The Nineteenth Byte

DJMcMayhem

18:00

C golfing question: which compilers allow f(a,b) in place of int f(int a, int b)?

quartata

@DJMcMayhem GCC is fine with K&R for the most part.

DJMcMayhem

You're right, GCC seems very forgiving: Try it online!

At least, for C. C++ less so

quartata

Yeah, most of the weird weak typing possible in C is not allowed in any C++ compiler.

Part of the standard.

Kritixi Lithos

@DJMcMayhem Try it online!

Erik the Outgolfer

Actually, it seems TCC is even more forgiving, given that you do not even need return statements in functions, and that it's based of GCC.

Kritixi Lithos

18:10

@EriktheOutgolfer You don't need returns in GCC under special circumstances: tio.run/nexus/…

2

DJMcMayhem

Woah. That's a huge golfing tip. What are those circumstances?

Erik the Outgolfer

Huh? I'd swear this didn't work earlier that I had tried.

Anonymous

@DJMcMayhem The implicit return type is the result of the last expression (usually/sometimes)

Erik the Outgolfer

@DJMcMayhem Yeah, it even beats preprocessor solutions.

Anonymous

Err, rather, it's stored in the first argument

Kritixi Lithos

18:12

7

A: Tips for golfing in C

Assign instead of return. This is not really standard C, but works with every compiler and CPU that I know of: int sqr(int a){return a*a;} has the same effect as: int sqr(int a){a*=a;} Because the first argument is stored into the same CPU register as the return value. X-Macros Another u...

DJMcMayhem

@Mego Then why doesn't this work: Try it online!

Anonymous

You have to store it in a

DJMcMayhem

Nevermind

Then why does this work? Try it online!

Anonymous

That's weird

Kritixi Lithos

@DJMcMayhem Because you are assigning something to something

quartata

18:14

That might be a GNU C extension.

Anonymous

I always thought it was the first arg

quartata

Oh wait nevermind

I misread it

Kritixi Lithos

Apparently when I do a+=2 (or even b+=2) it returns 0

DJMcMayhem

Also, why does this work Try it online! but this doesn't: Try it online!

Anonymous

But when you do a+=a, it works

DJMcMayhem

18:15

(I'm filled with questions today)

Anonymous

It must be because a temporary copy of a is pushed on the stack, and that is implicitly popped and returned

Anonymous

a+=2 probably gets optimized

Kritixi Lithos

@DJMcMayhem But this works: Try it online!

Anonymous

@DJMcMayhem Second one is a constant function that doesn't depend on the args, so it gets optimized

DJMcMayhem

@KritixiLithos woooooaaah o_O

Kritixi Lithos

18:17

It's like magiC

2

New Main Posts

0

Q: Find Recursively Prime Primes

The Recursively Prime Primes is are sequence of primes such that p(1) = 2 p(n) = the p(n-1)th prime Here is an example of how one might calculate the 4th Recursively Prime Prime. p(4) = the p(3)th prime p(3) = the p(2)th prime p(2) = the p(1)th prime p(1) = 2 p(2) = the 2nd prime p(2) = 3 p(...

DJMcMayhem

I regularly use C, I'm obsessed with code-golf, how have I never known this before?

Kritixi Lithos

@DJMcMayhem That's how I felt when I saw this tip for golfing in Processing being used in an answer.

DJMcMayhem

It's even cooler when it's a language you use regularly. Good vim answers blow my mind

Doorknob

@KritixiLithos wait, what?

That's so bizarre

Riley

18:31

@Doorknob I think eax is just a convenient register, so the compiler puts whatever it can there, and that happens to be where it looks for a return value later.

Dennis

@Doorknob Not really. gcc doesn't try very hard to optimize by default, but it still recognizes int c = 42; as useless and optimizes it out. With -O1, the int c = a*b; version also stops working.

Doorknob

I mostly meant the whole "return without return" thing in general

Kritixi Lithos

@Dennis But why is int c = 42; useless but c = 42 + (b=0); not?

