The Nineteenth Byte

9:01 PM

Because we're your friends <3

adapter AdapterName for SomeInterface<T>{
     void give(T) -> void add(T)
}

I'm also considering making automatic adapters

Sherlock9

@Haskell people: How does fix (n&k)q=[x|x<-[foldl(\z->(-1)*div((k*z),(1-k)))(q*k-mod(k-1)q)[1..]],x>n*(k-1)]!‌!0?

Nathan Merrill

@QPaysTaxes for computers, not people

Sherlock9

When it takes z in the div it says z is for infinite type

@QPaysTaxes t(-__-t

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@QPaysTaxes ಠ_ಠ

Nathan Merrill

9:03 PM

actually, I need it to have a name

Sherlock9

So is telling people to stop using a language when they're asking for help

@QPaysTaxes Mine too :P

I use middle fingers as a joke among friends

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@Sherlock9 ಠ_ಠ

2 mins ago, by Cᴏɴᴏʀ O'Bʀɪᴇɴ

@QPaysTaxes ಠ_ಠ

Sherlock9

So to me, it was friendly gesture of annoyance. I apologize for not making that clear

Cᴏɴᴏʀ O'Bʀɪᴇɴ

We're good people, don't worry

Sherlock9

@QPaysTaxes Well, we bash a few languages, but I've never seen Haskell bashing so I didn't know if it was serious or not

Fair enough XD

Cᴏɴᴏʀ O'Bʀɪᴇɴ

9:09 PM

Assembly is perfect.

El'endia Starman

TIL Assembly is the perfect language.

flawr

"perfect"

FryAmTheEggman

MOV ELENDIA, PERFECT_LANGUAGE
SEGFAULT

Cᴏɴᴏʀ O'Bʀɪᴇɴ

That's why I like semicolon comments

cat

@QPaysTaxes :P

LegionMammal978

9:12 PM

Hey

cat

Hey!

El'endia Starman

@AlexA.: Just early-voted for Bernie since I'll be out of state on primary day. :D

LegionMammal978

strawpoll.me/7420086

New Main Posts

0

Q: Federal income tax calculator for procrastinators

Today is Tax Day! Oops. Well, today is tax day if you are a resident of Maine or Massachusetts. So you're probably still completing your return and need a calculator for when you get to Line 44. Given an input of taxable income (US$, accurate to 2 decimal places) and a string representing fil...

El'endia Starman

@QPaysTaxes I can't vote for him though.

I would actually slightly prefer that Trump be the nominee over Cruz because he is so obviously incompetent that I'm sure he wouldn't hold office for very long.

Digital Trauma

9:20 PM

@QPaysTaxes Hi

cat

Does anyone want an invite to retrocomputing.stackexchange.com?

Doorknob

You know you can get into private betas without having committed, right?

flawr

@cat What is this?

El'endia Starman

@cat Invites are actually not necessary. Go to the Area 51 page and then click the "Visit" button.

Doorknob

@QPaysTaxes You don't need one

cat

9:21 PM

:o

El'endia Starman

It's been an open secret for a couple years now, I think.

cat

0

Retrocomputing – retrocomputing.stackexchange.com

Beta Q&A site for vintage-computer hobbyists interested in restoring, preserving, and using the classic computer and gaming systems of yesteryear.

Currently in private beta.

there you go :P

El'endia Starman

IIRC the reasoning was basically "If you're willing to go to that much effort, there's no real reason to stop you."

cat

"Where can I find software for the PDP-6?"

WHERE DO YOU GET A PDP 6

I WANT 1 2 :C

Doorknob

no, it's one two three

cat

9:22 PM

one two see

flawr

Yeah I want to see that, too!

cat

"We are planning to build a reconstruction of the PDP-6." There you go.

Nathan Merrill

another design question: I'm separating "queries" (gets data) from "commands" (performs actions). That said, its important to know whether commands succeeded. Therefore, does returning an Optional<Error> make sense for a command?

Doorknob

In Rust, there's a Result<T, E> type, which returns Ok(T) on success (i.e. the regular return value) and Err(E) on failure

(so your Optional<Error> would become a Result<(), Error>, with the unit type ("nothing") as T)

Nathan Merrill

is there a real reason you need a return value of commands?

