# Both IntValue and FloatValue are specified with [lookahead != {Digit, `.`, NameStart}]
00
2.
2.2.
2.2.2
2e2.
2e2.2
2.2e2.
2.2e2.2
2_
2.2_
2e2_
2.2e2_
2x
2.2x
2e2x
2.2e2x
2e2e
2e2e2