DJMcMayhem

This is shorter: Try it online!

@KritixiLithos because it forces the compiler to evaluate b?

Dennis

@KritixiLithos Both are useless, but the first is easier to recognize.

Anonymous

18:35

@KritixiLithos Because it references one of the args. Since gcc isn't trying too hard to optimize at default optimization, it doesn't expend the effort to realize that is the same.

betseg

is youtube down

New Sandboxed Posts

0

A: Sandbox for Proposed Challenges

Solve The Halting Problem Write a program that will take the text of another program as input. Your program will examine the code and output a result that the program either halts or will keep running forever. That's impossible? Nonsense! To show how wrong you are, I've written this program tha...

Kritixi Lithos

@DJMcMayhem But int c = 42+b-b; doesn't work...

@betseg Not for me

betseg

gives 500 for me

Business Cat

downforeveryoneorjustme.com/youtube.com

betseg

18:37

> It's not just you! youtube.com looks down from here.

DJMcMayhem

@KritixiLithos super weird

Dennis

@KritixiLithos That's also an easy optimization, as -b+b is superfluous in all well-defined situations. This isn't the case for /b*b; you have to know the value of b to know the result.

Business Cat

Other similar sites say it's up though.

Dennis

Oh, it was *b/b, not /b*b.

Pavel

Is b an int or a double?

DJMcMayhem

18:39

Int

@Dennis because it might be zero or out of bounds?

Pavel

3/2*2==2

Dennis

@DJMcMayhem Yeah, it looks like gcc has reservations about this, even with -Ofast. Division by 0 is still UB though, so the compiler could technically optimize out *b/b out if it wanted to.

So is signed integer overflow.

TuxCopter

@Downgoat Yeah, basically >_>

Downgoat

@TuxCopter In that case I am dead

TuxCopter

Well no, visibly the angine -> angina is only fr -> en

Pavel

18:52

Is angina sore throat?

TuxCopter

@LegionMammal978 No, this is welsh

Riker

Nov 28 '16 at 17:08, by Eᴀsᴛᴇʀʟʏ Iʀᴋ

LegionMammal978

19:14

@Riker Yr wyf yn $100% yn rhugl yn y Gymraeg wyf yn golygu dod ar ymladd mi MBGI (mewn bywyd go iawn)

Riker

lol

LegionMammal978

Huh

I translated the lyrics to "Never Gonna Give You Up" and got the TTS to read it

TuxCopter

@LegionMammal978 There's nothing really surprising, Old Frisian shares a common ancestor with Old English

LegionMammal978

It (the Welsh TTS) sounds like it's saying stuff in English (or at least the same syllables)

Luke

@TuxCopter Old English actually "evolved" out of an old germanic language

The language that gets closest to that and is still spoken today is Frisian.

TuxCopter

19:24

@Luke Old English and Old Frisian has the same ancestor which is a child of Old Germanic

Luke

Yes

TuxCopter

@LegionMammal978 Welsh has the same phonemes of English with some exceptions, so it's not surprising

Riker

Peidiwch â gadael eich breuddwydion fod breuddwydion
Ddoe dywedasoch yfory
Felly dim ond yn ei wneud
Gwnewch eich breuddwydion yn dod yn wir
Dim ond yn ei wneud

@LegionMammal978 relevant ^

lol google prettifier thinks welsh is code

Pavel

If you have it on, won't it force anything formatted as code to be highlighted?

Riker

yeah, but it has particular formatting for welsh

single characters are green, and the first word of every line is purple

Pavel

19:30

Screenshot, please?

TuxCopter

@Riker CMC: Make a programming language using Welsh keywords

Riker

@Pavel blue highlight bc my message

@TuxCopter "for"?

Pavel

@TuxCopter Welsh is a subset of Latin-1, right?

Riker

like using welsh versions of keywords?

