12 ms·

Why Racket? Why Lisp?

327 points by alokrai 7y ago

deleted 7y ago
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leetrout 7y ago
That’s a longer read than I expected but there are some good, frank points like non programmers seeing some of the praise for Lisp called “unsubstantiated hoodoo”. I like that the author addresses the “what’s in it for me” head on as well. Makes it a bit more clear what some of the immediate benefits are.
mark_l_watson 7y ago
I have written books on Common Lisp and Scheme. Their power feature to me is the combination of functional programming (functions without side effects) and how these small functions can be built bottom-up in an interactive repl. Other languages like Python and Ruby also support repl style development, but aren't sufficiently functional. A little off topic, but I am working on a commercial product (KGcreator, a tool for generating graph data for knowledge graphs) and started prototyping in both Racket and Haskell. It was a tough call but I chose Haskell. I think of Haskell as being another Lisp language that also supports repl style development.
- soapdog 7y ago
  Tell us more about your books. I'm addicted to scheme books :-) Also, what made you choose Haskell for your project? Can you share some of the reasoning?
  - deepaksurti 7y ago
    See Mark’s books here [1] [1]: http://markwatson.com/books/ http://markwatson.com/books/
  - mark_l_watson 7y ago
    I think the deployment story for Haskell is better than Racket. It is easy enough make standalone Racket executables but with stack and cabal it is baked in to easily build multiple executables, separate libraries, keep everything tidy. Racket is much better to get something done and working quickly. Same comment for Common Lisp. Haskell has great support for strongly types web services (servant) and lots of great libraries. Racket has a very rich ecosystem of libraries, custom languages (like Typed Racket). Both are great. EDIT: It takes me longer to get to working code in Haskell but once written the code has higher value to me because it is so much faster/easier to refactor, change APIs, reuse in other projects, etc. I just did a major refactoring/code-tidying this morning, and it was very simple to do.
- xfer 7y ago
  > functional programming (functions without side effects) CL has mutable data structures(lists are mutable by default) and setf etc. Scheme/Clojure makes a much pleasant functional programming without side effects experience.
  - fiddlerwoaroof 7y ago
    RxRS Scheme has mutable conses as well. One of the reasons Racket isn’t called MzScheme anymore is that its primitive conses are immutable (iirc)
    - darkpuma 7y ago
      Immutable cons cells also lets Racket implement a constant time `list?`, which is kind of nice. https://docs.racket-lang.org/reference/pairs.html?q=list?#%28def._%28%28quote._~23~25kernel%29._list~3f%29%29 https://docs.racket-lang.org/reference/pairs.html?q=list?#%2...
      - fiddlerwoaroof 7y ago
        This doesn’t require immutable conses if you just update the cache whenever the cdr is mutated.
        darkpuma 7y ago
        If the last cdr in a list is modified, then you need to propagate that change up to the front of the list during that modification, or check the whole list when you run `list?`. Either way, you pay linear time for it.
        fiddlerwoaroof 7y ago
        Only if the new value makes it no longer a list (or changes a dotted list into a real list). My hunch is that this would, in normal usages, work out to constant time (setf (cdr foo) ...) with the occasional (setf (cdr foo) atom) requiring the change in state to be propagated in linear time.
- momentoftop 7y ago
  I love Haskell, but as far as GHC goes, its REPL story is awful: your environment doesn't even survive loading a new file! You can ask it to replay your bindings, but that's a pretty crappy solution, likely to produce unpredictable errors and, if you're doing any serious computation (such as when theorem proving), it's probably useless. Compare this to a language like Ocaml, where I have worked at the exact same REPL, modifying the same environment, for months at a time. This was such a standard thing to do in the Lisp and ML worlds that these languages traditionally include a save-lisp-and-die function which saves your entire runtime to disk so it can be reloaded later. (We used DMTCP in Ocaml for the same effect). Not to moan too much. Haskell is still my favourite language. I just wish it had a decent REPL.
  - schwurb 7y ago
    Isn't the lack of a stateful REPL a feature in Haskell? Don't get my wrong, I love image/state-based developing (having working knowledge with SmallTalk and just getting into emacs). But I think it is quite haskelly to introduce functions that create the state rather than create the state interactively yourself. This should be good for mocking and tests also. Yes, this is more work than in most other practical languages, but this is Haskell for you ;)
soapdog 7y ago
I really recommend that book, not just this section. I really enjoyed it and it was crucial for me in creating a talk I gave after reading it about the fun in creating little languages.
pelasaco 7y ago
As computer scientist, 20 years in the software development field, worked with different languages, I still think that Ruby is the best LISP: https://www.reddit.com/r/ruby/comments/58xevn/ruby_is_lisp/ https://www.reddit.com/r/ruby/comments/58xevn/ruby_is_lisp/
geokon 7y ago
I've done some elisp (and a tiny bit of racket) and some Clojure and honestly I struggle to see why I would ever pick a racket/scheme/elisp over Clojure unless I desperately needed to do a ton of C ffi. Clojure is much more opinionated but I never find myself feeling like it's constraining or a straightjacket When do people say to themselves "screw this, I need a more flexible tool like Racket"? Is it when you get super deep in the macro magic? (I'm not reallt sure how the Clojure macro system compares to the Scheme one)
- darkpuma 7y ago
  I just find racket to be more fun. If I'm blowing off some steam on the weekend, racket is what I reach for. It feels clean like scheme, but has the "batteries included" feeling of python. Clojure is alright, but it feels more like work than fun. I don't really know how to justify that feeling, but that's how it feels. I guess it's little things like racket/match being an 'included battery', and having a ton of useful forms already defined out of the box (e.g. match-lambda and match-letrec-values.) Clojure's core.match is pretty spartan in comparison, last I checked. As far as macros go, I greatly prefer racket's syntax-parse to anything else I've tried.
  - Profan 7y ago
    I think I was trying to articulate the same thing before, why Racket instead of more-practical-tool-here for "experiments/fun" and it really is just because it's more fun to work with, nearly everything you need is in there! Also personally something I wish more functional languages would have is a little bit of Racket's maximalism with its forms like: (for/list ([e (range 10)]) e) [1] and for/fold, including the nested ones and the like that make mapping over things and even filtering a dream! [1] https://docs.racket-lang.org/reference/for.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._for%2Flist%29%29 https://docs.racket-lang.org/reference/for.html#%28form._%28...
    - deleted 7y ago
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    - 7y ago
truth_seeker 7y ago
Nice write-up. Waiting for Racket-on-Chez effort to come with more optimizations and multi-core access
- xfer 7y ago
  Just to be clear: multi-core already works with racket places(basically running a separate racket vm thread) :). Chez-scheme has a pthread-style interface to OS threads, which has it's own set of problems with respect to concurrency(knowing which operators are thread safe). Not sure how racket would expose this.
gaze 7y ago
More lines of prose praising lisp are being written than lines of lisp these days it seems. I recently asked how to write a tree shaker in #sbcl because I thought it’d be cool. All I got was a “why would you do that?” and “ok fine your time to waste” and no substantial answers. The Common Lisp community is small and curmudgeonly. Who needs this?
- nickpsecurity 7y ago
  With a quick search, I found an example for SBCL below. I can't say anything about its quality cuz I dont do CL. https://gist.github.com/burtonsamograd/f08f561264ff94391300 https://gist.github.com/burtonsamograd/f08f561264ff94391300
- mruts 7y ago
  Yeah they're kind of assholes. Racket has a much nicer community, though.
  - gaze 7y ago
    Yeah the racket community is super sweet. What can I say though, I like the Common Lisp experience. Slime/sly are appealing, as is the totally cross sectional view from high level code to machine code. There’s a lot to like. I should give racket a second shot though. I love Chez.
    - fiddlerwoaroof 7y ago
      FWIW, stylewarning in #lisp was offering to pay someone to finish a tree shaker someone had started for sbcl, so it’s not the case that no one is interested in your project.
      - fiddlerwoaroof 7y ago
        https://twitter.com/stylewarning/status/1052006872587202560?s=20 https://twitter.com/stylewarning/status/1052006872587202560?...
      - 7y ago
civility 7y ago
