6 ms·

Ask HN: How to start programming language design?

12 points by poseid 12y ago

Hello, as far as I know, programming started out with translating expressions like: (number) (operation) (number) := (result) Now, I want to understand a bit more on programming language principles, but reading references quickly results into discussion of abstract algebra. So here is my question: How can I start designing simple programming languages? What are some simple, but useful grammars to understand programming language principles? What are these "treetop" like parsing libraries about, and are these for beginners or advanced users?

wilsonfiifi 12y ago
You could take a look at Marc Cournoyer's course http://createyourproglang.com http://createyourproglang.com, check out the compiler course on Cousera https://www.coursera.org/course/compilers https://www.coursera.org/course/compilers and watch Rob Pikes talk on lexical scanning http://www.youtube.com/watch?v=HxaD_trXwRE.b http://www.youtube.com/watch?v=HxaD_trXwRE.b That should get you going. Oh and don't forget to have a look at Go language specification as well.
- poseid 12y ago
  thanks! what about these "PEG" parsers? when/why do they make sense?
  - jonjacky 12y ago
    "PEG-based transformer provides front-, middle and back-end stages in a simple compiler" http://www.vpri.org/pdf/tr2010003_PEG.pdf http://www.vpri.org/pdf/tr2010003_PEG.pdf
- poseid 12y ago
  what makes the go language a good example?
  - hariharan_uno 12y ago
    The language spec is very short compared to others.
chton 12y ago
For some quick hands-on learning, it might be interesting to read up on Resursive Descent Parsers (http://en.wikipedia.org/wiki/Recursive_descent_parser http://en.wikipedia.org/wiki/Recursive_descent_parser). They're easy to understand and easy to code in a language of your choice. Once you have a working one, you can expand it to experiment with your own grammar. Spend some time experimenting that way and you'll be able to get a lot of insight in what the pitfalls of language design are and how you can work with your parser to minimize them.
- poseid 12y ago
  thanks! do you have some tool that you would recommend to run programs with these grammars. e.g. I have calculator.ycomb and a ycomb grammar. which programs would you recommend to get an output of calculator.ycomb ?
  - chton 12y ago
    honestly, I would recommend you write your own parser for it. A grammar is meaningless by itself, and you'll learn a lot more about why yours might work or not work if you do the work yourself. I can't say I know of any good PEG implementations, and even if there were, you'd be limited to what you can express in PEG. A real language can be far broader, encompassing inputs, outputs, complicated functions, etc.
    - poseid 12y ago
      interesting advice to get hands dirty with source code directly. I might think to experiment a bit with C/lexx/yacc then. one thing, I am curious about, what are the kind of "hello_world()" functions, that would print something on a screen... hmm..
      - chton 12y ago
        Getting in on the ground floor tends to be my advice for a lot things. It's hard to make something click if you can't see it work in the flesh. For the typical functions that print output or take input or the likes, I'm always partial to keeping them separate from the grammar itself. You can see the distinction clearly between for example Python: print myVar and Java: System.out.println(myVar); In Python, the print verb is defined in the grammar, and as such needs to be parsed and handled properly. In Java's case, it's regarded as any other method. It's irrelevant to the parser what it does, it just needs to handle it like it would a normal method. This tends to make the whole easier to debug and adapt, since you never need to touch the parser to change behavior of one of these standard methods. This does ofcourse lead to more complex applications, which may not be desirable, depending on the intent of the language. Just my 2 cents :)
CmonDev 12y ago
Check the next generation approach for a modern IDE: http://blog.jetbrains.com/blog/2014/05/27/nitra-goes-open-source http://blog.jetbrains.com/blog/2014/05/27/nitra-goes-open-so... https://github.com/JetBrains/Nitra https://github.com/JetBrains/Nitra
- poseid 12y ago
  with Nitra, how would a "hello_world()" of a programming language print something to the screen?
EdwardCoffin 12y ago
You should probably spend some time browsing through Lambda the Ultimate [1], a discussion forum devoted to this kind of thing (it is very academic though). There's a collectively authored set of guidelines "How to Design (Declarative) Programming Languages" [2] posted in comp.lang.lightweight, curated by Scott McKay that you might find useful. [1] http://lambda-the-ultimate.org http://lambda-the-ultimate.org [2] http://thread.gmane.org/gmane.comp.lang.lightweight/2547/focus=2552 http://thread.gmane.org/gmane.comp.lang.lightweight/2547/foc...
sprobertson 12y ago
Here's the best "hands-on" introduction I've seen: http://nathansuniversity.com/ http://nathansuniversity.com/ He walks you through the basics of compiling, parsing, and interpreting to create your own scheme-like language (complete with exercises along the way).