8 ms·

Excellently written, great topic, and done w/o flaming/too much bias. I'm amazed as many older folks in the industry would not be able to have this level of co

by bfung 7y ago

Excellently written, great topic, and done w/o flaming/too much bias. I'm amazed as many older folks in the industry would not be able to have this level of content and maturity to write an informative article.

WalterBright 7y ago
It's difficult to write a fair comparison without being a fairly competent programmer in each of the languages. The trouble is, if a person is an expert C programmer and then translates it to Python that he's only modestly familiar with, the Python program will look like C. It won't be idiomatic Python. For example, my early Fortran programs looked like Basic. My early C programs looked like Fortran. My early C++ programs looked like C. And my early D code looked like C++. It takes much more than being able to write a program in X to be able to write one that makes proper use of the language.
- galaxyLogic 7y ago
  That is all true. At the same time here the groups were allowed to use the language of their choice. Presumably they chose languages they felt they were competent in. Of course an expert of a given programming language can write much better in it than a novice. But a comparison like this is not necessarily about comparing top-programmers in every language, but average programmers, because we want to know results that are true "on average" . The author does note he "knew (they) were highly competent". So they were not exactly novices in their language of choice. Writing a compiler is not a task for novices in general.
  - anaphor 7y ago
    The article says that the instructor for the course cautioned against using Haskell because some people overestimated their competency with it. I think it is actually very likely that people would chose a programming language or system for reasons other than how competent they are with it. E.g. to seem "smart" because you wrote your compiler in Haskell, even though you actually have much more experience with Java or Python. FTA: > Another interesting thing to note is that at the start of every offering of the course the professor says that students can use any language that can run on the school servers, but issues a warning that teams using Haskell have the highest variance in mark of any language, with many teams using Haskell overestimating their ability and crashing and burning then getting a terrible mark, more than any other language, while some Haskell teams do quite well and get perfect like my friends.
    - galaxyLogic 7y ago
      > would chose a programming language or system for reasons other than how competent they are with it Good point these were students so they were eager to learn new things. Can't blame them. At the same time much of programming is learning new things continually. Some things are harder to learn and master than others. Seems like Haskell might be one such thing, based on what the professor says.
      - anaphor 7y ago
        Yeah, I think the problem comes when you try to learn too many new things at once. If you're still learning about compilers, then trying to learn about functional programming on top of that is just asking for trouble.
    - willtim 7y ago
      Sounds like he (edit: or more accurately, the university) has hasn't taught them enough functional programming and Haskell.
      - epse 7y ago
        He teaches compilers. Not programming or fp, so definitely not the professors fault
        willtim 7y ago
        Yes, but it's still a great pity, as Haskell, a descendent of ML (the "meta-language") is a suberb fit for writing a compiler.
      - anaphor 7y ago
        It's my understanding that UW offers some undergrad courses in Racket, but apparently they're optional so if you hadn't taken that course you might not know much about functional programming.
      - 256 7y ago
        There is a mandatory compilers-lite course at UW and he teaches the advanced version of it, where the project is to fill in pieces of a Scala-lite compiler written in Scala.
  - nine_k 7y ago
    I'd say that "on average" results may be very misleading, in formal statistics and in results like this. Variance and median are very important: see comments about Haskell downthread. (Ideally you have a histogram.) In particular, some languages with a good average may contain pitfalls that could lead to abysmal outlier results (e.g. C++ or Scala, in entirely different ways), some would keep you from doing really dangerous things but also would not let you achieve spectacular things (e.g. Go).
  - nybble41 7y ago
