On 7/12/2010 10:17 PM, Casey Ransberger wrote:
> I thought this was a bang-up idea. Any particular reason the
> Configurations package hasn't made it into the Trunk? Anything I can do
> to help?

Mostly because I've been second-guessing myself. After playing with it 
for a while it felt like bad fit for the job. Perhaps others have an 
insight on this, but my feeling of what this is supposed to be doing is 
to provide an easy and straightforward way to install "new stuff". As 
such, I would expect it to look more like a Windows (or Mac) installer 
that is listing features for example:

	WebClient Options:
		[x] Code (required)
		[x] Tests (optional)
		[x] Documentation (optional)

instead of something like apt or rpm (i.e., even in the Ubuntu Software 
Center it's virtually impossible to figure out what the name of the 
package with the necessary headers for X11 is). Unfortunately, Metacello 
resembles more the latter than the former and I'm not sure it's a good 
idea to try to transform from one into the other.

In addition, Metacello's heavyweight nature keeps bothering me. It may 
be fine to load Metacello for something complex like Seaside, but *lots* 
of good things (say the games) are single MCZ package installs where the 
overhead of installing Metacello completely dominates everything else. 
And given that in such a case Metacello does nothing that Installer 
can't do in a single line it leaves me wondering why we'd use such a 
high-overhead solution.

So I've been thinking if it isn't better to regroup things and define 
that the stuff that comes with the image is more light-weight than 
Metacello by default - it may *use* Metacello for installing it where 
that's desirable but it wouldn't require Metacello for simple things. 
Instead, it would focus more on those "installer options" that say from 
a user perspective here are the things that you may want to install and 
they boil down into some packages.

Basically, it would boil down to a "configuration" (needs a different 
name to avoid confusion) being a container of information about a piece 
of software. It contains the authore, description, and other meta info, 
has a set of installable options, and knows what further code to run 
when any such option is selected. So that, for example, in Seaside your 
options might be something along the lines of:

	Seaside 3.0 options:
		[x] Seaside (required)
		[x] Pier (optional)
		[x] Extras (optional)

which then map into installing particular targets from the associated 
Metacello configuration.

The other advantage of this approach would be that it can introduce a 
form of "late-binding" in the installation process. For people who want 
to maintain their package(s) elsewhere (Seaside or OB) it introduces an 
indirection where the "in-image" configuration simply defers to the 
"ex-image" configuration. We had talked about this in the past and this 
would make that pattern explicit.

And of course, for the simple packages we'd literally just use the 
one-line Installer loading mechanism.

Comments welcome.

Cheers,
   - Andreas