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Designing a programming language to speedrun Advent of Code
- lawn 3y agoSuch a fantastic and inspiring post, and a very cool language. Kudos!
- hnlmorg 3y ago> Before we move on, I want to point out that “being able to write code from left to right without backtracking” is a completely bonkers thing to optimize a programming language for. This should not be anywhere in the top hundred priorities for any “serious programming language”! There are plenty of serious languages that are written this way. Most noticeably are shell scripting languages but I’ve seen stack based and functional languages that are written like this too.
- bmitc 3y agoI don't really even understand what is meant by "being able to write code from left to right without backtracking”, much less why that is bonkers. Scrolling down and seeing the code examples, the language even seems quite conventional, so I'm even more confused.
- KeplerBoy 3y agoIsn't that a whole lot more "being able to write code without making a lot of dumb mistakes", which is a feature of the programer. So it boils down to getting gud and practice?
- Cthulhu_ 3y agoThat's what it sounds like to me. Thinking about a line of code before writing it down, or knowing what the code will do instead of trial and error (which... is what I often do, lol)
- ThreeToZero 3y agoThe post gives an example of how python doesn't have this feature in the section [https://blog.vero.site/post/noulith#coding-with-and-without-infix-functions https://blog.vero.site/post/noulith#coding-with-and-without-...] Python fails this criteria because if you type as you think through the process, you have to move the cursor to the beginning to prefix the 'map' around the input. For example this series of transforming the input: puzzle_input.split("\n\n") map(ints, puzzle_input.split("\n\n")) map(sum, map(ints, puzzle_input.split("\n\n"))) max(map(sum, map(ints, puzzle_input.split("\n\n")))) ---------------------- Compare to this postfix syntax where you can write this incrementally as you think through the operations: puzzle_input split "\n\n" map ints map sum then max
- bmitc 3y agoThanks for pointing out that specific example and comparison. The solution seems like it's just a less readable pipeline. puzzle_input split "\n\n" map ints map sum then max; puzzle_input split "\n\n" map ints map sum then sort then (_[-3:]) then sum;
- dekhn 3y agoafter a while, my brain reorganized and i think of the map() first, before thinking about the content of the map, basically to avoid the keystrokes required to go to beginning of line, then back to where I was typing.
- hnlmorg 3y agoNo, what the author is discussing is a syntax thing. Lets take a hypothetical C-like language: result = C(B(A())) In this your result is on the left hand side. The first function to be executed is A and then B and lastly C, which also reads right to left. This is a pretty common way to write code, it's by no means unique to C-like languages. So you'd have gotten so good at reading code like this that you probably don't even realise you're reading right to left. Now lets look at a POSIX-like shell language: result = $(A | B | C) Here the result is still on the left hand side but now you're reading the functions from left to right (ie pipes) I'm not the article author by my own programming language takes things a step further from conventional shells and you can do the following: A -> B -> C -> set result Here it reads fully left to right. There is zero confusion about which order to read this. ---------------- Going back to the more general point about reading left to right, it's worth noting that even math operators can be extended this way. For example with polish notation (https://en.wikipedia.org/wiki/Polish_notation https://en.wikipedia.org/wiki/Polish_notation) your operators precede your values. Effectively turning those symbols into function names: + 2 5 ...would return 7 Though personally I prefer the more traditional format of operators sitting between their values (2+5), but that's purely because that is what I'm used to.
- xiaq 3y agoYou can write A | B | C | result=$(cat) in shell. Edit: this only works if the shell runs the last command in the current environment (as opposed to a subshell), and only ksh and zsh seem to do that...
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- _0ffh 3y agoOr with uniform function call syntax result = A().B().C()
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- Strilanc 3y agoHere's an example. In SQL the "select" clause comes at the start. In C# LINQ queries, "select" comes at the end. A major resulting difference is autocomplete works in the latter case but not the former. A more pervasive example is how OOP languages do x.f(...) instead of f(x, ...). This also helps with autocomplete. Also it results in calls chaining like x.y(...).z(...) instead of nesting like z(y(x(...), ...), ...). These kinds of things have noticeable effects on how easy it is to discover relevant methods and how fast they are to type.
- frou_dh 3y agoTalking of shell, the preference for left-to-right is often used to justify "useless use of cat", i.e. `cat file | command` instead of `command <file`, but it can just be written `<file command` instead.
- robertlagrant 3y agoI'm surprised that file> command isn't the preferred idiom. Does that mean something else?
- hnlmorg 3y agoYes, that would write to a file called "command". So the correct way to write that would be: command > file https://www.gnu.org/software/bash/manual/html_node/Redirections.html https://www.gnu.org/software/bash/manual/html_node/Redirecti...
- smrq 3y agoThat would execute the command `file` and put the output into the file `command`.
- robertlagrant 3y agoOh, now I re-read it - of course! Hah.
- sgarland 3y agoIs `<file` shorthand for `cat file`, or is that only true when used in a sub-shell?
