5 ms·

If it's an exaggeration, it's not much of one. Two parts to your argument: - Writing a Scheme implementation quickly: Google "Write a Scheme in 48 hours" and

If it's an exaggeration, it's not much of one. Two parts to your argument: - Writing a Scheme implementation quickly: Google "Write a Scheme in 48 hours" and "Scheme from scratch." 48 hours to a functioning Scheme implementation seems to be a feat replicated in multiple programming languages. - Performance: I haven't benchmarked every hobby scheme, but given the proliferation of Scheme implementations that, despite limited developer resources, beat (pure) Python with it's massive pool of developers (CPython, PyPy), I still don't buy the idea that optimizing Scheme is a harder task than optimizing Python. Again, I'd strongly suggest that optimizing Scheme is a much easier task than optimizing Python simply by virtue of how often the feat has been accomplished.

mrtranscendence 4y ago
If you can give me an implementation that implements almost all of R5RS, in 48 hours, beating Python in performance, and all by a single developer, I’ll tip my hat to that guy or gal. But I can’t imagine it’s too commonly done.
- eatonphil 4y ago
  Nobody said you can implement a full Scheme implementation in 48 hours or two weeks. That's very much besides the point about how poor CPython performance is.
  - mrtranscendence 4y ago
    > Nobody said you can implement a full Scheme implementation in 48 hours or two weeks. Fair enough, you're right. But if we're only talking about incomplete Scheme implementations it's not a very interesting claim. As I pointed out in another comment, even I could write a fast Scheme implementation in 48 hours if I kept my scope very limited. That doesn't say much about Scheme performance overall or how it relates to Python.
    - eatonphil 4y ago
      What is it that you think makes a full Scheme implementation as slow as CPython?
      - mrtranscendence 4y ago
        I don’t think a full Scheme implementation is as slow as Python in general. What I’m hung up on is the claim that it’s so absolutely trivial to write a language implementation faster than Python that basically anybody at any skill level could do it in a weekend, and still have time for Sunday afternoon bocce.
        pjmlp 4y ago
        Start with, "An Incremental Approach to Compiler Construction" http://scheme2006.cs.uchicago.edu/11-ghuloum.pdf http://scheme2006.cs.uchicago.edu/11-ghuloum.pdf
    - peatmoss 4y ago
      Well let's flip this around: do you think you could write a performant minimal Python in a weekend? Scheme is a very simple and elegant idea. Its power derives from the fact that smart people went to considerable pains to distill computation to limited set of things. "Complete" (i.e. rXrs) schemes build quite a lot of themselves... in scheme, from a pretty tiny core. I suspect Jeff Bezanson spent more than a weekend writing femtolisp, but that isn't really important. He's one guy who wrote a pretty darned performant lisp that does useful computation as a passion project. Check out his readme; it's fascinating: https://github.com/JeffBezanson/femtolisp https://github.com/JeffBezanson/femtolisp You simply can't say these things about Python (and I generally like Python!). It's truer for PyPy, but PyPy is pretty big and complex itself. Take a look at the source for the scheme or scheme-derived language of your choice sometime. I can't claim to be an expert in any of what's going on in there, but I think you'll be surprised how far down those parens go. The claim I was responding to asserted that lisps and smalltalks can only be fast because of complex JIT compiling. That is trueish in practice for Smalltalk and certainly modern Javascript... but it simply isn't true for every lisp. Certainly JIT-ed lisps can be extremely fast, but it's not the only path to a performant lisp. In these benchmarks you'll see a diversity of approaches even among the top performers: https://ecraven.github.io/r7rs-benchmarks/ https://ecraven.github.io/r7rs-benchmarks/ Given how many performant implementations of Scheme there are, I just don't think you can claim it's because of complex implementations by well-resourced groups. To me, I think the logical conclusion is that Scheme (and other lisps for the most part) are intrinsically pretty optimizable compared to Python. If we look at Common Lisp, there are also multiple performant implementations, some approximately competitive with Java which has had enormous resources poured into making it performant.
eatonphil 4y ago
I would not include PyPy in a list of easy to beat implementations.
- JulianWasTaken 4y ago
  Nor ones with massive pools of developers.
  - peatmoss 4y ago
    Compared to most Scheme implementations?

mrtranscendence 4y ago

If you can give me an implementation that implements almost all of R5RS, in 48 hours, beating Python in performance, and all by a single developer, I’ll tip my hat to that guy or gal. But I can’t imagine it’s too commonly done.

eatonphil 4y ago
Nobody said you can implement a full Scheme implementation in 48 hours or two weeks. That's very much besides the point about how poor CPython performance is.
- mrtranscendence 4y ago
  > Nobody said you can implement a full Scheme implementation in 48 hours or two weeks. Fair enough, you're right. But if we're only talking about incomplete Scheme implementations it's not a very interesting claim. As I pointed out in another comment, even I could write a fast Scheme implementation in 48 hours if I kept my scope very limited. That doesn't say much about Scheme performance overall or how it relates to Python.
  - eatonphil 4y ago
    What is it that you think makes a full Scheme implementation as slow as CPython?
    - mrtranscendence 4y ago
      I don’t think a full Scheme implementation is as slow as Python in general. What I’m hung up on is the claim that it’s so absolutely trivial to write a language implementation faster than Python that basically anybody at any skill level could do it in a weekend, and still have time for Sunday afternoon bocce.
      - pjmlp 4y ago
        Start with, "An Incremental Approach to Compiler Construction" http://scheme2006.cs.uchicago.edu/11-ghuloum.pdf http://scheme2006.cs.uchicago.edu/11-ghuloum.pdf
  - peatmoss 4y ago
    Well let's flip this around: do you think you could write a performant minimal Python in a weekend? Scheme is a very simple and elegant idea. Its power derives from the fact that smart people went to considerable pains to distill computation to limited set of things. "Complete" (i.e. rXrs) schemes build quite a lot of themselves... in scheme, from a pretty tiny core. I suspect Jeff Bezanson spent more than a weekend writing femtolisp, but that isn't really important. He's one guy who wrote a pretty darned performant lisp that does useful computation as a passion project. Check out his readme; it's fascinating: https://github.com/JeffBezanson/femtolisp https://github.com/JeffBezanson/femtolisp You simply can't say these things about Python (and I generally like Python!). It's truer for PyPy, but PyPy is pretty big and complex itself. Take a look at the source for the scheme or scheme-derived language of your choice sometime. I can't claim to be an expert in any of what's going on in there, but I think you'll be surprised how far down those parens go. The claim I was responding to asserted that lisps and smalltalks can only be fast because of complex JIT compiling. That is trueish in practice for Smalltalk and certainly modern Javascript... but it simply isn't true for every lisp. Certainly JIT-ed lisps can be extremely fast, but it's not the only path to a performant lisp. In these benchmarks you'll see a diversity of approaches even among the top performers: https://ecraven.github.io/r7rs-benchmarks/ https://ecraven.github.io/r7rs-benchmarks/ Given how many performant implementations of Scheme there are, I just don't think you can claim it's because of complex implementations by well-resourced groups. To me, I think the logical conclusion is that Scheme (and other lisps for the most part) are intrinsically pretty optimizable compared to Python. If we look at Common Lisp, there are also multiple performant implementations, some approximately competitive with Java which has had enormous resources poured into making it performant.

eatonphil 4y ago

I would not include PyPy in a list of easy to beat implementations.

JulianWasTaken 4y ago
Nor ones with massive pools of developers.
- peatmoss 4y ago
  Compared to most Scheme implementations?