The Third Stack

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MegaTom

17:38

Brain-Flak, 97 bytes (96 for code, 1 for flag) {}<>(())({<(<()>)<>({<({}[()])><>([{}]())<>}{})<>(<{}>())<>{({}[()])<>([{}])<>}{}<>({}{})>()}{}) Run with the -a flag. Try it online! Explanation: {} #skip the first open bracket and <>(()) #place a 1 on stack B, representing the nesting d...

This beat the older solution by a good margin.

2 hours later…

DJMcMayhem

19:25

CMC: Stack-clean mod 2 snippet

Wheat Wizard

Oh I've done this

lemme see if I can find it

DJMcMayhem

For reference, pushing two and using the general purpose modulus is (()())({}(<>))<>{(({})){({}[()])<>}{}}{}<>([{}()]{}) which is 52 bytes, and the non stack-clean mod 2 is: (({})){({}[()]<>)}<> for 20.

I'm sure that hardcoding 2 into the algorithm can come up with something shorter than general purpose modulus

Riley

(()()(<>))<>{(({})){({}[()])<>}{}}{}<>([{}()]{}) is 48 (the general mod with 2 hardcoded)

DJMcMayhem

Oh yeah, that's right, PPR

I am so bad at that

Riley

44 bytes: (({})(<>))({({}[()]<>)}{}){({}[()]<>)}{}{}<>

>0 only, and gives 0 or input

I guess that's just is_even not %2

DJMcMayhem

19:38

Yeah...

And what the heck is going on here: Try it online!

Riley

[({}<(())>(<>))({({}[()]<>)}{}){({}[()]<>)}{}{}<>] 48 bytes

What are you trying to do?

DJMcMayhem

Push mod 2 of each input

But for some reason it says 3 % 2 == 2

Try it online!

Ahh, there we go

Mod 2 is actually ({}(<(()())><>))<>{(({})){({}[()])<>}{}}{}<>([{}()]{})

Wheat Wizard

20:04

CMC: Implement the Klein-4 group

(In brain-flak)

MegaTom

21:00

On another note, I have a new, shorter set of logic operators.

tio.run/nexus/…

It is all based on the idea of ({...}()), using an if block to get the value to push.

Wheat Wizard

@MegaTom Nice! I'll add them to the wiki

Now to golf every answer that ever used a not

Riley

Can AND be ({<{}>{}(<()>)}<{}>)

It's 4 bytes shorter.

MegaTom

No. on 0,0 yours gives 0,0 not 0

see: tio.run/nexus/brain-flak#@69RbVNda1ddq2GjoWmnWQviaP7/b8BlCAA

Wheat Wizard

21:16

@MegaTom you should make a new answer for this question

Riley

@MegaTom Yep, that makes sense.

What about ((){<{}>{[()](<{}>)}}<{}{}>) for NAND? I just removed ({}) which I think will always pop and push 0.

Wheat Wizard

jeez we have to golf xnor

DJMcMayhem

@WheatWizard Done

50% off

Wheat Wizard

xor

DJMcMayhem

21:32

Woah.

I think I just golfed equals without realizing it

Wheat Wizard

wait what?

then it it not xnor?

DJMcMayhem

Xnor and equals are pretty much the same

Wheat Wizard

No?

DJMcMayhem

Yeah?

> The two-input version implements logical equality, behaving according to the truth table to the right. A high output (1) results if both of the inputs to the gate are the same. If one but not both inputs are high (1), a low output (0) results.

Wheat Wizard

It does look like you made equals

Oh for the wiki we were taking to values and seeing if their truthiness was the same

eg xnor(6,7) = 1

DJMcMayhem

21:34

Oh, I thought input was restricted to 1 and 0?

Wheat Wizard

DJMcMayhem

That's for the challenge?

Wheat Wizard

but equals is much more useful than xnor so...

DJMcMayhem

Yeah, a shorter equals will be really useful

I golfed it without realizing, lol

Wheat Wizard

@DJMcMayhem I don't think so. As far as I could tell we were just golfing informally

DJMcMayhem

21:35

And it looks like there's still some PPR in there that could be removed

Not sure though

Wheat Wizard

I doubt it

Looks solid

Riley

Looks good to me.

DJMcMayhem

Ah, on the challenge it is restricted to 1 and 0, but xnor is shorter too: ({}{}[()])

Actually, I don't think that's valid cause it'll sometimes give -1

Wheat Wizard

here is a true xnor its a little longer

DJMcMayhem

Just added my new equals to the wiki

Wheat Wizard

21:39

Nice, I have updated the logical operators

DJMcMayhem

@WheatWizard s/curtesy/courtesy

Wheat Wizard

I thought it looked weird but my spell checker was fine with it

we need to work on the wiki

we still haven't added that less than zero that we keep saying we need to add

DJMcMayhem

Yeah, we still don't have a general purpose less/greater than

Ninja'd

I'd add it, but I'm not sure what the shortest one is

Wheat Wizard

same

DJMcMayhem

I wonder if it would be worth adding a few sections that don't have snippets, but rather go over useful concepts

Wheat Wizard

21:42

yeah that would be a good idea

DJMcMayhem

Such as constant-multiplication, the third stack, evaluating loops, integer golfing, integer distance golfing

Wheat Wizard

yeah all of those things seem like good ideas

though third stack is a rather complex topic

DJMcMayhem

Yeah, maybe just the basic examples of it, e.g. ({}<foo...>)

Wheat Wizard

I'd make an entire page, I'm just saying it ain't gonna be easy

I could probably borrow from the tips page rather heavily to make it easier

DJMcMayhem

When should/shouldn't we credit users for coming up with snippets?

Wheat Wizard

21:48

I credit everyone but myself, you and 1000000000

DJMcMayhem

Wheat Wizard

I guess I should really ask people if I can include their snippets.

DJMcMayhem

There's nothing wrong with that, but I wonder if it would be worthwhile to credit those three also

I think most of them are probably you though

Probably >70%

Wheat Wizard

or ask them what license its under

Some of them are certainly not work citing, for instance add and subtract are very easy to find even for beginners

DJMcMayhem

Yeah, sure

Riley

21:51

I think there is only one of mine on there, but feel free to use anything of mine without credit.

Wheat Wizard

With a short search this is the shortest less than zero I could find, I'm going to add it to the wiki if no one has any objections

DJMcMayhem

Is there also a general purpose less than? e.g. (a < b)

Wheat Wizard

Less than can be made pretty simply from less than zero

just subtract and run

Riley

Here is < 0 in 62 bytes

I'm pretty sure that's stack clean

Yep, it seems to be clean

MegaTom

tio.run/nexus/brain-flak#FcixDQAwDALBdaDLAMiLRJkEMbtjV6/…

The above link is to grater than or equal to zero. in 50 bytes.

Riley

22:07

48 byte <0

@MegaTom Why ((<{}>)) instead of (<()>)?

MegaTom

@Riley I don't know. It has bean a bit since I wrote the code. I have no clue how it works.

DJMcMayhem

Hmm, well I've got an 18 byte equals, but it isn't stack clean: ({}[{}]){{}}([]{})

It could probably be modified to be stack clean though

MegaTom

@DJMcMayhem looks stack clean to me. can you give a counter example?

DJMcMayhem

Try it online!

It consumes every consecutive truthy on the main stack

Riley

46 byte <0

MegaTom

22:53

@Riley your last solution (46 byte) seams not to work.

Wheat Wizard

23:06

@Riley Neither does your 48 byte one

Riley

23:33

I don't know why it worked when I was testing it. It shouldn't.

try this for 54

And this <= 0 in 52 bytes

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