`l[0] = l` would be fine for me, indeed. Though I am not sure I understand
the suggested solution. Notice that the type of the slice is
`[]interface{}`. This...
ll := l[0].([]interface{})
println(&l == &ll)
...would print `false`.
I think the main challenge is that l and ll, or l[0] for that matter, are
not the same values. I tried with reflection, too, but couldn't figure a
way.
PS: I am quite aware how unearthy this problem is, and how it should not
ever happen in case of actual programs. My use case is that I want to
pretty print in-memory objects for debug purposes during testing, and one
of the features would be to point out such cycles as this.
On Wednesday, November 11, 2020 at 8:13:55 AM UTC+1
[email protected] wrote:
> The question was about detecting cyclic references. For that, the `l[0] =
> l` case is enough.
>
> On Wed, Nov 11, 2020 at 2:31 AM [email protected] <[email protected]>
> wrote:
>
>> FYI, that does detect the simple case of l[0] = l, but not more
>> complicated circular cases like l[1] = l[1:]
>>
>> On Tuesday, November 10, 2020 at 2:38:26 AM UTC-5
>> [email protected] wrote:
>>
>>> If the slice is empty, it doesn't reference anything.
>>> If it is not empty, &x[0] can be used to identify the slice (potentially
>>> also using len/cap, if it's interesting).
>>>
>>> On Tue, Nov 10, 2020 at 4:11 AM arpad ryszka <[email protected]>
>>> wrote:
>>>
>>>> Hi,
>>>>
>>>> is there a way to detect the cyclic reference in the following example
>>>> somehow? Either via reflection or by other means? My understanding is that
>>>> slices cannot be compared with == (unless to nil), or used as keys in
>>>> maps.
>>>> Is there a different way?
>>>>
>>>> l := []interface{}{"foo"}
>>>> l[0] = l
>>>> fmt.Println(l)
>>>>
>>>> or here it is as a playground link:
>>>> https://play.golang.org/p/T0qZlF8m-vi
>>>>
>>>> Cheers,
>>>> Arpad
>>>>
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>>>>
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