Struct syn::parse::StepCursor
source · [−]pub struct StepCursor<'c, 'a> { /* private fields */ }
Expand description
Cursor state associated with speculative parsing.
This type is the input of the closure provided to ParseStream::step
.
Example
use proc_macro2::TokenTree;
use syn::Result;
use syn::parse::ParseStream;
// This function advances the stream past the next occurrence of `@`. If
// no `@` is present in the stream, the stream position is unchanged and
// an error is returned.
fn skip_past_next_at(input: ParseStream) -> Result<()> {
input.step(|cursor| {
let mut rest = *cursor;
while let Some((tt, next)) = rest.token_tree() {
match &tt {
TokenTree::Punct(punct) if punct.as_char() == '@' => {
return Ok(((), next));
}
_ => rest = next,
}
}
Err(cursor.error("no `@` was found after this point"))
})
}
Implementations
Trait Implementations
sourceimpl<'c, 'a> Clone for StepCursor<'c, 'a>
impl<'c, 'a> Clone for StepCursor<'c, 'a>
sourceimpl<'c, 'a> Deref for StepCursor<'c, 'a>
impl<'c, 'a> Deref for StepCursor<'c, 'a>
impl<'c, 'a> Copy for StepCursor<'c, 'a>
Auto Trait Implementations
impl<'c, 'a> RefUnwindSafe for StepCursor<'c, 'a>
impl<'c, 'a> !Send for StepCursor<'c, 'a>
impl<'c, 'a> !Sync for StepCursor<'c, 'a>
impl<'c, 'a> Unpin for StepCursor<'c, 'a>
impl<'c, 'a> UnwindSafe for StepCursor<'c, 'a>
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<T> ToOwned for T where
T: Clone,
impl<T> ToOwned for T where
T: Clone,
type Owned = T
type Owned = T
The resulting type after obtaining ownership.
sourcefn clone_into(&self, target: &mut T)
fn clone_into(&self, target: &mut T)
🔬 This is a nightly-only experimental API. (
toowned_clone_into
)Uses borrowed data to replace owned data, usually by cloning. Read more