00:00:03 It's not boring. from should, given a function a -> b, make a Getter' b a 00:01:49 -!- Frooxius has quit (Read error: Connection reset by peer). 00:02:49 -!- Frooxius has joined. 00:05:28 Are there going to be SQL extensions for dealing with pictures, sounds, music, internet, GUI, plotting graph of the data, typesetting, printer, ephemeris, as well as such a thing as databases containing various data such as chemical, political, geographical, weather, word lists, etc...? 00:07:34 Therefore you can combine all of these things by using ATTACH command and LOAD_EXTENSION and various functions (including aggregates). 00:11:15 Many sets of data are posted in other formats such as CSV (although I think tab separated is better anyways), HTML, Microsoft Excel, and sometimes also XML; but I would like to see many such thing in SQLite format. 00:11:55 At least I think it would make the data easier to deal with. 00:12:07 I don't know quite what is your opinion. 00:12:59 -!- doesthiswork has joined. 00:17:13 Virtual tables could be used for accessing RDF and other XML based formats; virtual table could also be for accessing other file formats, for accessing the windows on the screen, manage network connections, etc 00:19:15 shachaf: what's the name of the profunctor used by from? 00:19:29 Un? 00:19:36 Exchange, in lens? 00:21:47 Exchange sounds like a good name. Don't really know what Un is, I thought that was that unlens thing 00:32:38 It is. 00:32:51 from turns an optic into the corresponding unoptic. 00:32:57 I think we called it re. 00:33:09 It was how I sold edwardk on pure profunctor optics. 00:38:49 Another thing I want to see in SQLite format are comparison tables. 00:39:08 (for comparing various kinds of things, whether computer software or otherwise) 00:54:26 I still don't get what an unoptic is 00:59:44 -!- MoALTz_ has joined. 01:02:52 -!- MoALTz has quit (Ping timeout: 260 seconds). 01:11:52 -!- Lorenzo64 has quit (Ping timeout: 245 seconds). 01:21:27 -!- FreeFull has quit (Ping timeout: 245 seconds). 01:23:45 -!- FreeFull has joined. 01:23:47 -!- FreeFull has quit (Changing host). 01:23:48 -!- FreeFull has joined. 01:27:10 -!- Lorenzo64 has joined. 01:34:10 -!- up2quark has joined. 01:34:15 Hello 01:35:09 -!- up2quark has left. 01:59:08 `addquote Rule of thumb is that if I can understand it you're not using enough fancy stuff 01:59:09 1218) Rule of thumb is that if I can understand it you're not using enough fancy stuff 02:03:07 Other things I want to have in SQL (with data files, extensions, and/or network services) include surveys and collaborative tables. 02:03:14 Are there such things? 02:04:11 ( :t (<$) 02:04:11 Prelude.Applicative.(<$) : Applicative f => f a -> f b -> f a 02:04:20 ( :t ($>) 02:04:20 Prelude.Applicative.($>) : Applicative f => f a -> f b -> f b 02:04:29 bah 02:04:50 That's different from Haskell, which is (<*) and (*>) 02:05:10 i know. Melvar mentioned <$> in the logs, which is also different. 02:05:29 Why are they calling these things differently like this? 02:05:34 so i was wondering if idris had actually done the logical thing i'd thought of with the two others. 02:05:37 but no. 02:06:09 zzo38: well <$> _is_ more logical than <*> if you are starting out naming them 02:06:32 except if you do that, i think fmap should be $> 02:06:49 and it isn't that in idris either 02:07:24 although part of the problem is that < and > are also used in two senses in applicative notation 02:07:51 sometimes it means "this is something applicative", other times it means "return the right or left part as pointed to" 02:08:30 oerjan: what would you rename (<*) and (*>) to? 02:08:41 I don’t know how the operators got named as they are. 02:08:42 I guess you'd want operators for const and flip const and use that or something. 