I think one of the most amazing parts of Racket, and one of the reasons someone should try it out if they haven't, is that the source code and evaluator support images and not just text. The following link shows one aspect of this: https://docs.racket-lang.org/quick/ https://docs.racket-lang.org/quick/ Just being able to put an image in a comment explaining your algorithm into your code would be huge improvement over the traditional syntax colored ascii you get with most languages and editors. There are many times I've written an algorithm which is difficult to understand without the associated diagram I drew on the whiteboard or in an image editor. Racket lets you insert that image or photo directly into your source, and I think this is a significant improvement over putting a link to that image in a comment. Racket also goes a step beyond that by letting images be values which can be assigned to variables or returned from functions. The link above shows this clearly. I'm sure there is some value in this as a teaching aid, and I think that's why they did it, but you can also return mathematical plots from your functions and so on. This feature is similar to the various interactive notebooks people use for Mathematica or Python, so it's not really specific to Racket, but it is interesting to play with. Obviously there are downsides to putting images in your source. After you do that, your code is no longer ascii, and it won't be something you can edit with vi, emacs, or any non-Racket IDE. Also I doubt it will play nicely with git any time soon. However, it's a neat feature of Racket whereas many of the other benefits in the article apply to any Scheme (Chez, Gambit, Chicken, Guile, etc...) or lisp. I wish there was some reasonable standard (like a better version of Rich Text) that was commonly adopted so other languages could put graphical pictures in the source code.
- SomeHacker44 7y ago
  Mathematica allows similar things to be done in its notebooks. Fun!
- dbcurtis 7y ago
  > I wish there was some reasonable standard (like a better version of Rich Text) that was commonly adopted so other languages could put graphical pictures in the source code. I have felt exactly the same for many years. It would need to be something that was totally open (to achieve wide adoption), and reasonably easy to support in IDE's for edit and preview. And git-friendly. Belly-flopping on an existing standard is probably the easiest way to make that happen. One thought is to presume a block comment with a language-specific marker, and make the contents a restricted subset of Postscript. a) You get one or two open-source fonts. Deal with it. b) The rendering area is strictly limited, c) the operator subset is limited to something reasonable -- like just enough to do a monochrome version of 80% of the kind of graphics that PowerPoint-ish programs give you. Of course, you would never want to write Postscript by hand (although it isn't hard) but an IDE should be able to support a graphical editor plug-in. Or in a pinch you could even use another tool that left the rest of the code alone, and just edited the graphical block comments.
craftinator 7y ago
I've long stayed away from Lisps, precisely because of what the author describes in the first section, that there is a huge amount of praise over all of it's wonders, without ever specifying what those wonders are or how they are actually good things. I've had similar issues with the cargo-cult following of Rust; yes I have heard it is great, but WHY!? Great article, it de-mystifies these vague praises and addresses them clearly and specifically. I'm gonna try Racket this afternoon =D
- craftinator 7y ago
  Ah, seems the Rust cargo cult is taking revenge on my disparagement by downvoting me; feel free to reply and explain why you think my comment is not constructive to the conversation, rather than just drive-by down voting. Thanks! Edit: changed "Racket" to "Rust"
  - dang 7y ago
    Your post was probably downvoted for being a generic programming language flamewar comment, which is something we don't want here. Would you mind reviewing the site guidelines, which ask you not to go on about downvotes like this? https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
    - deleted 7y ago
      [deleted]
    - craftinator 7y ago
      Ah I misread you the first time around. My original comment had no flamewar material in it, and it received a bunch of drive-by downvotes (and upvotes), with no attempts to add to the conversation. This behaviour is hardly conducive to well thought out conversation. I took an educated guess and assumed some Rustaceans skimmed my comment and took offense because they didn't thoroughly read it, as that was the only thing that I could even imagine causing downvotes, so I attempted to start a conversation. I'm well aware of the guidelines, I chose to ignore them in this instance because, as stated above, drive-by downvoting is not how one adds to the discussion. Now there are at least people discussing, which is the only reason for HN as a platform to exist. You're welcome HN!
ken 7y ago
> If __ are so great, then it should be possible to summarize their benefits in concise, practical terms. It should be possible to demonstrate the power of __ in one hour, not 100. If __ advocates refuse to do this, then we shouldn’t be surprised when __ remain stuck near the bottom of the charts. This paragraph seems like it would be equally true for almost any subject you filled in the blanks with. As someone who had to learn a foreign (natural) language in school, I can see the benefit now, but there's no way I could explain it, and certainly not in an hour. It's a type of learning which causes a change in how you organize things you already know. How do you sell that? (No, I don't believe "so you can talk to people in that language" is a realistic benefit. I don't think even my school thought that. The selection of languages offered is simply not useful. I've never met anyone this side of Stuttgart with which to use my German. Of the top 10 non-English languages spoken in my state, only 1 was offered as a class at my school. It almost looked like they went out of their way to find teachers in less common languages.) (BTW, that's also the same answer as "If Lisp is so great why isn't anyone using it?" It works for any subject. If trig is so great, why aren't you using it? If music is so great, why did you stop playing after you graduated, and were no longer required?) I'm not trying to downplay the importance. It's a real problem, for many fields. As a Lisp programmer, it's my nature to try to sell everyone on learning Lisp even if they won't use it, and also to over-generalize problems to nearly the point of absurdity. How do you get someone to want to learn something when it may have no immediate and apparent practical value to them? Especially today when their whole "learning" slice is competing with Netflix and Facebook and all the rest. I guess the trendy answer right now is something in the neighborhood of "freemium gamification" and for reasons I can't explain that makes me sad.
- gameswithgo 7y ago
  The problem of people failing top provide empirical evidence for claims of things is indeed universal and common. But it is possible to do so, sometimes it requires a ton of work, but if we want to know things, we have to do that work. Until we do, we don't know things.
- pjc50 7y ago
  > It's a type of learning which causes a change in how you organize things you already know. How do you sell that? That's potentially a good pitch all by itself. > Of the top 10 non-English languages spoken in my state, only 1 was offered as a class at my school. It almost looked like they went out of their way to find teachers in less common languages. This is a great example of language education being frozen in time for essentially cultural reasons. Pre-20th century, and probably up to about WW2, the common choices of foreign languages to study were determined on cultural grounds and largely for ""elite"" purposes. You'd learn German so you could read Goethe and Schiller, or the various scientific papers published there. Wind forwards to the present day and the obvious choices for US language learners would have Spanish at the top of the list, but that would involve the complex politics of the relationship between the US, the rest of Latin America, and its immigrants. Much easier to carry on pretending that someone might want to read Goethe.
hzhou321 7y ago
> 1. Everything is an expression. I am not sure this argument is given. Immediately, I see there is a mismatch between what I want to program -- an objective, an algorithm, a procedure, a series of side effects that is outside the axioms of the programming language can support -- a mismatch between these objectives and this confinement of everything being an expression. An expression is a value. So to program in a language where everything is an expression is to map our idea into a (list of) value. This may be natural for programs that is seeking a value, but often not so. Even for programs that is seeking a value, the bulk of the program is to control the process of finding this value. There is no easy way or even correct way to map a process and side effects into a value. Math is logic or equivalency. To establish equivalency is to discard the effect of path or side effects. Therefore, to map the desired process and side effects into value, we have to add back the implicit knowledge of how these values are actually transformed. In stead of directly stating the transformation of values -- an imperative programming style -- we express that with dependency and relying on the understanding how these dependency is being resolved. The latter is very hard. Of course, in practice, we have to give up on the fine control of our program to some extent and relying on the compiler implementation giving us desired result (the path and its side effects), then we only need worry about the value. When it works, it works great; when it does not work, we need either lower our expectations or give up the language, or transfer the burden/blame to compilers. The argument for everything being an expression is the composability(although I thought the reason was ease and flexibility of writing compilers for it). This is similar to the argument that: if every object is a lego piece, then building something is easy. Well, it depends. First we need accept that lego pieces are all what we have. Second, we have to contend that what lego pieces can build is good for our needs. There are amazing lego projects, but they are nowhere I would find easy.
