Even and Odd Integers

[Ben_Cohen]

@rob

over 4,000 results for var isEven: Bool on Github

Good point! At first glance, most seem to be extensions on Int which reinforces the point in the Consistency section regarding choosing the appropriate protocol to extend.

There may well be lots of good uses out there that can be enumerated in a proposal, just saying I'd be wary of GitHub counts. My (unscientifically conducted) review of a sample of these 4,000 results suggests they are almost entirely:

• unused extensions (i.e. lots of copies of the definition of isEven in the same IntExtensions.swift file, but hardly any calls to it); or
• sample code using isEven as an example of a function being passed to a higher-order function like filter. Makes sense – it's my go-to example function to use for these purposes too! (But defining it as a property would be unsatisfactory for these purposes since I usually want to use it point-free :)

Several of the handful of real uses I could spot were ones that have better equivalents: for example, arc4random().isEven for a version of Bool.random().