feat(stdlib): Add user-friendly file system module

[alex-snezhko]

Add a file system module that is more high-level and user-friendly than the current sys/file

Closes #211

[spotandjake]

The code looks good to me, Most of my comments were related to graindoc.

Two other things:

• Currently the sys/ path is used for more low level wasi interactions. I think we should either move these wasi interactions elsewhere or put this module elsewhere.
• Are we currently able to add some better streaming functions such as File.open, File.readLine and File.close?

[ospencer]

Overall, I love the API design! My major piece of feedback here is that I don't think this module belongs in the sys subdirectory, but in the regular stdlib folder. The sys folder was really just meant for the low-level wasi stuff (and probably should have been named just wasi).

I envision that moving forward to Preview 2, the wasi folder will just have the generated bindings to each of the wasi standards, and we'll have high-level libraries in the regular standard library. We can note in the module doc that use of that library incurs a dependency on a particular wasi world. For now, we can say that use of the module requires WASI Preview 1.

[marcusroberts]

I read all the way through and didn't spot anything, looks like a nice usable interface too.

[spotandjake]

Overall, I love the API design! My major piece of feedback here is that I don't think this module belongs in the sys subdirectory, but in the regular stdlib folder. The sys folder was really just meant for the low-level wasi stuff (and probably should have been named just wasi).

I envision that moving forward to Preview 2, the wasi folder will just have the generated bindings to each of the wasi standards, and we'll have high-level libraries in the regular standard library. We can note in the module doc that use of that library incurs a dependency on a particular wasi world. For now, we can say that use of the module requires WASI Preview 1.

Thoughts on maybe in 0.6 we rename the sys folder to wasi and keep it in the sys subdirectory? I do kind of like the separation especially when considering grain for web development or embedded development where you would not have file system access.

[ospencer]

Thoughts on maybe in 0.6 we rename the sys folder to wasi and keep it in the sys subdirectory? I do kind of like the separation especially when considering grain for web development or embedded development where you would not have file system access.

We did make that rename happen. I do see a world in which it makes sense to still have this separated, though in environments where you're not allowed a filesystem or otherwise, WASI makes it pretty easy to virtualize.

[ospencer]

@alex-snezhko Do you mind rebasing this?

[alex-snezhko]

@ospencer rebased

[spotandjake]

Everything looks great, I've been using this library for months locally and haven't run into a single problem.

Should we provide a Utf8.readLine? in cases with big files having a streamed api seems helpful, maybe this is a future addition when we have scoped resouces so the user doesn't need to worry about File.open and File.close.

[alex-snezhko]

I was thinking we could build out a more comprehensive streaming API in the future, I feel like there are a few different directions we could go

[ospencer]

I think this should be called createSymlink.

[alex-snezhko]

Ok going to rename makeDir to createDir as well for consistency