5 ms·

We have a macro expander for pascal written in scheme (quick and dirty draft made by me that worked so well it stayed). We had some performance problems with so

We have a macro expander for pascal written in scheme (quick and dirty draft made by me that worked so well it stayed). We had some performance problems with some crazy recursive macros (it generates a _lot_ of code. Don't ask, I am not allowed to talk much about it), so I investigated porting it to chez. Instead I just switched to guile (scheme implementation) trunk and got a 3x speedup. Did some optimizing work and it ended up at 4x, which is good enough.

davexunit 10y ago
What Scheme implementation did the code originally use?
- Johnny_Brahms 10y ago
  The Guile 2.0 branch. I don't know what magic optimisation dust they sprinkled over the upcoming 2.2, but it sure is fast. We thought about using chicken, but it depends quite a lot on using syntax-case to deconstruct everything, and I didn't want to learn their implicit renaming stuff. Apparently the 2.2 branch has full elisp support. Can't wait for Emacs to run on it.
  - davexunit 10y ago
    Ah, that makes sense! Guile 2.2 has a completely rewritten compiler and virtual machine. I'm happy to see some real-world instances of it greatly improving performance.
    - Johnny_Brahms 10y ago
      "greatly improving performance" is an understatement! It was literally 3x. I didn't even have to change anything. Not bad for a language that usually beats python by quite a large margin :)
  - wtbob 10y ago
    > Apparently the [guile] 2.2 branch has full elisp support. Can't wait for Emacs to run on it. I really wish folks would spend the time they spent porting elisp to guile Scheme porting elisp to Lisp instead. Scheme's great for what it is (really), but what it is not is an industrial-strength systems programming language. Common Lisp is.
    - davexunit 10y ago
      >porting elisp to guile Scheme This is a common misunderstanding. Emacs Lisp is not being rewritten as Scheme. What is actually happening is that there is a compiler for Emacs Lisp that runs on Guile's virtual machine. Elisp isn't going anywhere.
      - wtbob 10y ago
        Regardless, I wish that they'd spent that effort writing an elisp→Lisp compiler rather than an elisp→Scheme compiler.
        davexunit 10y ago
        It's not an elisp->scheme compiler.
        wtbob 10y ago
        What does it compile to, if not Scheme? And, regardless, I wish that they'd not used Scheme. I really, really wish that they'd not used Scheme.
        jabl 10y ago
        I'm not that familiar with guile internals, but IIRC they have some intermediate representation (bytecode?) that the VM then runs. So the frontend languages (Scheme, Elisp, even Javascript IIRC) are compiled to bytecode, the Guile VM then interprets the bytecode.

davexunit 10y ago

What Scheme implementation did the code originally use?

Johnny_Brahms 10y ago
The Guile 2.0 branch. I don't know what magic optimisation dust they sprinkled over the upcoming 2.2, but it sure is fast. We thought about using chicken, but it depends quite a lot on using syntax-case to deconstruct everything, and I didn't want to learn their implicit renaming stuff. Apparently the 2.2 branch has full elisp support. Can't wait for Emacs to run on it.
- davexunit 10y ago
  Ah, that makes sense! Guile 2.2 has a completely rewritten compiler and virtual machine. I'm happy to see some real-world instances of it greatly improving performance.
  - Johnny_Brahms 10y ago
    "greatly improving performance" is an understatement! It was literally 3x. I didn't even have to change anything. Not bad for a language that usually beats python by quite a large margin :)
- wtbob 10y ago
  > Apparently the [guile] 2.2 branch has full elisp support. Can't wait for Emacs to run on it. I really wish folks would spend the time they spent porting elisp to guile Scheme porting elisp to Lisp instead. Scheme's great for what it is (really), but what it is not is an industrial-strength systems programming language. Common Lisp is.
  - davexunit 10y ago
    >porting elisp to guile Scheme This is a common misunderstanding. Emacs Lisp is not being rewritten as Scheme. What is actually happening is that there is a compiler for Emacs Lisp that runs on Guile's virtual machine. Elisp isn't going anywhere.
    - wtbob 10y ago
      Regardless, I wish that they'd spent that effort writing an elisp→Lisp compiler rather than an elisp→Scheme compiler.
      - davexunit 10y ago
        It's not an elisp->scheme compiler.
        wtbob 10y ago
        What does it compile to, if not Scheme? And, regardless, I wish that they'd not used Scheme. I really, really wish that they'd not used Scheme.
        jabl 10y ago
        I'm not that familiar with guile internals, but IIRC they have some intermediate representation (bytecode?) that the VM then runs. So the frontend languages (Scheme, Elisp, even Javascript IIRC) are compiled to bytecode, the Guile VM then interprets the bytecode.