The Nineteenth Byte - 2021-06-07 (page 4 of 4)

« first day (3782 days earlier) ← previous day next day → last day (1063 days later) »

7:00 PM

@ngn Pretty sure destructuring assignment's an example of pattern matching, but that'd be something like [1, 2 | A] = ... instead (not totally sure, though)

@ngn Python's destructuring assignment only works on iterables, and can't have defaults. Python's now (last I checked like a year ago) added a dunder method to allow pattern matching from most objects.

@Peilonrayz so, when it's with an iterable, it's called destructuring assignment, and when it's with an arbitrary object, it's called pattern matching?

@ngn When it's an assignment where you look at the structure of an iterable or an object, it's destructuring assignment

Pattern matching can also be a switch-style thing where you have multiple branches, like if + assignment instead of just assignment

@ngn Python's analogue to destructuring assignment is *args. But I don't think it has a name... or at least I forget it every time I learn it.

@Peilonrayz Python can't do destructuring assignment on objects?

7:13 PM

No

Oh, that's weird

Yeah. Every time I use JS I always leave thinking "it'd be nice if Python had {foo, bar} = obj"

@Peilonrayz splat?

i think that's what it's called under some contexts

what does (~0 << 3) mean in C?

caird coinheringaahing

-1 << 3 = -1 * 2 ^ 3 = -8

I think. I can never remember the precedence of <<

7:17 PM

unary always takes precedence i believe

~ takes precedence over << (which is pretty low on the list anyway)

@hyper-neutrino Splat comes back with unpacking, which AFAIK is different to destructuring assignment. head, *tail = value vs values = head, *tail.

@Peilonrayz ah, never mind then. i've just seen the term thrown around when it comes to functions like lambda *x: ... and f(a, *b)

@cairdcoinheringaahing this is in code optimized for speed. Why would you do that?

:58266186 tio.run/##Sy4o0E1PTv7/XzkzLzmnNCVVwaa4JCUzXy/…

7:18 PM

@cairdcoinheringaahing It's -8

@hyper-neutrino lol imagine using good formatting

@Anush context?

@hyper-neutrino github.com/AwardOfSky/Fast-Radix-Sort/blob/master/radix.c

@user better?

@hyper-neutrino Nah, get rid of those spaces :P

I thought shifting a negative sign value was undefined

7:20 PM

@hyper-neutrino The joys of every language seeming to having different terminologies ;)

In my language, "splat" is when a pigeon poops on your head

@Anush why would it be? you just need to move the bits over

0 is 00000000000000000000000000000000

@hyper-neutrino it's what gcc says :)

@Anush Shifting by a negative sign value probably is

so ~0 is 11111111111111111111111111111111 or -1

caird coinheringaahing

7:21 PM

@Anush Shifting by a negative value is undefined IIRC

so ~0 << 3 is 11111111111111111111111111111000

@Peilonrayz try this :) locals().update({"foo":123,"bar":45});print(foo)

why would it be in this code? I mean why not just write -8?

which is -2147483648 + 2147483640 which is -8

@Anush probably clarity

@hyper-neutrino ???

7:22 PM

@ngn Are you trying to trigger me, being a CR mod and all ;)

it's a bitmask

@hyper-neutrino how is it clearer?

the whole line is confusing

for(m = (unsigned char *)(&vector[size & (~0 << 3)]); n < m;) {

@Peilonrayz being a CR mod in this room is a risky endeavor ;)

@Anush true

can anyone translate it?

@Peilonrayz Here, get triggered >:)

@Anush Guess it's to make them look smarter :P

7:24 PM

@user :)

@hyper-neutrino oh!

size & (~0 << 3) is just "truncate the size to a multiple of 8"

@Anush That was an odd edit

I replied before your message by mistake

:)

size & -8 truncates to a multiple of 8....?

doesn't size * size%8 do the same?

@hyper-neutrino That's smart (and actually looks clearer now)

@Anush % and * isn't fast enough maybe?

ah maybe

7:26 PM

Shifting bits is probably trivial

yes

I get 62 warnings from clang :)

mostly warning: shifting a negative signed value is undefined [-Wshift-negative-value]

but it is very fast

@Anush wait what how would that work

caird coinheringaahing

Doesn't C optimise bitshifts? Maybe it actually is faster to do ~0 << 3 than use negative numbers?

also (size >> 3) << 3 would be clearer IMO

@cairdcoinheringaahing Probably won't be faster, but it'll be done at compile time

7:28 PM

@Anush yes because -8 is 11111111111111111111111111111000

and so & -8 will just set the last three bits to 0

thus truncating to a multiple of 0b1000 or 8

@hyper-neutrino is it wrong?8*(63%8) = 56

ah I made a typo above

@Anush I think what HN meant is that it rounds to a multiple of 8 by clearing the last 3 bits

I mean 8*size%8

@user thanks

okay and 8*(62%8) isn't 56

@hyper-neutrino oops

7:30 PM

Did you mean 62 - 62%8?

