Add whitespace in tag match regex

[Inori]

I'm not sure if this fix matches YAML standard, but sometimes these is whitespace in tag suffix, for example, it is widely used in Unity Engine's meta file, like this:

%YAML 1.1
%TAG !u! tag:unity3d.com,2011:
--- !u!1 &29818312667802682
GameObject:
  m_ObjectHideFlags: 0
  m_CorrespondingSourceObject: {fileID: 0}
  m_PrefabInstance: {fileID: 0}
  m_PrefabAsset: {fileID: 0}
  serializedVersion: 6

Without the patch, we'll only get unity3d.com,2011:1 for the tag, but what I need is unity3d.com,2011:1 &29818312667802682. Or are there some better ways to achieve this?

[jbeder]

This is likely not what you're looking for - the & represents an anchor (that can be referred to later by an alias with *), so this should be parsed as (1) a tag and (2) an anchor for the entire document. This is what yaml-cpp does; you can see this easily by adding an alias at the end:

%YAML 1.1
%TAG !u! tag:unity3d.com,2011:
--- !u!1 &29818312667802682
GameObject:
  m_ObjectHideFlags: 0
  m_CorrespondingSourceObject: {fileID: 0}
  m_PrefabInstance: {fileID: 0}
  m_PrefabAsset: {fileID: 0}
  serializedVersion: 6
foo: *29818312667802682

and running this through util/parse:

$ ./util/parse test.yaml
!<tag:unity3d.com,2011:1> &1
GameObject:
  m_ObjectHideFlags: 0
  m_CorrespondingSourceObject: {fileID: 0}
  m_PrefabInstance: {fileID: 0}
  m_PrefabAsset: {fileID: 0}
  serializedVersion: 6
foo: *1

(Note that yaml-cpp renames the anchor to 1, which is its standard behavior.)