ez:=proc(): print(` RatToCF, NuToCF, CF(L) `): end:


RatToCF:=proc(a) local L,a1,b:

if type(a,integer) then
 RETURN([a]):
else
 a1:=trunc(a):
 b:=1/(a-a1):
 L:=RatToCF(b):
 RETURN([a1,op(L)]):
fi:

end:


NuToCF:=proc(a,N) local L,a1,b:

if N=1 then
 RETURN([trunc(a)]):
fi:

 a1:=trunc(a):
 b:=1/(a-a1):
 L:=NuToCF(b,N-1):
[a1,op(L)]:
end:



#CF(L): the continued fraction of L
CF:=proc(L) local L1:
 
if not (type(L,list) and nops(L)>0) then
  RETURN(FAIL):
fi:

if nops(L)=1 then
  RETURN(L[1]):
else

L1:=[op(2..nops(L),L)]:
 RETURN(normal(L[1]+1/CF(L1))):

fi:

end: