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
1.21.0 · sourcefn max(self, other: Self) -> Self
fn max(self, other: Self) -> Self
Compares and returns the maximum of two values. Read more
1.21.0 · sourcefn min(self, other: Self) -> Self
fn min(self, other: Self) -> Self
Compares and returns the minimum of two values. Read more
1.50.0 · sourcefn clamp(self, min: Self, max: Self) -> Selfwhere
Self: PartialOrd<Self>,
fn clamp(self, min: Self, max: Self) -> Selfwhere
Self: PartialOrd<Self>,
Restrict a value to a certain interval. Read more
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>
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 moresourceimpl ToTokens for NotEof
impl ToTokens for NotEof
sourcefn to_tokens(&self, _tokens: &mut TokenStream)
fn to_tokens(&self, _tokens: &mut TokenStream)
sourcefn to_token_stream(&self) -> TokenStream
fn to_token_stream(&self) -> TokenStream
sourcefn into_token_stream(self) -> TokenStream
fn into_token_stream(self) -> TokenStream
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 Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
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 Twhere
T: Spanned + ?Sized,
impl<T> Spanned for Twhere
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 moresourceimpl<T> SpannedExt for Twhere
T: Spanned + ?Sized,
impl<T> SpannedExt for Twhere
T: Spanned + ?Sized,
sourcefn byte_range(&self, source: &str) -> Range<usize>
fn byte_range(&self, source: &str) -> Range<usize>
TODO(H2CO3): a faster, less naive implementation would be great.
We should use the byte offset of start
to compute that of end
,
sparing the double scan of the source up until the start location.
let source = r#"
-3.667
1248 "string ű literal"
"wíőzs"
"#;
let tokens: Many<Lit> = source.parse()?;
assert_eq!(tokens.len(), 4);
assert_eq!(tokens[0].byte_range(source), 4..10);
assert_eq!(tokens[1].byte_range(source), 13..17);
assert_eq!(tokens[2].byte_range(source), 19..38);
assert_eq!(tokens[3].byte_range(source), 45..54);
sourcefn char_range(&self, source: &str) -> Range<usize>
fn char_range(&self, source: &str) -> Range<usize>
TODO(H2CO3): a faster, less naive implementation would be great.
We should use the char offset of start
to compute that of end
,
sparing the double scan of the source up until the start location.
let source = r#"
-3.667
1248 "string ű literal"
"wíőzs"
"#;
let tokens: Many<Lit> = source.parse()?;
assert_eq!(tokens.len(), 4);
assert_eq!(tokens[0].char_range(source), 4..10);
assert_eq!(tokens[1].char_range(source), 13..17);
assert_eq!(tokens[2].char_range(source), 19..37);
assert_eq!(tokens[3].char_range(source), 44..51);