←2019-08-27 2019-08-28 2019-08-29→ ↑2019 ↑all
00:14:04 <esowiki> [[Special:Log/newusers]] create * Toel F * New user account
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01:36:33 <esowiki> [[Special:Log/newusers]] create * SoundOfScripting * New user account
01:41:07 <esowiki> [[Esolang:Introduce yourself]] https://esolangs.org/w/index.php?diff=65718&oldid=65717 * SoundOfScripting * (+303) Followed instructions.
01:42:14 <esowiki> [[User:SoundOfScripting]] N https://esolangs.org/w/index.php?oldid=65719 * SoundOfScripting * (+1067) Created page with "This is the page of the terrible language designer [https://www.esolangs.org/wiki/User:SoundOfScripting User:SoundOfScripting]. I like to make esolangs, even if they are not p..."
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01:48:15 <esowiki> [[TwoFiftyFive]] M https://esolangs.org/w/index.php?diff=65725&oldid=53836 * SoundOfScripting * (+5) Sorry for the eidit spam! Just a handful more pages. ======= Changed to User:SoundOfScripting
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01:49:21 <esowiki> [[Neg]] M https://esolangs.org/w/index.php?diff=65727&oldid=55788 * SoundOfScripting * (+5) maybe I'm just dumb and I could've changed my username
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08:15:21 <esowiki> [[Spin]] https://esolangs.org/w/index.php?diff=65733&oldid=33886 * Dtuser1337 * (+18) Adding a year category.
08:24:58 <esowiki> [[Spin]] https://esolangs.org/w/index.php?diff=65734&oldid=65733 * Dtuser1337 * (+140) Adding examples.
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08:55:22 <cpressey> Good morning. Idea for the day: design an esoteric parsing combinator library.
08:55:38 <cpressey> Maybe based on Fokker's X combinator. Except for parsing, of course.
08:56:58 <shachaf> Good morning.
08:57:15 <shachaf> I feel like I should know a whole bunch more about parsing.
09:07:52 <cpressey> Recursive descent parsing is easy and fun, but only works on some grammars. If you write a RDP manually you can manually add code to do non-context-free things like track a symbol table or generate code.
09:08:49 <cpressey> There are algorithms that will return all possible parses for general context-free grammars. They're not as efficient, most programming languages don't need them, but they're also fun in their way.
09:09:11 <cpressey> I don't know what a PEG is, I should probably find out some day.
09:12:16 <cpressey> Table-based parsing of LR-type grammars I find not-fun and have basically ignored all my life.
10:03:41 <cpressey> The LR-grammar parsing stuff is very esoteric, though, and should not be ignored. Maybe someone could make an esolang where it works like shift/reduce parsing, except it's not just a parser, it's a Turing-complete language.
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10:13:08 <cpressey> Not that different from a push-down automaton, really, I guess
10:13:21 <shachaf> This reminds me of the mostly unrelated topic of alternating finite automata.
10:13:45 <shachaf> I wanted to figure out whether they're a realistic implementation strategy for regular expressions.
10:14:52 <cpressey> It sounds realistic in the sense that you could implement it. Whether there would be any advantages to doing so or not, I don't know.
10:16:22 <cpressey> I think it's conventional to convert NFAs to DFAs, but you can also execute NFAs directly. Which is more efficient in the modern era probably depends on cache configuration and all that gory stuff.
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10:42:51 <cpressey> s/conventional/traditional/
10:50:29 <shachaf> The advantage would be support for intersection and complement.
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11:02:43 <cpressey> I assume you mean, improved support... I think most regex implementations aren't oriented at optimizing the compilation-to-FA step.
11:03:03 <cpressey> You only need to compile the RE once, and typically use it more than once
11:03:21 <cpressey> Also, you should probably sleep
11:08:00 <rain1> https://github.com/kragen/peg-bootstrap/blob/master/peg.md
11:08:05 <rain1> this is my favorite page to learn about PEG
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12:05:57 <cpressey> The Wikipedia article is also not bad (as they go). My understanding is, someone looked at how CFGs actually get implemented (as RDPs) and turned that back into a grammar formalism.
12:06:21 <cpressey> Expedient yes; mathematically satisfying, not really
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12:15:34 <int-e> Oh, that kind of RDP. (Google finds something entirely different.)
