# Struct syn::buffer::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()`.

Two cursors are equal if they have the same location in the same input stream, and have the same scope.

This type is available only if Syn is built with the `"parsing"` feature.

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

1.0.0 · source

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

Performs copy-assignment from `source`. Read more

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

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

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

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#### fn ne(&self, other: &Rhs) -> bool

This method tests for `!=`.

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

This method 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

This method 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

This method 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

This method 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

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

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

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

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

### 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,

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, 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.