proc_macro::TokenTree - Rust
Description: API documentation for the Rust `TokenTree` enum in crate `proc_macro`.
Keywords: rust, rustlang, rust-lang, TokenTree

# 1.29.0[−][src]Enum proc_macro::TokenTree

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

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.

## Methods

###

`impl TokenTree`

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####

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

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

####

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

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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

###

`impl From<TokenTree> for TokenStream`

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Creates a token stream containing a single token tree.

####

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

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Performs the conversion.

###

`impl FromIterator<TokenTree> for TokenStream`

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Collects a number of token trees into a single stream.

####

`fn from_iter<I: IntoIterator<Item = TokenTree>>(trees: I) -> Self`

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Creates a value from an iterator. Read more

###

`impl Extend<TokenTree> for TokenStream`

1.30.0
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####

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

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

###

`impl Clone for TokenTree`

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####

`fn clone(&self) -> TokenTree`

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Returns a copy of the value. Read more

####

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

1.0.0
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Performs copy-assignment from `source`. Read more

###

`impl !Send for TokenTree`

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###

`impl !Sync for TokenTree`

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###

`impl Debug for TokenTree`

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Prints token treee in a form convenient for debugging.

####

`fn fmt(&self, f: &mut Formatter) -> Result`

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Formats the value using the given formatter. Read more

###

`impl From<Group> for TokenTree`

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####

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

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Performs the conversion.

###

`impl From<Ident> for TokenTree`

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####

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

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Performs the conversion.

###

`impl From<Punct> for TokenTree`

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####

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

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Performs the conversion.

###

`impl From<Literal> for TokenTree`

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####

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

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Performs the conversion.

###

`impl Display for TokenTree`

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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.

####

`fn fmt(&self, f: &mut Formatter) -> Result`

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Formats the value using the given formatter. Read more

## Blanket Implementations

###

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

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####

`fn to_string(&self) -> String`

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

###

`impl<T> ToOwned for T where T: Clone,`

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#### `type Owned = T`

####

`fn to_owned(&self) -> T`

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

####

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

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🔬 This is a nightly-only experimental API. (`toowned_clone_into` #41263)

recently added

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

###

`impl<T, U> Into for T where U: From<T>,`

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####

`fn into(self) -> U`

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Performs the conversion.

###

`impl<T> From for T`

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####

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

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Performs the conversion.

###

`impl<T, U> TryFrom for T where T: From<U>,`

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#### `type Error = !`

🔬 This is a nightly-only experimental API. (`try_from` #33417)

The type returned in the event of a conversion error.

####

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

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🔬 This is a nightly-only experimental API. (`try_from` #33417)

Performs the conversion.

###

`impl<T> Borrow for T where T: ?Sized,`

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####

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

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Immutably borrows from an owned value. Read more

###

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

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####

`fn get_type_id(&self) -> TypeId`

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🔬 This is a nightly-only experimental API. (`get_type_id` #27745)

this method will likely be replaced by an associated static

Gets the `TypeId` of `self`. Read more

###

`impl<T, U> TryInto for T where U: TryFrom<T>,`

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

🔬 This is a nightly-only experimental API. (`try_from` #33417)

The type returned in the event of a conversion error.

####

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

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🔬 This is a nightly-only experimental API. (`try_from` #33417)

Performs the conversion.

###

`impl<T> BorrowMut for T where T: ?Sized,`

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####

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

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Mutably borrows from an owned value. Read more

###

`impl<E> SpecializationError for E`

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####

`fn not_found<S, T>(trait_name: &'static str, method_name: &'static str) -> E where T: ?Sized,`

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

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via `Cargo.toml` instead?

Create an error for a missing method specialization. Defaults to panicking with type, trait & method names. `S` is the encoder/decoder state type, `T` is the type being encoded/decoded, and the arguments are the names of the trait and method that should've been overridden. Read more

###

`impl<T> Erased for T`

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###

`impl<T> Send for T where T: ?Sized,`

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###

`impl<T> Sync for T where T: ?Sized,`

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###

`impl<T> Erased for T`

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