Encode unexported fields of go Structs

[heri16]

Fixes #63

Changes:

• Encode unexported fields of goStructs.
• Use encoding.TextMarshaler on unaddressable goStructs (e.g. golang stdlib time.Now())

Depends on #68

[halturin]

Instead of trying to encode "unexported" fields, I would add checking for the method Marshal() in the encoder and Unmarshal() for the TermIntoStruct/TermMapIntoStruct accordingly. I believe, "unexported" field must be hidden from the outside world. That's why they called it "unexported" isn't it? :)

var bin []byte
var err error
if obj, ok := term.(interface{Marshal()}); ok {
    bin, err = obj.Marshal()
    ...
}

[halturin]

There is Marshal/Unmarshal feature in the coming release. So this PR won't be accepted.

[halturin]

not valid any more

[heri16]

Nice one

[heri16]

Instead of trying to encode "unexported" fields, I would add checking for the method Marshal() in the encoder and Unmarshal() for the TermIntoStruct/TermMapIntoStruct accordingly. I believe, "unexported" field must be hidden from the outside world. That's why they called it "unexported" isn't it? :)

var bin []byte
var err error
if obj, ok := term.(interface{Marshal()}); ok {
    bin, err = obj.Marshal()
    ...
}

That may be true most of the time, but not all the time. Third-party libraries commonly have structs that have unexported fields that cannot be accessed unless you can modify the third-party source code to add accessor methods.

And unmarshall / marshall methods that you add would not be able to read those same unexported fields.

If the goal is transparent and efficient transport of in-memory state across the wire, then the use case could be valid.

Documenting how this could be done via the new ergo API would be great.