Enum Spacing

pub enum Spacing {
    Joint,
    Alone,
}

Indicates whether a Punct token can join with the following token to form a multi-character operator.

Variants

Joint

A Punct token can join with the following token to form a multi-character operator.

In token streams constructed using proc macro interfaces, Joint punctuation tokens can be followed by any other tokens. However, in token streams parsed from source code, the compiler will only set spacing to Joint in the following cases.

• When a Punct is immediately followed by another Punct without a whitespace. E.g. + is Joint in += and ++.
• When a single quote ' is immediately followed by an identifier without a whitespace. E.g. ' is Joint in 'lifetime.

This list may be extended in the future to enable more token combinations.

Alone

A Punct token cannot join with the following token to form a multi-character operator.

Alone punctuation tokens can be followed by any other tokens. In token streams parsed from source code, the compiler will set spacing to Alone in all cases not covered by the conditions for Joint above. E.g. + is Alone in + =, +ident and +(). In particular, tokens not followed by anything will be marked as Alone.

Trait Implementations

impl Clone for Spacing

fn clone(&self) -> Spacing

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Spacing

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

Formats the value using the given formatter.

impl<'a, S> DecodeMut<'a, '_, S> for Spacing

fn decode(r: &mut &'a [u8], s: &mut S) -> Self

🔬This is a nightly-only experimental API. (proc_macro_internals #27812)

impl<S> Encode<S> for Spacing

fn encode(self, w: &mut Buffer, s: &mut S)

🔬This is a nightly-only experimental API. (proc_macro_internals #27812)

impl Eq for Spacing

#[doc(hidden)] fn assert_receiver_is_total_eq(&self)

impl Mark for Spacing

type Unmarked = Spacing

🔬This is a nightly-only experimental API. (proc_macro_internals #27812)

fn mark(unmarked: Self::Unmarked) -> Self

🔬This is a nightly-only experimental API. (proc_macro_internals #27812)

impl PartialEq for Spacing

fn eq(&self, other: &Spacing) -> 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 Unmark for Spacing

type Unmarked = Spacing

🔬This is a nightly-only experimental API. (proc_macro_internals #27812)

fn unmark(self) -> Self::Unmarked

🔬This is a nightly-only experimental API. (proc_macro_internals #27812)

impl Copy for Spacing

impl StructuralPartialEq for Spacing