(outside of convenience)?

Maltysen

9:32 PM

I'm prolly missing something, but why is this on main: codegolf.stackexchange.com/q/78073/31343?

Doorknob

@Maltysen read the first paragraph

cat

Whoa, I have 101 rep and I can see votes and downvote. This is cool.

Doorknob

@NathanMerrill if you know that you'll never have to return anything from them, then sure, Option<Error> would also work

Maltysen

@Doorknob oic

Nathan Merrill

right, but this is a language, so I don't know all of the possible use cases

:(

Alex A.

9:35 PM

@LegionMammal978 This is a reference to what that random NPC in Half-Life 2 says, right?

@El'endiaStarman \o/

Nathan Merrill

@QPaysTaxes but isn't that convenience for Array.peek and Array.removeFirst ?

I'm ok with surprising people

Maltysen

@NathanMerrill what about generators? next will have side effects

quartata

@Doorknob What happens if you don't fulfill a commitment? Will SE comes over to my house with a shotgun?

Alex A.

@flawr haha amazing

Doorknob

@quartata through your window, yes

Alex A.

9:37 PM

And it's not a reference to that rap song

quartata

@Doorknob shit better learn more lojban so I can answer questions

Nathan Merrill

@Maltysen I'll have built in support for generators (using yield). But I think your point still stands with Iterators<>?

Alex A.

@quartata What happened to your avatar?

Nathan Merrill

hmmm, you're right

Alex A.

:(

Nathan Merrill

9:38 PM

even with generators, multiple queries don't return the same thing

Doorknob

@quartata .i ji'a do kakne lo nu preti cusku

flawr

2 hours ago, by Mego

@quartata Did your avatar get hit with radiation that caused it to mutate?

Maltysen

@NathanMerrill yeah I often confuse the two. I meant the thing in Python that uses next()

Alex A.

@NathanMerrill BOO!

Nathan Merrill

eek

Alex A.

9:38 PM

gotcha

Oh misread, you said you're okay with surprising people, not with people surprising you

quartata

I should really bookmark this lojban dictionary

Alex A.

It's ~~great and does all things~~ garbage and makes no sense >_>

Nathan Merrill

I don't want to be hypocritical, though

Maltysen

@quartata where did that quart of potatoes go and what did you do with him?

Anonymous

@QPaysTaxes I'm somewhat free

Alex A.

9:40 PM

@Mego And somewhat enslaved

quartata

@AlexA. Why are you frowning? I thought you hated the old avatar

Anonymous

I am relatively sure that I will not get killed AFKing in Lunaris 2

Alex A.

@quartata I love you no matter what.

quartata

@Maltysen itsa me

Maltysen

@quartata why did you kill him, pikachu?

quartata

9:41 PM

This avatar is both a drawing from a Brain Age TAS and exponentionally cuter so I thought it was a double winner

Anonymous

The static avatar was the best

Anonymous

And by the best I mean it was awful

Maltysen

@quartata hmmph. to prove its really you, transfer all your rep to my account :P

quartata

How does that prove anything?

Alex A.

Don't think about it, just do it

Maltysen

9:44 PM

if you have nothing to hide, you have nothing to fear ~~(except losing all your rep)~~

cat

me: *goes back to Facebook for 5 seconds*
me:
me: wow, this is dumb.

flawr

@AlexA. ju see bird pictur? chat.stackexchange.com/transcript/message/29125983#29125983

@QPaysTaxes Last line qpaystaxes-is-wrong

cat

me: *comes back to TNB*
me:
me:
me: no i'd rather do this than something productive

Maltysen

@QPaysTaxes yeah that last line…

Alex A.

@flawr Hahaha I've seen that before but I didn't see it in here.

@cat I'm not generally a fan of Facebook (though I work in the same building as their Seattle office) but I end up using Messenger often.

I turned my brain off long before I got home from work.

cat

9:50 PM

@AlexA. I used to use it a lot cause relationship, but now I use Stack Exchange too much and FB not at all :P

Nathan Merrill

hmmm, I think I found a good use case for not having command query separation

El'endia Starman

Thermite From An Etch A Sketch; Yes It Can Be Done!

