pub struct NotEof;
Expand description
Verifies that parsing did not yet reach the end of the input (i.e., the end of the parse stream at the current level of nesting). Useful for conditionally parsing an optional production with no other obvious prefix token.
Consumes no tokens when parsed, produces no tokens when printed.
#[derive(PartialEq, Eq, Debug, Parse)]
struct SimpleBlockBody {
statement: Lit,
semicolon: Semi,
expression: Maybe<NotEof, Lit>,
}
type SimpleBlock = Brace<SimpleBlockBody>;
let actual_short: SimpleBlock = "{ 54194; }".parse()?;
let expected_short: SimpleBlock = Brace::new(
SimpleBlockBody {
statement: Lit::from(54194_u128),
semicolon: Semi::default(),
expression: Maybe::default(),
},
Span::call_site(),
);
assert_eq!(actual_short, expected_short);
let actual_long: SimpleBlock = "{ 54194; true }".parse()?;
let expected_long: SimpleBlock = Brace::new(
SimpleBlockBody {
statement: Lit::from(54194_u128),
semicolon: Semi::default(),
expression: Maybe::from(Lit::from(true)),
},
Span::call_site(),
);
assert_eq!(actual_long, expected_long);
// an empty string / token stream should trivially fail to parse as `Eof`
let bad: Result<NotEof> = "".parse();
assert!(bad.is_err());
// an empty string / token stream should trivially fail to parse as `Eof`
let bad_ws_only: Result<NotEof> = " \t\n".parse();
assert!(bad_ws_only.is_err());
Implementations
Trait Implementations
sourceimpl Ord for NotEof
impl Ord for NotEof
sourceimpl PartialOrd<NotEof> for NotEof
impl PartialOrd<NotEof> for NotEof
sourcefn partial_cmp(&self, other: &NotEof) -> Option<Ordering>
fn partial_cmp(&self, other: &NotEof) -> Option<Ordering>
This method returns an ordering between self
and other
values if one exists. Read more
1.0.0 · sourcefn lt(&self, other: &Rhs) -> bool
fn lt(&self, other: &Rhs) -> bool
This method tests less than (for self
and other
) and is used by the <
operator. Read more
1.0.0 · sourcefn le(&self, other: &Rhs) -> bool
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
sourceimpl ToTokens for NotEof
impl ToTokens for NotEof
sourcefn to_tokens(&self, _tokens: &mut TokenStream)
fn to_tokens(&self, _tokens: &mut TokenStream)
Write self
to the given TokenStream
. Read more
sourcefn to_token_stream(&self) -> TokenStream
fn to_token_stream(&self) -> TokenStream
Convert self
directly into a TokenStream
object. Read more
sourcefn into_token_stream(self) -> TokenStream
fn into_token_stream(self) -> TokenStream
Convert self
directly into a TokenStream
object. Read more
impl Copy for NotEof
impl Eq for NotEof
impl StructuralEq for NotEof
impl StructuralPartialEq for NotEof
Auto Trait Implementations
impl RefUnwindSafe for NotEof
impl Send for NotEof
impl Sync for NotEof
impl Unpin for NotEof
impl UnwindSafe for NotEof
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> Spanned for T where
T: Spanned + ?Sized,
impl<T> Spanned for T where
T: Spanned + ?Sized,
sourcefn span(&self) -> Span
fn span(&self) -> Span
Returns a Span
covering the complete contents of this syntax tree
node, or Span::call_site()
if this node is empty. Read more