- lispm 7y ago
  Well, in languages like Scheme and Lisp, expressions are returning a value. But they can also be control structures. For example IF forms are an expression, but IF is also a control structure: (if (rocket-engine-running?) (start-rocket) (start-engine))
  - 7y ago
sctb 7y ago
A couple prior discussions: https://news.ycombinator.com/item?id=9268904 https://news.ycombinator.com/item?id=9268904 https://news.ycombinator.com/item?id=8206038 https://news.ycombinator.com/item?id=8206038
i_am_proteus 7y ago
I've read this article a few times and every time he takes beef with Python: x + (if is_true(): 1 else: 2) I think he just got he syntax wrong, it's supposed to be: x + (1 if is_true() else 2) And basically can't follow the rest of the argument. I have yet to learn a Lisp. Honestly, what am I missing?
- z3phyr 7y ago
  The macro system
  - memling 7y ago
    > The macro system To add a little more detail to a spare but correct (I think) comment: Outside of Beautiful Racket, some other helpful reading I've found in the past that covers macros: > Creating Languages in Racket (Matt Flatt, 2011, ACM Queue) [0] The details here are tantalizing, but there's a lot that goes unsaid. Code is available for download and review. As a longer-form example of something fun to do, it's good, and I've enjoyed it. > Automata using Macros [pdf] (Shriram Krishnamurthy, date unk., Educational Pearl) [1] This is a worthwhile read at only 14 pages. Krishnamurthy writes with clarity, iterating through several solutions to writing a finite state automaton. [0]: https://queue.acm.org/detail.cfm?id=2068896 https://queue.acm.org/detail.cfm?id=2068896 [1]: http://cs.brown.edu/~sk/Publications/Papers/Published/sk-automata-macros/paper.pdf http://cs.brown.edu/~sk/Publications/Papers/Published/sk-aut...
    - z3phyr 7y ago
      Thank you. Although it is against the norms of HN, I deliberately did not go on writing an explantion of the Macro system, because in my experience, I did not fully understand it's power until I used common lisp. Before that, I thought of the macro system to be like the #define preprocessor in C, nothing more. Thank you very much, for actually expanding it with great links!!
- jbotz 7y ago
  The point of the "if" example is that there is a difference between expressions and statements... yes, Python has a conditional expression (since Python 2.5, before it didn't), but it had to be a different syntax for that reason; the "if" expression is a completely different thing than the "if" statement (it's what's sometimes called a "ternary conditional") it just happens to use the same keywords (but without the ":"). In LISP everything is an expression, the syntax is totally uniform.
crimsonalucard 7y ago
This guy makes some statements about python that are completely and utterly wrong. He implies python doesn't have an "if" expression. It does. He specifically claims this is invalid in python implying that "if" expressions don't exist in python: x + (if is_true(): 1 else: 2) The following is written in python and is correct syntax: x + (1 if is_true() else 2) Although it's not "pythonic" to use python functionally, Python is a multi-paradigm language and has the facilities to be used as a very powerful functional language. It's not just a "functional" library. Functional is built into python syntax. The following is correct python syntax that will pass a type checker process as well. #List comprehensions using map and filter: x: List[int] = [i+2 for i in range(100) if i%2 == 0] #anonymous functions: x: Callable[[int], int] = lambda a: a + 2 With mypy, type annotations or any other external type checker, python approaches the power and correctness of typed functional programming languages like haskell or Ocaml, though it is missing many features.
- jbotz 7y ago
  The OP isn't trying to criticize Python... he was just trying to give an example of what it means for everything (in LISP) to be an expression. He didn't say that Python doesn't have an "if expression"... just that you can't use the if statement in an expression context.
  - crimsonalucard 7y ago
    OP literally says this: In Python, an if conditional is a statement, and can only be used in certain positions. This is categorically wrong. In python the if conditional exists in statement form and expression form. The if-expression also basically exists in every other imperative language out there, usually in this form: x + (is_true() ? 1 : 2) I know he's not trying to criticize python. Just want to correct his mistake and emphasize that python has intrinsic design features that can make it very very functional.
    - earenndil 7y ago
      Yep. Also most c-derived languages have 'progn' as the comma operator. Expression-...ism? is not really a problem.
bitmadness 7y ago
Beautifully written post.
scotty79 7y ago
I only learn new languages to be able to do something new. I learned BASIC to make my atari do what I want. Then 6502 assembler and ACTION to make it do it faster. Then Pascal to have complete flexibility of data structures. I learned C++ as a Pascal with dumb syntax but never used it before Pascal went completely out of style because there was nothing new C++ could do for me. Then I learned Java because you could do applets with that. Then HTML because you could make the browser display what you want. Then PHP and SQL because you could build websites with that. Then Python because PHP sucked for console programs and JS because you could make things happen without bothering the server. Then some XML and XSLT because that could process a lot of data fast on client side. Then C# because that was the comfiest way to make desktop apps since Delphi kicked the bucket. Then I learned Ruby because I was assigned to project written in it, but promptly forgot it since then because it could do only the things Python could already do. Then I got back to Java since you could make your phone do what you want with that but Java is (was then?) worst language I know so it was short lived. I still retain it though for occasional utiliy, like extrnding Solr or playing with Apache NiFi. The only language that kind of breaks away from this pattern of necessary imediate empowerment was CoffeeScript. It just exactly mirrors my way of thinking and was just an inch away from pseudo code I used for my notes since primary school. But then ES6 came and gave me enough CoffeeScript to almost be fine without it. Final nail was TypeScript that gave me stuff I wanted, smart, fast code completion and typechecking for places where I wanted types. Now if I could just have an editor that could display curly braces as indented blocks (python and coffee style) I'd be perfectly happy with state of browser coding. I tried Go, Elm, Haskel, Scala but nothing stuck or even went beyond simple programs. Nim was interesting because allowed you to run code at compile time to transform code (like Racket macros). I might use it for console programs that need speed (although I'll probably just dust off C++). Rust so far has the biggest potential because it allows you to have code running concurently without crazy bugs by forcing you to specifically track who owns what and for how long. That might be useful for me to make programs faster at some point since multicore is now firmly a thing.
revskill 7y ago
As i understand, the beauty of languages like LISP and Racket, is that, you can easily compose functions. Basically, as i read source code, i'm reading a "programming composition sheet", just like music sheet. The only annoying thing, is how to reduce brackets ( and ) from distracting content from its layout. Of course Python is not the answer (due to its strict identation on space/tabs) If i could teach newscomer about programming, i would say: Programming = composition of functions.
sleibrock 7y ago
I've been using Racket for a few years now as my main "fun" toy language and I can't stop using it or trying to come up with new ideas for it. I'm currently writing my new website's publishing code in Racket, using Racket programs to create my static pages. For anyone who enjoys programming language dives, I recommend Racket fully. It's simple and powerful in various ways.
- abhiyerra 7y ago
  I'm wondering if combining Racket with AWS Lambda (https://github.com/kpiljoong/aws-lambda-racket https://github.com/kpiljoong/aws-lambda-racket) would be a good way to play with Racket and do cool things with it. I've done a bunch with Emacs Lisp but always felt weird writing a server application with elnode.
deleted 7y ago
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yepguy 7y ago
Does Racket have a nice DSL for wrapping web APIs? I have a hard time believing it doesn't, but I can't find it. I'm thinking of something like API-Wrap.el (https://github.com/vermiculus/apiwrap.el https://github.com/vermiculus/apiwrap.el), but any approach that drastically reduces the boilerplate is fine by me.
- xrayspec 7y ago
  Riposte? https://docs.racket-lang.org/riposte/ https://docs.racket-lang.org/riposte/
  - yepguy 7y ago
    Riposte doesn't look all that useful outside of a test framework. I want to be able to use REST APIs in a full Racket program, which seems impossible in a DSL without control flow or functions.
- samth 7y ago
  https://github.com/greghendershott/wffi https://github.com/greghendershott/wffi is what you want
cracauer 7y ago
