floating-point-number = [ sign ] *DIGIT decimal-point *DIGIT [ exponent ]
/ [ sign ] 1*DIGIT [ decimal-point *DIGIT ] exponent
sign = "+" / "-"
decimal-point = "."
exponent = exponent-marker [ sign ] 1*DIGIT
exponent-marker = "e" / "s" / "f" / "d" / "l"
/ "E" / "S" / "F" / "D" / "L"