whitespace is permitted in the format,
except where none
appears at the end,
in which case no whitespace is permitted.
The value space
at least one space is required at that position.
the sequence of characters returned by curr_symbol()
is permitted, and
can be required.
the first (if any) of the sequence of characters returned by
(respectively as the monetary value is non-negative or negative) is required.
Any remaining characters of the sign sequence are required after
all other format components.
appears, the absolute numeric monetary value is required.