Hi Mira:

Josh proposed a good way to structure the main-entry of an APPC so that we have one integrated
main-entry and only one kind of APPC (something you wanted from the beginning):

[start]
[traversal]
[finish]
[return]

In the start and finish parts we use statement sequences that refer to participant parts.
If the traversal exists,  it is called a traversal style APPC that can enter "traversal fusion" with other APPCs.

Josh thinks of a non-existent traversal as an empty traversal that does not go anywhere. If there are before and after methods they are never executed
and a warning is produced.

Regarding integrating AspectJ and APPC, Josh thinks that APPCs should be distinct from aspects. Aspects are intrusive and APPCs are non-intrusive.

from A to B{
  before set*(*, ... ,*) { ....}
}

is an aspect adding before methods to set methods.

How does this look?

-- Karl