02:09:25 elliott: lessee, rename (<*) to *<* and (*>) to *>* 02:09:39 oerjan: wait, what? 02:09:48 now (<$) can be <* 02:09:52 :t (<$) 02:09:53 Functor f => a -> f b -> f a 02:10:39 elliott: i said i wanted to separate the two meanings of <>, didn't i? if we use $ instead of * then we can reuse * for the meaning that says "applicative" 02:11:01 (<$>) becomes $* 02:11:10 I see. 02:11:31 oerjan: perhaps the ideal symbol for * is banana brackets (depending on which side it's on) 02:11:33 the not standard but defined in lens (??) becomes *$ 02:11:49 since a (|$|) b would be (| a $ b |). 02:12:13 oerjan: and (<**>)? :p 02:12:18 oh that 02:12:28 *&* I guess 02:12:33 first we need a symbol for reverse application, so take lens... right 02:13:12 :t (<**>) 02:13:13 Applicative f => f a -> f (a -> b) -> f b 02:14:14 ( with List [| [1,2,3] + [4,5,6] |] 02:14:15 (input):1:14:When elaborating an application of function BotPrelude.LiftEq.<$>: 02:14:15 Can't unify 02:14:15 List a 02:14:15 with 02:14:15 x = y↵… 02:14:23 … 02:15:22 idris, the language that has even sillier type errors than haskell 02:17:26 ( with Applicative [| [1,2,3] + [4,5,6] |] 02:17:26 When elaborating an application of function Prelude.Applicative.pure: 02:17:27 Can't disambiguate name: Prelude.Classes.+, Prelude.Fin.+ 02:17:46 … 02:18:19 ( the (List Integer) [| [1,2,3] + [4,5,6] |] 02:18:19 [5, 6, 7, 6, 7, 8, 7, 8, 9] : List Integer 02:18:47 elliott: banana brackets seem a little heavy but maybe just | would be good 02:18:56 oerjan: they're a bit heavy in ascii, yeah. 02:19:02 except then <| clashes with Data.Sequence 02:19:18 but probably the others also clash with something i don't remember 02:19:20 Why did they decide to make both list comprehension notation and do notation in Haskell? It would be better to combine them into one kind of command. 02:19:28 oerjan: btw, *>* should be liftA2 (>) :p 02:19:51 the thing with <| is that the < looks like the outside and the | the inside... |<| and stuff is sorta weird 02:20:43 elliott: i have no scrubles repurposing < and > there, they're just not useful enough to do that with 02:20:47 *scruples 02:21:25 I sort of feel like a lot of the "only partially applicative" ones are a little redundant. 02:21:33 (const x <$> y) is just as good as (x <$ y), really. 02:21:47 I guess that's the only one. 02:22:45 elliott: Although <$ is convenient shortcut in many cases, I think 02:22:45 -!- tromp has quit (Read error: Connection reset by peer). 02:22:54 -!- tromp has joined. 02:24:15 First I would have do notation has a macro instead of built-in; another is that, rather each item in the block can be: Using a pattern and <- and the wrapped value and a semicolon, using a pattern and = and unwrapped value and a semicolon, a wrapped value and semicolon, or only at the end, unwrapped with no semicolon. Guards are allowed in all of these patterns, and so is a guard by itself with no pattern nor <- and = 02:25:11 What does a guard do? Force MonadPlus? 02:25:24 I wonder once more, is there a name for Monads where for all mx and f, do { x <- mx; y <- mx; f x y } ≡ do { x <- mx; f x x } ? 02:25:37 Sgeo_: the same thing as any refutable pattern, i assume 02:25:44 eww 02:27:00 Melvar: that reminds me of affine commutative IO proposal 02:27:09 so possibly "affine" 02:27:52 In particular the Monad instances of (Vect n) and Stream fulfill this equivalence. 02:29:06 Reader also, i think. 02:29:31 I've heard someone call monads where bind never calls the function it's passed more than once 'affine'. No idea if that's related 02:29:39 Or a reasonable use of that name 02:29:52 and the ACIO monad would fulfill it, as that was part of its purpose 02:29:52 (e.g. most things except []) 02:29:56 Well, both of those are equivalent to Readers. 