enum TokenTree {
    Token(Token),
    Delimited(DelimSpanDelimited),
    Sequence(DelimSpanSequenceRepetition),
    MetaVar(SpanIdent),
    MetaVarDecl(SpanIdentOption<NonterminalKind>),
    MetaVarExpr(DelimSpanMetaVarExpr),
}
Expand description

Similar to tokenstream::TokenTree, except that Sequence, MetaVar, MetaVarDecl, and MetaVarExpr are “first-class” token trees. Useful for parsing macros.

Variants§

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Token(Token)

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Delimited(DelimSpanDelimited)

A delimited sequence, e.g. ($e:expr) (RHS) or { $e } (LHS).

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Sequence(DelimSpanSequenceRepetition)

A kleene-style repetition sequence, e.g. $($e:expr)* (RHS) or $($e),* (LHS).

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MetaVar(SpanIdent)

e.g., $var.

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MetaVarDecl(SpanIdentOption<NonterminalKind>)

e.g., $var:expr. Only appears on the LHS.

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MetaVarExpr(DelimSpanMetaVarExpr)

A meta-variable expression inside ${...}.

Implementations§

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impl TokenTree

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fn is_delimited(&self) -> bool

Returns true if the given token tree is delimited.

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fn is_token(&self, expected_kind: &TokenKind) -> bool

Returns true if the given token tree is a token of the given kind.

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fn span(&self) -> Span

Retrieves the TokenTree’s span.

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fn token(kind: TokenKind, span: Span) -> TokenTree

Trait Implementations§

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impl Debug for TokenTree

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

Formats the value using the given formatter. Read more
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impl<__D: Decoder> Decodable<__D> for TokenTree

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fn decode(__decoder: &mut __D) -> Self

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impl<__E: Encoder> Encodable<__E> for TokenTree

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fn encode(&self, __encoder: &mut __E)

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impl PartialEq<TokenTree> for TokenTree

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

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl StructuralPartialEq for TokenTree

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for Twhere
    T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere
    T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere
    T: ?Sized,

const: unstable · source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere
    U: From<T>,

const: unstable · source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for Twhere
    U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
const: unstable · source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere
    U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
const: unstable · source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.

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: 88 bytes

Size for each variant:

  • Token: 24 bytes
  • Delimited: 48 bytes
  • Sequence: 88 bytes
  • MetaVar: 20 bytes
  • MetaVarDecl: 24 bytes
  • MetaVarExpr: 48 bytes