@Pavel yeah

TuxCopter

@Pavel The welsh alphabet is the latin alphabet + âêîôûŵŷ

Riker

19:32

once @DJMcMayhem figures out people's python then I'll work on welsh

it's practically the same thing

Pavel

Interpreter: Take input, feed through Google Translate, feed into Python.

Riker

no bc strings

what if you actually want to put in 'peidiwch' as a string?

you can't, because the translate would replace is with 'do'

muddyfish

@Riker every developer: "Why would anyone want to do that?"

Pavel

Ignore strings/names.

TuxCopter

tra 1:
    brint("Helo, Byd!")

Riker

19:34

@muddyfish yeah but for consistency

@Pavel how?

easier said than done

muddyfish

@Riker not really

Pavel

Eh, regex.

muddyfish

you just feed it through the tokenize module

Riker

ah

I'll try to do that later then

whenever I remember

Pavel

Leave anything matching /".*?"/

Riker

19:35

nested?

muddyfish

@Pavel commented out?

Pavel

If it's commented, then it doesn't matter what you do with it.

I supposed exec would be a bit broken.

muddyfish

@Pavel not if it's not closed

Pavel

/'''.*?(''')?/

Obviously implement for both ' and ", remember to escape \", etc.

Seems simple enough.

Riker

try it

it's harder than it looks

regex just isn't designed for arbitrarily nested stuff

Pavel

19:38

Why are we arbitrarily nesting anything

What exactly is being nested?

TuxCopter

@Riker Hence the parsing HTML with regex meme

Riker

yeah

@Pavel quotes

you can't make 1 or even a bunch of regexen to match quotes perfectly, because they can be arbitrarily nested

Pavel

Uh, you can't nest quotes.

Riker

since when?

Pavel

Like, can you give an example?

trichoplax

19:39

You can nest mixed quotes without ambiguity

Pavel

So '"'foobar'"' is literally the string "'foobar'"?

trichoplax

"this is a quote about 'this quote which quotes "this one" ' "

Pavel

I did not know that.

Riker

@Pavel no, that's just <error>

trichoplax

Depends on whether your language recognises that, but you could in principle

Riker

19:41

it would be the string of ", then the command foobar, and then " again

Pavel

We're talking about Python.

Riker

but that would error in most langs

Pavel

So, how do you nest quotes, then?

Riker

 "this is a quote about 'this quote which quotes \"this 'test \"test\" ' one\" ' "

trichoplax

Ah right. In python you can only nest one - it doesn't recognise beyond that

Pavel

19:41

You can use a lookbehind to check for \

Right?

DJMcMayhem

@Riker I have literally no clue where to start

Riker

prolly tokenizer module like muddy suggested

@DJMcMayhem I'll help when I get time if you want

just finished raging at sans, got some schoolwork to do, should be done in 15 min

DJMcMayhem

Haha

Riker

it's hard ok

and the disturbing smile

muddyfish

@DJMcMayhem I would tokenise it, replace NAME tokens with your tested values with the builtin ones and then untokenise it and then run exec on it or something

Pavel

19:46

/"(?<!\\).*?"/

muddyfish

See tokenize

Pavel

There, matches " quotes. Use or to make it work with ' quotes.

Riker

@muddyfish this is cool module thanks for telling me about it

Pavel

Wait no I put the lookbehind in the wrong spot.

Riker

rip

Pavel

19:49

Pretend it's before the last "

muddyfish

@Pavel "Hello"' '"World"

Pavel

Matches "Hello"and "World"

That string it an error, no?

muddyfish

@Pavel you're missing the space

@Pavel it's perfectly valid syntax

Riker

>>> "Hello"' '"World"
'Hello World'
>>>

Pavel

It's three strings in a row.

Riker

19:52

@Pavel concatenation by default

Pavel

Oh, I didn't know python did that.

Riker

yep

only certain cases

muddyfish

@Pavel it's really to provide strings separated across lines

Pavel

Like I said, it doesn't work with ', you can trivially modify it and use or. and then you get 3 strings instead of 1, which it technically is.