02:30:24 *-l 02:31:07 Sgeo_: I would say a guard would be forcing MonadPlus, yes 02:32:42 lambdabot what'd i ever do to you <-- "can't find file: L.hs" is essentially a kind of race condition in lambdabot 02:33:40 Okay, so I guess that’s affine. And the order the actions are specified in being irrelevant presumably is commutative? 02:33:54 yeah 02:34:22 although when i googled ACIO just now, the hits seemed to imply C is for "central". 02:34:23 Well, I would think, "commutative", as a commutative applicative at least, would mean that (x <* y) is same as (y *> x) 02:34:40 zzo38: that's at least implied 02:34:42 -!- Bike has quit (Quit: leaving). 02:35:02 Implied by what for what purpose? 02:35:12 or more generally, f <$> x <*> y = flip f <$> y <*> x 02:35:36 zzo38: by my understanding of what "commutative" means for monads 02:35:38 Well, yes, that is another way too 02:35:51 zzo38: possibly they are equivalent. 02:35:59 I don't seem to see what "commutative" means for monads, only for applicative. 02:36:14 but it's not obvious 02:36:15 -!- AndoDaan has joined. 02:36:35 zzo38: yes i think a monad is commutative exactly when its corresponding applicative is 02:36:53 OK 02:37:23 Maybe another way is: fmap swap . liftPair = liftPair . swap 02:37:59 -!- Bike has joined. 02:38:05 hm actually i think just <* vs. *> loses too many ways of combining the results to imply the full thing 02:39:23 Does it? Maybe 02:39:49 basically, you get no result information from y 02:40:24 If that is the only problem then the two other ways are working. 02:40:29 so you know the _effects_ commute, but not whether the whole thing does. 02:41:30 Ah, I suppose you are correct, then 02:41:41 It makes sense 02:42:18 Melvar: wait, what's Stream there? 02:42:37 oh. 02:42:42 presumably the obvious diagonalisation instance? 02:43:09 So then f <$> x <*> y = flip f <$> y <*> x or fmap swap . liftPair = liftPair . swap is doing it? 02:43:12 -!- tromp has quit (Ping timeout: 260 seconds). 02:43:35 elliott: That would be the only one I know of that agrees with its Applicative instance. 02:43:51 i saw someone in a stackoverflow question essentially reinventing the Monad instance for Maybe (he had got to Applicatives in the course) in order to solve a problem. except he had defined join and zzo38's liftPair. 02:44:03 *only got 02:44:09 oerjan: iow, f <$> x <*> y = y <**> f <$> x? 02:44:16 :t \f x y -> f <$> x <*> y == y <**> f <$> x 02:44:17 Precedence parsing error 02:44:17 cannot mix ‘<*>’ [infixl 4] and ‘==’ [infix 4] in the same infix expression 02:44:17 Precedence parsing error 02:44:24 :t \f x y -> (f <$> x <*> y) == (y <**> f <$> x) 02:44:25 Eq (a -> b) => (a -> a1 -> b) -> (a -> a) -> (a -> a1) -> Bool 02:44:39 :t (<**>) 02:44:40 Applicative f => f a -> f (a -> b) -> f b 02:44:42 oh 02:44:45 :t \f x y -> (f <$> x <*> y) == (y <**> f <*> x) 02:44:46 Occurs check: cannot construct the infinite type: b ~ a -> b 02:44:46 Expected type: a -> a1 -> a -> b 02:44:46 Actual type: a -> a1 -> b 02:44:52 :( 02:45:13 :t \f x y -> (f <$> x <*> y) == (y <**> (f <$> x)) 02:45:14 (Applicative f, Eq (f b)) => (a1 -> a -> b) -> f a1 -> f a -> Bool 02:45:14 elliott: well or simpler: (<*>) = flip (<**>) 02:45:20 oerjan: right. 02:46:55 elliott: That would be the only one I know of that agrees with its Applicative instance. <-- since Streams have only one "shape", the uniqueness of Monad from Applicative follows 02:47:03 oerjan: Do you mean only join and liftPair and not anything else? That wouldn't be very good. 02:47:16 I was mixing up Steram and ZipList or something. 02:47:49 And similarly (Vect n) has only one shape for each n, I guess. 02:48:17 ( the (Vect _ Integer) [| [1,2,3] + [4,5,6] |] 02:48:18 [5, 7, 9] : Vect 3 Integer 02:49:02 zzo38: yes, although e knew about Functors so e had fmap 02:49:30 i guess that's "no", really :P 02:50:24 elliott: well Stream is the subset of all ZipLists of that shape. 02:50:30 yeah. 02:50:33 and each shape is a Monad, i think. 