(x/y)*y works (assuming int division) in general

^^

8*(62//8) in python

@user yes.. sorry all

if you reverse the multiplication you can avoid brackets

@Peilonrayz I meant size - size%8

thanks for the deciphering all

but again & -8 is way faster lol. because bit operations are really quick

multiplication takes 4 ops i think?

division takes like 32 or 60? i don't know details

idk if the compiler or CPU will optimize division by a power of 2

7:34 PM

agner.org/optimize/instruction_tables.pdf

that code is designed to avoid the compiler needing to do any optimization

@Anush May I ask why?

it makes no difference if you use -Ofast or no optimization it seems

Isn't that the compiler's job?

@user I don't know. Maybe they wanted to make sure it was equally fast on all compilers?

github.com/AwardOfSky/Fast-Radix-Sort is all I know about it

¯\_(ツ)_/¯

7:35 PM

it is about 10 times faster than qsort

maybe they just didn't think the compiler could optimize as well as they could

I am amazed someone who makes that many typos in their English can write correct code!

English and C are completely different languages

yes but sloppiness is the same in all languages :)

@Anush IDEs catch typos in C, but not English (some do, but somehow I feel this person uses butterflies to code)

8:13 PM

@user that's a great expression :)

i believe it's a reference to

xkcd.com/378 (onebox is too large)

Why does SE chat even bother oneboxing xkcd? There's nothing special about it

because there is always a relevant xkcd (disclaimer: not an xkcd)

(if you visit that page, click the link in the comic panel. it's cool)

AAHHHHH RECURSION

@hyper-neutrino That's brilliant. Also, why didn't Randall draw such a cartoon?

8:23 PM

user image

@Adám Too busy doing this, I guess

I've been wondering too. With how prominent the meme is (or seems to be) having a relevant xkcd for "relevant xkcd" would be absolutely great

People regularly submit questions to him. Hint hint.

Has xkcd ever been mentioned in an xkcd?

caird coinheringaahing

I don't think so

Well maybe there was an xkcd about a relevant xkcd, but it's on meta.xkcd.com :P

I wish I could express thoughts directly without resorting to such imprecise methods as typing with my stupid fingers in this stupid language

caird coinheringaahing

8:32 PM

just use Jelly's "this is what I mean" builtin

I half suspect Mathematica has a ReadMindAndTransmitThoughtsDirectlyToSomeoneElsesMind builtin, but it's just that no one's found its true name yet :P

Its true name keeps changing; it's always what thoughts you are trying to transmit written in whatever language or medium you are trying to use.

@hyper-neutrino that's great!

@user YES! I found one mention.

caird coinheringaahing

@hyper-neutrino Are we sure it isn't some kind of fae or demon?

No one eat any food offered to you by Mathematica, you might be trapped in the world of Stephen Wolfram

8:36 PM

@hyper-neutrino in think Seinfeld was like that to a lot of older people too

It's too late, the TrapCairdCoinheringaahingIfTheyDiscoverStephenWolframsSecretPlanInStephenWolframsWorld builtin is already implemented

user image

Appears in xkcd.com/1416

@Adám Interesting

I love the interactive ones, Monroe seems to put a lot of work into those

caird coinheringaahing

I do love it when Jelly absolutely demolishes 05AB1E :P 53 vs 36 bytes

apparently chat feeds pull from meta half as often as main, which is why they are noticeably slower. TIL... presumably some of y'all already knew? i didn't :P

8:56 PM

@Wezl codegolf.codidact.com/posts/281956#comment-10576 sorry only just saw this, go ahead

9:09 PM

I am once again asking for solutions on my new challenge codegolf.codidact.com/posts/282075

@hyper-neutrino that was fast!

i am speed

0

Q: Evaluation order of an APL n-train

From Codidact with permission. Description APL trains are a series of functions, that get applied to an argument in this way: (f g) x = f g x (f g h) x = (f x) g (h x) (a b c d e f) x = (a (b c (d e f))) x = a (b x) c (d x) e (f x) Trains evaluate from the right to the left, so in the last examp...

code-golf parsing permutations apl

caird coinheringaahing

@NewPosts I'd steal HN's Codidact answer, but that's cheap :P

hey that looks familiar :P

I am Lobachevski.

caird coinheringaahing

9:17 PM

Out of interest @rak1507, why didn't you post it?

because I'm lazy and Adám said he'd do it :P

you already wrote up the post, it would've taken you like 20 seconds :p

lol, true

caird coinheringaahing

@Adám Lobachevski?

