A syntax for subaddresses in local parts,
Sensible definitions such as
The ``plus-terminated prefix'' of an address is everything up to and
not including the first "+" character, or the entire address if it
does not contain a "+" character.
or
The ``dash-separated components'' of an address are its maximal
substrings not containing "-" characters. For example, the
dash-separated components of "jean-marc-sos-request" are the strings
"jean", "marc", "sos", and "request".
are fine with me.
Such definitions might be useful in, e.g., an informational document
surveying common address formats and their uses.
The one and only rule that
is necessary is that the primary address always identifies the same
entity regardless of what subaddress is attached.
What does this mean? What is an ``entity''? Why is this rule necessary?
More importantly, that rule is inconsistent with reality. There are
a+b(_at_)host and a+c(_at_)host addresses that are _not_ the same entity.
I've been asking for alternatives, but the only
suggestion so far is that we throw away combinations of agents that
don't already understand one another. Not very helpful either to those
who'd like to change existing agents to be able to understand, nor to
those who want to write new agents.
On the contrary. Someone who wants to write (e.g.) a UNIX delivery agent
that supports qmail's address hierarchy simply has to use the variables
supplied by qmail-local: LOCAL, USER, EXT, EXT2, EXT3, etc.
---Dan
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