Operators / Symbols
Contains all possible operators and symbols that have a predefined functionality.
Operators
If a trait is overloadable the relevant trait to use, to overload that operator is listed.
OPERATOR | EXAMPLE | EXPLANATION | OVERLOADABLE? |
! | ident!(...) , ident!{...} , ident![...] | Macro expansion | |
! | !expr | Bitwise or logical complement | Not |
!= | expr != expr | Nonequality comparison | PartialEq |
% | expr % expr | Arithmetic remainder | Rem |
%= | var %= expr | Arithmetic remainder and assignment | RemAssign |
& | &expr , &mut expr | Borrow | |
& | &type , &mut type , &'a type , &'a mut type | Borrowed pointer type | |
& | expr & expr | Bitwise AND | BitAnd |
&= | var &= expr | Bitwise AND and assignment | BitAndAssign |
&& | expr && expr | Short-circuiting logical AND | |
* | expr * expr | Arithmetic multiplication | Mul |
*= | var *= expr | Arithmetic multiplication and assignment | MulAssign |
* | *expr | Dereference | Deref |
* | *const type , *mut type | Raw pointer | |
+ | trait + trait , 'a + trait | Compound type constraint | |
+ | expr + expr | Arithmetic addition | Add |
+= | var += expr | Arithmetic addition and assignment | AddAssign |
, | expr, expr | Argument and element separator | |
- | - expr | Arithmetic negation | Neg |
- | expr - expr | Arithmetic subtraction | Sub |
-= | var -= expr | Arithmetic subtraction and assignment | SubAssign |
-> | fn(...) -> type , |...| -> type | Function and closure return type | |
. | expr.ident | Member access | |
.. | .. , expr.. , ..expr , expr..expr | Right-exclusive range literal | PartialOrd |
..= | ..=expr , expr..=expr | Right-inclusive range literal | PartialOrd |
.. | ..expr | Struct literal update syntax | |
.. | variant(x, ..) , struct_type { x, .. } | “And the rest” pattern binding | |
... | expr...expr | (Deprecated, use ..= instead) In a pattern: inclusive range pattern | |
/ | expr / expr | Arithmetic division | Div |
/= | var /= expr | Arithmetic division and assignment | DivAssign |
: | pat: type , ident: type | Constraints | |
: | ident: expr | Struct field initializer | |
: | 'a: loop {...} | Loop label | |
; | expr; | Statement and item terminator | |
; | [...; len] | Part of fixed-size array syntax | |
<< | expr << expr | Left-shift | Shl |
<<= | var <<= expr | Left-shift and assignment | ShlAssign |
< | expr < expr | Less than comparison | PartialOrd |
<= | expr <= expr | Less than or equal to comparison | PartialOrd |
= | var = expr , ident = type | Assignment/equivalence | |
== | expr == expr | Equality comparison | PartialEq |
=> | pat => expr | Part of match arm syntax | |
> | expr > expr | Greater than comparison | PartialOrd |
>= | expr >= expr | Greater than or equal to comparison | PartialOrd |
>> | expr >> expr | Right-shift | Shr |
>>= | var >>= expr | Right-shift and assignment | ShrAssign |
@ | ident @ pat | Pattern binding | |
^ | expr ^ expr | Bitwise exclusive OR | BitXor |
^= | var ^= expr | Bitwise exclusive OR and assignment | BitXorAssign |
| | pat | pat | Pattern alternatives | |
| | expr | expr | Bitwise OR | BitOr |
|= | var |= expr | Bitwise OR and assignment | BitOrAssign |
|| | expr || expr | Short-circuiting logical OR | |
? | expr? | Error propagation | |
Non-operator Symbols
Symbols that don’t function as operators (they don’t behave like a function or method call).