02:50:48 You had fmap? Then you have liftPair, you should need pure, too, then. 02:50:52 because it's really Reader on a subset of Nat 02:51:08 yeah. 02:51:14 on (Fin n) for some n. 02:51:33 zzo38: well e had pure also, but e didn't use it for Maybe iirc 02:52:01 ...or all of Nat, for Streams. 02:53:06 n = fix Succ! 02:53:24 that works. you could define FinOrMaybeInfin as Conat -> Type. maybe. probably. 02:53:30 it'd have to be codata of course. 02:54:30 i still haven't quite wrapped up the proof that ZipList monad is impossible. i discovered that if the lists are length <= n then the result must also be, because take n is join . replicate n = join . fmap (replicate n) if join exists 02:55:03 um 02:55:13 yes, that was it 02:55:55 and so if you take n at any depth in the m (m a) it commutes out with the join 02:56:40 For optimizing Z-machine text encodings, I have one thing already, which is figuring out the preferred states before each character, in order to figure out which way is shortest (you must skip spaces and fwords in order to do so, since they are unaffected by shift states). However, there are the two other things: Suffix optimization, and filling in the frequent words table. 02:57:14 ( :t fibs 02:57:14 No such variable fibs 02:57:31 * oerjan is obviously mixing notation there 02:57:40 ( :let fibs : Stream Nat; fibs = 0 :: 1 :: [| fibs + tail fibs |] 02:57:40 defined 03:00:38 For filling in the frequent words table, I have thought of counting the number of "demerits" for each possibility and using the ones with negative demerits. However, this would be really slow and inefficient if all possibilities are counted like this. 03:02:41 For suffix optimization I could make it to sort by reverse, although also one case is if the suffix is capitalized first letter when used by itself but not when together with the prefix, is also usable in Z-machine encoding; perhaps a way to work this is to use a different character order than the ASCII order when sorting. 03:04:29 -!- tromp has joined. 03:06:13 And then there is the case that a frequent word (which, despite the name, can be any string and doesn't have to consist of a single word) spans the part of the prefix and suffix (or even the beginning of the suffix alone if it is capitalized). 03:07:07 Do any of you know???? 03:07:14 I do not know 03:17:17 -!- Lorenzo64 has quit (Ping timeout: 245 seconds). 03:23:07 -!- conehead has quit (Quit: Computer has gone to sleep). 03:25:49 * Sgeo_ rewatches In the Pale Moonlight 03:50:42 -!- sebbu has quit (Ping timeout: 245 seconds). 04:00:41 -!- MoALTz__ has joined. 04:03:28 -!- MoALTz_ has quit (Ping timeout: 260 seconds). 04:05:30 -!- MoALTz has joined. 04:08:08 -!- MoALTz__ has quit (Ping timeout: 260 seconds). 04:20:15 -!- Lorenzo64 has joined. 04:20:55 This is one idea of Magic: the Gathering card: Put the top card of each player's library on the stack. 04:21:38 zzo38: They've said that they don't want to make any cards that mention the stack explicitly. 04:22:04 Yes, I know that, but still *I* want to mention the stack explicitly. 04:22:45 What would its mana cost be? 04:24:01 What would it mean to put a card on a stack? 04:24:04 What if it has targets? 04:24:17 What if it's land? 04:24:22 If it has targets then it fails when it resolves, I suppose. 04:24:34 If it is a land, then I would think it would just come into play anyways 04:24:46 Lands don't go on the stack normally, though. 04:24:53 I know that 04:24:57 shachaf: I'm curious where they've said they don't want to mention the stack? 04:25:02 What if you've already played a land? 04:25:04 Might be more fun reading 04:25:09 All sorts of places. 