Availability:built-in
atom_number(?Atom, 
?Number)Realises the popular combination of atom_codes/2 
and number_codes/2 
to convert between atom and number (integer or float) in one predicate, 
avoiding the intermediate list. Unlike the ISO number_codes/2 
predicates, atom_number/2 
fails silently in mode (+,-) if Atom does not represent a 
number.102Versions prior to 6.1.7 
raise a syntax error, compliant to number_codes/2 
See also atomic_list_concat/2 
for assembling an atom from atoms and numbers.