testcase {
    input "if (bar!) baz!;";
    output "IfThen:{id:{x:{b x:{a r}}} id:{x:{b x:{a z}}}}";

    s             = Expr ";"
    Expr          = IfThen
                  | IfThenElse
                  | id:: id "!"
    id = [a-z] | x:: [a-z] id
    IfThen        = IfThen::
                       "if" "(" Expr ")"
                       Expr
                           /ws
    IfThenElse    = IfThenElse::
                       "if" "(" Expr ")"
                       NotIfThenExpr
                       "else"
                       Expr
                           /ws
    NotIfThenExpr = (Expr & [a-z]+)
    SpaceIfThen   = (~[])*// !IfThen
    ws            = [\n ]**
}