DOUBLE method
Parser
DOUBLE()
Implementation
Parser DOUBLE() =>
pattern('+-').repeat(0, 1) &
((pattern('0-9').plus() &
string('.') &
pattern('0-9').star() &
ref0(EXPONENT)) |
(string('.') & pattern('0-9').plus() & ref0(EXPONENT)) |
(pattern('0-9').plus() & ref0(EXPONENT)));