def String.append
import Base1987def String.append(a: String, b: String) -> String:
1988 match a:
1989 case SNil{}:
1990 b
1991 case SCon{h, t}:
1992 SCon{h, String.append(t, b)}
import Base1987def String.append(a: String, b: String) -> String:
1988 match a:
1989 case SNil{}:
1990 b
1991 case SCon{h, t}:
1992 SCon{h, String.append(t, b)}