# Cursor in syn::buffer - Rust
A cheaply copyable cursor into a `TokenBuffer`.

syn::buffer

# Struct Cursor

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    pub struct Cursor<'a> { /* private fields */ }

Expand description

A cheaply copyable cursor into a `TokenBuffer`.

This cursor holds a shared reference into the immutable data which is used internally to represent a `TokenStream`, and can be efficiently manipulated and copied around.

An empty `Cursor` can be created directly, or one may create a `TokenBuffer` object and get a cursor to its first token with `begin()`.

## Implementations§

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### impl<'a> Cursor<'a>

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#### pub fn empty() -> Self

Creates a cursor referencing a static empty TokenStream.

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#### pub fn eof(self) -> bool

Checks whether the cursor is currently pointing at the end of its valid scope.

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#### pub fn ident(self) -> Option<(Ident, Cursor<'a>)>

If the cursor is pointing at a `Ident`, returns it along with a cursor pointing at the next `TokenTree`.

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#### pub fn punct(self) -> Option<(Punct, Cursor<'a>)>

If the cursor is pointing at a `Punct`, returns it along with a cursor pointing at the next `TokenTree`.

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#### pub fn literal(self) -> Option<(Literal, Cursor<'a>)>

If the cursor is pointing at a `Literal`, return it along with a cursor pointing at the next `TokenTree`.

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#### pub fn lifetime(self) -> Option<(Lifetime, Cursor<'a>)>

If the cursor is pointing at a `Lifetime`, returns it along with a cursor pointing at the next `TokenTree`.

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#### pub fn group( self, delim: Delimiter, ) -> Option<(Cursor<'a>, DelimSpan, Cursor<'a>)>

If the cursor is pointing at a `Group` with the given delimiter, returns a cursor into that group and one pointing to the next `TokenTree`.

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#### pub fn any_group(self) -> Option<(Cursor<'a>, Delimiter, DelimSpan, Cursor<'a>)>

If the cursor is pointing at a `Group`, returns a cursor into the group and one pointing to the next `TokenTree`.

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#### pub fn token_stream(self) -> TokenStream

Copies all remaining tokens visible from this cursor into a `TokenStream`.

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#### pub fn token_tree(self) -> Option<(TokenTree, Cursor<'a>)>

If the cursor is pointing at a `TokenTree`, returns it along with a cursor pointing at the next `TokenTree`.

Returns `None` if the cursor has reached the end of its stream.

This method does not treat `None`-delimited groups as transparent, and will return a `Group(None, ..)` if the cursor is looking at one.

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

Returns the `Span` of the current token, or `Span::call_site()` if this cursor points to eof.

## Trait Implementations§

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### impl<'a> Clone for Cursor<'a>

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

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<'a> PartialEq for Cursor<'a>

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

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

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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### impl<'a> PartialOrd for Cursor<'a>

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#### fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between `self` and `other` values if one exists. Read more
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#### fn lt(&self, other: &Rhs) -> bool

Tests less than (for `self` and `other`) and is used by the `<` operator. Read more
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#### fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more
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#### fn gt(&self, other: &Rhs) -> bool

Tests greater than (for `self` and `other`) and is used by the `>` operator. Read more
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#### fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more
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### impl<'a> Copy for Cursor<'a>

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### impl<'a> Eq for Cursor<'a>

## Auto Trait Implementations§

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### impl<'a> Freeze for Cursor<'a>

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### impl<'a> RefUnwindSafe for Cursor<'a>

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### impl<'a> !Send for Cursor<'a>

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### impl<'a> !Sync for Cursor<'a>

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### impl<'a> Unpin for Cursor<'a>

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### impl<'a> UnwindSafe for Cursor<'a>

## 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,

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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 T
where 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> CloneToUninit for T
where T: Clone,

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#### unsafe fn clone_to_uninit(&self, dst: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit`)
Performs copy-assignment from `self` to `dst`. 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 T
where 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 T
where 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, U> TryFrom<U> for T
where 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 T
where 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.