    > So they were not exactly novices in their language of choice. The Haskell team had "maybe a couple thousand lines of Haskell each" at the start. This one project ended up being 9.7k lines, so it constitutes half of their collective experience with the language. I'd say that counts as "novice" in terms of prior Haskell experience. Under the circumstances I think they did remarkably well to produce a thoroughly tested and maintainable end product in just twice the lines of code of the quick-and-dirty Python implementation.
    - danielscrubs 7y ago
      I thought it very amusing that the teams focus would reflect the language: The Python implementation was as you say quick-and-dirty, while the Haskell one "caught a few edge cases that our team did not" and the C++-team did "optimizations on their IR".
  - tigershark 7y ago
    There were people with 2k to 10k loc of experience in some language. That seems extremely low for any meaningful comparison and I would really hope that “average” programmers have way more experience than that... I think I was pretty junior after writing north of 100k loc and working on 1M loc projects. And for sure I don’t consider myself highly competent in F# after writing some thousands lines. I agree with the conclusions when they say that the design decisions are much more important than the language of choice. But I still firmly believe that the language makes a very big difference in real world projects. In toy throw away projects obviously metaprogramming cuts a lot of locs.
    - speedplane 7y ago
      > There were people with 2k to 10k loc of experience in some language. That seems extremely low for any meaningful comparison ... It's low if you're comparing languages based on the skills of experienced programmers, but most programmers are not terribly experienced. A comparison of languages by programmers that are novices to the language is still meaningful. A language that is easier for a novice to pick up and write good code is at the very least one good measure for the quality of the language.
    - StreamBright 7y ago
      Sure but 100k LOC Java is bot equal to 100k LOC Rust or Clojure because there is a huge discrepancy between expressiveness of those languages.
      - pjmlp 7y ago
        It also depends if one is using Java 12 or Java 1.4 programming style.
        StreamBright 7y ago
        Exactly. Even within the same lang, it does not work.
    - jodrellblank 7y ago
  - 59nadir 7y ago
    > So they were not exactly novices in their language of choice. Writing a compiler is not a task for novices in general. Only having a few thousand lines of code written in Haskell very much makes you a novice. With that said, writing a compiler in Haskell is actually pretty trivial. It's at the very least considerably easier than most other languages.
- objektif 7y ago
  How do you like D btw? Is it worth learning for a c++ programmer? I find the syntax very appealing.
  - deleted 7y ago
    [deleted]
  - trishume 7y ago
    Fun fact the person you're replying to is the creator of D, I'm pretty sure he likes it. I've personally played around with D a bit and written maybe 1kloc in it and I like it. It doesn't have good pattern matching or the borrow checker, but it does have much better metaprogramming than Rust. I think a lot of the metaprogramming used in the Python project could also be done basically as easily in D, which is a big accomplishment.
    - WalterBright 7y ago
      D has many characteristics of lifetime checking in that it can track lifetimes across function calls and issue errors for incorrect usage. I've been looking into increasing its reach, and it looks promising.
  - mhh__ 7y ago
    Walter Bright is (along with Andrei Alexandrescu - which should be a good enough reason if you like c++) the BDFL of D. D won't get you hired (probably), but D is designed with hindsight from a C++ compiler writer and a C++ template wizard: It shows, D is objectively better than C++ is many ways. It's worth checking out, at the very least (It's also not hard to learn, so I say go for it) An example of the power of D: The Pegged library for D can generate a parser, D code which gets compiled, directly from a grammar specification in a text file [inside a D program, e.g. mixin(Grammar("Your Grammar Here"))]
    - WalterBright 7y ago
      > D won't get you hired (probably) On the contrary. Many members of the D community have managed to leverage their D expertise into well-paying jobs. Many industrial D users recruit from the D community.
- ChuckMcM 7y ago
  I would have liked to see what a team using C would have come up with in the author's set.
lapw 7y ago
The older folks wouldn't compare toy compilers in this pseudo-serious manner. I find it annoying that any trivial topic is dealt with in a self-important, "mature" manner.

