[CMake] Need some directions for non-trivial setup

[Marcel Loose]

Hi Klaim,

It's a bit clearer to me  now ;-)
Reading between the lines I get the feeling that you're probably better
off using just a single project anyway.
A developer doesn't need to continuously update the whole project when
working on his subproject. Building the whole thing once in his working
copy should suffice.

Personally, I have not yet gained any experience with
EXTERNAL_PROJECT(), so I cannot really help you there. If your
subsystems are *really* stand-alone pieces of software, then you should
create different CMake projects for them. However, like I said, I get
the feeling that that's not the case in your situation.

You might consider to use multiple PROJECT() commands inside your
source tree. It will make your life slightly easier when you later
decide you do want to split things up.

Hope this helps.
Marcel Loose.

>>> On 3-12-2010 at 13:13, in message
<AANLkTimfWeyEJP+MAQKZcg-7a92beBvxhGO0BXRLjP9x at mail.gmail.com>, Klaim
<mjklaim at gmail.com> wrote: 
> Thanks for pointing EXTERNAL_PROJECT , I've looked at it but can't
> understand how to get the path from outside.
> I'll try again see if I missed something about this feature and get
back to
> you.
> 
> The projects are almost all independent and I need to allow working
with a
> clone of one subproject without retrieving everything, just it
dependencies.
> 
> I'll try to be more clear :
>  - there is a common language used to describe a "Sequence" (it's
not
> important so just understand that the important projects in the
framework
> will require this)
>  - there are tools, all made to manipulate the sequences, so each
project is
> independant (separate repo) but some projects need to use other
projects, so
> we need to provide their path in their Cmake
>  - there are players that are like tools but are just interpreter
projects -
> anyway they are as indpendant or dependant as tools
projects/subrepos
>  - now I have central repository ("default") that is just meant to
gather
> everything together; That's for people wanting everything but they
are few.
> Most subproject developers will just get their dependencies and work
from
> their, without updating the dependencies while developping. If you
get the
> "default" repo, you have synchronized repos togethere (read: we use
specific
> tags for each subrespo). So the default repository is mainly for the
> developers needing to touch everything. Like me.
> 
> Is it more clear?
> 
> On Fri, Dec 3, 2010 at 11:16, Marcel Loose <loose at astron.nl> wrote:
> 
>> >>> On 2-12-2010 at 16:12, in message
>> 
>
<AANLkTimJU5WAv=EKxnbmkpLnL7dN_c+XsSgKOEFm5Le6 at mail.gmail.com<EKxnbmkpLnL7dN_c%
> 2BXsSgKOEFm5Le6 at mail.gmail.com>>,
>> Klaim
>> <mjklaim at gmail.com> wrote:
>> > Hi!
>> >
>> > I'm currently trying to understand how to use CMake for a
non-trivial
>> setup
>> > of multiple-projects-framework. I'm a beginner at CMake (as
developer
>> I
>> > mean, not as library user).
>> > I've read the docs and I tried to read the Ogre project CMake
>> organization
>> > but it's a bit overkill for my project I think. Anyway, I'm lost
>> here
>> > because
>> > I think I don't understand all I need to achieve what I want.
>> >
>> > My project is made of several sub projects that are all in
separate
>> > (mercurial) repositories.
>> > There is one "default" repository that use the mercurial subrepos
>> feature to
>> > gather everything in one big framework project.
>> > You can see the repos there :
>> > http://code.google.com/p/art-of-sequence/source/browse/ (it's an
open
>> source
>> > project but Idon't have the website ready yet to explain the
>> concept)
>> >
>> > The Cmake organisation I want to setup I've already seen
somewhere
>> else I
>> > think, but I'm a bit lost with all the ways to do it and I think
I'll
>> make
>> > something very bad if I don't ask here for help here.
>> > I need each project (subrepo) to be available separately and can
be
>> built
>> > giving to Cmake the paths of the project's dependencies.
>> > And I need the default repo to provide the paths.
>> >
>> > So I have this folder organisation in the default repo (that
gather
>> all
>> > subrepos) :
>> >
>> > /language                       # the intermediate language
(AOSL)
>> > definition project/subrepo
>> > /tools/                            # the folder that will contain
all
>> the
>> > tools projects/subrepos
>> > /tools/aosdesigner           # a tool project/subrepo (in fact
the
>> most
>> > important) - an executable
>> > /tools/aoslcpp                 # a tool project/subrepo that is a
>> dependency
>> > of aosdesigner - a library (shared)
>> > /players/                         # the folder that will contain
all
>> the
>> > players (AOSL interpreters)
>> > /players/aoswebplayer     # a player project/subrepo
>> >
>> > There will be additional "tools" and "players" projects, and I
think
>> I'll
>> > need another folder for "exporters" but that's another subject.
>> >
>> > Here, what I'm trying to do, is to have a CMakeLists.txt for each
>> project
>> > (but "/language" that is not source code but xsd, xml and text).
>> > Those projects will need the path of dependencies, like
>> "/tools/aosdesigner"
>> > will require the path of "/tools/aoslcpp".
>> >
>> > Then I want to set the paths of each project at the root level.
It
>> would be
>> > perfect if I could symply get the name of all folders in
"/tools/"
>> and
>> > "/players/"
>> > and simply provide them to the CMakeLists.txt of the sub
projects.
>> >
>> > Is there a simple example of this kind of organisation out there
that
>> I
>> > could be inspered of?
>> > Do you have some guidance to give me to setup all this?
>> > I tried to write this organisation but I'm clueless on how to
gather
>> and
>> > provide the paths of each projects...
>> >
>> > Once I understand how to do this I think I'll use this
organisation
>> for
>> > another big project too.
>> >
>> > Any help would be really.....helpful :)
>> > Thanks for reading. Tell me if I was not clear on some points.
>> >
>> > Klaim
>>
>> Hi Klaim,
>>
>> It's not completely clear to me how tightly your subprojects are
>> coupled.
>>
>> I would suggest you'd create a CMake project for each of your
>> subprojects and use the EXTERNAL_PROJECT feature to import the
required
>> subproject. UNLESS: your subprojects cannot really exist as
stand-alone
>> products, but are just parts of one overall project. In that case,
I
>> would choose to create just one CMake project.
>>
>> HTH,
>> Marcel Loose.
>>