@cairdcoinheringaahing Yes.

caird coinheringaahing

9:20 PM

@Adám Ah, Lobachevski

Yes.

caird coinheringaahing

Any feedback?

Redwolf Programs

I think I'll do some more work on my chatbot library

I'm going to make NP/SP use it eventually

caird coinheringaahing

Imagine needing a diamond to edit mod tags. Made by the Ryan Donovan gang :P

Redwolf Programs

Oh nice, a new user's started posting lots of answers so I can get Late Answers reviews :p

9:23 PM

a staff without a diamond? o.O

caird coinheringaahing

They usually only give staff a diamond if it's likely they'll need it (e.g. the CMs, devs and higher ups)

ah, I see

caird coinheringaahing

Besides, they can usually do stuff directly to the database if they want to :P

true

Redwolf Programs

I'd be absolutely terrified I'd forget part of the UPDATE and ruin everything

caird coinheringaahing

9:25 PM

What can non-diamond staff do?

docs.microsoft.com/en-us/sql/t-sql/language-elements/…

that's what BEGIN TRANSACTION is for :)

Redwolf Programs

I have a habit of managing to destroy production code, development and testing copies, and backups with a single mistake, so I'm sure my superpowers could evolve to find workarounds for transactions too :p

or you could pull a tom scott and just forget to use BEGIN TRANSACTION and destroy a ton of prod data :)

caird coinheringaahing

I love that Tom Scott could be 25 or 45 and I'd have no idea

Redwolf Programs

16 or 60 is a more accurate range honestly

caird coinheringaahing

9:30 PM

> When working on a database, you don't work on the live version. So I was working on the live version, ...

Redwolf Programs

You know how sometimes golfing languages can be painful to use? Well I decided to make one. I got the pain part right, but I might have added too much of that to compensate for reduced golfiness. Can't share any details yet, but it should be released within a day.

As far as I can tell it includes a major feature never before seen in a golfing language.

(Or any languages (that I know of))

caird coinheringaahing

Is it a golfy feature?

exciting

How do you keep a code golfer in suspense?

caird coinheringaahing

9:45 PM

Hmm, there are ~28716 bugs/FRs on MM with no [status] tag

Sounds like a fun cleanup for the staff :P

@Adám Hw do u ⌸p a cdglfr∊suspense? ftfy

further golfing can be accomplished through string compression

caird coinheringaahing

This looks like a minor issue that isn't impacting how things are working which is why we status-declined this. However, if there are more instances of users being awarded the same badge twice please let us know and we may revisit if this is a larger bug. — Rosie ♦ 4 hours ago

Idk, letting lyxal have two silver code golf badges severely affects his ability to brag about having two silver code golf badges :P

Redwolf Programs

The condition that caused that to happen is known, right?

caird coinheringaahing

I guess so, otherwise it'd be [status-reproduced]?

Redwolf Programs

Probably has something to do with one of the conditions getting fulfilled, then unfulfilled, then fulfilled again

9:49 PM

So status-wtf?

Redwolf Programs

Since badges can't get revoked

caird coinheringaahing

Tag badges can

Redwolf Programs

Oh they can?

caird coinheringaahing

Yep

If you delete a bunch of answers, or get a heavily downvoted one, you can lose your tag badge

caird coinheringaahing

10:29 PM

Apparently, I had this answer in my SE app drafts for the past month (converting my comment to an answer) and only realised just now :/

@hyper-neutrino well, (set 'a b) is syntactic sugar for (set (quote a) b), where quote is what the q of setq stands for. setq apparently also takes an even number of arguments, while set always takes two; I don't know why that is.

@hyper-neutrino did you mean the link in the 4th panel of the comic, the link in the 4th panel of the comic in the 2nd panel of the comic, or the link in the 4th panel of the comic in the 2nd panel of the comic in the 2nd panel of the comic?

