Naming Conventions

Rust prefers snake case for variables and functions, so a function or method would be called read_str instead of readStr. For structs, traits and enums, camel case is used, for example HttpClient.

Name your Functions, Types, etc. (Naming Conventions)

Rust follows specific naming conventions to maintain consistency and readability in code. Here are some key guidelines:

• Crates: Use lowercase with underscores (snake_case), avoiding -rs or -rust suffixes. Prefer a single word.
• Modules: Use snake_case for module names.
• Types & Traits: Use UpperCamelCase (e.g., MyStruct, MyTrait).
• Enum Variants: Use UpperCamelCase (e.g., MyEnum::VariantName).
• Functions & Methods: Use snake_case (e.g., my_function()).
  • General constructors: Use new or with_more_details.
  • Conversion constructors: Use from_some_other_type.
• Local Variables: Use snake_case (e.g., my_variable).
• Macros: Use snake_case!.
• Constants & Statics: Use SCREAMING_SNAKE_CASE (e.g., MY_CONSTANT).
• Type Parameters: Use concise UpperCamelCase, usually a single uppercase letter (T, U, etc.). Use more descriptive names like ItemType only when clarity is needed.
• Lifetimes: Use short lowercase names, usually a single letter ('a, 'b, 'de, 'src).

In UpperCamelCase, acronyms and contractions of compound words count as one word: use Uuid rather than UUID, Usize rather than USize or Stdin rather than StdIn. In snake_case, acronyms are lower-cased: is_xid_start. In UpperCamelCase names multiple numbers can be separated by a _ for clarity: Windows10_1709 instead of Windows101709.

In snake_case or SCREAMING_SNAKE_CASE, a "word" should never consist of a single letter unless it is the last "word". So, we have btree_map rather than b_tree_map, but PI_2 rather than PI2.

Decide Between as_* vs to_* vs into_* for Conversion Methods

Conversions should be provided as methods, with names prefixed as follows:

Examples:

• str::as_bytes() gives a view of a str as a slice of UTF-8 bytes, which is free. The input is a borrowed &str and the output is a borrowed &[u8].
• Path::to_str performs an expensive UTF-8 check on the bytes of an operating system path. The input and output are both borrowed. It would not be correct to call this as_str because this method has nontrivial cost at runtime.
• str::to_lowercase() produces the Unicode-correct lowercase equivalent of a str, which involves iterating through characters of the string and may require memory allocation. The input is a borrowed &str and the output is an owned String.

When a type wraps a single value to associate it with higher-level semantics, access to the wrapped value should be provided by an into_inner() method. This applies to wrappers that provide buffering like BufReader, encoding or decoding like GzDecoder, atomic access like AtomicBool, or any similar semantics.

Name Getters

With a few exceptions, the get_ prefix is not used for getters in Rust code. Follow the field name by _mut for mutating getters.

pub struct S {
    first: First,
}

impl S {
    // Not `get_first`.
    pub fn first(&self) -> &First {
        &self.first
    }

    // Not `get_first_mut`, `get_mut_first`, or `mut_first`.
    pub fn first_mut(&mut self) -> &mut First {
        &mut self.first
    }
}

For getters that do runtime validation such as bounds checking, consider adding unsafe _unchecked variants.

Name Iterators

For a container with elements of type U, iterator methods should be named:

fn iter(&self) -> Iter             // The `Iter` struct implements `Iterator<Item = &U>`.
fn iter_mut(&mut self) -> IterMut  // `IterMut` implements `Iterator<Item = &mut U>`.
fn into_iter(self) -> IntoIter     // `IntoIter` implements `Iterator<Item = U>`.

References

The above is adapted from:

• Rust API Guidelines: Naming↗.
• RFC430↗.
• RFC199↗.

Related Topics

• Constants and Statics.
• Functions.
• Language.
• Macros.
• Modules and Paths.
• Traits.
• Variables.