How many special cases can you have for Strings >_>

I suppose I also need to account for r"foobar\", if I recall how r"" works.

Riker

raw

backslashes are literal, not used to escape stuff

it's really just escapes turned off iirc

Pavel

19:55

So yeah, case for that.

Wait, python 3 has f"" now.

Riker

@Pavel also unicode

Pavel

That breaks everything

Riker

but that's prolly pretty easy

Pavel

Yeah, unicode doesn't seem like an issue, just a check for u?

Exec is kill tho

muddyfish

ATaco

19:59

That's a bit of a horrifying Regex.

8

Riker

@DJMcMayhem -1 peoples python does not pop up on google for "peoples python dj <your name>"

muddyfish

@ATaco hg.python.org/cpython/file/3.6/Lib/tokenize.py#l168

Riker

or any combination of those words

@ATaco Congratulations, you have just won the understatement of the year award!

muddyfish

I don't even know regex

Riker

good

you should stay that way

seshoumara

20:04

hello

ATaco

Regex is a very useful tool and the moment you learn it you will wish you never did.

Riker

@seshoumara o/

Business Cat

Or you learn Retina, which is even worse than normal regex.

seshoumara

If I see an answer that isn't golfed, and I mean verbose C or Java program, would downvoting be in the spirit of this site or not?

or any language for that matter, python etc

ATaco

You can flag for not an answer.

If there was obviously no effort put into golfing it, using a language difficult to golf in is to be rewarded.

seshoumara

20:09

The answer does what is needed and no, it was an easy language to golf in. Even if it wasn't, variable names are verbose, so not even that.

ATaco

Leave a comment, flag for non-answer.

muddyfish

@seshoumara flag it then

ATaco

Assuming it is a code-golf

muddyfish

@ATaco I've flagged non-code-golf answers as nongolfed in review before

needless to say they were rejected

DJMcMayhem

@Riker sowee ;_;

Riker

20:12

lol

Conor O'Brien

CMC: find the pattern

0 -> 2
1 -> 12
2 -> 59160
3 -> 110160221250592251028406545681140772978982039413717521677966633224768994790960

Riker

@DJMcMayhem V's repo pops up for "dj github" in my search history tho so I found it

@ConorO'Brien there isn't one?

Conor O'Brien

oh, there is

DJMcMayhem

@Riker it also shows up if you search my username

Riker

oh true

DJMcMayhem

20:14

As well as some really random imgur posts I've never seen before

WTF?

Riker

@ConorO'Brien that was the "i am too lazy to try to figure it out so heres an answer half hoping it's right but knowing it's not" answer

Conor O'Brien

@ConorO'Brien programmed in 69 bytes in stacked

@Riker lol

Riker

@DJMcMayhem what, "djmcmayhem"? nope

all I get is twitter + GH + SE

hahahahaha

DJMcMayhem

Really? I get V as the second link

Riker

oh it does

GH meant your repos

I was commenting on the lack of imgur

@DJMcMayhem I found your dumplogs from ascension.run/dank.ninja, the nethack server

DJMcMayhem

20:16

Try images

Riker

ascension.run/userdata/DRHamJam

for user DRHamJam

and your current one, djmcmayhem

ascension.run/userdata/DJMcMayhem

DJMcMayhem

That's funny

Riker

hahahaha @DJMcMayhem I found a aviation.se question you commented on once

tons of images from SE posts you've commented on, but no "weird imgur stuff"

DJMcMayhem

@Riker That's hilarious. Link?

Riker

9

Q: What aircraft did this canopy come from?