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12:24:03 <esowiki> [[Special:Log/newusers]] create * Thecatlover1996 * New user account
12:25:01 <cpressey> Remote Drocedure Pall
12:28:22 <esowiki> [[Esolang:Introduce yourself]] https://esolangs.org/w/index.php?diff=65735&oldid=65718 * Thecatlover1996 * (+242) /* Introductions */
12:28:27 <esowiki> [[Brainfuck]] https://esolangs.org/w/index.php?diff=65736&oldid=65605 * Thecatlover1996 * (+50) /* Language overview */ Tape has length 30,000
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12:59:10 <esowiki> [[Brainfuck]] https://esolangs.org/w/index.php?diff=65737&oldid=65736 * Ais523 non-admin * (+168) /* Language overview */ clarify the nature of the tape
13:00:50 <esowiki> [[Brainfuck]] https://esolangs.org/w/index.php?diff=65738&oldid=65737 * Ais523 non-admin * (+106) /* Computational class */ clarify that BF requires an unbounded tape or unbounded values to be TC
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13:19:32 <esowiki> [[Esolang:Introduce yourself]] https://esolangs.org/w/index.php?diff=65740&oldid=65735 * Trickbrain26 * (+140) /* Introductions */
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13:41:42 <rain1> hpy
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14:13:29 <rain1> perhaps Stephen Wolfram's ideas presented in "A New Kind of Science" can provide useful insight for your endeavour
14:22:42 <esowiki> [[User:Orby]] https://esolangs.org/w/index.php?diff=65749&oldid=60360 * Orby * (+12)
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15:36:09 <ais523> cpressey: have you seen recursive ascent parsers? it's basically the open-coded version of LR, but much easier to understand than the table-driven version
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15:37:59 <ais523> the basic idea is that whenever you have a grammar ambiguity that can't immediately be resolved with your lookahead symbols but can be resolved later, you call a function that can parse either of the two things you want to be able to parse, and returns which of the two it parsed
15:38:30 <ais523> (occasionally you'll need multiple functions that disambiguate in different ways depending on what comes next, but that's rare)
15:43:45 <cpressey> No, I haven't
15:48:07 <cpressey> You could also fall back to something like CYK for the non-LL parts (overkill, of course)
15:48:13 <cpressey> Unfortunately must be off.
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15:50:15 <rain1> just use s-expressinos
15:52:51 <ais523> for what? the language you're parsing? that doesn't work too well if you don't control the format
15:53:06 <ais523> even when you do, s-expressions tend to have some amount of variety in what constants they support
15:53:43 <ais523> I've been working with SMT2 recently, whose syntax is a proper subset of Common Lisp's (although the semantics are quite different), and it can be hard to find off-the-shelf parsers for it even though it's just s-expressions
15:53:57 <ais523> due to things like #x1234 as a hexadecimal number
15:54:11 <rain1> that's a frustrating problem
15:54:35 <rain1> i feel like lisp and s-expressions has more potential but kind of flopped because of issues like the one you state
15:55:04 <ais523> lisp is basically designed to be manipulated by lisp code, it isn't really designed to be manipulated by code in arbitrary other languages
15:58:14 <rain1> i would design READ to be based on a list of regexes
15:58:22 <rain1> for the tokens
16:02:16 <ais523> (there's also the problem that SMT2 is very strongly typed, so, e.g., #x00 and #x0000 are constants of different type, the former is 8 bits wide, the latter 16 bits wide; this is something a generic parser is unlikely to tell you about)
16:03:06 <rain1> ah yes you would definitely need a custom reader for that
16:13:42 <ais523> in general I think the idea of a generic parser that handles a wide range of languages wouldn't really work, languages' semantics often ends up being mirrored in the syntax
16:15:54 * ais523 tries to imagine what a sexpy version of Incident would look like
16:15:56 <ais523> I don't think it works
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17:27:22 <esowiki> [[Hello world program in esoteric languages]] https://esolangs.org/w/index.php?diff=65753&oldid=65697 * Dtuser1337 * (+110) /* Macmac */ new lang and removing newline as a shortcut.