by bfung 7y ago

WalterBright 7y ago

It's difficult to write a fair comparison without being a fairly competent programmer in each of the languages. The trouble is, if a person is an expert C programmer and then translates it to Python that he's only modestly familiar with, the Python program will look like C. It won't be idiomatic Python. For example, my early Fortran programs looked like Basic. My early C programs looked like Fortran. My early C++ programs looked like C. And my early D code looked like C++. It takes much more than being able to write a program in X to be able to write one that makes proper use of the language.

galaxyLogic 7y ago
That is all true. At the same time here the groups were allowed to use the language of their choice. Presumably they chose languages they felt they were competent in. Of course an expert of a given programming language can write much better in it than a novice. But a comparison like this is not necessarily about comparing top-programmers in every language, but average programmers, because we want to know results that are true "on average" . The author does note he "knew (they) were highly competent". So they were not exactly novices in their language of choice. Writing a compiler is not a task for novices in general.
- anaphor 7y ago
  The article says that the instructor for the course cautioned against using Haskell because some people overestimated their competency with it. I think it is actually very likely that people would chose a programming language or system for reasons other than how competent they are with it. E.g. to seem "smart" because you wrote your compiler in Haskell, even though you actually have much more experience with Java or Python. FTA: > Another interesting thing to note is that at the start of every offering of the course the professor says that students can use any language that can run on the school servers, but issues a warning that teams using Haskell have the highest variance in mark of any language, with many teams using Haskell overestimating their ability and crashing and burning then getting a terrible mark, more than any other language, while some Haskell teams do quite well and get perfect like my friends.
  - galaxyLogic 7y ago
    > would chose a programming language or system for reasons other than how competent they are with it Good point these were students so they were eager to learn new things. Can't blame them. At the same time much of programming is learning new things continually. Some things are harder to learn and master than others. Seems like Haskell might be one such thing, based on what the professor says.
    - anaphor 7y ago
      Yeah, I think the problem comes when you try to learn too many new things at once. If you're still learning about compilers, then trying to learn about functional programming on top of that is just asking for trouble.
  - willtim 7y ago
    Sounds like he (edit: or more accurately, the university) has hasn't taught them enough functional programming and Haskell.
    - epse 7y ago
      He teaches compilers. Not programming or fp, so definitely not the professors fault
      - willtim 7y ago
        Yes, but it's still a great pity, as Haskell, a descendent of ML (the "meta-language") is a suberb fit for writing a compiler.
    - anaphor 7y ago
      It's my understanding that UW offers some undergrad courses in Racket, but apparently they're optional so if you hadn't taken that course you might not know much about functional programming.
    - 256 7y ago
      There is a mandatory compilers-lite course at UW and he teaches the advanced version of it, where the project is to fill in pieces of a Scala-lite compiler written in Scala.
- nine_k 7y ago
  I'd say that "on average" results may be very misleading, in formal statistics and in results like this. Variance and median are very important: see comments about Haskell downthread. (Ideally you have a histogram.) In particular, some languages with a good average may contain pitfalls that could lead to abysmal outlier results (e.g. C++ or Scala, in entirely different ways), some would keep you from doing really dangerous things but also would not let you achieve spectacular things (e.g. Go).
- nybble41 7y ago
  > So they were not exactly novices in their language of choice. The Haskell team had "maybe a couple thousand lines of Haskell each" at the start. This one project ended up being 9.7k lines, so it constitutes half of their collective experience with the language. I'd say that counts as "novice" in terms of prior Haskell experience. Under the circumstances I think they did remarkably well to produce a thoroughly tested and maintainable end product in just twice the lines of code of the quick-and-dirty Python implementation.
  - danielscrubs 7y ago
    I thought it very amusing that the teams focus would reflect the language: The Python implementation was as you say quick-and-dirty, while the Haskell one "caught a few edge cases that our team did not" and the C++-team did "optimizations on their IR".
- tigershark 7y ago
  There were people with 2k to 10k loc of experience in some language. That seems extremely low for any meaningful comparison and I would really hope that “average” programmers have way more experience than that... I think I was pretty junior after writing north of 100k loc and working on 1M loc projects. And for sure I don’t consider myself highly competent in F# after writing some thousands lines. I agree with the conclusions when they say that the design decisions are much more important than the language of choice. But I still firmly believe that the language makes a very big difference in real world projects. In toy throw away projects obviously metaprogramming cuts a lot of locs.
  - speedplane 7y ago
    > There were people with 2k to 10k loc of experience in some language. That seems extremely low for any meaningful comparison ... It's low if you're comparing languages based on the skills of experienced programmers, but most programmers are not terribly experienced. A comparison of languages by programmers that are novices to the language is still meaningful. A language that is easier for a novice to pick up and write good code is at the very least one good measure for the quality of the language.
  - StreamBright 7y ago
    Sure but 100k LOC Java is bot equal to 100k LOC Rust or Clojure because there is a huge discrepancy between expressiveness of those languages.
    - pjmlp 7y ago
      It also depends if one is using Java 12 or Java 1.4 programming style.
      - StreamBright 7y ago
        Exactly. Even within the same lang, it does not work.
  - jodrellblank 7y ago
- 59nadir 7y ago
  > So they were not exactly novices in their language of choice. Writing a compiler is not a task for novices in general. Only having a few thousand lines of code written in Haskell very much makes you a novice. With that said, writing a compiler in Haskell is actually pretty trivial. It's at the very least considerably easier than most other languages.
objektif 7y ago
How do you like D btw? Is it worth learning for a c++ programmer? I find the syntax very appealing.
- deleted 7y ago
  [deleted]
- trishume 7y ago
  Fun fact the person you're replying to is the creator of D, I'm pretty sure he likes it. I've personally played around with D a bit and written maybe 1kloc in it and I like it. It doesn't have good pattern matching or the borrow checker, but it does have much better metaprogramming than Rust. I think a lot of the metaprogramming used in the Python project could also be done basically as easily in D, which is a big accomplishment.
  - WalterBright 7y ago
    D has many characteristics of lifetime checking in that it can track lifetimes across function calls and issue errors for incorrect usage. I've been looking into increasing its reach, and it looks promising.
- mhh__ 7y ago
  Walter Bright is (along with Andrei Alexandrescu - which should be a good enough reason if you like c++) the BDFL of D. D won't get you hired (probably), but D is designed with hindsight from a C++ compiler writer and a C++ template wizard: It shows, D is objectively better than C++ is many ways. It's worth checking out, at the very least (It's also not hard to learn, so I say go for it) An example of the power of D: The Pegged library for D can generate a parser, D code which gets compiled, directly from a grammar specification in a text file [inside a D program, e.g. mixin(Grammar("Your Grammar Here"))]
  - WalterBright 7y ago
    > D won't get you hired (probably) On the contrary. Many members of the D community have managed to leverage their D expertise into well-paying jobs. Many industrial D users recruit from the D community.
ChuckMcM 7y ago
I would have liked to see what a team using C would have come up with in the author's set.

lapw 7y ago

The older folks wouldn't compare toy compilers in this pseudo-serious manner. I find it annoying that any trivial topic is dealt with in a self-important, "mature" manner.