10.20.1 New Features
     
- New format/[2,3]format sequences:
- `~Nh'- `~NH'
- (Print float precisely.) 
The argument is a float, which will be printed in `f' or
`e' (or `E' if `H' is used) notation with d
significant digits, where d is the smallest number of digits that
will yield the same float when read in.  `E' notation is used if
N<0 or if the exponent is less than -N-1 or greater than or
equal to N+d, otherwise `f' notation.  N defaults to 3. 
 
- New write_term/[2,3]options:
- character_escapes(+Boolean- )
- If selected, quoted atoms containing special characters will be
printed using escape sequences.  The default value depends on the
character_escapesProlog flag.
 
- float_format(+Spec- )
- How to print floats.  Spec should be an atom of the form
`~NC', like one of the format sequences for printing
floats.  The default is `~H'.
          
 
- priority(+Prio- )
- The term is printed as if in the context of an associative
operator of precedence Prio, where Prio is an
integer.  The default is 1200.