, without checking for NaN

Ginger

someday I too will accidentally move a story about lizards to another site's main room

Rydwolf Programs

Maybe so that (0 / 0) ** 0 is still 1, since (x / y) ** z might be expected to behave like x ** z / y ** z in all situations?

Bbrk24

which is honestly fair because in context it’s never supposed to get a NaN, I had to hardcode that NaN in to even see it

@RydwolfPrograms that would make sense

Sandbox Posts

0

A: Sandbox for Proposed Challenges

Monopoly, But its in Creative Mode (sort of) koth Starting Grid: 8x8 grid: +--+--+--+--+--+--+--+--+ |XX| | | | | | |XX| +--+--+--+--+--+--+--+--+ | |+1| | | | |+1| | +--+--+--+--+--+--+--+--+ | | |+2|+1|+1|+2| | | +--+--+--+--+--+--+--+--+ | | |+1|x2|x2|+1| | | +--+--+--+--+-...

lyxal

gotta love how Microsoft says it should return NaN yet has a try online box that returns 1

5

Number Basher

13:45

@SandboxPosts plz give feedback thnx

Rydwolf Programs

It feels almost entirely randomness-based

I can't think of any strategy that would give you a particular edge

lyxal

thanks microsot

Number Basher

@RydwolfPrograms perhaps choosing between saving money, or collectively building a utility

Rydwolf Programs

That's only a few things that can vary between bots

Number Basher

or whether it is worth it to risk losing money to demolish structures

Rydwolf Programs

13:49

When would it ever be

Number Basher

and for this question https://codegolf.meta.stackexchange.com/a/25784/111945 i think we should specify which stats we should output

@RydwolfPrograms if a structure has too high a rank, taking it down benefits everyone (except owner)

Rydwolf Programs

Oh so you can demolish someone else's structure?

That's interesting but the 25% success chance means it's basically pointless

You on average have to pay rent to someone four times to destroy their property

Number Basher

i just changed the pay btw

cuz i figured out the same thing

PlaceReporter99

@NumberBasher and idk what you mean by “IHATE15CHAR”.

@NumberBasher fixed

Number Basher

@PlaceReporter99 there is a 15 character limit in comments

to avoid spam like thank you

PlaceReporter99

13:57

@NumberBasher oh

Number Basher

like i mean

do i print stats like 7 days in beta?

or just the 6 stats in the center

so sample output would be

28.3
95
58
599
2.7
191

PlaceReporter99

@NumberBasher just 6 stats in center

Number Basher

ok just add that :-)

PlaceReporter99

@NumberBasher and there has to be the label names as well.

Number Basher

@PlaceReporter99 so like...?

just put a sample output there

PlaceReporter99

14:03

Number Basher

oh ok

PlaceReporter99

@NumberBasher everything should be fixed now.

Number Basher

much better, upvoted

btw view-source:area51.stackexchange.com/proposals/127456/… doesnt work for safari

Ginger

> view-source:https://area51.stackexchange.com/proposals/127456/programming-language-design-and-implementation

do... do you understand how URIs work

PlaceReporter99

Number Basher

14:11

nnnnnnnnnnnnnnnno

PlaceReporter99

works for me

Ginger

w h a t

bruh

Number Basher

.?

PlaceReporter99

@Ginger what web browser do you use?

@SandboxPosts is the challenge ready?

Ginger

14:59

@RydwolfPrograms can we get star clears on ^^^ and ^^^^?

PlaceReporter99

@Ginger :(

they were worthy of a star

Rydwolf Programs

"star this message as useful / interesting for the transcript"

Those were not useful or interesting

PlaceReporter99

@RydwolfPrograms intrestingness is subjective

i found them intresting

Rydwolf Programs

The starboard isolates messages from their context

"w h a t" on its own isn't interesting or funny

Unrelated String

it's not even interesting or funny in context

it's just a situationally appropriate response

also what's the other one that got starred lmao

Rydwolf Programs

15:03

Plus also two adjacent messages should almost never be starred

Unrelated String

^

wait did the bruh get starred

bruh

Rydwolf Programs

We don't need a repeat of 2015 y'all :p

Unrelated String

did the 2015 thing even happen in 2015 or was that someone going back way later to star messages from 2015

Rydwolf Programs

I assume it was 2015

Number Basher

@RydwolfPrograms what thing

Unrelated String

15:05

because i feel like it would have been cleaned up if it actually was 2015

Number Basher

i feel so missed out even tho its no good thing lol

who the X is messing around with the stars again...