04:25:11 http://archive.wizards.com/Magic/magazine/article.aspx?x=mtgcom/daily/mr255 04:25:32 ty 04:25:32 If you have already played a land, at least what I would think, is, that isn't a problem and doesn't prevent you from playing another land. 04:32:10 But I also believe that Magic: the Gathering is too klugy and should be made up from the beginning over in the more mathematically elegant way, fixing other problems too (so, instead of a library it will be called a draw pile, a graveyard is now a discard pile, antes are returned at the end of a match and the ante zone exists even though it is initially empty, "outside of the game" *never* refers to a player's collection of cards they physically o 04:32:38 what a zzo38y thing to say 04:32:50 You were cut off after "physically o", by the way. 04:33:06 No, that's all I wrote 04:33:32 O, now I see. 04:34:39 you'd be taking all the flavor of the game, alienate the few remaining fans and kill the franchise! 04:34:40 "Cards you own outside of the game" is instead not used; "sideboard" is used instead and is always how it work anyways. 04:37:05 "This is, for example, one of the reasons we've been shifting X spells away from common over time. The concept of X throws a lot of people. " 04:37:11 Buh... uh.... huh? 04:38:25 I will admit Dead Ringers is confusingly worded :/ 04:38:50 int-e: Maybe, but I still think would be better to do such thing as remove the rule that auras which is also creatures are discarded, change the tokens ceasing to existing rule into one instead having to do with initial states, make copies of spells to be tokens (so that non-instantsorcery spells can be copied too), and of course other thing too. 04:39:51 Also some of things it looks like they try to make it easier to understand, tend to either make it instead more klugy (and therefore more confusing) or less strategic. 04:40:10 And they mess up existing cards too even though they explicitly try not to. 04:40:56 The implementation (and name) of Planeswalkers cards is also bad (although it is not a bad idea). 04:42:09 I think I read once that they wanted to try to make it into another player, but they couldn't figure out how. But I figured out how! 04:42:37 (Doing this would also avoid some of the klugy rules relating to it) 04:45:19 It is also my opinion that the size of the text box ought to vary in order to make the text fit (even if this leaves no room for a picture; conversely a card with no text has a larger picture). 04:53:38 -!- copumpkin has joined. 05:43:03 Is this accurate? instance Profunctor Exchange where dimap a b e = Exchange (dimap b a (runExchange e)) 05:43:08 Something along those lines? 05:43:25 Wait, no 05:44:00 instance Profunctor Exchange where dimap a b e = Exchange (\p -> dimap b a (runExchange e p)) 05:44:45 Ok, I think I need to think a bit more 05:57:04 ok i think i finally have a watertight proof that there is no ZipList monad. although i'm not sure whether I've just forgotten the previous ones :P 05:58:56 basically, consider [[[1,2],[3,4]],[[],[7,8]]], then zjoin $ zjoin xs _must_ be [1,8] and zjoin $ fmap zjoin xs _must_ be [1]. 05:59:10 but by the monad laws those two must be equal 06:01:46 all of this follows from how zjoin must be the main diagonal of rectangular lists of lists, _except_ for zjoin [[], [7,8]] = [] which follows from my proof that zjoin . take n = take n . zjoin when you put n = 1. 06:02:33 *, when you put 06:11:19 zzo38: ugh, no. I think the fixed size picture and fixed size text box is fine. 06:11:35 variable size would be ugly 06:11:47 But maybe you want to put a lot of text and the picture won't fit 06:12:02 I for one don't like the Zendikar full art lands that everyone seems to like so much 06:12:35 I don't really care, but I wanted variable size in order that large amounts of text can fit on the card. 06:12:49 zzo38: if there's too much text, then the card is wrong. cards shouldn't have too much text. the existing textbox (which, incidentally, got slightly larger both time they changed the card frame template) already allows a wall of text to fit 06:14:20 don't forget that