SYMBOL | EXPLANATION |
'ident | Named lifetime or loop label |
...u8 , ...i32 , ...f64 , ...usize , etc. | Numeric literal of specific type |
"..." | String literal |
r"..." , r#"..."# , r##"..."## , etc. | Raw string literal, escape characters not processed |
b"..." | Byte string literal; constructs an array of bytes instead of a string |
br"..." , br#"..."# , br##"..."## , etc. | Raw byte string literal, combination of raw and byte string literal |
'...' | Character literal |
b'...' | ASCII byte literal |
|...| expr | Closure |
! | Always empty bottom type for diverging functions |
_ | “Ignored” pattern binding; also used to make integer literals readable |
Item paths
SYMBOL | EXPLANATION |
ident::ident | Namespace path |
::path | Path relative to the crate root (i.e., an explicitly absolute path) |
self::path | Path relative to the current module (i.e., an explicitly relative path). |
super::path | Path relative to the parent of the current module |
type::ident , <type as trait>::ident | Associated constants, functions, and types |
<type>::... | Associated item for a type that cannot be directly named (e.g., <&T>::... , <[T]>::... , etc.) |
trait::method(...) | Disambiguating a method call by naming the trait that defines it |
type::method(...) | Disambiguating a method call by naming the type for which it’s defined |
<type as trait>::method(...) | Disambiguating a method call by naming the trait and type |
Generic type parameters
SYMBOL | EXPLANATION |
path<...> | Specifies parameters to generic type in a type (e.g., Vec<u8> ) |
path::<...> , method::<...> | Specifies parameters to generic type, function, or method in an expression; often referred to as turbofish (e.g., "42".parse::<i32>() ) |
fn ident<...> ... | Define generic function |
struct ident<...> ... | Define generic structure |
enum ident<...> ... | Define generic enumeration |
impl<...> ... | Define generic implementation |
for<...> type | Higher-ranked lifetime bounds |
type<ident=type> | A generic type where one or more associated types have specific assignments (e.g., Iterator<Item=T> ) |
Type bounds
SYMBOL | EXPLANATION |
T: U | Generic parameter T constrained to types that implement U |
T: 'a | Generic type T must outlive lifetime 'a (meaning the type cannot transitively contain any references with lifetimes shorter than 'a ) |
T: 'static | Generic type T contains no borrowed references other than 'static ones |
'b: 'a | Generic lifetime 'b must outlive lifetime 'a |
T: ?Sized | Allow generic type parameter to be a dynamically sized type |
'a + trait , trait + trait | Compound type constraint |
Macros
SYMBOL | EXPLANATION |
#[meta] | Outer attribute |
#![meta] | Inner attribute |
$ident | Macro substitution |
$ident:kind | Macro capture |
$(…)… | Macro repetition |
ident!(...) , ident!{...} , ident![...] | Macro invocation |
SYMBOL | EXPLANATION |
// | Line comment |
//! | Inner line doc comment |
/// | Outer line doc comment |
/*...*/ | Block comment |
/*!...*/ | Inner block doc comment |
/**...*/ | Outer block doc comment |
Tuples
SYMBOL | EXPLANATION |
() | Empty tuple (aka unit), both literal and type |
(expr) | Parenthesized expression |
(expr,) | Single-element tuple expression |
(type,) | Single-element tuple type |
(expr, ...) | Tuple expression |
(type, ...) | Tuple type |
expr(expr, ...) | Function call expression; also used to initialize tuple struct s and tuple enum variants |
expr.0 , expr.1 , etc. | Tuple indexing |
Curly Brackets
CONTEXT | EXPLANATION |
{...} | Block expression |
Type {...} | struct literal |
Square Brackets
CONTEXT | EXPLANATION |
[...] | Array literal |
[expr; len] | Array literal containing len copies of expr |
[type; len] | Array type containing len instances of type |
expr[expr] | Collection indexing. Overloadable (Index , IndexMut ) |
expr[..] , expr[a..] , expr[..b] , expr[a..b] | Collection indexing pretending to be collection slicing, using Range , RangeFrom , RangeTo , or RangeFull as the “index” |