@hyper-neutrino I think the first client-server database that I used turned transactions on my default, so if you typed "delete from foo;" then all that would happen is that everyone's application would wait for you to ~~commit~~ rollback. I don't know why that setting isn't more popular.

caird coinheringaahing

10:49 PM

For anyone who wants to play it: Unikong - SE themed Donkey Kong style game from 2016's April Fools

@Neil (setq a 1 b 2)=(set 'a 1)(set 'b 2) so in the quoting and multiple assignment cases, it's a feature set' adds

and set is the lower-level work-doer

however picolisp allows direct access to the dynamic environment, so set may actually be a function implemented in terms of replacd

@user this is an epic victory royale

@Neil btw 'a is the same as (quote . a) in picolisp

@Neil oh, okay, that makes more sense. from mathematica's naming Q seems like a predicate lol

@Neil yeah that sounds like... a very wise choice

in lisp (not scheme), predicates usually end with a p (listp, evenp), however picolisp chooses to have no suffix (atom, pair, not) or have a ? (num?, sym?, flg?)

caird coinheringaahing

11:01 PM

2 hours ago, by caird coinheringaahing

i think ? is what racket uses so that makes enough sense to me

Picolisp? What inspired your choice to use that language?

caird coinheringaahing

I'd like to post that soon, feedback would be appreciated :)

@ hyper-neutrino same

@Downgoat Wow, welcome back!

11:04 PM

@Wezl O.o huh how in tarnation did this ping me

hello!

oh sorry for that

haha all good, just curious

caird coinheringaahing

Hey Downgoat, been a while!

How's things?

in Sandbox, 7 hours ago, by Wezl

@person-it-looks-like-i'm-pinging I present to you...

...A new generation of stealth pings!

caird coinheringaahing

Oh please no

11:06 PM

only if you get on my bad side :P

Redwolf Programs

If they won't fix what's practically an XSS, they probably won't fix that :/

> fix

caird coinheringaahing

Hang on, let me rephrase that: Don't do that. Stealth pings got banned for a reason. Pinging can be disruptive, and you should only use it to ping people you're trying to talk to

Redwolf Programs

It's worse than a stealth ping because it works regardless of the time delay

caird coinheringaahing

If you want to "double ping" someone by reply and @ing them, go ahead. But don't ping someone who isn't a part of the conversation

11:09 PM

@Wezl it's probably status-bydesign because placing the name of the user messes up alignment, example:

@Wezl .--.
'--'

Redwolf Programs

I can't find the exact message, but the policy here will stay that stealth pings result in a kick-mute.

gtg for now o/

.--.
'--'

@Wezl Except of course that it doesn't apply when alignment is most important; multi-line code blocks.

\○/

and people probably shouldn't be replying with ascii-art usually anyway

No, but I've often wanted to reply with a code block as an answer to a "how do I" question in chat.

Instead, I end up writing
@user Like this:

And then the block.

caird coinheringaahing

11:12 PM

@Downgoat Jelly, 6 bytes: ḢḤ;ṖḅƓ

@cairdcoinheringaahing good! I'm at work now, so I suppose I shouldn't be here :P but I see a lot has changed

caird coinheringaahing

Given that you're around, I figure the old ping won't be too disruptive :P

@Downgoat Yeah, not all for good unfortunately :(

Now working at the Swift team, and w/ WWDC here, it's a big week!

@cairdcoinheringaahing did the community ever migrate to another platform? Axtell, was never finished, but I recall other people working on other sites

caird coinheringaahing

A few people moved to Codidact, a few to Top Answers

codidact has seen some activity

caird coinheringaahing

11:15 PM

Codidact really took off after Monica's firing (actually, wasn't it created because of that?)

@cairdcoinheringaahing I am idiot

Jelly, 5 bytes Ḥ1¦Ṗḅ

Top Answers Code Golf is basically dead.

@Wezl woah, it looks pretty well fleshed out

caird coinheringaahing

It's pretty good tbh. The biggest issue is activity - it gets maybe 1 question every few days, if that

Plus, I can't speak for others, but I'm definitely "sunken-cost fallacy"-ed for CGCC

@hyper-neutrino the chaining in this answer really confuses me. Why does ) not create a new monadic chain so that it's parsed as (×BS)€(ċ>1)# instead of (×BS)ċ>1)#?

aw, did something happen while I was at dinner again :P

hey there Downgoat :D

@cairdcoinheringaahing I believe µ creates a new chain and groups the old chain into a subchain which if you apply a quick to, loses the "new chain" meaning

don't quote me on that

@Adám Not sure if you meant to ping me there

Unrelated String

11:29 PM

yeah I think the quick subsumes the chain into the next chain

but how I see it is ((×BS -- €)ċ>1)#

@user That's what you get for having such a user name ;-)