In my mind there is one killer feature in Lisp, and that is Compile-Time-Computing. You have a macro system that isn't some lameass additional language with severe limitations like the C preprocessor or C++ templates. You have all the language available both at compile time and at run time. You can even use functions you already have (and tested) in both places. This allows you to leave every single assumption you make during programming in one place. You don't have to splatter uncertainty about what the program is supposed to do into multiple places because you language isn't expressive enough, e.g. you cannot just redefine control structures to express an assumption. That is what leads to "changeable software", not just "readable software". My writings on the subject: https://medium.com/@MartinCracauer/a-gentle-introduction-to-compile-time-computing-part-1-d4d96099cea0 https://medium.com/@MartinCracauer/a-gentle-introduction-to-... https://medium.com/@MartinCracauer/a-gentle-introduction-to-compile-time-computing-part-2-cb0a46f6cfe8 https://medium.com/@MartinCracauer/a-gentle-introduction-to-... Example - using scientific units attached to literals in source code, but keep them at compile time and don't slow down runtime with unit checking: https://medium.com/@MartinCracauer/a-gentle-introduction-to-compile-time-computing-part-3-scientific-units-8e41d8a727ca https://medium.com/@MartinCracauer/a-gentle-introduction-to-... And speaking about early or late (static/dynamic) type checking. If you have compile-time computing you don't have to choose. How silly would it be to make a programming language that can only do one or the other. https://medium.com/@MartinCracauer/static-type-checking-in-the-programmable-programming-language-lisp-79bb79eb068a https://medium.com/@MartinCracauer/static-type-checking-in-t... Finally, there is turnaround time during development: https://hackernoon.com/software-development-at-1-hz-5530bb58fc0e https://hackernoon.com/software-development-at-1-hz-5530bb58...
- benji_is_me 7y ago
  You should check out Zig. Here's the part of the documentation concerning compile-time code. https://ziglang.org/documentation/master/#comptime https://ziglang.org/documentation/master/#comptime
namelosw 7y ago
I love Scheme and Racket. Personally, I prefer Scheme over Clojure and Common Lisp. It supports multiple paradigms well but not too bloated as Common Lisp, having a really good optional gradual type system, really easy to use reader macro system, etc. I always wanted to use Racket in a bigger project to have a deeper understanding of macro/language creating. I always believe to achieve real 'domain driven design' is to create a layer of real business language which could interpret to a software system. However, every time I want to do this I found Clojure is actually a much better choice. I guess to be fully practical is not #1 priority for Racket right now. But I really hope Racket can improve some of the following: 1. Encourage efficient data structures by default. I know lists are the soul of lisp but it's not good to use lists for everything. Clojure by default let you use highly optimized persistent data structures -- namely vectors and hash maps. These two data structures are highly practical, performant in most of the cases. On the other hand, lists are more like write-heavy data structure, with really bad reading performance. This is like, a plain file system writes faster than databases, but most of the websites use a database because most of the business has much more reads than writes. 2. ClojureScript. JavaScript is a big thing until WASM fully arrives. Clojure has several really solid ClojureScript workflow, which makes me feel ClojureScript is really a first-class citizen. 3. IDE and debugging. I use Emacs + Geiser for editing, but Drracket for debugging. Drracket is really good, but still not great for editing hundreds of files. For Clojure, Cider and Cursive are IDEs makes me feel solid and complete. 4. Frameworks. I guess if the other 3 points are really good there would be many good frameworks come out every day.
- neilv 7y ago
  I have to type this as a quick stream right now. > 1. Encourage efficient data structures by default. I know lists are the soul of lisp but it's not good to use lists for everything. Clojure by default let you use highly optimized persistent data structures -- namely vectors and hash maps. These two data structures are highly practical, performant in most of the cases. Scheme has vectors, and Racket adds hash tables and structs: https://docs.racket-lang.org/guide/vectors.html https://docs.racket-lang.org/guide/vectors.html https://docs.racket-lang.org/guide/hash-tables.html https://docs.racket-lang.org/guide/hash-tables.html https://docs.racket-lang.org/guide/define-struct.html https://docs.racket-lang.org/guide/define-struct.html There's also some work on matrices and arrays (beyond Scheme vectors): https://docs.racket-lang.org/math/index.html https://docs.racket-lang.org/math/index.html There are some older libraries where lists (or alists) are used, when today you'd probably use hashes or structs. We could consider this an educational opportunity: there are still times when knowing how to do old-school list-processing is exactly what you need, and it's pretty fundamental data structures (e.g., singly-linked lists, trees), so we could consider it practice. :) BTW, one difference between modern Racket lists and Scheme's is that Racket's default pairs are immutable. This turns out to be useful for optimizations, as well as encourage a healthy amount of functional programming. Regarding #2, good point. I raised the WASM issue a couple years ago, and my thinking then (and now) is to build it for the forthcoming Chez backend, while getting plugged into the WASM standards work in the meantime. There are various ways to do JS with Racket (a big HTML5 Offline app of mine does it by generating JS and HTML from Racket), but WASM seems most promising. Regarding #3, if Geiser works for you, great. You might also take a look at Greg Hendershott's racket-mode for Emacs: https://github.com/greghendershott/racket-mode https://github.com/greghendershott/racket-mode I appreciate that DrRacket's student-emphasizing IDE is very different than most IDEs, and it's missing some things I'd like, for editing many modules at once. If you're up to adding some features you'd like, there's an extension mechanism, and you can also do git pull requests to the DrRacket source itself. https://docs.racket-lang.org/drracket/extending-drracket.html https://docs.racket-lang.org/drracket/extending-drracket.htm... https://docs.racket-lang.org/framework/index.html https://docs.racket-lang.org/framework/index.html Regarding #4, there are Web frameworks, and the main Racket Web Server (which you don't have to use; you can also do things like SCGI or proxy another HTTP server implementation), and you can also whip up your own frameworks very rapidly in Racket unlike many languages. I'm hoping a couple startups use Racket to get to launch, and release the light frameworks that they make along the way. Regarding reader extensions, Racket has those, as well as a ton of great syntax extension mechanisms: https://docs.racket-lang.org/guide/hash-reader.html https://docs.racket-lang.org/guide/hash-reader.html
strangattractor 7y ago
Racket is great and fun. I find it truly amazing that after all these many years people are still trying to justify Lisp. Frankly - if it was going to be adopted in mass it would have happened by now and no amount of explaining is going to change that. There are many reasons why languages get adopted and "logic" is not the primary one. Take JS for example - it would have been in the dust bin if not for the fact it is the only language that runs in browsers.
todd8 7y ago
One of the benefits of Lisp based languages is that they usually come with powerful macro based meta-programming facilities. I've use macro systems quite often in more or less complicated ways: as a professional assembly language programmer, in school when studying Lisp DSLs, when using my favorite editor Emacs and its elisp, in systems I've built similar to Moores TRAC programming language, M4, my extensive use of TeX and LaTeX for decades, C++ STL, sendmail configurations, etc. Over the years, I've lost my enthusiasm for powerful meta-programming facilities like Lisp macros. The underlying languages are Turing complete and don't strictly need meta-programming, and most modern languages aren't lacking in abstraction mechanisms available to programming without meta-linguistic alterations. Like operator overloading, sophisticated macro systems change the semantics of program source code in ways that are not obvious. They allow new variants of the programming language to be created willy nilly placing demands on me the reader, maintainer, or user of a programming language package to fully understand the implementation of the meta-linguistic features. Powerful macro systems encourage a thick frosting of magic to be applied on the implementation of complex systems. Some systems, like Lisp or Scheme or TeX, would be difficult to use without macro extensions, but it seems to me that identifying a good set of built-in abstractions for writing programs and building the language around them is a better approach. I am so grateful for the TicZ graphics package for LaTeX, it's all built out of TeX's crazy flexible macro system, but I'm even more grateful that I've never had to touch the source for it. Take a peek at: [1]. [1] https://github.com/pgf-tikz https://github.com/pgf-tikz
- wtetzner 7y ago
  I think it all comes down to what kind of programs you're writing. For example, without a powerful macro system, something like the nanopass framework [1] would not have been possible. Sure, you could write an external code generator, but at that point you've just implemented a bad macro system. [1] https://github.com/nanopass/nanopass-framework-scheme https://github.com/nanopass/nanopass-framework-scheme

