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Comment by neuland | Hacker News Reader

It's cool to see another type checker! I haven't had any big issues with MyPy, but competition is good in a healthy ecosystem.

The language server / editor integrations are an interesting goal and that seems to be why they have the watchman stuff in there.

I was initially kinda put off by that, as tools that watch for file events never end up working for me because I save like every 10 seconds.

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You can run Pyre without using watchman if your editor-of-choice supports LSP -- the two modes are basically complementary. You can also run `pyre check` in non-incremental mode, though that may be slower depending on the size of your codebase.

So you're saying the LSP portion checks the file(s) you're currently editing, whereas the watchman (also incremental) check or the non-incremental check do the whole project?

Edit: for the active file / LSP part, I mean it shows errors mainly for the active file.

Exactly - the LSP portion of pyre works for files you have open in an editor, but might miss changes due to a rebase or files you edit on the terminal. The watchman integration is there to make sure that pyre's aware of changes outside your editor.

Edit: pyre will show type errors for all files in your repository, not just the ones you have open.

Ah, that's nice. So you can change the type of a function in one file that you are editing, and pyre will show you all the other places that are now using the wrong types.

Someone should do a proper analysis of MyPy vs PyType vs Pyre. What features they support, how fast they run, what tooling there is around it, etc. But yeah, competition is definitely nice, as it'll lead it innovation and hopefully cross-project inspiration. All 3 are open-source so that's awesome.

Interesting - I also save very frequently (Cmd+S every few characters), and I think watchman is the first piece of software that has allowed me to work on a large remote folder seamlessly (I use it through Nuclide). I tried various options before that (using vim or emacs directly on the remote server, mounting the remote drive in various ways, etc). None of them come even close in my experience (slow sync, disconnects, etc).

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