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17:35:47 <esowiki> [[Hello world program in esoteric languages]] https://esolangs.org/w/index.php?diff=65754&oldid=65753 * InfiniteDonuts * (-404)
17:38:52 <b_jonas> hi all
17:39:41 <ais523> hi
18:01:30 <esowiki> [[User talk:Language]] M https://esolangs.org/w/index.php?diff=65755&oldid=60717 * Dtuser1337 * (+1) Moving category to the bottom
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18:05:18 <kmc> hello b_jonas
18:05:20 <kmc> what's new?
18:07:12 <esowiki> [[A]] https://esolangs.org/w/index.php?diff=65756&oldid=60788 * Dtuser1337 * (+23) Rerorerorerorero
18:11:39 <esowiki> [[RISBF]] https://esolangs.org/w/index.php?diff=65757&oldid=56849 * Dtuser1337 * (+18) I Love You Kitchen Gun :D
18:32:14 <arseniiv> chkdsk eats memory like crazy :o
18:32:25 <b_jonas> it has to
18:32:45 <b_jonas> well, depending on what parameters you start it with, obviously
18:32:53 <ais523> because it has to hold the entire filesystem metadata in memory?
18:33:09 <b_jonas> but it has to check for, like, blocks that are marked as occupied but to which nothing points, or inconsistent forwards-backwards pointers or cycles
18:33:13 <b_jonas> which could be anywhere in the file system
18:33:15 <arseniiv> (b_jonas: /F /R /X /I /C)
18:33:24 <b_jonas> arseniiv: oh, this is on Windows?
18:33:29 <arseniiv> yeah
18:33:39 <b_jonas> makes sense, it's not called chkdsk on unixen
18:33:42 <b_jonas> it's called fsck
18:35:27 <arseniiv> though I bet it could understand something like -f -r -x but I just copied the forms given in the help message
18:36:05 <arseniiv> it’s quite scary when low on memory
18:36:33 <arseniiv> apps crash, the screen turned black for some time for an unknown reason
18:37:04 <b_jonas> I don't run apps
18:37:13 <b_jonas> I don't use a smartphone
18:37:20 <b_jonas> I only run programs, and put my files into directories
18:37:51 <arseniiv> :D I mean, various software for entertaining purposes like skype or streamWriter
18:38:42 <arseniiv> (don’t ask me why skype is here. I don’t know either)
18:39:03 <b_jonas> well I do use skype
18:39:11 <b_jonas> but only the windows version, not the mobile phone version
18:39:22 <b_jonas> I use it because it lets me call some co-workers and relatives
18:40:22 <arseniiv> I meant the first one here, though I had to install the second to be able to chat with people for chatting who with the first skype remains
18:40:41 <b_jonas> I don't understand that
18:40:47 <b_jonas> what?
18:40:54 <b_jonas> install the mobile version to do what?
18:41:31 <arseniiv> basically to do what I do with the first one
18:41:45 <arseniiv> though I wanted to test the grammar a bit
18:43:21 <arseniiv> we had tested several different messengers out there these times and hadn’t migrate properly to any of them yet, so it’s skype for a while
18:43:51 <b_jonas> the people I know use like four different ones
18:44:00 <arseniiv> though it visibly degraded as a group chat software
18:45:46 <arseniiv> it upgraded in several regards, but many bugs were introduced, and sufficiently much of functionality, removed
18:46:47 <b_jonas> I know. you can no longer just invite another person by skype username. you have to do a search, which searches in all fields, and then choose the person with the given skype username, and you can't even easily tell the skype username, only the displayed name, you have to get some hidden properties box to find it out.
18:48:15 <b_jonas> you could probably DOS a user by registering thirty users with the same displayed name and avatar picture (and changing those to follow that person), because nobody would be able to invite them then
18:48:28 <arseniiv> and also I want to complain about widespread lack of support of composite fonts. It’s a pretty simple concept in light of modern font rendering libraries, and still does it appear so rarely in the software with multilingual potential like chat things not based on web browsers
18:49:13 <arseniiv> b_jonas: oh
18:49:36 <b_jonas> anything I say about skype might be imprecise of course, because it may have changed ten updates ago
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20:50:05 <esowiki> [[Brainfuck]] https://esolangs.org/w/index.php?diff=65758&oldid=65738 * PaniniTheDeveloper * (+5)
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21:25:01 <arseniiv_> I read a neat problem just now: given a small segment of a conic, how do you distinguish is it a circle, an ellipse, a parabola or a hyperbola?
