yaml.v2 Unmarshaller接口的状态实现？

Question

This could either be a file path question, or a question on how to best implement an interface.

Given the following very simple yaml:

name: MyYamlName
data: some/relative/path.txt

I would like to unmarshal it to the following struct:

type VerySimple struct {
    name string
    data io.Reader
}

I'm already using the yaml.v2 library, and know that for simple types, I can implement the Unmarshaller interface. However, in my program, I can't assume an absolute root from which to base the relative path in the data field.

Is there a way to implement the Unmarshaller interface to pass a working directory, or maybe a different way to handle relative paths in Go?

Answer 1

It's pretty clear from the API documentation that this isn't supported. The natural way to support it, IMO, would be with a Decoder type, analogous to the json.Decoder type. It could be initialized with a root include path, or a list of include paths to search.

There is already a request for such a feature. It does mention working with multiple documents, which probably implies including an include path, although that specific feature has not yet been explicitly mentioned. I suggest offering your ideas in that thread.