> On 25 Aug 2016, at 12:05, Nicholas Maccharoli wrote:
>
> I personally see merit in adding a function to bound the value of a variable
> within a range and think it would be simple to write with the existing
> implementations of `min` and `max` with something like:
>
> public func bounds<T : Comparable>(value: T, _ lower: T, _ upper: T) -> T
> {
> return max(lower, min(value, upper))
> }
>
> Does this sound like something the community thinks would be worthwhile to
> add?
I'd welcome that addition. In terms of function interface, I think we can do
better than the 3-argument `clamp(x, min, max)` function that is seen in
several math libraries.
Our ***Range types already have a `clamped(to:)` member function, e.g. here's
one for ClosedRange
<https://developer.apple.com/reference/swift/closedrange/1779071-clamped>. It
creates a new range constraining the receiver's bounds within the new bounds
given as argument.
I think the sensible thing would be to add a similar, and equally named, method
to the Comparable protocol, taking in the ClosedRange<Self> to limit the value
to:
extension Comparable {
public func clamped(to limits: ClosedRange<Self>) -> Self {
return self < limits.lowerBound ? limits.lowerBound
: self > limits.upperBound ? limits.upperBound
: self
}
}
(-0.1).clamped(to: 0 ... 1) // 0.0
3.14.clamped(to: 0 ... .infinity) // 3.14
"foo".clamped(to: "a" ... "f") // "f"
"foo".clamped(to: "a" ... "g") // "foo"
>From my experience, I'd say it'd be most useful for clamping floating-point
>numbers and collection indices.
— Pyry
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