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A generic framework for on-demand, incrementalized computation. Inspired by adapton, glimmer, and rustc's query system.
9eed580f51
304: entity-based salsa preview r=nikomatsakis a=nikomatsakis This PR is a squashed and updated version of my entity branch. This API is, I believe, what will become the long awaited (by me, anyway) Salsa 1.0 release. It's a complete overhaul of the Salsa API and implementation that feels a lot cleaner to me. The PR includes a tutorial and sample application (a compiler) that covers the major concepts. There is still more work needed to complete the tutorial and in particular to write up a bunch of tests (I had more tests but they were hacky so I deleted them). Right now, all the new stuff is in a pair of new crates, salsa-entity-mock and salsa-entity-macros, leaving the existing salsa intact. I would like to remove the old salsa but we have to reconcile the two and port over the tests. There is still a fair bit of work to do before we can release this new version of Salsa, but I expect a lot of it can happen after this PR is merged. The list is on #305. Co-authored-by: Niko Matsakis <niko@alum.mit.edu> |
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| calc-example/calc | ||
| components | ||
| examples | ||
| src | ||
| tests | ||
| .dir-locals.el | ||
| .gitignore | ||
| bors.toml | ||
| Cargo.toml | ||
| FAQ.md | ||
| LICENSE-APACHE | ||
| LICENSE-MIT | ||
| README.md | ||
| RELEASES.md | ||
salsa
A generic framework for on-demand, incrementalized computation.
Obligatory warning
Very much a WORK IN PROGRESS at this point. Ready for experimental use but expect frequent breaking changes.
Credits
This system is heavily inspired by adapton, glimmer, and rustc's query system. So credit goes to Eduard-Mihai Burtescu, Matthew Hammer, Yehuda Katz, and Michael Woerister.
Key idea
The key idea of salsa is that you define your program as a set of
queries. Every query is used like function K -> V that maps from
some key of type K to a value of type V. Queries come in two basic
varieties:
- Inputs: the base inputs to your system. You can change these whenever you like.
- Functions: pure functions (no side effects) that transform your inputs into other values. The results of queries is memoized to avoid recomputing them a lot. When you make changes to the inputs, we'll figure out (fairly intelligently) when we can re-use these memoized values and when we have to recompute them.
Want to learn more?
To learn more about Salsa, try one of the following:
- read the heavily commented
hello_worldexample; - check out the Salsa book;
- watch one of our videos.
Getting in touch
The bulk of the discussion happens in the issues and pull requests, but we have a zulip chat as well.