Dave talks about map representation here:
https://dave.cheney.net/2017/04/30/if-a-map-isnt-a-reference-variable-what-is-it
I don’t understand why you need a pointer to a map, can you provide a code
example?
Matt
On Tuesday, January 30, 2018 at 8:22:54 AM UTC-6, Trig wrote:
>
> Appreciate the response. I'm wanting to pass a *map[string]interface{}
> where the keys (strings) are already populated. I'm thinking of just
> creating a func which does this itself... checks to see if the keys exists
> and populate accordingly, and if not... return an error. Don't think this
> will be too difficult; however, would be a nice feature to discuss about
> being implemented into the json standard library.
>
> On Tuesday, January 30, 2018 at 5:31:01 AM UTC-6, Konstantin Khomoutov
> wrote:
>>
>> On Sun, Jan 28, 2018 at 10:59:58AM -0800, Trig wrote:
>>
>> > This works as intended when you pass it a pointer to a Struct; however,
>> it
>> > should also work (you would think, since the Unmarshaller can handle
>> both
>> > types) a pointer to a *map[string]interface{}; however, it does not.
>> Are
>> > there any future plans to implement this option on both types?
>>
>> You're talking about [1], are you?
>>
>> If yes, the commit [2] which closed it specifically talks about struct
>> types, so the function behaves as documented.
>>
>> On the other hand, I have two questions to narrow the scope of your
>> claim down.
>>
>> - To carry out its intended task, DisallowUnknownFields() has to operate
>> on a value which it can use to figure out the set of known fields.
>>
>> In the case of a map this suggests that the map passed to that method
>> must be populated with the keys which would define the names of
>> the known fields (and the values assigned to those keys are expected
>> to be overwritten by the decoding process). Is this what you're
>> proposing?
>>
>> - Why a pointer to a map?
>>
>> In my eyes, this suggests that you may legitimately pass a pointer
>> to an unitialized map value and expect the decoder to create one for
>> you; is that correct?
>>
>> If "yes" is the answer to the both points, they cannot be satisfied
>> together: to fulfill the first requirement the map value must be
>> non-nil,
>> and you cannot expect the decoder to initialize it for you.
>>
>> All in all, I suggest you to create a proposal in the issue tracker.
>> Just be sure to be crystal clear, when laying it out -- to save the devs
>> from guessing what you really meant.
>>
>> 1. https://github.com/golang/go/issues/15314
>> 2.
>> https://github.com/golang/go/commit/2596a0c075aeddec571cd658f748ac7a712a2b69
>>
>>
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