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rust-analyzer / rowan

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[question] Line/column information #17

Closed suhr closed 5 years ago

suhr commented 5 years ago

It seems like SyntaxNode only has TextRange which contains only infomation about absolute offsets. But how do you handle line/column ranges (necessary for printing errors)?

matklad commented 5 years ago

In rust-analyzer, we maintain a separate index to translate utf8-offsets into (invalid) utf-16 line/column as per LSP:

https://github.com/rust-analyzer/rust-analyzer/blob/fcdb387f0d7e76f325a858e4463efd5d7ed3efc3/crates/ra_ide_api/src/line_index.rs https://github.com/rust-analyzer/rust-analyzer/blob/fcdb387f0d7e76f325a858e4463efd5d7ed3efc3/crates/ra_ide_api/src/db.rs#L61-L68

suhr commented 5 years ago

A separate index sounds somewhat inconvenient. By the way, why UTF-16?

matklad commented 5 years ago

By the way, why UTF-16?

LSP requires UTF-16

This is actually one of the main reasons why a separate index makes sense: there's no universal definition of line/column: for some editors it is UTF-16 codepoints (VS Code), for some it is Unicode Characters (Emacs), and I bet for others it could be grapheme clusters as well.

shilangyu commented 1 year ago

FYI: thanks to @azdavis line-index has been extracted to a crate, so you can use it directly.