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What I learned at the Emerging Languages Camp
- stephenjudkins 16y agoThe author also presented on his own language, Finch (http://bitbucket.org/munificent/finch http://bitbucket.org/munificent/finch). It was a great presentation, and the language implementation is incredibly easy to read and understand. I don't see using Finch for any real projects (like many of the languages presented) but it was inspiring to see so many people presenting well-crafted labors of love. For someone interested in programming language design or implementation, Emerging Languages Camp had a lot to offer. It received universal praise from everyone I talked to.
- munificent 16y ago> the language implementation is incredibly easy to read and understand. Thanks! After wading through an SML compiler whose author apparently thought single-letter variables and no documentation was perfectly fine in a language that doesn't even have fucking type annotations, I figured the least I could do to advance the state of the art was make the code legible.
- monkey 16y agoThe author's talk on Finch was indeed awesome. He was very funny and modest and self-deprecating, but it was obvious to everyone that he was really smart. And his talk had some of the most quotable bits in the whole conference. "I'm writing a recursive descent parser by hand because I keep it real." LOL His listings of the things his language couldn't do were hilarious too. In response to a question from the audience, he discussed how he designed a programming language for the first time, which was really edifying and an interesting discussion of the mental journey. His answer was really good and I can't do it justice, but it talked about how he solved the problems by working in little stages. He knew that he could break up a text file into tokens, and that's how he built a lexer. Next, he realized that a parser was a lot like a lexer, and recognized groups of tokens, so he could build a parser. So he then had a tree, and he found that he could walk that tree. As he walked the tree, he realized he could emit bytecode. It was a really good description, and better than any single lecture in an entire semester of my college Compiler Construction class. The fact that the author didn't even know he was going to be able to speak until the day of the presentation, and came up with a very polished and professional and engaging presentation says volumes about his ability. I think everyone really enjoyed his talk, and it really had a sense of joy and fun and discovery about it. And it was funny as hell. There is no doubt that we'll be seeing much more from him.
- arohner 16y agoGood article, but I have to nitpick here: Any well-versed programming language person can tell you about both recursive-descent parsers and generated parsers. They’ll also tell that generated parsers are the “right” way to do that. Most of the time that advice will save you from wasted effort, but sometimes I think it keeps people from going down paths that may actually be fruitful. Sometimes the thing that everyone knows is true isn’t. (For example, every language I know of with a lot of real-world users actually does use a hand-written parser.) Recursive descent parsers are good when 1) you have a simple grammar and 2) you want fewer dependencies. Most lisps have hand-written recursive descent parsers because lisp grammar is easy. Also, MRI ruby (aka CRuby1.8) uses a generated parser.
- carterschonwald 16y agoI think the recursive descent ones are also worth favoring when you want to have more informative error messages
- joe_the_user 16y agoYes, I like writing recursive descent parsers but I don't know of any in "industrial" use, beside the lisp parser you just mentioned. I'd like to know if there are more.
- tedunangst 16y agoIndustries using a recursive descent parser: http://www.edg.com/index.php?location=customers_oc http://www.edg.com/index.php?location=customers_oc
- panic 16y agoLLVM's clang uses a recursive-descent parser to parse C, ObjC, and C++ (http://clang.llvm.org/features.html#unifiedparser http://clang.llvm.org/features.html#unifiedparser). Clang is the "C Language Family Front-end", which means we intend to support the most popular members of the C family. We are convinced that the right parsing technology for this class of languages is a hand-built recursive-descent parser. Because it is plain C++ code, recursive descent makes it very easy for new developers to understand the code, it easily supports ad-hoc rules and other strange hacks required by C/C++, and makes it straight-forward to implement excellent diagnostics and error recovery.
- scott_s 16y agoGlad I read this, because I learned about Frink: http://futureboy.homeip.net/frinkdocs/ http://futureboy.homeip.net/frinkdocs/ and the FAQ: http://futureboy.homeip.net/frinkdocs/faq.html http://futureboy.homeip.net/frinkdocs/faq.html This guy knows units of measurement.
- jasonwatkinspdx 16y agoHis presentation was a pleasure to watch. I'd seen the pitch for frink in a video some time ago, but he's a charismatic speaker that keeps your attention even if you're roughly familiar with the material. During the QA portion someone gave him a "gotcha" question only to have the tables turned when it was made clear the speaker new _far_ _far_ more about standards and units of measurement than anyone in that room, city and possibly state.
- isnoteasy 16y agoI would prefer a conference about emerging features in languages, since many languages only differs in superficial aspects. Is better to located what new features are needed.
- jckarter 16y agoThere were a number of talks in that vein. Rich Hickey's talk about his experimental "pod" feature in Clojure for safe scoped mutation, Joe Pamer's talk about making F# suitable as a first-class .NET language, and Jonathan Shapiro's talk about the correctness constraints guiding BitC's design all focused more on problem domains and the features necessary to fill those domains than superficial language features.
- jasonwatkinspdx 16y agoI'd estimate that only half of the languages presented were of the sort that differ only in minor aspects. Several of the languages presented were _far_ outside the mainstream, particularly the two visual languages which were surprisingly practical. On the whole I'd say factor was likely the most unconventional language besides those mentioned above. The breadth of libraries they have built while being so iconoclast is impressive.