This canopy was found near Wetumka, Oklahoma in a small creek running through my best friend's property. The canopy is about 12 feet long. Can anyone tell me what aircraft it came from, or who I could contact to ask? A loving cup from 1906 dedicated to a Miss Grace Walling Spore from the USS All...

military aircraft-identification

Please do not vandalize your own posts. If you really want to delete it, either hit the delete button, or flag it and ask a moderator to delete it for you. — DJMcMayhem Oct 17 '16 at 1:10

DJMcMayhem

20:20

Hahahaha

Riker

@DJMcMayhem imgur.com/gallery/ADcSE imgur gallery you once commented on

that's the only imgur stuff

DJMcMayhem

Check edit history, that's probably something charcoal reported

seshoumara

@ATaco hmm, flagging an ungolfed answer is a bit too much, even for code-golf. The answer shouldn't win, maybe a few downvotes and a comment, but it is still a valid answer, is it not?

Riker

nope

the consensus is not golfed = invalid

Dennis

34

A: Definitive policy about answers not meeting the challenge specification

Scope As I see it, there are five types of invalid answers: Answers that produce incorrect results. This is the most common type, and usually an accident. Answers that produce correct results, but break a rule of the challenge, ignore parts of the spec or violate a loophole. For example, ans...

Item 3 of the scope, specifically.

muddyfish

20:23

I think this is probably the most obviously NAA answers has appeared in review

DJMcMayhem

Yeah, just saw that

Riker

@Dennis mod hammer plz

seshoumara

ok, I'll stick to the policy with no regret then

Riker

yep

muddyfish

does everyone else see this as your own reviews? They should be Martin's in the first posts queue

wat

20:27

> Unix has been used as a brand name for various products including book shelves, ink pens, bottled glue, diapers, hair driers and food containers.

-- Wikipedia

Riker

@muddyfish yes

seshoumara

so, is there a queue for flagged answers to be reviewed?

muddyfish

@Riker bug?

Riker

@seshoumara that's it

@muddyfish think so

@seshoumara VLQ generally

muddyfish

@seshoumara A moderator only one

Riker

20:28

well yeah, but very low quality flags also put it in the low quality posts queue

@muddyfish hm, the tokenize module strips out delimiters (as it should), do you know if there's a way to find them back?

muddyfish

@Riker do you need them?

(hasn't a clue what the technical term for delimiters is)

seshoumara

ok, thanks

Riker

@muddyfish yes

for outputting the code w/ replaced words

muddyfish

so you don't get the same(ish) thing as you put in when you do untokenize?

AdmBorkBork

@muddyfish Why would my review history show Martin's?

Riker

20:32

@muddyfish 1 sec

@AdmBorkBork the URL has the userid of 8478

martin's user id

AdmBorkBork

Oh, hah, didn't even notice.

New Main Posts

0

Q: How did I end up with this FizzBuzz?

FizzBuzz is so simple, bet you can do it backwards. In this challenge, you will be given the length of the FizzBuzz string and must give the positive integer that produced that string. Description To break this down, a FizzBuzz string for n is generated by the following algorithm. Start with ...

code-golf

0

Q: Calculate ELO Rating Expected Score

Your task is to calculate the expected chance of winning for 2 players in some game, each with their own Elo Rating. Player A has ELO Ra and player B has ELO Rb The expected score for Player A (Ea) is: 1 / (1 + 10(Rb - Ra) / 400). There is a similar equation for Player B (Ea): 1 / (1 + 10(Ra - R...

code-golf math

LegionMammal978

lol, was just reading through O'Hair v. Paine

The allegations are pretty silly to begin with

Riker

Martin peter
	return "food"
you "pls test me"

@muddyfish ^ is input

should output:

False for
    return "food"
print "pls test me"

nonsense but it works as a test

seshoumara

@Dennis today I was getting incorrect results from a dc code that I was running on TIO

Riker

20:35

but it doesn't have some spaces, it actually outputs

Falsefor
    return"food"
print"pls test me"

no spaces between a keyword and the next

muddyfish

try Untokenizer().compat(tokens.next(), tokens)

Dennis

@seshoumara There's not much I can do with that information. I'd need the permalink of whatever you tried to run and the expected output.

seshoumara

@Dennis Example: AZ5E^z-f taken from my answer codegolf.stackexchange.com/a/110768/59010 The 5E trick wasn't working, see details there.

