[−][src]Struct egg::Symbol
An interned string.
Internally, egg
frequently compares Var
s and elements of
Language
s. To keep comparisons fast, egg
provides Symbol
a simple
wrapper providing interned strings.
You may wish to use Symbol
in your own Language
s to increase
performance and keep enode sizes down (a Symbol
is only 4 bytes,
compared to 24 for a String
.)
A Symbol
is simply a wrapper around an integer.
When creating a Symbol
from a string, egg
looks up it up in a global
table, returning the index (inserting it if not found).
That integer is used to cheaply implement
Copy
, Clone
, PartialEq
, Eq
, PartialOrd
, Ord
, and Hash
.
The internal symbol cache leaks the strings, which should be fine if you only put in things like variable names and identifiers.
Example
use egg::Symbol; assert_eq!(Symbol::from("foo"), Symbol::from("foo")); assert_eq!(Symbol::from("foo"), "foo".parse().unwrap()); assert_ne!(Symbol::from("foo"), Symbol::from("bar"));
Implementations
impl Symbol
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Trait Implementations
impl Clone for Symbol
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impl Copy for Symbol
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impl Debug for Symbol
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impl Display for Symbol
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impl Eq for Symbol
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impl<S: AsRef<str>> From<S> for Symbol
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impl FromStr for Symbol
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type Err = Infallible
The associated error which can be returned from parsing.
fn from_str(s: &str) -> Result<Self, Self::Err>
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impl Hash for Symbol
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fn hash<__H: Hasher>(&self, state: &mut __H)
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fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
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H: Hasher,
impl Ord for Symbol
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fn cmp(&self, other: &Symbol) -> Ordering
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#[must_use]fn max(self, other: Self) -> Self
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#[must_use]fn min(self, other: Self) -> Self
1.21.0[src]
#[must_use]fn clamp(self, min: Self, max: Self) -> Self
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impl PartialEq<Symbol> for Symbol
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impl PartialOrd<Symbol> for Symbol
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fn partial_cmp(&self, other: &Symbol) -> Option<Ordering>
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fn lt(&self, other: &Symbol) -> bool
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fn le(&self, other: &Symbol) -> bool
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fn gt(&self, other: &Symbol) -> bool
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fn ge(&self, other: &Symbol) -> bool
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impl StructuralEq for Symbol
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impl StructuralPartialEq for Symbol
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Auto Trait Implementations
impl RefUnwindSafe for Symbol
impl Send for Symbol
impl Sync for Symbol
impl Unpin for Symbol
impl UnwindSafe for Symbol
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<Q, K> Equivalent<K> for Q where
K: Borrow<Q> + ?Sized,
Q: Eq + ?Sized,
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K: Borrow<Q> + ?Sized,
Q: Eq + ?Sized,
fn equivalent(&self, key: &K) -> bool
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T
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fn clone_into(&self, target: &mut T)
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impl<T> ToString for T where
T: Display + ?Sized,
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T: Display + ?Sized,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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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>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,