►

Thermite!

Alex A.

@cat Relationship? Pfft. The only relationship you need is with golfing.

cat

@QPaysTaxes no, it's the sadder one, but it's okay c:

Alex A.

@NathanMerrill oooo do tell

cat

9:51 PM

@AlexA. pfffFT

Nathan Merrill

Order.submit() should return a receipt, which is more than just a "it worked"

basically, information about the command needs to be returned

which includes information in the failure case and information in the success case

Alex A.

That moment when you engage someone regarding an idea they have but soon realize that you missed so much of the prior discussion that you have no idea what's going on.

What is Order.submit()? Is this related to a restaurant somehow?

Nathan Merrill

no, its an example

CQS basically says that there should be two types of functions, Commands which do something, but return nothing, and Queries that return a value, but do nothing

Maltysen

@AlexA. yeah he's starting an online restaurant

(not really, he's not actually doing that)

Nathan Merrill

I was going to allow Commands to return Optional<Exception>

but the problem, is that if you wanted to submit an order, you often need information about the submission itself

Maltysen

9:54 PM

@NathanMerrill well the response to your example is that instead of relying on return values to get you that info, you do Order.submit() and then call Order.didSucceed() for the info

Nathan Merrill

whether or not it was successful

Maltysen

just like when you broke apart Array.pop

Nathan Merrill

@Maltysen while its possible that way, it isn't good design.

the reason is that an Order then has two "states"

(or more)

Alex A.

@NathanMerrill I'm having a hard time mentally separating those. I can only think of a query like a SQL query where you're looking at the data you have but you haven't affected the database in any way (assuming there's no create, drop, whatever)

trichoplax

@quartata now I will no longer confuse you with apsillers

Nathan Merrill

9:56 PM

a query is basically a purely functional function

but yes, very much like a SQL select

Alex A.

@Maltysen I keep reading Array.pop as Array.poop because apparently I'm both illiterate and 12.

Maltysen

@AlexA. array.poop is like array.pop except that it poops out the value from the end of the array :P

Alex A.

@NathanMerrill Can you give an example outside of SQL? That's what I'm having trouble with.

Nathan Merrill

@AlexA. Array.get(1)

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@El'endiaStarman whoa

Nathan Merrill

9:58 PM

that would be a query

Maltysen

@AlexA. basically by query he means pure function

trichoplax

@quartata your chat profile still says "yes hello this is glider"...

Nathan Merrill

correct

Alex A.

Ooooooh okay

Nathan Merrill

as long as it doesn't affect the state of the program, its a query

Alex A.

9:59 PM

That makes sense

Maltysen

@QPaysTaxes what array would have…

Nathan Merrill

that said, does it make any sense to separate queries from commands anymore?

now that commands can return whatever they want?

Maltysen

@NathanMerrill oooooh idea

Nathan Merrill

hmmm?

Maltysen

how about instead of having "return values" you can mentally separate them by giving commands a getReturnValue query

like Array.pop().getReturnValue()

Nathan Merrill

10:03 PM

so, commands, return a Query?

Maltysen

yup

Nathan Merrill

(where a query is a first class function)?

Alex A.

I don't understand the advantage

Nathan Merrill

I'm not sure if that's a good idea. I mean, lets say I have a Receipt object

Maltysen

@NathanMerrill you would still use a return statement, but if you say that the thing is a command, to get the return value you would have to use the query

Nathan Merrill

10:04 PM

and an Order object

Mars Ultor

Hello

Nathan Merrill

my Order.submit() would have to create a Reciept object, then create a function that simply returns the created receipt object

cat

@MarsUltor hi!

Maltysen

@NathanMerrill well that would be done automatically

if you designate .submit() as a command

all return statements would be absorbed by the getReturnValue query

Nathan Merrill

so, if the "wrap in a query" is done automatically

then what advantage does it provide the caller

they basically would have to do Order.submit().get()

Maltysen

10:06 PM

I just thought you mentally wanted to separate commands and queries

Nathan Merrill

@Maltysen it breaks the concept of CQS, (because the command is still returning something)

hmmm. there's got to be a better way of doing this

because status is currently anything

returning a bool doesn't work

Maltysen

that's a good idea

Nathan Merrill

but sometimes commands need to return information about their success

which is more than just a string

El'endia Starman

Include a dictionary or something.