the textbox provides graphical clues other than just containing the text: for one, it's colored according to the color of the text or the color of mana a land produces, that's very useful for non-basic lands, 06:14:40 it also contains a nice mana icon for basic lands (and also guild and faction and klan sybmols which I don't like so much) 06:16:39 I prefer the text for the basic lands though 06:17:50 zzo38: consider for example the newer cycling lands like Secluded Steppe. Luckily for the reprints, the inner border and the name and type line is colored white, but even then the color of the text box helps too. 06:17:59 Or gold and hybrid cards. 06:18:29 Yes I know those thing can help too 06:18:58 I admit it's much less important in the post-Mirrodin frame 06:19:02 which has the inner border for this 06:19:11 But they aren't considered as a requirement by the rules of the game, since there are other things that says so on the cards. 06:19:16 But even without the color, I do like the fixed size text box and fixed size art 06:19:42 (especially if you are playing with grayscale copies of the cards; I have seen this) 06:20:30 Heh, imagine playing with grayscale copies of cards with color markers on the type line. 06:20:44 -!- MoALTz has quit (Quit: Leaving). 06:20:54 Anyway, as for basic lands, I guess that's a matter of taste, I prefer just the big mana symbol, but a text isn't too bad either. 06:22:54 zzo38: as for improving card faces, do you know what I'd like? I wish there were fewer new expansion symbols introduced, because there's now over a hundred and they're running out of space of recognizable and rememberable expansion symbols. I think each block should have only one expansion symbol, not one for each set. 06:23:40 (And some series of extra products like Duel Decks shouldn't take up expansion symbols.) 06:24:07 Basically, especially for a player that isn't so experienced, but even for me, it can be hard to remember all the expansion symbols. 06:25:56 They could be much easier to relate to if there was only one expansion symbol for the Urza's block (instead of three, the cogwheels, the lab breaker, and whatever is the third), one for the Judgement block (set of scales, some kind of ouroboros, and one more strange thingy), one for the Invasion block (I don't even remember what any of those look like), one for the Onslaught block (a morph spider). 06:26:08 We can't change the old sets, but new blocks should do this. 06:26:44 And I don't think it would cause too much problems with new sets either, would it? 06:28:18 I mean, yeah I know, sword, shield and helm of Kaldra and all, but still. 06:29:42 Morning 06:32:00 (Also, Spreading Seas should have gotten a remainder text saying that the land loses abilities printed on it; and Hollow Dogs should be a Skeleton) 06:33:47 -!- sebbu has joined. 06:34:26 -!- sebbu has quit (Changing host). 06:34:26 -!- sebbu has joined. 06:36:02 [wiki] [[///]] http://esolangs.org/w/index.php?diff=40382&oldid=38040 * B jonas * (+131) /* Implementation */ 06:36:48 (I mean, come on, a Zombie with no flesh is not a Zombie, it's a Skeleton or a Ghost depending on whether it has bones.) 06:37:16 what if it's the zombie of an invertebrate 06:39:24 Bike: the DnD rules at http://www.d20srd.org/srd/monsters/skeleton.htm says a skeleton needs a base creature with bones. If you have a creature with no bones and make an undead without flesh, what's its body made of? If there's no body, it's a ghost. If there's a body of soft tissue (not necessarily literally flesh), then it's a zombie (or maybe some higher level undead like ghoul). 06:39:49 Bike: so basically when I said "flesh", I mean parts of the body other than the bones 06:40:01 An exoskeleton 06:40:18 dunno 06:40:44 what about a cartilaginous animal, like a shark? who'd begrudge a zombie shark 06:41:16 technically, the DnD rule says "skeletal system", not bones 06:41:57 -!