327 points by alokrai 7y ago

deleted 7y ago

[deleted]

That’s a longer read than I expected but there are some good, frank points like non programmers seeing some of the praise for Lisp called “unsubstantiated hoodoo”. I like that the author addresses the “what’s in it for me” head on as well. Makes it a bit more clear what some of the immediate benefits are.

mark_l_watson 7y ago

I have written books on Common Lisp and Scheme. Their power feature to me is the combination of functional programming (functions without side effects) and how these small functions can be built bottom-up in an interactive repl. Other languages like Python and Ruby also support repl style development, but aren't sufficiently functional. A little off topic, but I am working on a commercial product (KGcreator, a tool for generating graph data for knowledge graphs) and started prototyping in both Racket and Haskell. It was a tough call but I chose Haskell. I think of Haskell as being another Lisp language that also supports repl style development.

soapdog 7y ago
Tell us more about your books. I'm addicted to scheme books :-) Also, what made you choose Haskell for your project? Can you share some of the reasoning?
- deepaksurti 7y ago
  See Mark’s books here [1] [1]: http://markwatson.com/books/ http://markwatson.com/books/
- mark_l_watson 7y ago
  I think the deployment story for Haskell is better than Racket. It is easy enough make standalone Racket executables but with stack and cabal it is baked in to easily build multiple executables, separate libraries, keep everything tidy. Racket is much better to get something done and working quickly. Same comment for Common Lisp. Haskell has great support for strongly types web services (servant) and lots of great libraries. Racket has a very rich ecosystem of libraries, custom languages (like Typed Racket). Both are great. EDIT: It takes me longer to get to working code in Haskell but once written the code has higher value to me because it is so much faster/easier to refactor, change APIs, reuse in other projects, etc. I just did a major refactoring/code-tidying this morning, and it was very simple to do.
xfer 7y ago
> functional programming (functions without side effects) CL has mutable data structures(lists are mutable by default) and setf etc. Scheme/Clojure makes a much pleasant functional programming without side effects experience.
- fiddlerwoaroof 7y ago
  RxRS Scheme has mutable conses as well. One of the reasons Racket isn’t called MzScheme anymore is that its primitive conses are immutable (iirc)
  - darkpuma 7y ago
    Immutable cons cells also lets Racket implement a constant time `list?`, which is kind of nice. https://docs.racket-lang.org/reference/pairs.html?q=list?#%28def._%28%28quote._~23~25kernel%29._list~3f%29%29 https://docs.racket-lang.org/reference/pairs.html?q=list?#%2...
    - fiddlerwoaroof 7y ago
      This doesn’t require immutable conses if you just update the cache whenever the cdr is mutated.
      - darkpuma 7y ago
        If the last cdr in a list is modified, then you need to propagate that change up to the front of the list during that modification, or check the whole list when you run `list?`. Either way, you pay linear time for it.
        fiddlerwoaroof 7y ago
        Only if the new value makes it no longer a list (or changes a dotted list into a real list). My hunch is that this would, in normal usages, work out to constant time (setf (cdr foo) ...) with the occasional (setf (cdr foo) atom) requiring the change in state to be propagated in linear time.
momentoftop 7y ago
I love Haskell, but as far as GHC goes, its REPL story is awful: your environment doesn't even survive loading a new file! You can ask it to replay your bindings, but that's a pretty crappy solution, likely to produce unpredictable errors and, if you're doing any serious computation (such as when theorem proving), it's probably useless. Compare this to a language like Ocaml, where I have worked at the exact same REPL, modifying the same environment, for months at a time. This was such a standard thing to do in the Lisp and ML worlds that these languages traditionally include a save-lisp-and-die function which saves your entire runtime to disk so it can be reloaded later. (We used DMTCP in Ocaml for the same effect). Not to moan too much. Haskell is still my favourite language. I just wish it had a decent REPL.
- schwurb 7y ago
  Isn't the lack of a stateful REPL a feature in Haskell? Don't get my wrong, I love image/state-based developing (having working knowledge with SmallTalk and just getting into emacs). But I think it is quite haskelly to introduce functions that create the state rather than create the state interactively yourself. This should be good for mocking and tests also. Yes, this is more work than in most other practical languages, but this is Haskell for you ;)

soapdog 7y ago

I really recommend that book, not just this section. I really enjoyed it and it was crucial for me in creating a talk I gave after reading it about the fun in creating little languages.

pelasaco 7y ago

As computer scientist, 20 years in the software development field, worked with different languages, I still think that Ruby is the best LISP: https://www.reddit.com/r/ruby/comments/58xevn/ruby_is_lisp/ https://www.reddit.com/r/ruby/comments/58xevn/ruby_is_lisp/

geokon 7y ago

I've done some elisp (and a tiny bit of racket) and some Clojure and honestly I struggle to see why I would ever pick a racket/scheme/elisp over Clojure unless I desperately needed to do a ton of C ffi. Clojure is much more opinionated but I never find myself feeling like it's constraining or a straightjacket When do people say to themselves "screw this, I need a more flexible tool like Racket"? Is it when you get super deep in the macro magic? (I'm not reallt sure how the Clojure macro system compares to the Scheme one)

darkpuma 7y ago
I just find racket to be more fun. If I'm blowing off some steam on the weekend, racket is what I reach for. It feels clean like scheme, but has the "batteries included" feeling of python. Clojure is alright, but it feels more like work than fun. I don't really know how to justify that feeling, but that's how it feels. I guess it's little things like racket/match being an 'included battery', and having a ton of useful forms already defined out of the box (e.g. match-lambda and match-letrec-values.) Clojure's core.match is pretty spartan in comparison, last I checked. As far as macros go, I greatly prefer racket's syntax-parse to anything else I've tried.
- Profan 7y ago
  I think I was trying to articulate the same thing before, why Racket instead of more-practical-tool-here for "experiments/fun" and it really is just because it's more fun to work with, nearly everything you need is in there! Also personally something I wish more functional languages would have is a little bit of Racket's maximalism with its forms like: (for/list ([e (range 10)]) e) [1] and for/fold, including the nested ones and the like that make mapping over things and even filtering a dream! [1] https://docs.racket-lang.org/reference/for.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._for%2Flist%29%29 https://docs.racket-lang.org/reference/for.html#%28form._%28...
  - deleted 7y ago
    [deleted]
  - 7y ago

truth_seeker 7y ago

Nice write-up. Waiting for Racket-on-Chez effort to come with more optimizations and multi-core access

xfer 7y ago
Just to be clear: multi-core already works with racket places(basically running a separate racket vm thread) :). Chez-scheme has a pthread-style interface to OS threads, which has it's own set of problems with respect to concurrency(knowing which operators are thread safe). Not sure how racket would expose this.

gaze 7y ago

More lines of prose praising lisp are being written than lines of lisp these days it seems. I recently asked how to write a tree shaker in #sbcl because I thought it’d be cool. All I got was a “why would you do that?” and “ok fine your time to waste” and no substantial answers. The Common Lisp community is small and curmudgeonly. Who needs this?

