Expressions

Expressions are constructs that evaluate to a value.

Literals

"hello"         // String literal
42              // Integer literal
3.14            // Float literal
true            // Boolean literal
null            // Null literal
()              // Unit literal

Binary Expressions

a + b           // Addition
x - y           // Subtraction
m * n           // Multiplication
p / q           // Division
a % b           // Modulo

x == y          // Equality
x != y          // Inequality
x < y           // Less than
x > y           // Greater than
x <= y          // Less than or equal
x >= y          // Greater than or equal

a && b          // Logical AND
a || b          // Logical OR

Unary Expressions

!flag           // Logical NOT
-num            // Negation
*ptr            // Dereference
&value          // Reference
&mut value      // Mutable reference

Member Access

obj.property    // Dot notation
obj?.property   // Optional chaining
arr[index]      // Bracket notation

Function Calls

foo()                    // No arguments
bar(arg1, arg2)         // With arguments
obj.method(arg)         // Method call
fn<T>(arg)              // Generic call

Match Expression

match value {
    Pattern1 => result1,
    Pattern2 => result2,
    _ => default
}

If Expression

let value = if condition {
    42
} else {
    0
};

Block Expression

let result = {
    let x = compute();
    x * 2
};

String Formatting

format!("Hello, {}!", name)
format!("Count: {}", count)

Collection Construction

vec![1, 2, 3]                    // Vector
HashMap::new()                    // HashMap
HashSet::new()                    // HashSet

Struct Construction

Point { x: 10, y: 20 }
Person { name, age: 30 }         // Shorthand

See Syntax Overview for more details.