Nathan Merrill

@El'endiaStarman not type safe

for example, an Order.submit() should return a Reciept, which contains aggregated data of the submitted data

Mars Ultor

10:11 PM

@NathanMerrill A type safe dictionary.

@NathanMerrill Doesn't that break CQS?

Nathan Merrill

@QPaysTaxes 2 lines above

@MarsUltor Yes

@QPaysTaxes no it doesn't. Or it shouldn't.

it contains the raw data, but not the aggregate

for example, say I did Order.submit(Country)

and it did all of the calculations of taxes, and other country specific stuff

all of that "processed data" needs to be submitted

so, while its possible to get around it by storing the "processed" data in a temporary variable, its basically a hack

Mars Ultor

If you want CQS, then you need Order.process and Order.get or something

@NathanMerrill Just make Order an object?

Nathan Merrill

it is

Mars Ultor

Then make process change itself and get return itself?

Nathan Merrill

@MarsUltor I was actually going to do this for a long time

Mars Ultor

10:18 PM

Why not anymore?

Nathan Merrill

but then I realized that (1) I needed exceptions, and (2), people would start doing Order.add().process().getSomeValue()

I've never heard of a CQS language returning itself

Maltysen

@QPaysTaxes holy shit that globe one

Nathan Merrill

where commands return the containing object

Cᴏɴᴏʀ O'Bʀɪᴇɴ

return

Nathan Merrill

I'm a big proponent of writing clean code, and languages that make you write clean code

Cᴏɴᴏʀ O'Bʀɪᴇɴ

10:23 PM

@QPaysTaxes I look up to this guy.

Nathan Merrill

which is why I wanted to do CQS

Easterly Irk

^^^

@Downgoat js golfer alert

Mars Ultor

Command–query separation

Command–query separation (CQS) is a principle of imperative computer programming. It was devised by Bertrand Meyer as part of his pioneering work on the Eiffel programming language. It states that every method should either be a command that performs an action, or a query that returns data to the caller, but not both. In other words, Asking a question should not change the answer. More formally, methods should return a value only if they are referentially transparent and hence possess no side effects. == Connection with design by contract == Command–query separation is particularly well suited...

Yes it is

This is based on CQS

Nathan Merrill

@QPaysTaxes maybe. I'm still not convinced that all code shouldn't be CQS

but I need to figure out a way to do it that makes for clean code

Mars Ultor

CQS should be a choice

CQS pretty much prevents fluent interfaces

Nathan Merrill

10:25 PM

@QPaysTaxes CQS isn't about cleanliness, its about unexpected side effects

if I make Array.get(), I should expect that the array is unchanged

Maybe? I'm not convinced that I can't get it to work in a clean manner

I'm not sure how, but I'm going to keep thinking about it

Easterly Irk

10:40 PM

pls halp how delete 5 gig .txt file

i tri and computer freez

Mars Ultor

@EasterlyIrk sudo rm -rf /

Easterly Irk

okai thx brb trying

Mars Ultor

Don't actually do that

Easterly Irk

omg pls halp i kill all comp

Mars Ultor

Use liveCD

Easterly Irk

10:41 PM

@MarsUltor now you say? :P

no

fortee

Mars Ultor

No juic?

Easterly Irk

IT NO WORK

@MarsUltor yah juic juic of mashed up files juic

pls halp

El'endia Starman

@EasterlyIrk Hit delete and wait.

poi830

@MarsUltor sudo rm -rf --no-preserve-root /

New Main Posts

1

Q: Linear Independence

Given a set of vectors all of the same positive finite dimension, output a falsey value if they are linearly dependent and a truthy value if they are linearly independent. A set of vectors v1, v2, ... is linearly dependent if for some scalars a1, a2, ... not all equal to 0, a1v1 + a2v2 + ... = 0...

code-golf math linear-algebra

quartata

10:49 PM

@NewMainPosts I'm surprised we haven't had that before.

poi830

yeah i was too

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