support encoding/decoding struct from/to an encoded array about go

[ugorji]

I'm struggling with this feature request, but I think it has some merit.

The c/c++ msgpack lib is somewhat complicated, but the MSGPACK_DEFINE macro may be something that may help give a hint to the library, possibly allowing it encode a struct as a map.

However, there is still merit on the Go library to decode to support decoding an encoded array in to a struct. After some thoughts and prototyping it, I'd add support for the feature and let you know when to test it.

Thanks.

[ugorji]

Please test this out and let me know that it worked for you.

[zx9597446]

hi, I've test this feature, it works well both with encoded map and encoded array, without any change in my test code, thanks!
however, after reading souce code that you commited, I realized that I also need an option can encode a struct to encoded array, for communation with msgpack cpp lib.
I understand that the cpp lib would be better accept encoded map as struct, but cpp is complicated, so I think better provide this option in golang lib.
comment?

[ugorji]

Hi,

I'm not comfortable with the idea of supporting a feature so that it works as the cpp library works. I'm more comfortable is we can defend the feature on its own merits.

Let me think about it and follow up.

[ugorji]

I thought about this, and the feature has merit on its own.

It allows user to create a non-homogenous but fully typed array in code.

For example, if you expect a 4-element array of integer, bool, string and map[string]int, you can define it using a type like:

type MyRequest struct {
  _struct bool `codec:",toarray"`
  Num int
  Flag bool
  Name string
  Properties map[string]int
}

Usage model is via one of the following:

type mh codec.MsgpackHandle
mh.StructToArray = true
// ...

Or by defining it in the struct tag:

type Mystruct struct {
  _struct bool `codec:",toarray"`
  // ...
}

Please test out and let me know if this works for you.

[zx9597446]

great! that's all I wanted.
I'll test this feature later.

[ugorji]

FYI: I've fixed the bugs I found while testing. Specifically, we have to use the same consistent logic during encoding and decoding. Please test out and let me know so I can close the issue.

Thanks.

[zx9597446]

I've test encode struct as array, it works fine with cpp lib.

thanks for providing these great features!

[ugorji]

Made more robust with change b25a055 .