On Saturday, August 6, 2016 at 4:06:07 PM UTC+8, [email protected] wrote:
>
> Possibily, if you freeze the type of things that can be boxed by the
> interface. But what would it be useful for ?
> That would just mean that an interface is constant. Not even that the
> value it wraps can't be changed (because with the current implementation,
> the values an interface wraps need to be addressable).
>
you mean a value should be addressable to let an interface wraps wrap it?
Not true, "_ = interface{}(1)" is valid in current implementation.
>
>
>
> On Saturday, August 6, 2016 at 9:53:26 AM UTC+2, T L wrote:
>>
>> Is it possible to make an interface constant if its concrete value type
>> is bool/number/string?
>>
>> On Saturday, August 6, 2016 at 3:48:17 AM UTC+8, Ian Lance Taylor wrote:
>>>
>>> On Fri, Aug 5, 2016 at 11:21 AM, T L <[email protected]> wrote:
>>> >
>>> > For an interface value, its internal values will never change.
>>> > Are there any problems if golang supports constant interface values?
>>>
>>> Pedantically, in Go, constants are untyped by default. It doesn't
>>> make sense to speak of an untyped interface value. I would describe
>>> what you are asking for as an immutable variable. I've often thought
>>> that immutable variables would be useful in Go, but since they have to
>>> be initialized it's not that simple. For example, io.EOF is
>>> initialized using a function call. That means that it can't actually
>>> be in read-only memory, and of course it's possible to take it's
>>> address. How do we prevent it from being changed, without introducing
>>> an immutable qualifier into the type system? It's a complex problem
>>> for which I have no solution. And the benefits of an immutable
>>> variable aren't all that high.
>>>
>>> Ian
>>>
>>
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