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Logs: freenode/#haskell

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2020-10-18 00:14:29 <koz_> christo: Paste the code again?
2020-10-18 00:14:36 <ski> er, sorry
2020-10-18 00:14:39 <ski> christo ^
2020-10-18 00:14:47 × wroathe quits (~wroathe@c-68-54-25-135.hsd1.mn.comcast.net) (Ping timeout: 258 seconds)
2020-10-18 00:14:52 <christo> • No instance for (RealFrac Integer) arising from a use of ‘floor’
2020-10-18 00:14:55 <christo> ooops sorry
2020-10-18 00:15:15 <koz_> christo: You don't need floor in this case then.
2020-10-18 00:15:18 <koz_> :t floor
2020-10-18 00:15:20 <lambdabot> (RealFrac a, Integral b) => a -> b
2020-10-18 00:15:28 <Axman6> floor also doesn['t wokr on Integers
2020-10-18 00:15:30 → conal joins (~conal@64.71.133.70)
2020-10-18 00:15:32 <christo> https://paste.tomsmeding.com/QutEatIe#file-1
2020-10-18 00:15:40 <koz_> You don't have a RealFrac anything, since if you use div, you don't get a fractional thing back.
2020-10-18 00:15:42 <ski> christo : `fromInteger' can be used to convert from `Integer' to another numeric type
2020-10-18 00:15:51 <Axman6> > 13 `div` 3
2020-10-18 00:15:53 <lambdabot> 4
2020-10-18 00:15:55 × elliott_ quits (~elliott_@pool-108-51-141-12.washdc.fios.verizon.net) (Read error: Connection reset by peer)
2020-10-18 00:16:02 <christo> :t fromInteger
2020-10-18 00:16:04 <lambdabot> Num a => Integer -> a
2020-10-18 00:16:07 × ephemera_ quits (~E@122.34.1.187) (Remote host closed the connection)
2020-10-18 00:16:28 → elliott_ joins (~elliott_@pool-108-51-141-12.washdc.fios.verizon.net)
2020-10-18 00:16:35 <ski> (e.g., you could convert to `Rational' ..)
2020-10-18 00:16:36 <christo> > fromInteger 2
2020-10-18 00:16:38 <lambdabot> 2
2020-10-18 00:16:42 <christo> > fromInteger 2.0
2020-10-18 00:16:44 <lambdabot> error:
2020-10-18 00:16:44 <lambdabot> • Could not deduce (Fractional Integer)
2020-10-18 00:16:44 <lambdabot> arising from the literal ‘2.0’
2020-10-18 00:16:59 × untseac quits (~emanuel@2001:818:e8dd:7c00:32b5:c2ff:fe6b:5291) (Remote host closed the connection)
2020-10-18 00:17:01 <ski> > floor (fromInteger 18 / fromInteger 7)
2020-10-18 00:17:04 <lambdabot> 2
2020-10-18 00:17:23 → ephemera_ joins (~E@122.34.1.187)
2020-10-18 00:17:24 <ski> > 18 - 7 * floor (fromInteger 18 / fromInteger 7)
2020-10-18 00:17:26 <lambdabot> 4
2020-10-18 00:17:28 → untseac joins (~emanuel@2001:818:e8dd:7c00:32b5:c2ff:fe6b:5291)
2020-10-18 00:17:41 <ski> > 18 - 7 * floor (fromInteger 18 / fromInteger 7 :: Rational)
2020-10-18 00:17:43 <lambdabot> 4
2020-10-18 00:18:17 <christo> :t (/)
2020-10-18 00:18:17 <ski> (without the type ascription, it'll default to `Double', iirc)
2020-10-18 00:18:18 <lambdabot> Fractional a => a -> a -> a
2020-10-18 00:18:50 <christo> what does :: Rational do? some sort of type Cast or ?
2020-10-18 00:19:54 <Axman6> :t \x -> fromInteger x
2020-10-18 00:19:56 <lambdabot> Num a => Integer -> a
2020-10-18 00:20:12 <Axman6> :t \x -> (fromInteger x :: Rational)
2020-10-18 00:20:13 <lambdabot> Integer -> Rational
2020-10-18 00:20:34 <Axman6> it's picking the type to use, there is no casting in Haskell*
2020-10-18 00:22:03 <christo> ahh ok
2020-10-18 00:22:12 <christo> so is Num like a generic or something?
2020-10-18 00:22:23 <koz_> christo: Num is kind of like an interface.
2020-10-18 00:22:35 <koz_> Something that is an instance of Num is 'kinda sorta number-like' in some sense.
