# Enum proc_macro2::TokenTree

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    pub enum TokenTree {
        Group(Group),
        Ident(Ident),
        Punct(Punct),
        Literal(Literal),
    }

Expand description

A single token or a delimited sequence of token trees (e.g. `[1, (), ..]`).

## Variants

### `Group(Group)`

A token stream surrounded by bracket delimiters.

### `Ident(Ident)`

An identifier.

### `Punct(Punct)`

A single punctuation character (`+`, `,`, `$`, etc.).

### `Literal(Literal)`

A literal character (`'a'`), string (`"hello"`), number (`2.3`), etc.

## Implementations

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### impl TokenTree

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#### pub fn span(&self) -> Span

Returns the span of this tree, delegating to the `span` method of the contained token or a delimited stream.

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#### pub fn set_span(&mut self, span: Span)

Configures the span for only this token.

Note that if this token is a `Group` then this method will not configure the span of each of the internal tokens, this will simply delegate to the `set_span` method of each variant.

## Trait Implementations

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### impl Clone for TokenTree

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#### fn clone(&self) -> TokenTree

Returns a copy of the value. Read more

1.0.0 · source

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

Performs copy-assignment from `source`. Read more

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### impl Debug for TokenTree

Prints token tree in a form convenient for debugging.

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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 Display for TokenTree

Prints the token tree as a string that is supposed to be losslessly convertible back into the same token tree (modulo spans), except for possibly `TokenTree::Group`s with `Delimiter::None` delimiters and negative numeric literals.

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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 Extend<TokenTree> for TokenStream

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#### fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, streams: I)

Extends a collection with the contents of an iterator. Read more

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#### fn extend_one(&mut self, item: A)

🔬 This is a nightly-only experimental API. (`extend_one`)

Extends a collection with exactly one element.

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#### fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (`extend_one`)

Reserves capacity in a collection for the given number of additional elements. Read more

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### impl From<Group> for TokenTree

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#### fn from(g: Group) -> TokenTree

Converts to this type from the input type.

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### impl From<Ident> for TokenTree

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#### fn from(g: Ident) -> TokenTree

Converts to this type from the input type.

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### impl From<Literal> for TokenTree

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#### fn from(g: Literal) -> TokenTree

Converts to this type from the input type.

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### impl From<Punct> for TokenTree

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#### fn from(g: Punct) -> TokenTree

Converts to this type from the input type.

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### impl From<TokenTree> for TokenStream

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#### fn from(token: TokenTree) -> Self

Converts to this type from the input type.

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### impl FromIterator<TokenTree> for TokenStream

Collects a number of token trees into a single stream.

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#### fn from_iter<I: IntoIterator<Item = TokenTree>>(streams: I) -> Self

Creates a value from an iterator. Read more

## Auto Trait Implementations

### impl RefUnwindSafe for TokenTree

### impl !Send for TokenTree

### impl !Sync for TokenTree

### impl Unpin for TokenTree

### impl UnwindSafe for TokenTree

## Blanket Implementations

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### impl<T> Any for T where
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 T where
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 T where
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 T where
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> ToOwned for T where
T: Clone,

#### type Owned = T

The resulting type after obtaining ownership.

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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more

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#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more

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### impl<T> ToString for T where
T: Display + ?Sized,

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#### default fn to_string(&self) -> String

Converts the given value to a `String`. Read more

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### impl<T, U> TryFrom<U> for T where
U: Into<T>,

#### 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 T where
U: TryFrom<T>,

#### 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.