[−][src]Struct syntax_pos::symbol::Symbol
A symbol is an interned or gensymed string. A gensym is a symbol that is never equal to any other symbol.
Conceptually, a gensym can be thought of as a normal symbol with an
invisible unique suffix. Gensyms are useful when creating new identifiers
that must not match any existing identifiers, e.g. during macro expansion
and syntax desugaring. Because gensyms should always be identifiers, all
gensym operations are on Ident
rather than Symbol
. (Indeed, in the
future the gensym-ness may be moved from Symbol
to hygiene data.)
Examples:
assert_eq!(Ident::from_str("x"), Ident::from_str("x")) assert_ne!(Ident::from_str("x").gensym(), Ident::from_str("x")) assert_ne!(Ident::from_str("x").gensym(), Ident::from_str("x").gensym())
Internally, a symbol is implemented as an index, and all operations
(including hashing, equality, and ordering) operate on that index. The use
of newtype_index!
means that Option<Symbol>
only takes up 4 bytes,
because newtype_index!
reserves the last 256 values for tagging purposes.
Note that Symbol
cannot directly be a newtype_index!
because it
implements fmt::Debug
, Encodable
, and Decodable
in special ways.
Methods
impl Symbol
[src]
pub fn intern(string: &str) -> Self
[src]
Maps a string to its interned representation.
pub fn as_str(self) -> LocalInternedString
[src]
pub fn as_interned_str(self) -> InternedString
[src]
pub fn as_u32(self) -> u32
[src]
impl Symbol
[src]
pub fn is_doc_keyword(self) -> bool
[src]
Used for sanity checking rustdoc keyword sections.
Trait Implementations
impl Clone for Symbol
[src]
fn clone(&self) -> Symbol
[src]
fn clone_from(&mut self, source: &Self)
1.0.0[src]
Performs copy-assignment from source
. Read more
impl PartialEq<Symbol> for Symbol
[src]
impl PartialOrd<Symbol> for Symbol
[src]
fn partial_cmp(&self, other: &Symbol) -> Option<Ordering>
[src]
fn lt(&self, other: &Symbol) -> bool
[src]
fn le(&self, other: &Symbol) -> bool
[src]
fn gt(&self, other: &Symbol) -> bool
[src]
fn ge(&self, other: &Symbol) -> bool
[src]
impl Eq for Symbol
[src]
impl Ord for Symbol
[src]
fn cmp(&self, other: &Symbol) -> Ordering
[src]
fn max(self, other: Self) -> Self
1.21.0[src]
Compares and returns the maximum of two values. Read more
fn min(self, other: Self) -> Self
1.21.0[src]
Compares and returns the minimum of two values. Read more
fn clamp(self, min: Self, max: Self) -> Self
[src]
clamp
)Restrict a value to a certain interval. Read more
impl Copy for Symbol
[src]
impl Display for Symbol
[src]
impl Debug for Symbol
[src]
impl Hash for Symbol
[src]
fn hash<__H: Hasher>(&self, state: &mut __H)
[src]
fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
1.3.0[src]
H: Hasher,
Feeds a slice of this type into the given [Hasher
]. Read more
impl Encodable for Symbol
[src]
impl Decodable for Symbol
[src]
Auto Trait Implementations
Blanket Implementations
impl<T, U> Into<U> for T where
U: From<T>,
[src]
U: From<T>,
impl<T> From<T> for T
[src]
impl<T> ToOwned for T where
T: Clone,
[src]
T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T
[src]
fn clone_into(&self, target: &mut T)
[src]
impl<T> ToString for T where
T: Display + ?Sized,
[src]
T: Display + ?Sized,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
[src]
U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
[src]
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
[src]
U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
[src]
impl<T> Borrow<T> for T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
[src]
impl<T> Any for T where
T: 'static + ?Sized,
[src]
T: 'static + ?Sized,
impl<T> Encodable for T where
T: UseSpecializedEncodable + ?Sized,
[src]
T: UseSpecializedEncodable + ?Sized,
impl<T> Decodable for T where
T: UseSpecializedDecodable,
[src]
T: UseSpecializedDecodable,
impl<E> SpecializationError for E
[src]
default fn not_found<S, T>(
trait_name: &'static str,
method_name: &'static str
) -> E where
T: ?Sized,
[src]
trait_name: &'static str,
method_name: &'static str
) -> E where
T: ?Sized,
impl<T> Erased for T
[src]
impl<T> Send for T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> Sync for T where
T: ?Sized,
[src]
T: ?Sized,