Interval arithmetic for Axiom was implemented by Mike Dewar in form of Aldor files.
Juergen Weiss converted the files to Spad and they are included in current FriCAS
distribution.
fricas
(1) -> x:=interval(1.1,2.2)$Interval(Float)
Type: Interval(Float)
fricas
sin(x)
Type: Interval(Float)