Reference
An immutable Rust reference is a non-owning borrow that provides read-only access to a value without taking ownership of it.
Learn Rust in a Month of Lunches
An immutable reference is a Rust reference through which the referent cannot be modified and which can coexist with other immutable references.
- How it is used
- Uses immutable references to let multiple parts of a program view shared data without modifying it.
- How deep it goes
- Explains sharing rules, mixed-borrow errors, and compiler reasoning about when a mutable borrow ends.
- Examples
- Uses a presentation analogy, a shared-viewer scenario, and Rust code that triggers and then avoids a borrow conflict.
- What you can do after
- Evaluate borrow arrangements and reorder operations to avoid conflicting mutable and immutable references.
Read how Learn Rust in a Month of Lunches explains reference →
Refactoring to Rust
An immutable reference is a Rust non-owning reference that permits access to a value without modifying it through that reference.
- How it is used
- Uses borrowing to let functions inspect values without taking ownership or repeatedly creating and destroying them.
- How deep it goes
- Explains &T, borrowing rules, scope, and the contrast with &mut T through small artwork programs.
- Examples
- Demonstrates repeated artwork admiration and contrasts it with a mutable view counter.
- What you can do after
- Apply immutable references by changing owned parameters to &T and passing borrowed values without moving them.
Code Like a Pro in Rust
An immutable reference is a read-only reference through which the referenced value cannot be modified.
- How it is used
- Uses immutable references for shared read-only access while enforcing memory safety at compile time.
- How deep it goes
- Explains reference exclusivity, scope checking, and copy-related signatures, stopping short of exhaustive language-reference treatment.
- Examples
- Demonstrates string slices, lowercase conversion, owned strings, and in-place ASCII mutation.
- What you can do after
- Diagnose likely copying and mutation behavior by reading Rust function inputs and outputs, then verify uncertain cases in source.
Related concepts
- mutable referencecontrasts with · A mutable reference is a reference or handle through which the referenced value or storage location may be modified, subject to language-specific access rules.
- referencekind of · A reference is an indirect value or relationship that identifies or provides access to another value, object, resource, or source.
- copycontrasts with · Copying is the creation of a separate representation of an existing value, object, or data, preserving some or all of its contents or state.
- immutable collectioncontrasts with · An immutable collection is a collection whose membership and contents cannot be changed after creation.
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