- sebbu has quit (Read error: Connection reset by peer). 06:42:52 -!- sebbu has joined. 06:43:11 and nethack does seem to go with this distinction: 06:43:20 -!- sebbu has quit (Changing host). 06:43:21 -!- sebbu has joined. 06:44:33 consider Rimebound Dead, which is a Skeleton created by a necromancer from bones according to the flavor text, and Legions of Lim-Dûl, Zombies which have "faces of my dead friends" according to the flavor text and are created by a necromancer according to its card name. 06:45:58 Both Heidar and Lim-Dul are necromancers, and both have both zombie and skeleton cards created by them: Zombie Musher and Kjeldoran Dead are the other cases. 06:46:41 ghouls in nethack have the creature type Zombie, and ghosts have the type Spirit 06:48:01 That sounds like more of a MtG thing than a NetHack thing. 06:54:05 moin 06:55:04 b_jonas: where do lemurs fit into this 07:01:59 -!- Frooxius has quit (Read error: Connection reset by peer). 07:02:06 -!- Frooxius has joined. 07:10:27 -!- oerjan has quit (Quit: BANANAAAAAAA). 07:54:19 -!- doesthiswork has quit (Quit: Leaving.). 08:06:36 -!- AnotherTest has joined. 08:11:35 -!- drdanmaku has quit (Quit: Connection closed for inactivity). 08:24:17 -!- Phantom_Hoover has joined. 08:35:02 -!- Patashu has joined. 08:42:41 Frooxius: yes, sorry 08:42:48 shachaf: ugh, lemurs and lemures, yeah 08:43:06 which one of those is the Animal and which one is an undead spirit? 08:43:55 see http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=2457 hth 08:49:42 -!- Patashu_ has joined. 08:49:43 -!- Patashu has quit (Disconnected by services). 08:52:51 -!- Patashu has joined. 08:56:23 -!- Patashu_ has quit (Ping timeout: 272 seconds). 08:57:45 -!- Patashu_ has joined. 08:57:45 -!- Patashu has quit (Disconnected by services). 08:58:15 Is there a equ f = (\a b -> (f a) == (f b))? 08:58:18 much like comparing 08:58:25 i.e. sortBy (comparing foo) 08:58:33 => groupBy (equ foo) 08:59:04 or something like using f g = (\a b -> (f a) `g` (f b))? 08:59:39 @let using f g = (\a b -> (f a) `g` (f b)) 08:59:41 Defined. 08:59:58 comparing = (compare `on`) 09:00:02 > groupBy (using length (==)) ["a","bb","c","dd"] 09:00:05 So just use ((==) `on`) 09:00:06 [["a"],["bb"],["c"],["dd"]] 09:00:15 > groupBy (using length (==)) ["a","bb","c","dd","ee"] 09:00:17 can't find file: L.hs 09:00:26 whaaat 09:00:39 That sometimes happens randomly. 09:00:41 > groupBy (using length (==)) ["a","bb","c","dd","ee"] 09:00:44 [["a"],["bb"],["c"],["dd","ee"]] 09:00:47 ic 09:00:52 But "on" is what you wanted. 09:00:53 -!- Patashu has joined. 09:01:09 @type on 09:01:10 (b -> b -> c) -> (a -> b) -> a -> a -> c 09:01:56 > groupBy ((==) `on` length) ["a","bb","c","dd","ee"] 09:01:58 [["a"],["bb"],["c"],["dd","ee"]] 09:02:00 oh 09:02:01 neat 09:02:03 @hoogle on 09:02:05 Data.Function on :: (b -> b -> c) -> (a -> b) -> a -> a -> c 09:02:06 Control.Exception.Base onException :: IO a -> IO b -> IO a 09:02:06 Control.Exception onException :: IO a -> IO b -> IO a 09:03:47 Also, (==) `on` length is too strict. :-( 09:03:57 -!- Patashu_ has quit (Ping timeout: 240 seconds). 09:06:19 -!- Patashu has quit (Disconnected by services). 09:06:19 -!- Patashu_ has joined. 09:10:51 shachaf: "too strict"? 09:11:26 > take 1 $ groupBy ((==) `on` length) [[1],[1]] 09:11:27 [[[1],[1]]] 09:11:30 For example if you compare a finite list to an infinite list it'll never return. 09:11:31 > take 1 $ groupBy ((==) `on` length) [[1],[1],[1..]] 09:11:36 mueval-core: Time limit exceeded 09:11:42 well yeah 09:11:55 length on infinite lists isn't really a clever thing to do 09:13:06 Well, on finite lists it'll just be inefficient rather than nonterminating. 09:13:10 -!- Patashu has joined. 09:13:29 ok then 09:13:39 How do *you* group by length then? 09:13:50 Hmm. 09:14:01 efficiently ;) 09:14:08 ((==) `on` map (const ())) will at least be asymptotically optimal. 