nickpsecurity 7y ago
With a quick search, I found an example for SBCL below. I can't say anything about its quality cuz I dont do CL. https://gist.github.com/burtonsamograd/f08f561264ff94391300 https://gist.github.com/burtonsamograd/f08f561264ff94391300
mruts 7y ago
Yeah they're kind of assholes. Racket has a much nicer community, though.
- gaze 7y ago
  Yeah the racket community is super sweet. What can I say though, I like the Common Lisp experience. Slime/sly are appealing, as is the totally cross sectional view from high level code to machine code. There’s a lot to like. I should give racket a second shot though. I love Chez.
  - fiddlerwoaroof 7y ago
    FWIW, stylewarning in #lisp was offering to pay someone to finish a tree shaker someone had started for sbcl, so it’s not the case that no one is interested in your project.
    - fiddlerwoaroof 7y ago
      https://twitter.com/stylewarning/status/1052006872587202560?s=20 https://twitter.com/stylewarning/status/1052006872587202560?...
    - 7y ago

civility 7y ago

I think one of the most amazing parts of Racket, and one of the reasons someone should try it out if they haven't, is that the source code and evaluator support images and not just text. The following link shows one aspect of this: https://docs.racket-lang.org/quick/ https://docs.racket-lang.org/quick/ Just being able to put an image in a comment explaining your algorithm into your code would be huge improvement over the traditional syntax colored ascii you get with most languages and editors. There are many times I've written an algorithm which is difficult to understand without the associated diagram I drew on the whiteboard or in an image editor. Racket lets you insert that image or photo directly into your source, and I think this is a significant improvement over putting a link to that image in a comment. Racket also goes a step beyond that by letting images be values which can be assigned to variables or returned from functions. The link above shows this clearly. I'm sure there is some value in this as a teaching aid, and I think that's why they did it, but you can also return mathematical plots from your functions and so on. This feature is similar to the various interactive notebooks people use for Mathematica or Python, so it's not really specific to Racket, but it is interesting to play with. Obviously there are downsides to putting images in your source. After you do that, your code is no longer ascii, and it won't be something you can edit with vi, emacs, or any non-Racket IDE. Also I doubt it will play nicely with git any time soon. However, it's a neat feature of Racket whereas many of the other benefits in the article apply to any Scheme (Chez, Gambit, Chicken, Guile, etc...) or lisp. I wish there was some reasonable standard (like a better version of Rich Text) that was commonly adopted so other languages could put graphical pictures in the source code.

SomeHacker44 7y ago
Mathematica allows similar things to be done in its notebooks. Fun!
dbcurtis 7y ago
> I wish there was some reasonable standard (like a better version of Rich Text) that was commonly adopted so other languages could put graphical pictures in the source code. I have felt exactly the same for many years. It would need to be something that was totally open (to achieve wide adoption), and reasonably easy to support in IDE's for edit and preview. And git-friendly. Belly-flopping on an existing standard is probably the easiest way to make that happen. One thought is to presume a block comment with a language-specific marker, and make the contents a restricted subset of Postscript. a) You get one or two open-source fonts. Deal with it. b) The rendering area is strictly limited, c) the operator subset is limited to something reasonable -- like just enough to do a monochrome version of 80% of the kind of graphics that PowerPoint-ish programs give you. Of course, you would never want to write Postscript by hand (although it isn't hard) but an IDE should be able to support a graphical editor plug-in. Or in a pinch you could even use another tool that left the rest of the code alone, and just edited the graphical block comments.

craftinator 7y ago

I've long stayed away from Lisps, precisely because of what the author describes in the first section, that there is a huge amount of praise over all of it's wonders, without ever specifying what those wonders are or how they are actually good things. I've had similar issues with the cargo-cult following of Rust; yes I have heard it is great, but WHY!? Great article, it de-mystifies these vague praises and addresses them clearly and specifically. I'm gonna try Racket this afternoon =D

craftinator 7y ago
Ah, seems the Rust cargo cult is taking revenge on my disparagement by downvoting me; feel free to reply and explain why you think my comment is not constructive to the conversation, rather than just drive-by down voting. Thanks! Edit: changed "Racket" to "Rust"
- dang 7y ago
  Your post was probably downvoted for being a generic programming language flamewar comment, which is something we don't want here. Would you mind reviewing the site guidelines, which ask you not to go on about downvotes like this? https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
  - deleted 7y ago
    [deleted]
  - craftinator 7y ago
    Ah I misread you the first time around. My original comment had no flamewar material in it, and it received a bunch of drive-by downvotes (and upvotes), with no attempts to add to the conversation. This behaviour is hardly conducive to well thought out conversation. I took an educated guess and assumed some Rustaceans skimmed my comment and took offense because they didn't thoroughly read it, as that was the only thing that I could even imagine causing downvotes, so I attempted to start a conversation. I'm well aware of the guidelines, I chose to ignore them in this instance because, as stated above, drive-by downvoting is not how one adds to the discussion. Now there are at least people discussing, which is the only reason for HN as a platform to exist. You're welcome HN!

ken 7y ago

> If __ are so great, then it should be possible to summarize their benefits in concise, practical terms. It should be possible to demonstrate the power of __ in one hour, not 100. If __ advocates refuse to do this, then we shouldn’t be surprised when __ remain stuck near the bottom of the charts. This paragraph seems like it would be equally true for almost any subject you filled in the blanks with. As someone who had to learn a foreign (natural) language in school, I can see the benefit now, but there's no way I could explain it, and certainly not in an hour. It's a type of learning which causes a change in how you organize things you already know. How do you sell that? (No, I don't believe "so you can talk to people in that language" is a realistic benefit. I don't think even my school thought that. The selection of languages offered is simply not useful. I've never met anyone this side of Stuttgart with which to use my German. Of the top 10 non-English languages spoken in my state, only 1 was offered as a class at my school. It almost looked like they went out of their way to find teachers in less common languages.) (BTW, that's also the same answer as "If Lisp is so great why isn't anyone using it?" It works for any subject. If trig is so great, why aren't you using it? If music is so great, why did you stop playing after you graduated, and were no longer required?) I'm not trying to downplay the importance. It's a real problem, for many fields. As a Lisp programmer, it's my nature to try to sell everyone on learning Lisp even if they won't use it, and also to over-generalize problems to nearly the point of absurdity. How do you get someone to want to learn something when it may have no immediate and apparent practical value to them? Especially today when their whole "learning" slice is competing with Netflix and Facebook and all the rest. I guess the trendy answer right now is something in the neighborhood of "freemium gamification" and for reasons I can't explain that makes me sad.

gameswithgo 7y ago
The problem of people failing top provide empirical evidence for claims of things is indeed universal and common. But it is possible to do so, sometimes it requires a ton of work, but if we want to know things, we have to do that work. Until we do, we don't know things.
pjc50 7y ago
> It's a type of learning which causes a change in how you organize things you already know. How do you sell that? That's potentially a good pitch all by itself. > Of the top 10 non-English languages spoken in my state, only 1 was offered as a class at my school. It almost looked like they went out of their way to find teachers in less common languages. This is a great example of language education being frozen in time for essentially cultural reasons. Pre-20th century, and probably up to about WW2, the common choices of foreign languages to study were determined on cultural grounds and largely for ""elite"" purposes. You'd learn German so you could read Goethe and Schiller, or the various scientific papers published there. Wind forwards to the present day and the obvious choices for US language learners would have Spanish at the top of the list, but that would involve the complex politics of the relationship between the US, the rest of Latin America, and its immigrants. Much easier to carry on pretending that someone might want to read Goethe.

hzhou321 7y ago

> 1. Everything is an expression. I am not sure this argument is given. Immediately, I see there is a mismatch between what I want to program -- an objective, an algorithm, a procedure, a series of side effects that is outside the axioms of the programming language can support -- a mismatch between these objectives and this confinement of everything being an expression. An expression is a value. So to program in a language where everything is an expression is to map our idea into a (list of) value. This may be natural for programs that is seeking a value, but often not so. Even for programs that is seeking a value, the bulk of the program is to control the process of finding this value. There is no easy way or even correct way to map a process and side effects into a value. Math is logic or equivalency. To establish equivalency is to discard the effect of path or side effects. Therefore, to map the desired process and side effects into value, we have to add back the implicit knowledge of how these values are actually transformed. In stead of directly stating the transformation of values -- an imperative programming style -- we express that with dependency and relying on the understanding how these dependency is being resolved. The latter is very hard. Of course, in practice, we have to give up on the fine control of our program to some extent and relying on the compiler implementation giving us desired result (the path and its side effects), then we only need worry about the value. When it works, it works great; when it does not work, we need either lower our expectations or give up the language, or transfer the burden/blame to compilers. The argument for everything being an expression is the composability(although I thought the reason was ease and flexibility of writing compilers for it). This is similar to the argument that: if every object is a lego piece, then building something is easy. Well, it depends. First we need accept that lego pieces are all what we have. Second, we have to contend that what lego pieces can build is good for our needs. There are amazing lego projects, but they are nowhere I would find easy.

