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kennytm
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Add Cell::update This commit adds a new method `Cell::update`, which applies a function to the value inside the cell. Previously discussed in: https://github.com/rust-lang/rfcs/issues/2171 ### Motivation Updating `Cell`s is currently a bit verbose. Here are several real examples (taken from rustc and crossbeam): ```rust self.print_fuel.set(self.print_fuel.get() + 1); self.diverges.set(self.diverges.get() | Diverges::Always); let guard_count = self.guard_count.get(); self.guard_count.set(guard_count.checked_add(1).unwrap()); if guard_count == 0 { // ... } ``` With the addition of the new method `Cell::update`, this code can be simplified to: ```rust self.print_fuel.update(|x| x + 1); self.diverges.update(|x| x | Diverges::Always); if self.guard_count.update(|x| x.checked_add(1).unwrap()) == 1 { // ... } ``` ### Unresolved questions 1. Should we return the old value instead of the new value (like in `fetch_add` and `fetch_update`)? 2. Should the return type simply be `()`? 3. Naming: `update` vs `modify` vs `mutate` etc. cc @SimonSapin
This directory contains the source code of the rust project, including:
rustcand its testslibstd- Various submodules for tools, like rustdoc, rls, etc.
For more information on how various parts of the compiler work, see the rustc guide.
Their is also useful content in the following READMEs, which are gradually being moved over to the guide:
- https://github.com/rust-lang/rust/tree/master/src/librustc/ty/maps
- https://github.com/rust-lang/rust/tree/master/src/librustc/dep_graph
- https://github.com/rust-lang/rust/blob/master/src/librustc/infer/region_constraints
- https://github.com/rust-lang/rust/tree/master/src/librustc/infer/higher_ranked
- https://github.com/rust-lang/rust/tree/master/src/librustc/infer/lexical_region_resolve