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21:26:42 <arseniiv> maybe someone not knowing it prior, would be interested to solve it for themselves or openly. I have already spoilered myself into a part of the solution so I don’t count
21:31:08 <b_jonas> arseniiv: should I tell the solution, or would you just like to figure it out yourself?
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21:35:41 <arseniiv> as you wish; I see at least two avenues: using foci and something related or drawing a cartesian coordinate system, taking coordinates of several points and then calculating some invariants. I don’t remember particularities of either except one thing about optics
21:36:41 <arseniiv> hopefully we won’t spoil it for anybody interested
21:36:57 <arseniiv> b_jonas: ^
21:37:05 <b_jonas> arseniiv: what I'd do is to just the sort of brute force way, which is to compute the parameters of the quadratic form of the conic from five points on the arc.
21:37:28 <arseniiv> so the second way then
21:37:37 <b_jonas> there's a nice easy but not very well known way to do that efficiently that is described in the yellow geometry book that I bought only this year, which I can tell if you want.
21:38:02 <arseniiv> something determinant-y?
21:38:23 <b_jonas> it would probably be possible to do something more geometric, that is, going most of the way with a straightedge construction to find points on the involution that the conic implies on the ideal line,
21:38:55 <b_jonas> but I don't think that helps, because that's the sort of theoretical construction that you either couldn't do in real life, or only engineers could do in real life and I'm not an engineer
21:39:15 <b_jonas> arseniiv: something matrix-y, yes
21:40:26 <arseniiv> I am aligned more to the second, algebraic/computational way here, too. I’m profound in forgetting essential theorems of synthetic geometry needed for the first path
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21:40:47 <b_jonas> this is one that you can't forget once you learn about it, it's a beautiful method
21:40:58 <b_jonas> it's a pity I hadn't learned it earlier
21:41:27 <arseniiv> b_jonas: like, some 5th-order matrix? or less, 3rd order, something from projective linear algebra?
21:41:52 <b_jonas> yes, you have to solve a rank 5 linear equation
21:43:08 <arseniiv> hm, with a row for every point?
21:43:34 <b_jonas> take the 6x5 matrix where each row is [x0**2, x1**2, x2**2, 2*x0*x1, 2*x0*x2, 2*x1*x2] where [x0, x1, x2] is a coordinate for a point, one row per point
21:44:30 <arseniiv> oh, homogeneous coordinates, makes sense
21:45:06 <arseniiv> and what is the right part and what are unknowns here?
21:46:26 <b_jonas> it's 6x5, so you solve for a nonzero vector orthogonal to each row
21:46:53 <b_jonas> if that vector is [a00, a11, a22, a01, a02, a12], then its components give the quadratic form
21:47:51 <b_jonas> this works because [a00, a11, a22, a01, a02, a12]^T*[x0**2, x1**2, x2**2, 2*x0*x1, 2*x0*x2, 2*x1*x2] is exactly the equation of the conic
21:48:04 <b_jonas> = 0 obviously
21:49:01 <arseniiv> hm neat
21:49:30 <b_jonas> so once you have that, just check the sign of the determinant of [a00,a10;a01,a11] to tell if it's a hyperbola
21:50:08 <b_jonas> this one even lets you make this more numerically stable if you take more than five points
21:50:35 <arseniiv> oh! this part is great
21:50:41 <b_jonas> that is, if you have a lot of sample points but each one has some error
21:50:57 <int-e> hyperbole is totally on topic for this channel.
21:52:19 <arseniiv> and then, I guess, we can take four points and deduce something like “the most <something> quadratic form” using least squares to solve the underdetermined system
21:52:54 <b_jonas> I would like to note that it gets much harder to find the conic if you have three points and two tangents. Apart from degenerate cases, there are always exactly four real solutions or no real solutions. It was REALLY not obvious to me why there can't be exactly two solutions.
21:52:55 <arseniiv> (or three points, but that would be more boring probably)
21:53:49 <arseniiv> int-e: how about parables?
21:54:12 <arseniiv> and I presume ellipsis is…
21:54:36 <arseniiv> (hopefully we wouldn’t talk in circles)
21:54:51 <b_jonas> Four points and one tangent is easier. Apart from degenerate cases, there are zero or two possible conics; there's an easy way to test which one of those is the case; and a not too hard way to solve the conic, though harder than for five points.
