The next arg is printed as a float in either fixed-format or exponential notation as appropriate.
The full form is ~w,d,e,k,overflowchar,padchar,exponentcharG.
The format in which to print arg depends on the magnitude (absolute
value) of the arg. Let n be an integer such that
10^n-1 \le |arg| < 10^n.
Let ee equal e+2, or 4 if e is omitted.
Let ww equal w- ee,
or nil if w is omitted. If d is omitted, first let q
be the number of digits needed to print arg with no loss
of information and without leading or trailing zeros;
then let d equal (max q (min n 7)).
Let dd equal d- n.
If 0 \le dd \le d, then arg is printed as if by the format directives
~ww,dd,,overflowchar,padcharF~ee@T
Note that the scale factor k is not passed to the ~F
directive. For all other values of dd, arg is printed as if
by the format directive
~w,d,e,k,overflowchar,padchar,exponentcharE
In either case, an @
modifier is supplied to the ~F
or ~E directive if and only if one was supplied to the
~G directive.
~G binds
*print-escape* to false
and *print-readably* to false.