I see the ' Improved operator declarations ' , about lowerThan has this:
There are times when we want to insert an operator below an existing one. If that existing operator resides in another module, we can use lowerThan relationship.
So, I try:
precedencegroup aPrecedence {}
precedencegroup bPrecedence {
higherThan: aPrecedence
}
precedencegroup cPrecedence {
higherThan: bPrecedence
}
precedencegroup ePrecedence {
higherThan: cPrecedence
}
precedencegroup dPrecedence {
higherThan: bPrecedence
lowerThan: ePrecedence// error: Precedence group cannot be given lower precedence than group in same module; make the other precedence group higher than this one instead
}
but this is no error:
precedencegroup testPrecedence {
higherThan: ComparisonPrecedence
lowerThan: RangeFormationPrecedence
}
I cann't understand; How to use 'lowerThan'?