21:55:38 <b_jonas> The yellow book actually describes the case of computing a conic from four points and one tangent, but it doesn't even mention the more tricky case of three points and two tangents.
21:55:48 <b_jonas> I only know about that one from the wob.
21:56:05 <b_jonas> If you want me to spoil some of that later, you can ask me.
21:56:05 <arseniiv> (from what?)
21:56:15 <arseniiv> okay!
21:56:17 <int-e> arseniiv: parables seem to be rare. Ellipses on the other hand...
21:56:38 <int-e> `quote parable
21:56:39 <HackEso> 1060) <kmc> ah yes, like the parable of jesus feeding the masses with expired jell-o
21:56:49 <arseniiv> b_jonas: though currently I’m not interesting in going on a tangent
21:56:54 <int-e> `grWp parable
21:56:56 <HackEso> No output.
21:56:59 <kmc> roflwut
21:57:05 <b_jonas> The yellow book is Richter Gerbert: "Perspectives on Projective Geometry", Springer (2019). It was one of the best purchases I've done this year.
21:57:25 <int-e> b_jonas: is that a pun
21:57:42 <b_jonas> int-e: is what a pun?
21:57:57 <int-e> perspective in connection with projective geometry
21:58:05 <b_jonas> yes, the book title is a pun
21:59:29 <b_jonas> The other three geometry reference books on my shelf next to this one tell very little of this stuff, though they do tell some other useful info.
21:59:43 <int-e> I guess there's a certain pun potential in "purchase", but it's not realized in your statement.
22:00:05 <b_jonas> The Hajós does tell some of the basics, like about the equation of comics in general and classifying them.
22:00:40 <b_jonas> int-e: well yes, I rarely make English puns
22:02:44 <b_jonas> my hon. and learned friend fungot, has SGDQ 2019 started yet?
22:02:44 <fungot> b_jonas: unless it uses recursion or something. " i'll let you know
22:02:55 <b_jonas> oh thanks, that'll be great
22:03:06 <b_jonas> some of the games may have recursion
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22:04:14 <b_jonas> anyway, good night to all
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22:04:32 <arseniiv> fungot: maybe you also do know when my chkdsk will finish, too?
22:04:32 <fungot> arseniiv: the package name, obviously. ( wondering why i thought it was c, i don't see
22:05:06 <arseniiv> hm they too make puns, about seeing C, but none about chkdsk
22:06:04 <int-e> mmm chkdsk
22:06:34 <int-e> (chkdsk should just fsck off)
22:06:44 <int-e> (it's not good, but it's a pun)
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22:18:11 <arseniiv> int-e: lol
22:19:43 <arseniiv> ah, I was going to suggest a thing and then forgot it
22:20:05 <arseniiv> hyperbolic good, parabolic good and elliptic good!
22:20:20 <arseniiv> or evil
22:21:06 <arseniiv> or maybe the other way: lawful ellipse, chaotic ellipse and what is the other… neutral ellipse
22:24:42 <arseniiv> hm speaking of what, I’ve seen a 3×3 table of planar geometries in a geometric book. One axis was how angles behave (elliptic, parabolic, hyperbolic) and the other was the more known one, whether the quadratic form is ++ euclidean, +0 “galilean” (how is it called?) or +− pseudoeuclidean
22:25:06 <arseniiv> those are the only ones with some properties, I don’t remember which ones
22:25:37 <arseniiv> for instance, they are all constant-curvature
22:26:10 <arseniiv> oh wait I mixed something up
22:26:46 <arseniiv> how the angles behave is precisely what is the signature of the quadratic form, it was some other property
22:29:02 <arseniiv> for example, euclidean-0 should be the usual euclidean plane, euclidean-+ should be the elliptic plane and euclidean-− should be the hyperbolic plane
22:30:01 <arseniiv> yes it should be the sign of the constant curvature, though I don’t remember if it was defined in this way, and certainly the curvature wasn’t defined there for a general case
22:30:15 <arseniiv> okay I’m done
22:32:53 <esowiki> [[User:SoundOfScripting]] M https://esolangs.org/w/index.php?diff=65760&oldid=65719 * SoundOfScripting * (-21) Okay now I can be dormant again.
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