fdiv

static VALUE
nurat_fdiv(VALUE self, VALUE other)
{
    VALUE div;
    if (f_zero_p(other))
        return nurat_div(self, rb_float_new(0.0));
    if (FIXNUM_P(other) && other == LONG2FIX(1))
        return nurat_to_f(self);
    div = nurat_div(self, other);
    if (RB_TYPE_P(div, T_RATIONAL))
        return nurat_to_f(div);
    if (RB_FLOAT_TYPE_P(div))
        return div;
    return rb_funcall(div, idTo_f, 0);
}