"42r" and "3.14r" are evaluated as Rational(42, 1) and 3.14.rationalize,
respectively. But exponential form with r suffix like "6.022e+23r" is
not accepted because it is misleading.
"42i" and "3.14i" are evaluated as Complex(0, 42) and Complex(0, 3.14),
respectively.
"42ri" and "3.14ri" are evaluated as Complex(0, 42r) and Complex(0, 3.14r),
respectively.