Questions on acts_as_versioned

Thanks, Rick, for a great plugin. But one thgn leads to another, sort
of like pulling at the thread in the willy jumper .... :slight_smile:

Three questions about acts_as_versioned; the second leads to other
issues.

1. use of :sequence_name
     is this the "order_by"? How is this going to be different from
using the ':version_column' to order the
     revisions.

2. Derived from (1).
     If I have a ':version_column' set and I want optimistic locking
as well, how do I do that?

3. I'm very unclear about using ':extend' or the "acts_as_versioned
do ... end" construct.

Obviously I want to be able to reference any revision of the Page and
any field or method:

... something
    page.revision(rev_no).title = "Hello World".reverse
    page.revision(rev_no).updated_at.suc === page.updated_at
    display = page.revision(rev_no).render_content_to_html

If I wasn't using acts_as_versioned and was doing this with an
explicit revision table
I'd be writing thigns like

    class Page < ActiveRecord::Base
       has_many :revisions
       has_one :current_revision, :class_name => 'Revision', :order =>
'rev DESC'

but I'd really like to DRY and not have to have a separate Revision
model.

Any input or examples would be appreciated.

Thanks, Rick, for a great plugin. But one thgn leads to another, sort
of like pulling at the thread in the willy jumper .... :slight_smile:

Three questions about acts_as_versioned; the second leads to other
issues.

1. use of :sequence_name
     is this the "order_by"? How is this going to be different from
using the ':version_column' to order the
     revisions.

This is some postgres thing, you can probably ignore it on other databases.

2. Derived from (1).
     If I have a ':version_column' set and I want optimistic locking
as well, how do I do that?

I think you just set the version column to lock_version. I've never
used optimistic locking, so it may need some patches to get working
correctly. Feel free to contribute if you do this.

3. I'm very unclear about using ':extend' or the "acts_as_versioned
do ... end" construct.

It's similar to the :extend or block syntax of ActiveRecord
associations, only it defines the methods on both the current class
and the version class. For instance in Lighthouse (my Rails based
ticket tracker app), Ticket comments are really just versions of the
same ticket. But, I want the Ticket::Version model to quack like a
Ticket, so I add a lot of methods and associations inside the
acts_as_versioned block.

Obviously I want to be able to reference any revision of the Page and
any field or method:

... something
    page.revision(rev_no).title = "Hello World".reverse
    page.revision(rev_no).updated_at.suc === page.updated_at
    display = page.revision(rev_no).render_content_to_html

If I wasn't using acts_as_versioned and was doing this with an
explicit revision table
I'd be writing thigns like

    class Page < ActiveRecord::Base
       has_many :revisions
       has_one :current_revision, :class_name => 'Revision', :order =>
'rev DESC'

but I'd really like to DRY and not have to have a separate Revision
model.

Any input or examples would be appreciated.

acts_as_versioned creates another class for you. Check out the code
(http://projects.wh.techno-weenie.net/browser/plugins/acts_as_versioned/lib/acts_as_versioned.rb),
it sets up a versions association. You can define helper methods to
access them by version # if you want. I suppose the current way would
resemble:

@page.versions.find_by_version(234)