pub struct Symbol(_);
Expand description
An interned string.
This is provided by the symbol_table
crate.
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"));
A interned string in the global symbol table.
This requires the global
feature on the crate.
GlobalSymbol
is a wrapper around Symbol
that knows to refer to a
built-in, global SymbolTable
. Strings into the global table are never freed.
This enables a lot of convience methods and trait implementations over
GlobalSymbol
(see below). In particular,
you can convert it to &'static str
,
convert From
and Into
a &str
,
and de/serialize using serde
if the serde
feature is enabled.
Implementations
sourceimpl GlobalSymbol
impl GlobalSymbol
An interned string.
This is provided by the symbol_table
crate.
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"));
Trait Implementations
sourceimpl Clone for GlobalSymbol
impl Clone for GlobalSymbol
sourcefn clone(&self) -> GlobalSymbol
fn clone(&self) -> GlobalSymbol
Returns a copy of the value. Read more
1.0.0 · sourcefn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source
. Read more
sourceimpl Debug for GlobalSymbol
impl Debug for GlobalSymbol
sourceimpl<'de> Deserialize<'de> for GlobalSymbol
impl<'de> Deserialize<'de> for GlobalSymbol
sourcefn deserialize<__D>(
__deserializer: __D
) -> Result<GlobalSymbol, <__D as Deserializer<'de>>::Error> where
__D: Deserializer<'de>,
fn deserialize<__D>(
__deserializer: __D
) -> Result<GlobalSymbol, <__D as Deserializer<'de>>::Error> where
__D: Deserializer<'de>,
Deserialize this value from the given Serde deserializer. Read more
sourceimpl Display for GlobalSymbol
impl Display for GlobalSymbol
sourceimpl<'_> From<&'_ String> for GlobalSymbol
impl<'_> From<&'_ String> for GlobalSymbol
sourcefn from(s: &String) -> GlobalSymbol
fn from(s: &String) -> GlobalSymbol
Converts to this type from the input type.
sourceimpl<'_> From<&'_ str> for GlobalSymbol
impl<'_> From<&'_ str> for GlobalSymbol
sourcefn from(s: &str) -> GlobalSymbol
fn from(s: &str) -> GlobalSymbol
Converts to this type from the input type.
sourceimpl From<GlobalSymbol> for &'static str
impl From<GlobalSymbol> for &'static str
sourcefn from(sym: GlobalSymbol) -> &'static str
fn from(sym: GlobalSymbol) -> &'static str
Converts to this type from the input type.
sourceimpl From<String> for GlobalSymbol
impl From<String> for GlobalSymbol
sourcefn from(s: String) -> GlobalSymbol
fn from(s: String) -> GlobalSymbol
Converts to this type from the input type.
sourceimpl FromStr for GlobalSymbol
impl FromStr for GlobalSymbol
type Err = Infallible
type Err = Infallible
The associated error which can be returned from parsing.
sourcefn from_str(s: &str) -> Result<GlobalSymbol, <GlobalSymbol as FromStr>::Err>
fn from_str(s: &str) -> Result<GlobalSymbol, <GlobalSymbol as FromStr>::Err>
Parses a string s
to return a value of this type. Read more
sourceimpl Hash for GlobalSymbol
impl Hash for GlobalSymbol
sourceimpl Ord for GlobalSymbol
impl Ord for GlobalSymbol
sourceimpl PartialEq<GlobalSymbol> for GlobalSymbol
impl PartialEq<GlobalSymbol> for GlobalSymbol
sourcefn eq(&self, other: &GlobalSymbol) -> bool
fn eq(&self, other: &GlobalSymbol) -> bool
This method tests for self
and other
values to be equal, and is used
by ==
. Read more
sourcefn ne(&self, other: &GlobalSymbol) -> bool
fn ne(&self, other: &GlobalSymbol) -> bool
This method tests for !=
.
sourceimpl PartialOrd<GlobalSymbol> for GlobalSymbol
impl PartialOrd<GlobalSymbol> for GlobalSymbol
sourcefn partial_cmp(&self, other: &GlobalSymbol) -> Option<Ordering>
fn partial_cmp(&self, other: &GlobalSymbol) -> 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 Serialize for GlobalSymbol
impl Serialize for GlobalSymbol
sourcefn serialize<__S>(
&self,
__serializer: __S
) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error> where
__S: Serializer,
fn serialize<__S>(
&self,
__serializer: __S
) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error> where
__S: Serializer,
Serialize this value into the given Serde serializer. Read more
impl Copy for GlobalSymbol
impl Eq for GlobalSymbol
impl StructuralEq for GlobalSymbol
impl StructuralPartialEq for GlobalSymbol
Auto Trait Implementations
impl RefUnwindSafe for GlobalSymbol
impl Send for GlobalSymbol
impl Sync for GlobalSymbol
impl Unpin for GlobalSymbol
impl UnwindSafe for GlobalSymbol
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<Q, K> Equivalent<K> for Q where
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
impl<Q, K> Equivalent<K> for Q where
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
sourcefn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
Compare self to key
and return true
if they are equal.
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)
toowned_clone_into
)Uses borrowed data to replace owned data, usually by cloning. Read more