Crate generic_mutability

This crate enables the creation of functions, methods, traits or even structs generic over mutability.

The main use case is allowing crates to write pairs of getter functions of the form

fn get<'a>(&'a T, ...) -> &'a U
fn get_mut<'a>(&'a mut T, ...) -> &'a mut U

as a single function

fn get_gen<'a, M: Mutability>(GenRef<'a, M, T>, ...) -> GenRef<'a, M, U>

The main items of this crate are the GenRef struct, which represents a safe reference (like & and &mut) that is generic over mutability; and the Mutability trait, which is used as a bound on generic mutability parameters.

Macros

field

Maps a GenRef over field access and indexing.

gen_mut

This macro simplifies the implementation of generically mutable APIs, where the mutable and the shared code paths are (mostly) identical. It has the following syntax:

Structs

GenRef

This is the main type of this crate. It is the generic-mutability equivalent of safe reference types (& and &mut).

IsMutable

The existence of a value of this type guarantees that a specific mutability parameter M is Mutable. Unsafe code may rely on this guarantee. You can obtain this value by matching over M::mutability().

IsShared

The existence of a value of this type guarantees that a specific mutability parameter M is Shared. Unsafe code may rely on this guarantee. You can obtain this value by matching over M::mutability().

Enums

MutabilityEnum

This enum makes it possible to match over a mutability parameter. Not to be confused with the Mutability trait, which is used as a bound for mutability parameters; and Shared and Mutable, which are values of the mutability parameters.

Mutable

Represents the mutability of a mutable (unique) reference, &mut T.

Shared

Represents the mutability of a shared reference, &T.

Traits

GenRefMethods

This trait allows you to call associated functions of GenRef with method syntax.

Mutability

This trait is used as a bound on generic mutability parameters.