Each package using struct field tags assumes that
it is the only package storing data in the tag.
This CL adds support in package reflect for sharing
tags between multiple packages. In this scheme, the
tags must be of the form
key:"value" key2:"value2"
(raw strings help when writing that tag in Go source).
reflect.StructField's Tag field now has type StructTag
(a string type), which has method Get(key string) string
that returns the associated value.
Clients of json and xml will need to be updated.
Code that says
type T struct {
X int "name"
}
should become
type T struct {
X int `json:"name"` // or `xml:"name"`
}
Use govet to identify struct tags that need to be changed
to use the new syntax.
R=r, r, dsymonds, bradfitz, kevlar, fvbommel, n13m3y3r
CC=golang-dev
https://golang.org/cl/4645069
I have written up a Marshal and MarshalIndent pair that should
closely reflect the way that Unmarshal works. I would love feedback
on making this code more accessible and efficient... I haven't used
reflecton on this scale before, so there is probably a lot of work
that can be done on that.
Some potentially controversial things:
- All tag names are lower-cased by default.
- Zero-valued struct values are skipped.
- No namespace prefix (o:tag, etc) mechanism is supplied.
- You are allowed to marshal non-struct values (even though unmarshal
cannot handle them).
- A tag for a non-XMLName struct field that isn't "attr", "chardata",
or "innerxml" is used as the name of the tag. This could wreak
havoc if you try to marshal a protobuf struct.
- The "innerxml" and "chardata" are inserted verbatim. If you try to
marshal something straight from unmarshal, the results could be
unexpected (remove "innerxml" support from Marshal would be one
possible solution).
R=rsc
CC=golang-dev
https://golang.org/cl/4539082
