About merging and overriding

Hi everyone.

I was asked at work to implement some network protocol using a INI format. I was almost resigned when I heard for the first time about yaml and almost fell in love with it ;-) It's been a week now and I am trying to make a good case to use yaml instead of INI. As INI was chosen because of its extreme simplicity, one of the point I now have to make is that it is not *that* hard to load a yaml stream in memory (we have to use C++). That goal in mind, I am currently working on a test program which allows simple queries on *any* yaml file. It loads the yaml file (using libyaml) in a graph ; basically, each node is either a std::string (scalar), a std::vector of nodes (yaml sequence), a std::map of nodes (mapping) or pointer to another node (alias). In our final application, that graph would of
  course be used by a higher-level to read and write message according to our protocole description.

These are the few things that I still don't understand with yaml ; I haven't been able to find these answers by myself, yet I might have just not seen them in the various documents I read... Don't be afraid to RTFM me ! 

1) Am I right about aliasing ? When the parser sends me an alias event, should I create a fully duplicated node, should I keep a pointer to the original node or should that decision be taken at a higher application level ?

2) Is merging really supported in yaml ? It is not mentioned in the yaml spec and no specific merge event is sent by the parser. Currently, when my program finds a merge key (<<), it replaces it by a *copy* of all the key-value pairs of the referenced mapping. Is it the right thing to do or should I keep the merge key as if it were any other key and let a higher level of application handle the merging part ?  

3) When loading a mapping, how should my program behave when it encounters a duplicated key ? Should it produce an error and exit, allow the identical keys to peacefully cohabit in the graph, overrides the old key by the new one or, again, let a higher power decide of what to do ?


Thank you for you attention...
Alexis Guillaume.


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