AssociativeComparison

AssociativeComparisonPrecedence.swift

precedencegroup AssociativeComparisonPrecedence {
    associativity: left
    higherThan: ComparisonPrecedence
    lowerThan: NilCoalescingPrecedence
}

infix operator <: AssociativeComparisonPrecedence
infix operator <=: AssociativeComparisonPrecedence

public func < <V: Comparable>(lhs: V, rhs: V) -> (Bool, V) {
    return ((lhs < rhs), rhs)
}

public func <= <V: Comparable>(lhs: V, rhs: V) -> (Bool, V) {
    return ((lhs <= rhs), rhs)
}

public func < <V: Comparable>(lhs: (Bool, V), rhs: V) -> (Bool, V) {
    return ((lhs.0 && lhs.1 < rhs), rhs)
}

public func <= <V: Comparable>(lhs: (Bool, V), rhs: V) -> (Bool, V) {
    return ((lhs.0 && lhs.1 <= rhs), rhs)
}

public func < <V: Comparable>(lhs: (Bool, V), rhs: V) -> Bool {
    return lhs.0 && (lhs.1 < rhs)
}

public func <= <V: Comparable>(lhs: (Bool, V), rhs: V) -> Bool {
    return lhs.0 && (lhs.1 <= rhs)
}

Demo.swift

let a = 2
let b = 3
if 1 < a < b <= 3 {
    print("true") // true
}