Node:Rationals, Next:Partial Evaluation, Previous:Fragments and Bits, Up:Fragments and Bits
The internal data structure for rational numbers is rat(Num,Den).
Den is always positive, i.e. the sign of the rational number is the
sign of Num. Further, Num and Den are relative prime.
Note that integer N looks like rat(N,1) in this representation.
You can control printing of terms with portray/1.