Support for Groovy style "Power Assertion" in Kotlin?

Language Design
9

Nice suggestion. I will try to make something that gives you a similar feature to Swift’s guards.

EDIT: Would this suite your needs?

inline fun assert(predicate: () -> Boolean) = assert(predicate())

infix fun assert(result: Boolean) = Guard(result)

class Guard(val result: Boolean) {

	infix fun or(exception: Exception) {
		if (result)
			throw exception
	}

	infix fun or(body: () -> Any) {
		if (result)
			body()
	}

}

Example usage:

assert (param > 0) or IllegalArgumentException("My message")

And:

assert (param is String) or {
    ... do stuff ...
}

// unfortunately Kotlin doesn't do smart cast here (because it would slow compilation)
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