ExistsOrNonemptyCondition.ceylon
"An existence or nonemptiness condition, that is,
the keyword ‘`exists`’ or ‘`nonempty`’, followed by either
a specified pattern or a member name referencing an existing value.
Examples:
nonempty [employeeOfTheMonth, *others] = randomShuffle(employees)
exists String name = person.name"
shared abstract class ExistsOrNonemptyCondition()
of ExistsCondition | NonemptyCondition
extends Condition() {
"The value reference or pattern specification being tested."
shared formal SpecifiedPattern|LIdentifier tested;
"Whether the condition is negated or not.
If the condition is negated, the ‘`exists`’/‘`nonempty`’ keyword
is prefixed by a negation operator ‘`!`’."
shared formal Boolean negated;
shared actual formal [SpecifiedPattern|LIdentifier] children;
}