@top T { A+ }

@skip { spaces }

@skip { dashes } {
  A { "x" | "(" "b" ")" }
}

@tokens {
  spaces { " "+ }
  dashes { "-"+ }
}

# Applies the correct skip rules

x (---b---) (b)

==> T(A, A, A)

# Marks invalid whitespace

( b )

==> T(A(⚠, ⚠))
