# Enum proc_macro::TokenTree

1.29.0 · source ·

    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§

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### Group(Group)

A token stream surrounded by bracket delimiters.

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### Ident(Ident)

An identifier.

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### Punct(Punct)

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

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### 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
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#### 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
1.30.0 · source§

### impl Extend<TokenTree> for TokenStream

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#### fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, trees: 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` #72631)
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` #72631)
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

Creates a token stream containing a single token tree.

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#### fn from(tree: TokenTree) -> TokenStream

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>>(trees: I) -> Self

Creates a value from an iterator. Read more
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### impl !Send for TokenTree

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### impl !Sync for TokenTree

## Auto Trait Implementations§

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### impl RefUnwindSafe for TokenTree

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### impl Unpin for TokenTree

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### impl UnwindSafe for TokenTree

## 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,

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

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

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#### 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

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#### fn from(t: T) -> T

Returns the argument unchanged.

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

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#### 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 Twhere T: Clone,

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#### 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 Twhere 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 Twhere U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### 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.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.