Add or_insert_with_key to Entry of HashMap/BTreeMap #70996
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Going along with or_insert_with, or_insert_with_key provides the Entry's key to the lambda, avoiding the need to either clone the key or the need to reimplement this body of this method from scratch each time. This is useful when the initial value for a map entry is derived from the key. For example, the introductory Rust book has an example Cacher struct that takes an expensive-to-compute lambda and then can, given an argument to the lambda, produce either the cached result or execute the lambda.
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Add or_insert_with_key to Entry of HashMap Going along with `or_insert_with`, `or_insert_with_key` provides the `Entry`'s key to the lambda, avoiding the need to either clone the key or the need to reimplement this body of this method from scratch each time. This is useful when the initial value for a map entry is derived from the key. For example, the introductory Rust book has an example Cacher struct that takes an expensive-to-compute lambda and then can, given an argument to the lambda, produce either the cached result or execute the lambda. --- This is modified from rust-lang/rust#70996 and intended to sync the APIs of `std` and `hashbrown`.
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@bors r+ rollup |
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Add or_insert_with_key to Entry of HashMap Going along with `or_insert_with`, `or_insert_with_key` provides the `Entry`'s key to the lambda, avoiding the need to either clone the key or the need to reimplement this body of this method from scratch each time. This is useful when the initial value for a map entry is derived from the key. For example, the introductory Rust book has an example Cacher struct that takes an expensive-to-compute lambda and then can, given an argument to the lambda, produce either the cached result or execute the lambda. --- This is modified from rust-lang/rust#70996 and intended to sync the APIs of `std` and `hashbrown`.
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Add or_insert_with_key to Entry of HashMap/BTreeMap Going along with `or_insert_with`, `or_insert_with_key` provides the `Entry`'s key to the lambda, avoiding the need to either clone the key or the need to reimplement this body of this method from scratch each time. This is useful when the initial value for a map entry is derived from the key. For example, the introductory Rust book has an example Cacher struct that takes an expensive-to-compute lambda and then can, given an argument to the lambda, produce either the cached result or execute the lambda. --- I'm fairly new to Rust, so any optimizations, corrections to types, better names, better documentation, or whatever else would be appreciated. I'd like to thank Arnavion on freenode for helping me to implement a very similar method when I found that `or_insert_with_key` was unavailable. As a somewhat-related note, this implements rust-lang/rfcs#1202 from 2015, so if this pull request is accepted, that should be closed.
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Add or_insert_with_key to Entry of HashMap Going along with `or_insert_with`, `or_insert_with_key` provides the `Entry`'s key to the lambda, avoiding the need to either clone the key or the need to reimplement this body of this method from scratch each time. This is useful when the initial value for a map entry is derived from the key. For example, the introductory Rust book has an example Cacher struct that takes an expensive-to-compute lambda and then can, given an argument to the lambda, produce either the cached result or execute the lambda. --- This is modified from rust-lang/rust#70996 and intended to sync the APIs of `std` and `hashbrown`.
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Rollup of 5 pull requests Successful merges: - rust-lang#70644 (Clean up `ModuleConfig` initialization) - rust-lang#70937 (Fix staticlib name for *-pc-windows-gnu targets) - rust-lang#70996 (Add or_insert_with_key to Entry of HashMap/BTreeMap) - rust-lang#71020 (Store UNICODE_VERSION as a tuple) - rust-lang#71021 (Use write!-style syntax for MIR assert terminator) Failed merges: r? @ghost
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Going along with
or_insert_with,or_insert_with_keyprovides theEntry's key to the lambda, avoiding the need to either clone the key or the need to reimplement this body of this method from scratch each time.This is useful when the initial value for a map entry is derived from the key. For example, the introductory Rust book has an example Cacher struct that takes an expensive-to-compute lambda and then can, given an argument to the lambda, produce either the cached result or execute the lambda.
I'm fairly new to Rust, so any optimizations, corrections to types, better names, better documentation, or whatever else would be appreciated. I'd like to thank Arnavion on freenode for helping me to implement a very similar method when I found that
or_insert_with_keywas unavailable.As a somewhat-related note, this implements rust-lang/rfcs#1202 from 2015, so if this pull request is accepted, that should be closed.