Formatting suggestion

[KoosBusters]

When implementing a protocol using an message implementation guide it is nice to follow the notation of the specs. As I understand the PICTURE notation is used for implementation guides for Tradacoms based protocols. The edifact implementation guides follow the following structures:

a alphabetic characters n numeric characters an alpha-numeric characters a3 3 alphabetic characters, fixed length n3 3 numeric characters, fixed length an3 3 alpha-numeric characters, fixed length a..3 up to 3 alphabetic characters, variable length n..3 up to 3 numeric characters, variable length an..3 up to 3 alpha-numeric characters, variable length

As I would like to create my POCO classes using the edifact notation I created an interface 'IFormatSpec' that is now implemented by PictureSpec and by the newly created EdifactSpec.

The same formatting can now be achieved in 2 notations: [EdiValue("n3", FormatterType.EdifactSpec, Path = "DTM/0/0")] or [EdiValue("9(3)", FormatterType.PictureSpec, Path = "DTM/0/0")]

The difference is that the picture notation cannot support variable length so the Picuture class sets the VariableLength always to false in its class so the write can use the IFormatSpec interface and add padding to all EdiValues defined in the Picture notation. The EdiSpec looks for .. in the specification string and sets the VariableLength accordingly.

I'm not so happy with the fact that an enum has to be provided to the EdiValue attribute to switch between the EdifactSpec and PictureSpec but I didn't find a nicer solution for this at this moment. The EdiValueAttribute class is an sealed attribute at this moment and I think that is for a reason, otherwise a new class could extend EdiValueAttribute and set the type enum when calling its base constructor. It is also possible to differentiate between the two notations using some regex to determine either picture or edifact notation, but it feels wasteful to use resources for this determination.

This pull requests main purpose is to collect feedback on this first attempt of an format refactor.

Releated to #23 and #43

[cleftheris]

I am planning to work on this. I will change to a common base class. So instead of the Picture struct there will be a ValueSpec, Spec or something similar. I will not make use of an Enum for this because I feel that it is an overkill if done for performance reasons that makes value configurations more cumbersome. I love the work you have done so I will use it. When done please consider contributing your own tests.

[cleftheris]

@KoosBusters hi again. I know it has been some time since I posted to this thread.

I would like to know if you are willing to help maintaining the Edi.Net project. My suggestion is primarily based on your previous contributions. Moreover, I have been overwhelmed by other obligations and the project has attracted significant attention that needs to be addressed.

If you are interested let me know. We could start by merging the above pull request.