r[expr.range]

Range expressions

r[expr.range.syntax]

RangeExpression ->
      RangeExpr
    | RangeFromExpr
    | RangeToExpr
    | RangeFullExpr
    | RangeInclusiveExpr
    | RangeToInclusiveExpr

RangeExpr -> Expression `..` Expression

RangeFromExpr -> Expression `..`

RangeToExpr -> `..` Expression

RangeFullExpr -> `..`

RangeInclusiveExpr -> Expression `..=` Expression

RangeToInclusiveExpr -> `..=` Expression

r[expr.range.behavior] The .. and ..= operators will construct an object of one of the std::ops::Range (or core::ops::Range) variants, according to the following table:

ProductionSyntaxTypeRange
[RangeExpr]start..end[std::ops::Range]start ≤ x < end
[RangeFromExpr]start..[std::ops::RangeFrom]start ≤ x
[RangeToExpr]..end[std::ops::RangeTo]x < end
[RangeFullExpr]..[std::ops::RangeFull]-
[RangeInclusiveExpr]start..=end[std::ops::RangeInclusive]start ≤ x ≤ end
[RangeToInclusiveExpr]..=end[std::ops::RangeToInclusive]x ≤ end

Examples:

#![allow(unused)]
fn main() {
1..2;   // std::ops::Range
3..;    // std::ops::RangeFrom
..4;    // std::ops::RangeTo
..;     // std::ops::RangeFull
5..=6;  // std::ops::RangeInclusive
..=7;   // std::ops::RangeToInclusive
}

r[expr.range.equivalence] The following expressions are equivalent.

#![allow(unused)]
fn main() {
let x = std::ops::Range {start: 0, end: 10};
let y = 0..10;

assert_eq!(x, y);
}

r[expr.range.for] Ranges can be used in for loops:

#![allow(unused)]
fn main() {
for i in 1..11 {
    println!("{}", i);
}
}