On 1/6/15 7:16 AM, Usman Bhatti wrote:

Dale,

I couldn't make it work with the upgraded Metacello and the script you provided.

Steps I did:

1. Download moose image:��

https://ci.inria.fr/moose/job/moose-5.0/

2. Update my Metacello to the 'full' version:

Metacello new

�� baseline: 'Metacello';

�� repository: 'github://dalehenrich/metacello-work:master/repository';

�� get.

Metacello new

�� baseline: 'Metacello';

�� repository: 'github://dalehenrich/metacello-work:master/repository';

�� onConflict: [:ex | ex allow];

�� load

3. File in the ConfigurationOfDummyParser (see the first message in the thread).

4.��Run this script to downgrade to PetitParser version 1.51

Metacello new
�� configuration: 'DummyParser';
�� version: '1.0';
�� repository: '???';
�� onDowngradeUseIncoming: #('PetitParser');
�� load.

The desired version is still not loaded, am I missing something here?

Good question, I don't have a lot of time today to spend time trying to reproduce your problem, but if you send me a copy of the Transcript produced while doing the load I might be able to spot the problem ...

regards,

A question: I always use Metacello with ConfigOf and have never used the scripting API myself or saw it being used elsewhere.

Can you provide a link that describes the use cases for both: ConfigOf vs. Scripting API?��

I've noticed the same thing:)

My "elevator pitch" for the script api goes like this:
�� 1. The scripting api maintains a registry of the actual project versions loaded into the image,
�� making #currentVersion obsolete. #currentVersion is bad because it does a calculation of
�� the current version that can be very slow and sometimes completely incorrect.
�� 2. The old api has rules that it follows when loading projects (i.e., newer projects always win) and
�� there is no mechanism for altering those rules. The scripting api provides mechanisms for
�� for bending those rules to fit your needs ... like allowing a downgrade of a project.

Part of the reason that people haven't changed has to do with how incredibly difficult it is to change the existing inertia. Another part of it is that I continue to support the old way of doing things, so there is no explicit motivation to change.

If you look back 2-3 years in the archives of the Metacello mailing list[1] you should be able to find a number of posts where I make a more detailed cases for the scripting api:)

At the end of the day, it isn't important to me to "get people to use the scripting api," as I said, I continue to support using the old api. I figure that when enough people start asking questions about how to "bend the Metacello rules" that folks will begin to use the "new" scripting api:)

Dale
[1] https://groups.google.com/forum/#!forum/metacello