>(

Unrelated String

like I'm pretty sure the way applying quicks after separators works is if the current chain is empty it just substitutes the last chain

yeah that's how i believe it works

caird coinheringaahing

11:30 PM

Yeah, it's got a (chain or chains) condition in the parsing

Unrelated String

yeah the exact line is something like chain.pop() or chains.pop() except I think popping from an empty list in Python is an error so it's probably more like chain.pop() if chain else chains.pop()

caird coinheringaahing

Interestingly, I think µ doesn't actually create a new monadic chain, it creates a new variadic chain when followed by a quick: Try it online!

Unrelated String

:|

caird coinheringaahing

But I could be wrong, chains and quicks are weird

Shouldn't ^ be [[[1, [1, 2, 3]], [2, [1, 2, 3]], [3, [1, 2, 3]]]?

Unrelated String

speaking of ) i'm trying to golf hyper's train evaluation order solution and it may or may not be biting me in the ass that ) just isn't allowed at the start of a line

caird coinheringaahing

11:33 PM

That's what ,¶ç€ does anyway

Unrelated String

i say may or may not because i'm not sure it would actually work either way

caird coinheringaahing

@UnrelatedString Why would you start a line with )?

Unrelated String

as some kind of jank substitute for Rµ

except for also the whole

subsuming it into the next chain bit

caird coinheringaahing

I don't even think that would work as ) retains the left argument, so the bit after the ) would be dyadic

@cairdcoinheringaahing i don't see anything wrong with that

it could be starting a new monadic chain

it's just not ending one

oh. wait. we might have different interpretations as to what "create" a new monadic chain means

Unrelated String

11:35 PM

yeah come to think of it the "retains the left argument" caveat is also probably just a weird way of explaining how it doesn't really act like a separator to begin with

caird coinheringaahing

Speaking of golfing hyper's answer: -1 byte

Unrelated String

nice

does it end the current chain and create it as a monad, or does it end the current chain variadically and create a new one being a monad?

Unrelated String

...of course

@cairdcoinheringaahing thank

caird coinheringaahing

11:36 PM

If you ever have R and increment/decrement next to each other, there's almost always a one byte version :P

Unrelated String

R in general is usually suspect

@hyper-neutrino Actually the comic has three clickable regions

caird coinheringaahing

7 bytes, assuming 1 can output as 1 rather than [1]

Unrelated String

nice

it's always where it's useless that I try to do weird stuff with replacing normal stuff with ƒ

@Bubbler Oh wow, you're right.

Unrelated String

11:45 PM

I've just been trying extreme rearrangements and seeing if I've done the accounting wrong in my head and they turn out shorter

caird coinheringaahing

5 bytes porting xash's J answer :(

Unrelated String

ofc

caird coinheringaahing

I hate it when a port is shorter than an original, clever answer

(cc @hyper-neutrino - some golfs for you)

oh :/ well i'll probably just edit both in, thanks

will do it in a bit

caird coinheringaahing

It annoys me to no end that Ṛ is reverse digits on integers, but U is a no-op, rather than reverse range ಠ_ಠ

Unrelated String

11:53 PM

the classic

caird coinheringaahing

If it were, 4 bytes in Jelly :/

Uh, FU Jelly, for not being golfier.

i wish jelly had grade down

@Adám Hey, at least this way other languages have a small chance of beating it :P

@hyper-neutrino Adding grade down would be such an upgrade, wouldn't it?

11:56 PM

reverse+grade up doesn't work on non unique arrays right?

@Adám lol, good one

caird coinheringaahing

Also, for some reason, when reducing n-wise with ƒ, the initial value is prepended to each list (in this example with ;): tio.run/##y0rNyan8/z/I2ujYpP@GBkGH2x81rTk66eHOGUA68j8A

@hyper-neutrino No. Try it online!

@hyper-neutrino Negate and grade up maybe?

oh.

no still won't work

:( It's a common trick in Scala

@hyper-neutrino It seems to wok here

*work (not editing that because pings)

« first day (3782 days earlier) ← previous day next day → last day (1063 days later) »

Transcript for

Jun '217

The Nineteenth Byte

The Nineteenth Byte: General discussion for codegolf.stackexc...

join this room
about this room

00:00

06:00

12:00

18:00

all times are UTC

site design / logo © 2024 Stack Exchange Inc; legal

mobile