Switch fields action

Right now Mp3tag provides us with an option for clearing of fields. You choose "Remove fields" from the "Select action type" drop down list and you can list fields that you want to remove [clear them of any data]. We can even do the opposite and choose not to remove certain fields while wiping completely all out the remaining ones

How about a similar action for switching fields? If the user want the field A become B and B have the content of A, then a simple action like this can do the trick: Format value "TEMPORARY": "%A%"

Format value "A": "%B%"
Format value "B": "%TEMPORARY%"
Format value "TEMPORARY": $char(0)

It is clean, it is simple and it works. But also cleaning a single field is simple [it only takes a >>$char(0)<<]- and yet we have not one but two versions of action types for this task. And why? Because it saves us time in the long run

This new type of action that I am proposing would simply have two fields to fill in- with [in my example] literally "A" and "B". And that would be it- you could not possible make this even more cleaner and / or simpler

It should already be possible with an action of the type "Guess value" e.g. move contents of ARTIST to COMPOSER and delete ARTIST in one action would look like this:
Source: $char(0)==%artist%
Pattern: %artist%==%composer%

There could also be a check box that would create a third field and automatically fill it witch data of such kind: YYYY-MM-DD HH:MM:SS - switch between "A" and "B"

This would help when re-organizing your files, especially in a case of some fatal mistake discovered months later [as it would give the user some vital information of what has happened and when]

One such switch you can easily remember. But what about switching a couple of them within 2-3 days radius? And then having to go back with one of them [because you re-discover that Winamp does not display ORIGYEAR tag field]. You can get lost, especially if you display in Columns and Tag Panel some more descriptive names and not just bare tag fields

This is already there in the shape of the "Format value" action. You only have to write it.

In respect to the original post: there is an example for switching fields in the FAQs:
/t/967/1

And once again, that

And

That is very neat way of doing that. Two lines of codes less than solutions presented by me

As for

on top of that Mp3tag could also automatically after such task compare values- make sure there were moved correctly and completely

I am not sure but I think some values may not be moved, on the account of trying to place some signs like a >>.<< or >>/<<. I mean, there would be removed from the field A but not placed in the field B or placed not entirely. And so user would loose data

So Mp3tag making then a comment like >>YYYY-MM-DD HH:MM:SS - switch between "A" and "B" with errors<< would comunicate to the user if it was really moved in a correct / complete way or not, should that kind of an error occur. And how Mp3tag would know what to show [comment about]? Well, it would have to compare the data before and after [temporarily creating some tag fields and then wiping them out after the whole process]

Yes this is so if the separator that you used in the "Guess value" action is not unique - so the pattern would probably be invalid.

But here we are at a basic problem of data processing: most computers do exactly what the user told them to do and not what the user might have intended to tell him what to do.

But if you know about limitations or possible issues, then you go around them or counter them somehow [idiot-proof them]- so that the system won't fall apart

Bad designers of bad system do not think ahead. And I already propose a kind of checkup for this new option, that could / should be implemented all together with it, for the convienience of users