Riker

@muddyfish "StopIteration"?

muddyfish

(I have no idea what that might do but it looks older)

@Riker catch that. It just means it's done?

Riker

20:40

ah

muddyfish

actually

no

I have no idea what it's meant to do

Riker

lol

muddyfish

ok

Riker

idk either

muddyfish

create an Untokenizer object

run that function on it

catch the error

Riker

20:41

which function

muddyfish

compat

Riker

@muddyfish it doesn't output anything though, that's the problem

Dennis

@seshoumara Where does it work? 5Ep prints 59 on my computer, not 64.

DJMcMayhem

Just golfed 28 bytes off of someone else's bflack program :D

Riker

nice!

wat

20:41

cool

muddyfish

and look in Untokenizer.tokens

Riker

ah

muddyfish

maybe

wat

hey guys if anyone wants to submit new retina answer to the multiply challenge, do it now, the bounty ends in 3 days

Riker

@muddyfish []

seshoumara

20:42

@Dennis that's wrong, at least based on the dc version I've always had. This input trick in base 10 using hex letters surely is used across this site, nothing new.

muddyfish

are you running from the interpreter or a file?

Riker

file

not the repl

I assume that's what you mean by interpreter, the repl

muddyfish

could you pastebin it?

Dennis

@seshoumara I'm not sure what you mean by wrong. It's what dc does on both my desktop computer and TIO, both from a file and in the REPL.

Do do perhaps have a different version?

Riker

paste.ee/p/SuplR @muddyfish

seshoumara

20:45

@Dennis Most likely. Mine is dc (GNU bc 1.06.95) 1.3.95

Dennis

Both TIO and my desktop are running dc (GNU bc 1.06.95) 1.3.95.

OK, now I'm confused.

Riker

@seshoumara OS?

@Dennis ^?

it could be a linux/mac/windows thing, or different distros

muddyfish

do I get a peoples.txt?

Dennis

openSUSE at home, Fedora on TIO.

muddyfish

and assignments.txt

seshoumara

20:46

let's discuss further on chat.stackexchange.com/rooms/44639/bash-sed-and-dc if you wish

Riker

@muddyfish neither are particulary important, but pastebinning now. peoples.txt is the input code, and assignments.txt is a massive dict

paste.ee/p/C0giG

scroll down on the paste for more of it

DJMcMayhem

Scratch that, I just golfed 159 bytes off of a brain-flak answer. :D

Riker

nice!

how long was it to start?

wat

> scratch

DJMcMayhem

Theirs is 223, mine is 64

AdmBorkBork

20:50

@Riker 160 bytes

wat

Scratch that, I just golfed 3 blocks off a scratch answer

Riker

@DJMcMayhem nj

AdmBorkBork

Wait, I thought Brain-Flak had to be balanced? How did they have 223?

wat

> OpenSUSE

Why?

DJMcMayhem

@AdmBorkBork +3 for a flag

Dennis

20:51

Why not? It's an awesome distro.

AdmBorkBork

Ah, that makes sense.

wat

49 secs ago, by wat

Why?

Dennis

Everything works as intended. It's a very nice looking and stable KDE, and I had no problems with upgrades so far. Packages are not quite bleeding edge, but new enough and without weird bugs. That's a lot more than I can say about the distros I've tried before.

Riker

@muddyfish sorry, I have to go, thanks for the help you gave

muddyfish

@Riker I'll ping you when I get it working

Riker

20:57

thanks!

betseg

> bleeding edge

that reminds me,

sudo pacman -Syu

woah 3 updated packages in 2 hours

Riker

poll: how long is your shell profile/startup settings (whatever you use, sum of them if multiple) in lines and characters?

betseg

i use zsh, both are zero

Poke

my .profile-user is 73 lines. 1991 bytes

Riker

@betseg fixed

Transcript for