write a bash function that mimic 'return' builtin

Question

I'm trying to write a bash function that would do the equivalent of the return builtin, it could be used like this:

f() {
    echo a
    my_return 15
    echo c 
    return 17
}

It would have to behave exactly as return builtin is expected to work.

The context is that I'm looking in the depth of bash for fun/experiments to mainly see if we can implement some higher language constructs and notions as are exceptions, continuations or similar concepts in bash.

I actually managed to implement the breaking of the instruction flow by using DEBUG trap returning a value of 2 (as explained in extdebug part of the bash manual, this simulates a return in the current function, but doesn't set the return value of it), the only problem is that this return value of 2 is then passed as the return value of the whole function, thus removing me the possibility to set it to an arbitrary value.

Using RETURN trap did not seem to work neither. It seems we can't set the return value of the function in any way. I achieved already pretty impressive flow control feats thanks to DEBUG/RETURN traps, and the goal seems not so far anymore.

So would you know about a way to achieve this implementation of my_return in pure bash, with current implementation ? if not, what minimal modification would you suggest in bash implementation to allow this ? (I'm thinking of patches maybe on trap.c on run_{debug,return}_trap functions, allowing to set the return value of the returning function, or maybe adding a custom bash builtin, as it seems to be quite pluggable here).