[zeromq-dev] value arrays in ZPL

[Joshua Tacoma]

Hi there, I think ZDCF is real nifty so I've been working on an
implementation in one of my favourite languages.  Things are coming
along ok, but I'm not sure what I'm going to do about value arrays and
ZPL.

Both RFCs 5 and 17 mention three properties ("subscribe", "connect", and
"bind") that may be specified as value arrays, and both give examples in
JSON.  Is there a conformant way to represent these same arrays in ZPL?

Since ZPL itself doesn't seem to have any opinion about the
interpretation on property values, we could decide on an interpretation
that allows good old 0x20 to delimit values for the "subscribe" and
"connect" properties (it's not valid in addresses anyway).  I'm not sure
what to do about "subscribe", but this is a start.  An example:

    frontend
        bind = tcp://eth0:5555 inproc://device

Another opening in ZPL is that it doesn't explicitly require that
property names be unique within their scope.  This could solve the
problem perfectly:

    frontend
        option
            subscribe = "10001"
            subscribe = "10002"
        bind = tcp://eth0:5555
        bind = inproc://device

I'm not sure whether these approaches respect the specs, so a final
option is to accept this as a limitation of ZPL.  If I don't find any
clear answers, this is what I'll do.  Keep It Simple.

What do you think?

- Joshua