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Nice! I do still wish we had holes in Rust… would be super nice for the match arms/patterns ; _ ;
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Yeah, that's what I do - feels a bit hacky though, and can't really put them in patterns. Also can't use them interactively for case splitting etc. like in Agda, Idris, Haskell, etc.
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Like, it's a tad annoying when rust analyzer has to generate code that doesn't type check or even parse 😢
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One example is function completion, where it inserts a function call with argument names pulled from the parameters (which may not exist in scope). It would be super nice if it inserted a function call with a bunch of holes that you could jump to and fill interactively… 😅
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I personally disable this feature (`"rust-analyzer.completion.addCallArgumentSnippets": false`), as find it more distracting than useful. Parameter info popup and completion, if done right, should work just as good as holes.
Sadly, param info in code is
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Hmm, still seems like it generates broken code though? Like, it produces:
make::use_item(make::use_tree())
rather than something like:
make::use_item(make::use_tree({! !}, {! !}, {! !}))
Same goes for `match`, where this stuff becomes even more useful!
I mean, the proposal still seems like an improvement, but it would be neat to see more support for manipulating unfinished code. `todo!()` works sometimes, but it's limited in where it can be used, and can't be manipulated and jumped to in the editor.
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Oh, not to mention, it's also super handy to have a list of holes with their types that you can use to keep track of what you need to finish! That's one of the things I don't get from `todo!()`.
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Sure, the code is broken, but I don't think that by itself this means worse UX. If the ide highlights the error, provides type-driven completions for arguments, and shows popup with expected parameter types/names/docs, then I think the UX would be as nice.
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I guess I think it'd be really nice to be able to run the incomplete code, providing warnings at edit/compile time, and then panicking if the incomplete code is encountered at runtime. That way you can leave code incomplete, then come back to it later more smoothly.
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>Same goes for `match`, where this stuff becomes even more useful!
For match actually, I feel like `_` can play a syntactic role of a hole? "Split _" 💡is totally doable (but is not implemented yet).
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Yeah, Purescript and Haskell use `_` for holes, but you can name them, which lets you distinguish them in error messages/editor support: downloads.haskell.org/~ghc/7.10.1/do
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