- mpweiher 3y agoYeah, Smalltalk also works this way...mostly. 3 negated + 2 negated. Alas, as with the post, this also breaks down when you have more than 2 arguments (or in Smalltalk parlance, 1 argument in addition to the message receiver), as those are handled by keyword arguments and you can't tell where the keywords for one message stop and the ones for the next one start. Let's say we have some nested arrays, which are accessed with at: in Smalltalk: array at:4 at:2 at:1. Alas, that doesn't get interpreted as 3 messages, but as the single message at:at:at:. As it kind of has to be as there is no way to disambiguate. Surprisingly, Smalltalk does have a way to chain messages and thus separate the keywords, the semicolon: array at:4; at:2; at:1. Alas, this sends the subsequent messages to the original receiver, so it is equivalent to: array at:4. array at:2. array at:1. (And so this example doesn't actually make sense, it's just a syntax example). So what you have to do is add parens: ((array at:4) at:2) at:1. Hmm, not nice. For Objective-S (https://objective.st https://objective.st), I introduced the pipe for message chaining: array at:4 | at:2 | at:1. One way of looking at this is as a syntactic device that allows left-to-right typing without backtracking, which it is. And that is both nice to write and quite readable, IMNSHO. A second way of looking at it is as a version of the pipe/filter architectural style, with each message expression being a filter, the results from the filter on the left piped into the filter on the right as the receiver. This is a little bit like |> in some FP languages. But really only a little bit, because in Objective-S this is not the whole story, but just a way of integrating messaging into the way the pipe/filter architectural style is supported at the language level.
- firejake308 3y agoThe syntax reads similar to R with pipes
- rohithgilla 3y agoAmazing, the cross inspiration from python and rust is cool. Good work!
- dtx1 3y ago> I solve and write a lot of puzzlehunts, and I wanted a better programming language to use to search word lists for words satisfying unusual constraints, such as, “Find all ten-letter words that contain each of the letters A, B, and C exactly once and that have the ninth letter K.” So... Perl?
- jstanley 3y agogrep { len($_) == 10 && /^[^a]*a[^a]*$/i && /^[^b]*b[^b]*$/i && /^[^c]*c[^c]*$/i && /k.$/i } @words; Is there a simpler way?
- darrenf 3y agoPerl has `length`, not `len` :) Also I can't resist a bit of TIMTOWTDI: my @found = grep { local $_ = lc; length == 10 && substr($_,8,1) eq "k" && join("",sort [/([abc])/g]->@*) eq "abc" } @words;
- sltkr 3y agoMight as well do it on the command line at that point: $ grep '^........k.$' /usr/share/dict/words | grep a | grep b | grep c | grep -v 'a.*a' | grep -v 'b.*b' | grep -v 'c.*c' backstroke bailiwicks benchmarks branchlike bushwhacks greenbacks matchbooks piggybacks roadblocks scrapbooks slingbacks throwbacks thumbtacks
- cmdlineluser 3y agoNot sure if it would be considered simpler but lookaheads can be used to express it in a single pattern. ^(?=.{8}k.$)(?=[^a]*a[^a]*$)(?=[^b]*b[^b]*$)(?=[^c]*c[^c]*$)
- sltkr 3y agoIt does lead to a very concise invocation: $ perl -ne 'print if /^(?=.{8}k.$)(?=[^a]*a[^a]*$)(?=[^b]*b[^b]*$)(?=[^c]*c[^c]*$)/' /usr/share/dict/words
- shaftoe444 3y agoInspired me to have another run at the second half of Crafting Interpreters.
- ghj 3y agoI didn't realize who this was by the title, but this is betaveros, the guy who won 1st place in Advent of Code every single year since 2019: https://clist.by/account/32289/resource/adventofcode.com/ https://clist.by/account/32289/resource/adventofcode.com/
- cjbprime 3y agoIncluding in 2022 with the self-created programming language the post is about, which is just amazing, and lives somewhere in my head near FlaSh's 2020 decision to switch to playing pro StarCraft Brood War tournaments as the Random race -- requiring him to become world-class at three races (nine race matchups) while his opponents only have to be world-class at one race (three race matchups). FlaSh came third in the largest tournament that year. From the post: > I think I predicted that requiring myself to use only Noulith on Advent of Code would make my median leaderboard performance better but my worst-case and average performances significantly worse. I don’t think my median performance improved, but my worst-case performance definitely got worse. Somehow it still didn’t matter and I placed top of the leaderboard anyway. (I will note that 2021’s second to fourth place all didn’t do 2022.)
- dataengineer56 3y agoIt seems crazy that 2nd to 4th in 2021 didn't do 2022 at all! It's an annual ritual for me, I couldn't imagine being so heavily into it one year and then not competing at all the next. Was there a reason?
- cjbprime 3y agoI heard something about a large competitive programming tournament (i.e. a commercial one) happening at a nearby time to AoC, I think it was that for at least one person. (I also don't think it's unimaginable; lives change, everyone's going to have a point where they played one year and not the next, most obviously illness, but also life changes like marriage, kids, stressful new job, etc?)
