; good
println 3.14
println 42.
println 12_34.56_78
println 12.34_q.5
println 1_2.3_4_q15
println 1.q2

; warning
println 1.000_000_000_000_001
println 1.999_999_999_999_999
println 1.000_000_000_000_001q16
println 1.999_999_999_999_999q.16

; bad
println 12.34q0
println 12.34q_15 ; lexes as `12.34q` (invalid) then symbol `_15`
println 12.34q1_5 ; lexes as `12.34q1` (valid) then symbol `_5`
println 1_.2
println 1._2
println 1.__2
println 1.2q