为什么这个代码有效?匹配语句中的逗号只是一种约定吗?
for (index, character) in argv[1].chars().enumerate() {
match character {
'a' | 'A' => {println!("{}: 'A'", index)}
'e' | 'E' => {println!("{}: 'E'", index)}
'i' | 'I' => {println!("{}: 'I'", index)}
'o' | 'O' => {println!("{}: 'O'", index)}
'u' | 'U' => {println!("{}: 'U'", index)}
_ => {
let consonant: Vec<_> = character.to_uppercase().collect();
println!("{}: {:?} is not a vowel", index, consonant[0])
}
}