lispm 7y ago
Well, in languages like Scheme and Lisp, expressions are returning a value. But they can also be control structures. For example IF forms are an expression, but IF is also a control structure: (if (rocket-engine-running?) (start-rocket) (start-engine))
- 7y ago

sctb 7y ago

A couple prior discussions: https://news.ycombinator.com/item?id=9268904 https://news.ycombinator.com/item?id=9268904 https://news.ycombinator.com/item?id=8206038 https://news.ycombinator.com/item?id=8206038

i_am_proteus 7y ago

I've read this article a few times and every time he takes beef with Python: x + (if is_true(): 1 else: 2) I think he just got he syntax wrong, it's supposed to be: x + (1 if is_true() else 2) And basically can't follow the rest of the argument. I have yet to learn a Lisp. Honestly, what am I missing?

z3phyr 7y ago
The macro system
- memling 7y ago
  > The macro system To add a little more detail to a spare but correct (I think) comment: Outside of Beautiful Racket, some other helpful reading I've found in the past that covers macros: > Creating Languages in Racket (Matt Flatt, 2011, ACM Queue) [0] The details here are tantalizing, but there's a lot that goes unsaid. Code is available for download and review. As a longer-form example of something fun to do, it's good, and I've enjoyed it. > Automata using Macros [pdf] (Shriram Krishnamurthy, date unk., Educational Pearl) [1] This is a worthwhile read at only 14 pages. Krishnamurthy writes with clarity, iterating through several solutions to writing a finite state automaton. [0]: https://queue.acm.org/detail.cfm?id=2068896 https://queue.acm.org/detail.cfm?id=2068896 [1]: http://cs.brown.edu/~sk/Publications/Papers/Published/sk-automata-macros/paper.pdf http://cs.brown.edu/~sk/Publications/Papers/Published/sk-aut...
  - z3phyr 7y ago
    Thank you. Although it is against the norms of HN, I deliberately did not go on writing an explantion of the Macro system, because in my experience, I did not fully understand it's power until I used common lisp. Before that, I thought of the macro system to be like the #define preprocessor in C, nothing more. Thank you very much, for actually expanding it with great links!!
jbotz 7y ago
The point of the "if" example is that there is a difference between expressions and statements... yes, Python has a conditional expression (since Python 2.5, before it didn't), but it had to be a different syntax for that reason; the "if" expression is a completely different thing than the "if" statement (it's what's sometimes called a "ternary conditional") it just happens to use the same keywords (but without the ":"). In LISP everything is an expression, the syntax is totally uniform.

crimsonalucard 7y ago

This guy makes some statements about python that are completely and utterly wrong. He implies python doesn't have an "if" expression. It does. He specifically claims this is invalid in python implying that "if" expressions don't exist in python: x + (if is_true(): 1 else: 2) The following is written in python and is correct syntax: x + (1 if is_true() else 2) Although it's not "pythonic" to use python functionally, Python is a multi-paradigm language and has the facilities to be used as a very powerful functional language. It's not just a "functional" library. Functional is built into python syntax. The following is correct python syntax that will pass a type checker process as well. #List comprehensions using map and filter: x: List[int] = [i+2 for i in range(100) if i%2 == 0] #anonymous functions: x: Callable[[int], int] = lambda a: a + 2 With mypy, type annotations or any other external type checker, python approaches the power and correctness of typed functional programming languages like haskell or Ocaml, though it is missing many features.

jbotz 7y ago
The OP isn't trying to criticize Python... he was just trying to give an example of what it means for everything (in LISP) to be an expression. He didn't say that Python doesn't have an "if expression"... just that you can't use the if statement in an expression context.
- crimsonalucard 7y ago
  OP literally says this: In Python, an if conditional is a statement, and can only be used in certain positions. This is categorically wrong. In python the if conditional exists in statement form and expression form. The if-expression also basically exists in every other imperative language out there, usually in this form: x + (is_true() ? 1 : 2) I know he's not trying to criticize python. Just want to correct his mistake and emphasize that python has intrinsic design features that can make it very very functional.
  - earenndil 7y ago
    Yep. Also most c-derived languages have 'progn' as the comma operator. Expression-...ism? is not really a problem.

bitmadness 7y ago

Beautifully written post.

scotty79 7y ago

I only learn new languages to be able to do something new. I learned BASIC to make my atari do what I want. Then 6502 assembler and ACTION to make it do it faster. Then Pascal to have complete flexibility of data structures. I learned C++ as a Pascal with dumb syntax but never used it before Pascal went completely out of style because there was nothing new C++ could do for me. Then I learned Java because you could do applets with that. Then HTML because you could make the browser display what you want. Then PHP and SQL because you could build websites with that. Then Python because PHP sucked for console programs and JS because you could make things happen without bothering the server. Then some XML and XSLT because that could process a lot of data fast on client side. Then C# because that was the comfiest way to make desktop apps since Delphi kicked the bucket. Then I learned Ruby because I was assigned to project written in it, but promptly forgot it since then because it could do only the things Python could already do. Then I got back to Java since you could make your phone do what you want with that but Java is (was then?) worst language I know so it was short lived. I still retain it though for occasional utiliy, like extrnding Solr or playing with Apache NiFi. The only language that kind of breaks away from this pattern of necessary imediate empowerment was CoffeeScript. It just exactly mirrors my way of thinking and was just an inch away from pseudo code I used for my notes since primary school. But then ES6 came and gave me enough CoffeeScript to almost be fine without it. Final nail was TypeScript that gave me stuff I wanted, smart, fast code completion and typechecking for places where I wanted types. Now if I could just have an editor that could display curly braces as indented blocks (python and coffee style) I'd be perfectly happy with state of browser coding. I tried Go, Elm, Haskel, Scala but nothing stuck or even went beyond simple programs. Nim was interesting because allowed you to run code at compile time to transform code (like Racket macros). I might use it for console programs that need speed (although I'll probably just dust off C++). Rust so far has the biggest potential because it allows you to have code running concurently without crazy bugs by forcing you to specifically track who owns what and for how long. That might be useful for me to make programs faster at some point since multicore is now firmly a thing.

revskill 7y ago

As i understand, the beauty of languages like LISP and Racket, is that, you can easily compose functions. Basically, as i read source code, i'm reading a "programming composition sheet", just like music sheet. The only annoying thing, is how to reduce brackets ( and ) from distracting content from its layout. Of course Python is not the answer (due to its strict identation on space/tabs) If i could teach newscomer about programming, i would say: Programming = composition of functions.

sleibrock 7y ago

I've been using Racket for a few years now as my main "fun" toy language and I can't stop using it or trying to come up with new ideas for it. I'm currently writing my new website's publishing code in Racket, using Racket programs to create my static pages. For anyone who enjoys programming language dives, I recommend Racket fully. It's simple and powerful in various ways.

abhiyerra 7y ago
I'm wondering if combining Racket with AWS Lambda (https://github.com/kpiljoong/aws-lambda-racket https://github.com/kpiljoong/aws-lambda-racket) would be a good way to play with Racket and do cool things with it. I've done a bunch with Emacs Lisp but always felt weird writing a server application with elnode.

deleted 7y ago

[deleted]

yepguy 7y ago

Does Racket have a nice DSL for wrapping web APIs? I have a hard time believing it doesn't, but I can't find it. I'm thinking of something like API-Wrap.el (https://github.com/vermiculus/apiwrap.el https://github.com/vermiculus/apiwrap.el), but any approach that drastically reduces the boilerplate is fine by me.

