E3010#
只有带标签参数才可以有默认值。
错误示例#
pub fn greet(name : String = "World") -> Unit {
// ^ Error: Only labelled arguments can have default value.
println("Hello, " + name + "!")
}
建议#
Use an optional argument with ?
if you want to provide a default value:
///|
pub fn greet(name? : String = "World") -> Unit {
println("Hello, " + name + "!")
}
或者如果你想保持它为一个位置参数,移除默认值:
///|
pub fn greet_without_default(name : String) -> Unit {
println("Hello, " + name + "!")
}