Singular

So far I am using this procedure. It could exist in some library already?

[code]
//rational roots of a rational polynomial
proc Qroots(poly f)
{
ideal l = factorize(f,1);
list ret;
for (int i=1;i<=size(l);i++)
{
if (deg(l[i])==1)
{ //roots are rational
if (size(l[i])==1) { ret=ret+list(0);}
else { ret = ret + list(-leadcoef(l[i][2])/leadcoef(l[i][1])); }
}
}
return(ret);
}
[/code]

Consider this code:

[code]
ring A=0,x,lp;
poly f=(x-3/17)*(x+2/3);
[/code]

I don't see a straightforward way to find the exact (as rational numbers) roots of f. I looked a bit at the documentation and if I use the command [i][color=#626567]laguerre(f,5,1)[/color][/i], I obtain roots up to 5 digits (decimal) precision and not really the rational roots 3/17 and -2/3. Of course I can use [i][color=#626567]factorize(f)[/color][/i] and write a code that extracts the rational roots, but I am sure (I hope) there is a cleaner way to do this. Any hints would be much appreciated. Thanks!