PlaceReporter99

@RydwolfPrograms that message was actually useful!

Rydwolf Programs

Yeah, but if I unstarred five messages and only left one of my own it would look like RO abuse :p

If someone else agrees it's useful they can star it

PlaceReporter99

why did you remove the star from your super useful message?

Unrelated String

~~for starters it's common sense~~

Rydwolf Programs

15:08

In general singly-starred messages can and will be removed for any reason

Number Basher

again, appreciate feedback for codegolf.meta.stackexchange.com/a/25785/111945

PlaceReporter99

and for codegolf.meta.stackexchange.com/a/25784/117478

Does anyone have feedback for these sandbox posts listed above?

Ginger

:/

PlaceReporter99

:\

:|

^^^^

Rydwolf Programs

15:23

I don't think it adds anything new

We have a ton of internet/HTML-parsing challenges

It's just gonna get dupe closed

The Thonnu

^

PlaceReporter99

15:40

@RydwolfPrograms I searched through all the internet questions and found no dupes.

The Thonnu

@PlaceReporter99 there's no exact dupe, but it's quite similar to basically every other internet challenge

Rydwolf Programs

And there are at least half a dozen that involve parsing HTML too

PlaceReporter99

16:05

@Feeds I wonder who I’m replying to…

The Thonnu

@PlaceReporter99 ~~feeds is just a bot~~

Ginger

feeds isn't just a bot

sometimes it posts feed items, sometimes it posts room status changes, sometimes it dreams about electric unic♦rns

The Thonnu

user -2

There isn't even a user 0

I would have thought they would use #0 first

And #-1 (Community) isn't even on Chat

hyper-neutrino

16:56

Final reminder that bots aren't allowed here. I don't care if it's entirely manually controlled; in order to enforce consistent policies, unless we've approved it explicitly, chat bots that interact here (read-only bots are perfectly fine) are not allowed and I will take necessary action to stop them if this rule is not followed.

Bbrk24

Is that only for this room or a site policy?

Ginger

just this room, but it's generally good to assume that bots aren't allowed

bots are explicitly allowed in other rooms, like the Sandbox

hyper-neutrino

^. feel free to use the sandbox, make your own room, etc. this just applies to this room (and also I don't think we ever defined it but let's just say it also applies to our official off topic room)

Ginger

Since TST is a subsidiary of TNB it'd make sense that the rules would be inherited

Seggan

@hyper-neutrino would using a chat client count?

Ginger

17:03

Presumably not, since you're the one sending the messages

humans != bots

Seggan

> I don't care if it's entirely manually controlled

hyper-neutrino

ginger is correct. yes, I know that makes the definition of manually controlled bots vs. clients a bit fuzzy but in this case the account is literally called Utility Bot so I think it's fair to make that judgement lol

Ginger

I love being correct!

5

when the edge is sus

Adám

Technically is the best type of love.

hyper-neutrino

okay here's the thing - if I can't tell it's a bot then it's fine because the point is the health of chat and not because I hate fun and want to be very technical and literal with y'all lol

Ginger

17:06

we do hate fun here tho, so be sure not to have any fun

hyper-neutrino

so if nobody can tell it's a bot because it's effectively just you chatting then no harm done

Ginger

a bot in human clothing

Rydwolf Programs

18:47

@hyper-neutrino Yeah, we took advantage of the lack of rules on TST and put Snowpaw (a bot) in there, it ended up just being disruptive so copying the rule over to there would be for the best

@Ginger Arguably the other way around :p

Ginger

@RydwolfPrograms correction: you gave me explicit permission to put Snowy in there

there's no "we" here :p

Rydwolf Programs

...based on the lack of a rule saying I couldn't :p

Ginger

~~just wanted to make sure that you were completely under the bus~~

Rydwolf Programs

@Ginger I've been saying for a while we should fork TNB's chatiquette for TST (with a few changes)

Ginger

you have?

Rydwolf Programs

18:59

Yes

TST is a lawless place right now :p

Ginger

I assumed that the chattiquette was inherited by virtue of it implementing the OfficialRoom trait

Rydwolf Programs

> Do: Be On-Topic

Don't think so :p

Oh we should update TNB's chatiquette to include TST's existence

Ginger

the topic of TST is off-topic stuff, so by being off-topic you're being on-topic

logic™

Rydwolf Programs

Brilliant

Also I'm starting on that invisible MathJax script

It can transform arbitrary code into arbitrary MathJax

Ginger

good luck

PlaceReporter99

19:02

@Ginger but if it’s on-topic, then it’s off-topic…

Rydwolf Programs

Indeed

Ginger

correct

Rydwolf Programs

So people without the script (with proper Unicode rendering) will see x² = y² - y + 2 while people with the script will see \$x^2=y^2-y+2\$

The way it'll work for the sender is that you click a button next to "send" (or hit a shortcut), which opens a popup. In the popup, you can edit the code block and the MathJax, with a preview of each

Ginger

and presumably those of us without Unicode rendering will see x�²�� =�� y�² - y ��+ 2��?

Rydwolf Programs

The code block preview will show you how it looks both with and without Chat Monospace Fix

@Ginger Only if you don't have proper Unicode rendering

Which I checked yesterday:

24 hours ago, by Rydwolf Programs

CMP: Do you see any whitespace, boxes, or question marks in between the arrows in this code block? ->᠎‍‌⁠⁡⁢⁣⁤‎<-

Ginger

19:05

ugh, I thought I said "without Unicode rendering" :|

Rydwolf Programs

@Ginger maaaaybe :p

Ginger

��

Rydwolf Programs

(well actually in that specific case no invis chars would actually be needed whatsoever)

(aside from one soft hyphen at the start of the code block to indicate it's using CIMJ)

Ginger

so �x² = y² - y + 2

my font renders U+FFFD differently when it's in a code block lol

(right is in code block)

WAIT

�

I MADE IT ITALIC

Rydwolf Programs

You don't have Chat Monospace Fix?

Ginger

19:09

not on this device

PlaceReporter99

A�b

Rydwolf Programs

(fun fact I actually don't, I use a userstyle instead)

Seggan

@RydwolfPrograms whaz that

Rydwolf Programs

PlaceReporter99

@RydwolfPrograms only on my phone

@RydwolfPrograms Anyways, what's wrong with my sandbox post?:

-2

A: Sandbox for Proposed Challenges

How are you doing, Beta? In this challenge, you must write a full programme that takes the beta site number (e.g. PLDI is 127456), retrieves all the stats except the number of days in beta and prints the numbers to STDOUT along with their labels without any HTML tags. If the beta site does not ex...

Rydwolf Programs

19:19

Like I said, it's a dupe

It also doesn't specify the format of the Area 51 page

PlaceReporter99

@RydwolfPrograms something i'm certain it's not.

Rydwolf Programs

Which you need to do, since if it changes, it would break every answer

PlaceReporter99

@RydwolfPrograms $\mathbb{sigh}$

Rydwolf Programs

@PlaceReporter99 "Duplicate" for a challenge doesn't mean "the same challenge". It means "the hard part of doing this challenge is the same thing that makes another challenge hard"

Rydwolf Programs

19:33

→ 8 messages moved to Sandbox

Ginger

@RydwolfPrograms ~~finally, a worthy domain name~~

Rydwolf Programs

Well no purchases any time soon, I'm saving up for something :p

Ginger

does it have any relation to chat.stackexchange.com/transcript/message/63361244#63361244?

oh right, you said something about a concert

Rydwolf Programs

Yeah, upgrading from a seated ticket to GA because I'm a bigger fan of Paramore than I was when I bought the first tickets

Bbrk24

20:03

The number of unit tests I’ve seen today of the form x.y = z; Assert.Equal(z, x.y); is… concerning.

Rydwolf Programs

lol

Bbrk24

Like somewhere in the 30-40 range

Seggan

20:48

@Bbrk24 what

Bbrk24

@RydwolfPrograms it happened again

I left the tab open while my laptop was closed all day, and I guess the timer just kept ticking?

Ginger

21:46

Happy Pansexuality Awareness Day!

lyxal

22:30

@Ginger hey what about me?

I explicitly approved it too :p

Neil

23:32

@mousetail did you see my comment codegolf.stackexchange.com/questions/260931/…

Dannyu NDos

I wonder, can fastest-algorithm challenges employ parallelization?

I take this further: Perhaps the most parallizable code can be a winning criterion.

One would need a CPU with prolific amount of cores to actually see them parallelized tho. Like 65536.

Bbrk24

23:56

nodejs.org/en/blog/announcements/nodejs16-eol oh

They announced this almost a year ago and I'm just now finding out about it

Number Basher

https://codegolf.meta.stackexchange.com/a/25785/111945 just needs a better challenge name

(and controller script which i will write when i have time aka 10 months later

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