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- saagarjha 3y agoI think it’s interesting how similar a lot of this stuff is to what I do, except I’m not very good at Advent of Code and also I decided to hack Python to do this instead of writing my own language. For example: * I couldn’t really make operators first class functions, but I just autoimported operator which has this but in words * I wanted partial application and hated lambda syntax, so I hacked it together with some magic. “_0 + 1” is basically equivalent to lambda x: x + 1 * Python really likes to make everything a free function, which messes with the whole left-to-right thing. So I monkey-patched functional methods onto all the collections Together this means that if I have like a comma separated list of numbers in str and I want to, idk, count how many are above five I’d do something like str.split(",").map(int).filter(_0 > 5).len which matches how my brain things about it far better than how Python would like me to write it. It uses some tricks but it’s not actually that bad of a hack IMO: https://github.com/saagarjha/advent-of-code/blob/main/aoc.py https://github.com/saagarjha/advent-of-code/blob/main/aoc.py
- master-lincoln 3y agoreads a bit like javascript now. You might want to consider switching languages
- contravariant 3y agoHonestly I'm jealous of JavaScript's arrow syntax. I don't really need anything else but the arrows are nice (and Turing complete).
- maegul 3y agoI always figured that once Python got the walrus operator it would be a matter of time until arrow functions of some sort made more and more sense on Python.
- Spivak 3y agoI really hope not tbh, once you break that seal it will consume the entire language into nested anonymous function soup without all the facilities JS has accumulated over the years to mitigate it. Python is an iterator based language and it leads to some very nice code if you design with that in mind. It's really incredible how much such a small feature in the grand scheme of things `(function() { })()` influences all API and library design. Right now passing around functions in Python is ugly and reads as such which is enough of a deterrent for most people.
- tuukkah 3y agoOne key point I overlooked on first reading: > [--] I wanted access to Haskell’s list monad in a sloppier language. > I like static types, but only if they’re sufficiently expressive and supported by good inference, and I like not having to implement any of that stuff even more, so I settled for dynamic typing. Then it's some of the power of Haskell without any of the safeguards. Plus being able to write "x f y" to mean a function call to f with arguments x and y (whereas in Haskell you'd write "x `f` y").
- nemo1618 3y ago> The title is clickbait. I did not design and implement a programming language for the sole or even primary purpose of leaderboarding on Advent of Code. I did: https://github.com/lukechampine/slouch https://github.com/lukechampine/slouch "Find all ten-letter words that contain each of the letters A, B, and C exactly once and that have the ninth letter K" :load wordlist wordlist.txt words wordlist | filter -:(len == 10 and .8 == "k") A more interesting example: https://www.youtube.com/watch?v=i_zDbInYOpQ https://www.youtube.com/watch?v=i_zDbInYOpQ AoC solutions here: https://github.com/lukechampine/advent/tree/master/2022 https://github.com/lukechampine/advent/tree/master/2022 (The language has builtin commands for fetching inputs and submitting solutions)
- brandly 3y agoYou should write a longer post about it!
- jodrellblank 3y agoHow does that do the fiddly bit "contain each of the letters A, B, and C exactly once" ?
- nemo1618 3y agoShoot, I totally overlooked that part. Here's the proper version: :load wordlist wordlist.txt =hasABC { all (count _ x == 1) "abc" } words wordlist | filter -:(len == 10 and hasABC and .8 == "k") Notes: { } defines a lambda with parameters named x,y,z,a,b,c... _ is the same as in noulith -- it turns any expression into a lambda. Values can also be omitted from most expressions (e.g. len == 10) for the same effect. -: takes a lambda with n parameters and turns it into a lambda that takes 1 parameter and replicates it n times.
- cc_ashby 3y agoIn terms of speedrunning, couple of friends and I are trying to speedrun AoC using LLMs (sacrilegious i know). It’s been growing a bit; if interested, feel free to shoot me an email to [redacted] Or [redacted] on X
- __mharrison__ 3y agoI'm not a competitive Advent of Coder, but as a corporate trainer, I appreciate it for giving me insights into my coding style. Hopefully, I can use those insights for my students. The last time I did AOC, I tracked every error I made to reflect on my mistakes when coding. I think this year I will do "Advent of AI" and see how far AI tooling can get me.
- Joker_vD 3y agoWhy are people so insistent on having unary minus? In my experience, "0-whatever" is just as good as "-whatever" except in a single case where you're trying to write an INT_MIN but then again, unary minus doesn't help you in this case either — unless you, as e.g. SML does, make the unary minus the lexical part of the number itself. However, SML has to actually use the tilde "~" instead of the minus for the negation because otherwise "1 -2" would be ambiguous. IIRC Elm didn't have unary minus for quite some time just fine unless its author decided he really would like to have specifically unary minues but, weirdly, not any other unary operator. So, what's the deal with unary minus, why do people want it so much?