[Cuis] A small variation to use provides / requires

[Germán Arduino]

Hi again!

After a bit of talk with Ken and Juan and taking in account that the
packages without prereq (when they are moved to an installer package) get
broken and fail when a use try Feature require: 'mypackage', I'm reverting
the installer packages of Swazoo and Aida to it's original state, that
means each one with it's own prereq (Assuming that the duplication of
prereq between different packages is not a problem).

Ken: I'm closing the issue in Swazoo, with this solution and the Aida
problem is solved also with the original form of installation, but take in
account that Aida really take a long time to load in a Cuis image (and you
can see the repetition of this cycle scan, process, etc).





2013/8/25 Germán Arduino <garduino at gmail.com>

> HI again!
>
> This sort of discussions/opinions are aproximately the same that happened
> and originated Monticello/Metacello/etc.
>
> Each option have its own strengths and weakness but, with the current
> state of provides/requieres in Cuis, I still think that is a better
> approach to separate the req's from the packages with the code. (I know
> that this option have also the drawbacks that you mentioned).
>
> But still I think that I gain flexibility and reuse of the packages,
> separating the requirements from the real code packages.
>
> Time will say when we advance to a more complex situations with different
> versions of each package, but I really not think that is an easy stuff.
>
> As I've said before, is just an opinion and I will think about a bit more.
>
>
>
> Each option have its own strengths and weakness
>
> 2013/8/25 Ken Dickey <Ken.Dickey at whidbey.com>
>
>> > .. when I've a package that have several req and at the same time this
>> package is a req of more than 1 different package, that at the same time
>> might have different req between them and coexist in the same image,...
>>
>> My recollection of a discussion with Dave Simmons about Smalltalk Agents
>> is that one can associate revision information with selector
>> lookup/dispatch to allow for multiple, different versions of software to
>> run in the same image.  I believe this was done in SmalltalkAgents.
>>
>> This is very useful when developing so that the debug tools can use the
>> old, stable version when debugging new development tools.  [This is also
>> done in some Scheme systems].
>>
>> The current provide/requires allows for this by supplying the version &
>> revision information.
>>
>> It is true that we currently do not make use of this in package checking,
>> but the code would be easy to add.
>>
>> The guide is that we try to do useful things in the most simple way we
>> can and then make things more smarter and more complex when and if we need
>> to.
>>
>>
>> Having a package specify its direct requirements helps here.
>>
>> If one separates the requirement description from the package, then the
>> package and its description can get out of synchronization -- the wrong
>> version information could be used.
>>
>> One more thing I have to track and update.  One more thing to go wrong.
>>
>> This is less of a danger when the description is part of the package.
>>
>> IMHO, package management is easier.  When I change a package, the
>> revision number is incremented so when the package is saved I know it is a
>> new revision.
>>
>> If two packages have conflicting requirements, each package requiring
>> other packages with  incompatible versions, then the code can check and
>> deal with that.
>>
>> Incompatible requirements are like missing requirements -- it means that
>> you can't safely use the mix of code packages together.
>>
>> It is much better to know this before the code is loaded, no?
>>
>>
>> It would help me if
>>   Feature require: 'Swazoo'
>>
>> Actually loaded Swazoo...
>>
>> $0.02
>> --
>> Ken [dot] Dickey [at] whidbey [dot] com
>>
>> _______________________________________________
>> Cuis mailing list
>> Cuis at jvuletich.org
>> http://jvuletich.org/mailman/listinfo/cuis_jvuletich.org
>>
>
>
>
> --
> Saludos / Regards,
> Germán Arduino
> www.arduinosoftware.com
>



-- 
Saludos / Regards,
Germán Arduino
www.arduinosoftware.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://jvuletich.org/pipermail/cuis_jvuletich.org/attachments/20130828/b1836cf5/attachment-0004.html>