alt Hacker NewsIt looks like it only partially reindexes on save, but it completely reindexes the single file that’s saved, rather than doing partial reindex of the file on every keystroke like rust-analyser.
But importantly it’s not reindexing the entire project, which is the expensive operation. So you have higher peak RAM when opening a brand new project, but much lower RAM usage while working on the project.
Exactly. You pay higher RAM usage price once, for 5-30 seconds at the very beginning of the project (or if you make changes that invalidate the dependency graph, which is rather rare). In 95% of cases and 99.999% of idle time using the editor, you enjoy lower RAM usage.
And note that on dirty buffers Rust Glancer doesn't do reindexing at all: it reuses the last available analysis, plus it does syntax-based shallow overlay that is sufficient to be useful but doesn't necessarily detect semantic changes. It's a tradeoff, but this tradeoff makes Rust Glancer competitive in terms of latency with rust-analyzer without compromising RAM and while keeping your CPU cool.
> it completely reindexes the single file that’s saved
This is true, though I have to mention that change in the file might invalidate its reverse dependencies, which can make the partial analysis bigger than just one file/crate, but it's still very fast in practice.