09:14:42 how so? 09:15:10 It's terrible, though. 09:15:28 > let sameLength [] [] = True; sameLength (a:_) [] = False; sameLength [] (b:_) = False; sameLength (a:as) (b:bs) = sameLength as bs in sameLength [1..] [3,2,1] 09:15:29 -!- Patashu_ has quit (Ping timeout: 276 seconds). 09:15:29 False 09:15:32 Write your own function? Or use genericLength :: [a] -> Nat (the only valid use of genericLength) 09:15:40 Your own function would be what fizzie wrote. 09:18:42 -!- Patashu has quit (Remote host closed the connection). 09:18:54 -!- Patashu has joined. 09:19:47 ((==) `on` (() <$)) has a good punctuation-to-alpha ratio, however. 09:27:41 data T; instance Ord T where compare _ _ = EQ; (==) `on` (unsafeCoerce :: [a] -> [T]) 09:28:19 () will waste all those cycles "forcing" and comparing ()s 09:28:33 > compare () undefined 09:28:34 *Exception: Prelude.undefined 09:32:06 > length $ (map (const undefined)) [1..] 09:32:09 mueval-core: Time limit exceeded 09:32:12 > length $ (map (const undefined)) [1..20] 09:32:14 20 09:33:02 hm 09:33:04 better newtype over Any. 09:33:07 > zip [1..20] [1..19] 09:33:09 [(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8),(9,9),(10,10),(11,11),(12,1... 09:33:51 > length $ zip [1..20] [1..19] -- that's just the shorter, isn't it? 09:33:52 19 09:33:57 @let cmp xs ys = last (zip xs ys) == (last xs, last ys) 09:34:00 Defined. 09:34:05 > cmp [1..20] [1..19] 09:34:07 False 09:34:15 > cmp [1..20] [1..20] 09:34:15 > cmp [1,1,1,1] [1] 09:34:16 can't find file: L.hs 09:34:16 True 09:34:24 > cmp [1..20] [1..20] 09:34:26 True 09:34:30 > cmp [1,1,1,1] [1] -- still 09:34:31 True 09:35:09 > cmp [1,2,3,2,1] [1] -- and so on 09:35:10 True 09:35:33 k 09:35:42 cmpMonotonicSteadilyRisingLists 09:35:56 hm no 09:36:00 *hide* 09:36:36 Another benefit: sameLength :: [a] -> [b] -> Bool vs. ((==) `on` length) :: [a] -> [a] -> Bool. 09:48:41 -!- Patashu_ has joined. 09:48:46 -!- Patashu_ has quit (Client Quit). 09:48:47 -!- Patashu has quit (Disconnected by services). 09:50:59 -!- IAm_thor has joined. 09:51:00 -!- IAm_thor has left. 09:55:09 -!- IAm_thor has joined. 09:55:10 -!- IAm_thor has left. 10:12:02 -!- boily has joined. 10:20:52 except that groupBy requires [a] anyway 10:20:56 @type groupBy 10:20:57 (a -> a -> Bool) -> [a] -> [[a]] 10:26:17 hm 10:26:28 Can I have a data Pair a b = Pair a b 10:26:44 but with a Type Constructor Foo a = Pair a a? 10:26:59 newtype Foo a = Foo (Pair a a)? 10:27:12 (two contructors: one with two arguments and one with one argument) 10:27:40 hm 10:28:02 Pair a b = Pair a b | Pair' a a doesn't work 10:28:20 mroman_: wait, what exactly do you want? a wrapper function? a gadt with two constructors? I don't understand 10:28:21 (Pair' still takes two arguments) 10:28:30 well 10:28:36 I could just use foo a = Pair a a 10:28:40 but then foo isn't a type constructor 10:28:55 I think you're confusing all sorts of things here. 10:28:58 um 10:28:59 i.e. I can't match for that 10:29:07 and how would you want to match this? 10:29:35 foobar (Foo _) = ...; foobar (Pair _ _) = ... 10:29:46 foobar :: Pair a b -> ... 10:30:12 wait 10:30:49 I'm stupid 10:31:21 or am I 10:31:29 data Pair a b = Pair a b | Pair' a 10:31:36 but then Pair' only holds one value 10:31:37 :( 10:32:08 The first thing to do if you don't want to confuse people is to use a different name for the type constructor and the data constructor. 10:32:42 except, perhaps, for records. 10:32:54 well 10:33:17 There should be two "constructors". One with two arguments and one with one argument 10:33:26 and you can match against the one with only one argument of course 10:33:36 but the one with one argument shall also match for the one with two arguments 10:33:45 anyway I don't know what you want. 10:33:49 i.e. let's call them Pair1 and Pair2 10:34:20