| ▲ | lorenzleutgeb 5 hours ago | |
What is the data you actually store when caching a successful test run? Do you store the hash of the expression which is the test, and a value with a semantics of "passed". Or do you have a way to hash all values (not expressions/AST!) that Unison can produce? I am asking because if you also have a way to cache all values, this might allow to carry some of Unison's nice properties a little further. Say I implement a compiler in Unison, I end up with an expression that has a free variable, which carries the source code of the program I am compiling. Now, I could take the hash of the expression, the hash of the term that represents the source code, i.e., what the variable in my compiler binds to, and the hash of the output. Would be very neat for reproducibility, similar to content-addressed derivations in Nix, and extensible to distributed reproducibility like Trustix. I guess you'll be inclined to say that this is out of scope for your caching, because your caching would only cache results of expressions where all variables are bound (at the top level, evaluating down). And you would be right. But the point is to bridge to the outside of Unison, at runtime, and make this just easy to do with Unison. Feel free to just point me at material to read, I am completely new to this language and it might be obvious to you... | ||
| ▲ | pchiusano 4 hours ago | parent | next [-] | |
Yes, we have a way of hashing literally all values in the language, including arbitrary data types, functions, continuations, etc. For instance, here, I'm hashing a lambda function:[1] We only do this caching for pure tests (which are deterministic and don't need to be re-run over and over), enforced by the type system. You can have regular I/O tests as well, and these are run every time. Projects typically have a mix of both kinds of tests. It is true that you can only hash things which are "closed" / have no free variables. You might instead hash a function which takes its free variables as parameters. Overall I think Unison would be a nice implementation language for really anything that needs to make interesting use of hashing, since it's just there and always available. [1]: https://share.unison-lang.org/@unison/base/code/releases/7.4... [2]: https://share.unison-lang.org/@unison/base/code/releases/7.4... | ||
| ▲ | aryairani an hour ago | parent | prev [-] | |
(All Unison values can also be decompiled into an AST anyway.) | ||