Enum proc_macro2::Delimiter

pub enum Delimiter {
    Parenthesis,
    Brace,
    Bracket,
    None,
}

Describes how a sequence of token trees is delimited.

Variants

Parenthesis

( ... )

Brace

{ ... }

Bracket

[ ... ]

None

∅ ... ∅

An invisible delimiter, that may, for example, appear around tokens coming from a “macro variable” $var. It is important to preserve operator priorities in cases like $var * 3 where $var is 1 + 2. Invisible delimiters may not survive roundtrip of a token stream through a string.

Note: rustc currently can ignore the grouping of tokens delimited by None in the output of a proc_macro. Only None-delimited groups created by a macro_rules macro in the input of a proc_macro macro are preserved, and only in very specific circumstances. Any None-delimited groups (re)created by a proc_macro will therefore not preserve operator priorities as indicated above. The other Delimiter variants should be used instead in this context. This is a rustc bug. For details, see rust-lang/rust#67062.

Trait Implementations

impl Clone for Delimiter

fn clone(&self) -> Delimiter

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Delimiter

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for Delimiter

fn eq(&self, other: &Delimiter) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Delimiter

impl Eq for Delimiter

impl StructuralPartialEq for Delimiter

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 1 byte

Size for each variant:

• Parenthesis: 0 bytes
• Brace: 0 bytes
• Bracket: 0 bytes
• None: 0 bytes