1?\space?(?\digit\digit\digit?)?[\-\space]?\digit{3}-=\digit{4}
\digit{3}-=\digit{2}-=\digit{4}
(=[^()]+) <- without direction specification or >>(=!)+) <- with direction specification
>>\n\n=\space\P{4}!\n\n\space\space\space\space+\F\n\n=\space{4}
-3.14 e -21
":
[+\-]?\space?>>[0-9]+\.?[0-9]*\space?e?\space?[+\-]?\space?[0-9]+