2020-10-18 00:22:56 → olligobber joins (olligobber@gateway/vpn/privateinternetaccess/olligobber)
2020-10-18 00:22:59 <Axman6> @src Num
2020-10-18 00:22:59 <lambdabot> class Num a where
2020-10-18 00:22:59 <lambdabot> (+), (-), (*) :: a -> a -> a
2020-10-18 00:22:59 <lambdabot> negate, abs, signum :: a -> a
2020-10-18 00:22:59 <lambdabot> fromInteger :: Integer -> a
2020-10-18 00:23:02 <christo> Hmm, as a haskell beginner may be a bit beyond my head
2020-10-18 00:23:17 <koz_> christo: Type classes are a fairly important concept, even at beginner level.
2020-10-18 00:23:59 <koz_> (in terms of how to use their instances, at least)
2020-10-18 00:24:04 <Axman6> Num is the class of types which can do some number like things, such as addition, subtradction, multiplication this allows you to use the usual 1 + 2 * 3 syntax for your own types
2020-10-18 00:24:45 <Axman6> @let data MyNum = Val Integer | Add MyNum My
2020-10-18 00:24:46 <lambdabot> .L.hs:159:24: error:
2020-10-18 00:24:47 <lambdabot> Not in scope: type constructor or class ‘My’
2020-10-18 00:24:47 <lambdabot> Perhaps you meant ‘Mu’ (imported from Lambdabot.Plugin.Haskell.Eval.Trus...
2020-10-18 00:24:57 <Axman6> @let data MyNum = Val Integer | Add MyNum MyNum |
2020-10-18 00:24:58 <lambdabot> Parse failed: Parse error: EOF
2020-10-18 00:25:04 <Axman6> omg, typing on a couch is ahrd
2020-10-18 00:25:15 <koz_> Axman6: It's those axe hands.
2020-10-18 00:25:18 <christo> lol
2020-10-18 00:25:27 <koz_> Too much couch stuffing everywhere.
2020-10-18 00:25:32 <Axman6> @let data MyNum = Val Integer | Add MyNum MyNum | Mul MyNum MyNum
2020-10-18 00:25:33 <christo> btw, my (%) infix operator works now
2020-10-18 00:25:34 <lambdabot> Defined.
2020-10-18 00:25:47 <christo> but need
2020-10-18 00:25:55 <christo> maybe look into type classes then
2020-10-18 00:25:55 × CodeWeaver quits (49eff865@c-73-239-248-101.hsd1.wa.comcast.net) (Remote host closed the connection)
2020-10-18 00:25:56 <Axman6> koz_: congrats on your sane election btw
2020-10-18 00:26:10 <koz_> Axman6: Thanks! I gotta say I wasn't too surprised by the outcome.
2020-10-18 00:26:54 <Axman6> @let instance Num MyNum where a + b = Add a b; a * b = Mul a b; fromInteger i = Val i
2020-10-18 00:26:55 <lambdabot> .L.hs:162:10: error: [-Wmissing-methods, -Werror=missing-methods]
2020-10-18 00:26:55 <lambdabot> • No explicit implementation for
2020-10-18 00:26:55 <lambdabot> ‘abs’, ‘signum’, and (either ‘negate’ or ‘-’)
2020-10-18 00:27:17 <Axman6> @let instance Show MyNum
2020-10-18 00:27:19 <lambdabot> .L.hs:162:10: error: [-Wmissing-methods, -Werror=missing-methods]
2020-10-18 00:27:19 <lambdabot> • No explicit implementation for
2020-10-18 00:27:19 <lambdabot> either ‘showsPrec’ or ‘show’
2020-10-18 00:27:30 <Axman6> @let deriving instance Show MyNum
2020-10-18 00:27:31 <lambdabot> Defined.
2020-10-18 00:27:46 <Axman6> % 1 + 2 * 3 :: MyNum
2020-10-18 00:27:46 <yahb> Axman6: ; <interactive>:62:14: error: Not in scope: type constructor or class `MyNum'
2020-10-18 00:28:04 <ski> > 1 + 2 * 3 :: MyNum
2020-10-18 00:28:05 <Axman6> you're the worst yahb
2020-10-18 00:28:07 <lambdabot> error:
2020-10-18 00:28:07 <lambdabot> • No instance for (Num MyNum) arising from a use of ‘+’
2020-10-18 00:28:07 <lambdabot> • In the expression: 1 + 2 * 3 :: MyNum
2020-10-18 00:29:02 <Axman6> koz_: we had a similar result over the pond in our territory election, so it was as good night
2020-10-18 00:29:18 <koz_> Axman6: In that case, congratulations!
2020-10-18 00:30:09 → tromp joins (~tromp@dhcp-077-249-230-040.chello.nl)
2020-10-18 00:31:19 <koz_> Would someone be able to guide me in creating Nix environments wherein I can build _static_ Haskell applications for 32-bit x86?
2020-10-18 00:31:40 <koz_> So like, a chonky binary I can copy over to another machine and just run.
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