4 ms·

Check out the Pony tutorial for a good introduction to reference capabilities https://tutorial.ponylang.io/reference-capabilities.html https://tutorial.ponylan

Check out the Pony tutorial for a good introduction to reference capabilities https://tutorial.ponylang.io/reference-capabilities.html https://tutorial.ponylang.io/reference-capabilities.html They can be tricky to wrap your head around at first, but the idea (combined with object capabilities) is very powerful IMO.

spooneybarger 7y ago
There's also a section of the website with additional materials that we've found help people learn reference capabilities: https://www.ponylang.io/learn/#reference-capabilities https://www.ponylang.io/learn/#reference-capabilities And John Mumm recently did an excellent intro talk on them: https://www.reddit.com/r/ponylang/comments/ckagfw/john_mumm_safely_sharing_data_reference/ https://www.reddit.com/r/ponylang/comments/ckagfw/john_mumm_...
saagarjha 7y ago
> There aren’t currently any mainstream programming languages that feature reference capabilities. Does Rust not have something similar built into the borrow checker?
- foota 7y ago
  I don't think you can hold multiple mutable non-overlapping slices though, which this would appear to allow. Edit: I see you're talking about pony, not the op. It would seem your comment is correct. Although, pony seems to have a slightly different perspective on it.
  - dbaupp 7y ago
    Rust allows multiple mutable non-overlapping slices. They cannot be constructed by direct array[i..j] slicing, but there is a variety of convenience functions for it. Sequential: https://doc.rust-lang.org/std/primitive.slice.html#method.split_at_mut https://doc.rust-lang.org/std/primitive.slice.html#method.sp... https://doc.rust-lang.org/std/primitive.slice.html#method.split_at_mut https://doc.rust-lang.org/std/primitive.slice.html#method.sp... Parallel: https://docs.rs/rayon/1.2.0/rayon/slice/trait.ParallelSliceMut.html#method.par_chunks_mut https://docs.rs/rayon/1.2.0/rayon/slice/trait.ParallelSliceM...
    - foota 7y ago
      That's really cool, thanks for sharing!
    - kzrdude 7y ago
      And rust ndarray implements strided mutable "slices" too, interleaved.
- spooneybarger 7y ago
  Similar goals, very different implementation. The goal is memory safety, but rust has the borrow checker which is rather different than reference capabilities.
- nickpsecurity 7y ago
  They told me Rust uses affine types (i.e. its move semantics). Clay language (see Lea Wittie et al) used linear and singleton types. Pony has reference capabilities. http://jtfmumm.com/blog/2016/03/06/safely-sharing-data-pony-reference-capabilities/ http://jtfmumm.com/blog/2016/03/06/safely-sharing-data-pony-...

spooneybarger 7y ago

There's also a section of the website with additional materials that we've found help people learn reference capabilities: https://www.ponylang.io/learn/#reference-capabilities https://www.ponylang.io/learn/#reference-capabilities And John Mumm recently did an excellent intro talk on them: https://www.reddit.com/r/ponylang/comments/ckagfw/john_mumm_safely_sharing_data_reference/ https://www.reddit.com/r/ponylang/comments/ckagfw/john_mumm_...

saagarjha 7y ago

> There aren’t currently any mainstream programming languages that feature reference capabilities. Does Rust not have something similar built into the borrow checker?

foota 7y ago
I don't think you can hold multiple mutable non-overlapping slices though, which this would appear to allow. Edit: I see you're talking about pony, not the op. It would seem your comment is correct. Although, pony seems to have a slightly different perspective on it.
- dbaupp 7y ago
  Rust allows multiple mutable non-overlapping slices. They cannot be constructed by direct array[i..j] slicing, but there is a variety of convenience functions for it. Sequential: https://doc.rust-lang.org/std/primitive.slice.html#method.split_at_mut https://doc.rust-lang.org/std/primitive.slice.html#method.sp... https://doc.rust-lang.org/std/primitive.slice.html#method.split_at_mut https://doc.rust-lang.org/std/primitive.slice.html#method.sp... Parallel: https://docs.rs/rayon/1.2.0/rayon/slice/trait.ParallelSliceMut.html#method.par_chunks_mut https://docs.rs/rayon/1.2.0/rayon/slice/trait.ParallelSliceM...
  - foota 7y ago
    That's really cool, thanks for sharing!
  - kzrdude 7y ago
    And rust ndarray implements strided mutable "slices" too, interleaved.
spooneybarger 7y ago
Similar goals, very different implementation. The goal is memory safety, but rust has the borrow checker which is rather different than reference capabilities.
nickpsecurity 7y ago
They told me Rust uses affine types (i.e. its move semantics). Clay language (see Lea Wittie et al) used linear and singleton types. Pony has reference capabilities. http://jtfmumm.com/blog/2016/03/06/safely-sharing-data-pony-reference-capabilities/ http://jtfmumm.com/blog/2016/03/06/safely-sharing-data-pony-...