Range based clamping for `FloatingPoint` types.

FloatingPoint+Clamped.swift

// FloatingPoint extension

extension FloatingPoint {
    func clamped<T: ClampableRangeExpression>(to range: T) -> Self where T.Bound == Self {
        return range.clamping(self)
    }
}

// RangeExpression extension

protocol ClampableRangeExpression: RangeExpression where Bound: FloatingPoint {
    func clamping(_ value: Bound) -> Bound
}

// Conformance for various Range Types

extension PartialRangeFrom: ClampableRangeExpression where Bound: FloatingPoint {
    func clamping(_ value: Bound) -> Bound {
        return contains(value) ? value : lowerBound
    }
}

extension PartialRangeThrough: ClampableRangeExpression where Bound: FloatingPoint {
    func clamping(_ value: Bound) -> Bound {
        return contains(value) ? value : upperBound
    }
}

extension ClosedRange: ClampableRangeExpression where Bound: FloatingPoint {
    func clamping(_ value: Bound) -> Bound {
        return (lowerBound...).clamping((...upperBound).clamping(value))
    }
}

extension Range: ClampableRangeExpression where Bound: FloatingPoint {
    func clamping(_ value: Bound) -> Bound {
        guard !isEmpty else { return .nan }
        return (lowerBound...).clamping((..<upperBound).clamping(value))
    }
}

extension PartialRangeUpTo: ClampableRangeExpression where Bound: FloatingPoint {
    func clamping(_ value: Bound) -> Bound {
        return (...upperBound.nextDown).clamping(value)
    }
}