[racket-dev] new package system and versions

Any chance of revisiting the new package system's stances on versions -- 
specifically, on the two issues:
1. Can subsequent versions of a named package (which has an identity)  
be non-backward-compatible?
2. Can a Racket setup (and even an individual program) have multiple 
versions of a package at the same time?

Regarding #1, the requirement to never make a non-backward-compatible 
version of a package without giving up package identity is a burden, and 
a deterrent to third-party package releases.

For a real-world example, see "http://planet.racket-lang.org/", where it 
looks like most of the familiar names (who were going to a good amount 
of trouble to release already), managed to release packages marked as 
non-backward-compatible (i.e., PLaneT major version number other than 
1).  Wouldn't requiring them to never break backward compatibility be a 
deterrent to releasing at all? Or, if they still released, would 
`dherman`, following the instructions of Racket to create a new package 
identity for any backward-incompatible version, have given us packages 
`javascript`, `javascript2`, ... `javascript9`, rather than `javascript` 
versions `1.x` through `9.x`.

No-backward-incompatibility might make sense for core Racket (although 
even core Racket has broken this multiple times), but it's a big 
deterrent to researchers, and to industry developers who are willing to 
open source components of their larger systems in lightweight ways.

Regarding #2, I suggest that should be revisited if #1 is revisited.

I think PLaneT got both of these a lot closer to right, at least for 
third-party packages.

Neil V.