Thanks for the info.
The info does verify that reflect.Values are specially handled in fmt.Print,
and it also clearly sates String() method of the argument reflect.Values
are not called in fmt.Print:
The fmt package treats Values specially. It does not call their String
method
implicitly but instead prints the concrete values they hold.
It looks the docs is too simple, if not very accurate. It doesn't specify
clearly
whether or not the "prints" operation in "but instead prints the concrete
values they hold"
will call the String methods of the concrete values if the the concrete
values
are also reflect.Values (a.k.a., indirect reflect.Values). The fact is it
calls indeed.
IMHO, the design is some confusing.
On Friday, February 26, 2021 at 8:29:15 AM UTC-5 clba...@gmail.com wrote:
> Yes. You have to understand how "fmt.Print," etc., handle types with
> String() methods. From the docs:
>
> package fmt -
>
> 5. If an operand implements method String() string, that method will be
> invoked to convert the object to a string, which will then be formatted as
> required by the verb (if any).
>
> package reflect -
>
> func (Value) Elem
> <http://localhost:6060/src/reflect/value.go?s=25679:25706#L800>
> func (v Value <http://localhost:6060/pkg/reflect/#Value>) Elem() Value
> <http://localhost:6060/pkg/reflect/#Value>
>
> Elem returns the value that the interface v contains or that the pointer v
> points to. It panics if v's Kind is not Interface or Ptr. It returns the
> zero Value if v is nil.
>
> func (Value) String
> <http://localhost:6060/src/reflect/value.go?s=55738:55768#L1847>
>
> func (v Value <http://localhost:6060/pkg/reflect/#Value>) String() string
> <http://localhost:6060/pkg/builtin/#string>
>
> String returns the string v's underlying value, as a string. String is a
> special case because of Go's String method convention. Unlike the other
> getters, it does not panic if v's Kind is not String. Instead, it returns a
> string of the form "<T value>" where T is v's type. The fmt package treats
> Values specially. It does not call their String method implicitly but
> instead prints the concrete values they hold.
> On Thursday, February 25, 2021 at 11:42:32 PM UTC-7 tapi...@gmail.com
> wrote:
>
>> What I mean is
>>
>> fmt.Println(v3)
>>
>> and
>>
>> fmt.Println(v3.Elem())
>>
>> print the same thing. Is it an intended design?
>>
>> On Thursday, February 25, 2021 at 11:11:52 PM UTC-5 Kurtis Rader wrote:
>>
>>> On Thu, Feb 25, 2021 at 8:01 PM tapi...@gmail.com <tapi...@gmail.com>
>>> wrote:
>>>
>>>>
>>>> https://play.golang.org/p/-GZajVGPWYv
>>>>
>>>
>>> You need to clarify your question. I don't see any obvious problem with
>>> the output of your program. The reflect.Value.Elem() call is defined to
>>> return a reflect.Elem object. But that observation might be irrelevant
>>> since you have not clearly stated the problem.
>>>
>>> --
>>> Kurtis Rader
>>> Caretaker of the exceptional canines Junior and Hank
>>>
>>
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