xrayspec 7y ago
Riposte? https://docs.racket-lang.org/riposte/ https://docs.racket-lang.org/riposte/
- yepguy 7y ago
  Riposte doesn't look all that useful outside of a test framework. I want to be able to use REST APIs in a full Racket program, which seems impossible in a DSL without control flow or functions.
samth 7y ago
https://github.com/greghendershott/wffi https://github.com/greghendershott/wffi is what you want

cracauer 7y ago

In my mind there is one killer feature in Lisp, and that is Compile-Time-Computing. You have a macro system that isn't some lameass additional language with severe limitations like the C preprocessor or C++ templates. You have all the language available both at compile time and at run time. You can even use functions you already have (and tested) in both places. This allows you to leave every single assumption you make during programming in one place. You don't have to splatter uncertainty about what the program is supposed to do into multiple places because you language isn't expressive enough, e.g. you cannot just redefine control structures to express an assumption. That is what leads to "changeable software", not just "readable software". My writings on the subject: https://medium.com/@MartinCracauer/a-gentle-introduction-to-compile-time-computing-part-1-d4d96099cea0 https://medium.com/@MartinCracauer/a-gentle-introduction-to-... https://medium.com/@MartinCracauer/a-gentle-introduction-to-compile-time-computing-part-2-cb0a46f6cfe8 https://medium.com/@MartinCracauer/a-gentle-introduction-to-... Example - using scientific units attached to literals in source code, but keep them at compile time and don't slow down runtime with unit checking: https://medium.com/@MartinCracauer/a-gentle-introduction-to-compile-time-computing-part-3-scientific-units-8e41d8a727ca https://medium.com/@MartinCracauer/a-gentle-introduction-to-... And speaking about early or late (static/dynamic) type checking. If you have compile-time computing you don't have to choose. How silly would it be to make a programming language that can only do one or the other. https://medium.com/@MartinCracauer/static-type-checking-in-the-programmable-programming-language-lisp-79bb79eb068a https://medium.com/@MartinCracauer/static-type-checking-in-t... Finally, there is turnaround time during development: https://hackernoon.com/software-development-at-1-hz-5530bb58fc0e https://hackernoon.com/software-development-at-1-hz-5530bb58...

benji_is_me 7y ago
You should check out Zig. Here's the part of the documentation concerning compile-time code. https://ziglang.org/documentation/master/#comptime https://ziglang.org/documentation/master/#comptime

namelosw 7y ago

I love Scheme and Racket. Personally, I prefer Scheme over Clojure and Common Lisp. It supports multiple paradigms well but not too bloated as Common Lisp, having a really good optional gradual type system, really easy to use reader macro system, etc. I always wanted to use Racket in a bigger project to have a deeper understanding of macro/language creating. I always believe to achieve real 'domain driven design' is to create a layer of real business language which could interpret to a software system. However, every time I want to do this I found Clojure is actually a much better choice. I guess to be fully practical is not #1 priority for Racket right now. But I really hope Racket can improve some of the following: 1. Encourage efficient data structures by default. I know lists are the soul of lisp but it's not good to use lists for everything. Clojure by default let you use highly optimized persistent data structures -- namely vectors and hash maps. These two data structures are highly practical, performant in most of the cases. On the other hand, lists are more like write-heavy data structure, with really bad reading performance. This is like, a plain file system writes faster than databases, but most of the websites use a database because most of the business has much more reads than writes. 2. ClojureScript. JavaScript is a big thing until WASM fully arrives. Clojure has several really solid ClojureScript workflow, which makes me feel ClojureScript is really a first-class citizen. 3. IDE and debugging. I use Emacs + Geiser for editing, but Drracket for debugging. Drracket is really good, but still not great for editing hundreds of files. For Clojure, Cider and Cursive are IDEs makes me feel solid and complete. 4. Frameworks. I guess if the other 3 points are really good there would be many good frameworks come out every day.

neilv 7y ago
I have to type this as a quick stream right now. > 1. Encourage efficient data structures by default. I know lists are the soul of lisp but it's not good to use lists for everything. Clojure by default let you use highly optimized persistent data structures -- namely vectors and hash maps. These two data structures are highly practical, performant in most of the cases. Scheme has vectors, and Racket adds hash tables and structs: https://docs.racket-lang.org/guide/vectors.html https://docs.racket-lang.org/guide/vectors.html https://docs.racket-lang.org/guide/hash-tables.html https://docs.racket-lang.org/guide/hash-tables.html https://docs.racket-lang.org/guide/define-struct.html https://docs.racket-lang.org/guide/define-struct.html There's also some work on matrices and arrays (beyond Scheme vectors): https://docs.racket-lang.org/math/index.html https://docs.racket-lang.org/math/index.html There are some older libraries where lists (or alists) are used, when today you'd probably use hashes or structs. We could consider this an educational opportunity: there are still times when knowing how to do old-school list-processing is exactly what you need, and it's pretty fundamental data structures (e.g., singly-linked lists, trees), so we could consider it practice. :) BTW, one difference between modern Racket lists and Scheme's is that Racket's default pairs are immutable. This turns out to be useful for optimizations, as well as encourage a healthy amount of functional programming. Regarding #2, good point. I raised the WASM issue a couple years ago, and my thinking then (and now) is to build it for the forthcoming Chez backend, while getting plugged into the WASM standards work in the meantime. There are various ways to do JS with Racket (a big HTML5 Offline app of mine does it by generating JS and HTML from Racket), but WASM seems most promising. Regarding #3, if Geiser works for you, great. You might also take a look at Greg Hendershott's racket-mode for Emacs: https://github.com/greghendershott/racket-mode https://github.com/greghendershott/racket-mode I appreciate that DrRacket's student-emphasizing IDE is very different than most IDEs, and it's missing some things I'd like, for editing many modules at once. If you're up to adding some features you'd like, there's an extension mechanism, and you can also do git pull requests to the DrRacket source itself. https://docs.racket-lang.org/drracket/extending-drracket.html https://docs.racket-lang.org/drracket/extending-drracket.htm... https://docs.racket-lang.org/framework/index.html https://docs.racket-lang.org/framework/index.html Regarding #4, there are Web frameworks, and the main Racket Web Server (which you don't have to use; you can also do things like SCGI or proxy another HTTP server implementation), and you can also whip up your own frameworks very rapidly in Racket unlike many languages. I'm hoping a couple startups use Racket to get to launch, and release the light frameworks that they make along the way. Regarding reader extensions, Racket has those, as well as a ton of great syntax extension mechanisms: https://docs.racket-lang.org/guide/hash-reader.html https://docs.racket-lang.org/guide/hash-reader.html

strangattractor 7y ago

Racket is great and fun. I find it truly amazing that after all these many years people are still trying to justify Lisp. Frankly - if it was going to be adopted in mass it would have happened by now and no amount of explaining is going to change that. There are many reasons why languages get adopted and "logic" is not the primary one. Take JS for example - it would have been in the dust bin if not for the fact it is the only language that runs in browsers.

todd8 7y ago

One of the benefits of Lisp based languages is that they usually come with powerful macro based meta-programming facilities. I've use macro systems quite often in more or less complicated ways: as a professional assembly language programmer, in school when studying Lisp DSLs, when using my favorite editor Emacs and its elisp, in systems I've built similar to Moores TRAC programming language, M4, my extensive use of TeX and LaTeX for decades, C++ STL, sendmail configurations, etc. Over the years, I've lost my enthusiasm for powerful meta-programming facilities like Lisp macros. The underlying languages are Turing complete and don't strictly need meta-programming, and most modern languages aren't lacking in abstraction mechanisms available to programming without meta-linguistic alterations. Like operator overloading, sophisticated macro systems change the semantics of program source code in ways that are not obvious. They allow new variants of the programming language to be created willy nilly placing demands on me the reader, maintainer, or user of a programming language package to fully understand the implementation of the meta-linguistic features. Powerful macro systems encourage a thick frosting of magic to be applied on the implementation of complex systems. Some systems, like Lisp or Scheme or TeX, would be difficult to use without macro extensions, but it seems to me that identifying a good set of built-in abstractions for writing programs and building the language around them is a better approach. I am so grateful for the TicZ graphics package for LaTeX, it's all built out of TeX's crazy flexible macro system, but I'm even more grateful that I've never had to touch the source for it. Take a peek at: [1]. [1] https://github.com/pgf-tikz https://github.com/pgf-tikz

wtetzner 7y ago
I think it all comes down to what kind of programs you're writing. For example, without a powerful macro system, something like the nanopass framework [1] would not have been possible. Sure, you could write an external code generator, but at that point you've just implemented a bad macro system. [1] https://github.com/nanopass/nanopass-framework-scheme https://github.com/nanopass/nanopass-framework-scheme