Re: [Configobj-develop] Can I get a value through the interpolation path?

[David H. <neg...@gm...>]

Is there some reason you can't use validate to set the default?

Consider the following validation spec:

[project]
parcels = string_list()

    [[DEFAULT]]
    default_branch = string()

    [[__many__]]
    branch = string(default=$default_branch)


Applied to the following config:

[project]
parcels = parcel1,parcel2

    [[DEFAULT]]
    default_branch = master

    [[parcel1]]

    [[parcel2]]
    branch = someotherbranch


Now when you parse the config, and validate it against the spec, you
get the following:

>> cfg['project']['parcel1']['branch']
>> 'master'
>>
>> cfg['project']['parcel2']['branch']
>> 'someotherbranch'


No hackery.  And you get the usual added benefits of validation.


cheers,

-David



On Wed, Mar 17, 2010 at 18:23, Entity Reborn <ent...@gm...> wrote:
>
> On Wed, 2010-03-17 at 14:53 -0500, Jason Baker wrote:
> > On Wed, Mar 17, 2010 at 1:52 PM, Michael Foord
> > <fuz...@vo...> wrote:
> >
> >
> >         Well - as far as I can tell setdefault is exactly a "magical
> >         get_by_interpolation function" - so I guess I'm not
> >         understanding you (setdefault is also a standard dictionary
> >         method).
> >
> >         Michael
> >
> > Consider the following config file:
> >
> > [section]
> > foo = 'bar'
> >   [[subsection]]
> >   baz =  '$foo'
> >
> > Suppose I have a Section object that represents the subsection
> > (configobj['section']['subsection']).  Now suppose I do this:
> >
> > a = subsection['baz']
> >
> > Since the option baz contains a string '$foo', what happens is
> > something like the following:
> >
> >  1. The interpolater looks in subsection to see if it has a foo
> > option.
> >  2. When it sees that it doesn't exist, it checks the DEFAULT section.
> >  3. When it sees that *that* doesn't exist, it checks the parent
> > section
> >  4. The parent section has a foo option, so it returns it.
> >
> > Now suppose I do this:
> >
> > b = subsection['foo']
> >
> > What happens is more like the following:
> >
> >  1. Subsection is searched for a foo option.
> >  2. Subsection doesn't have a foo option, so it throws a KeyError.
> >
> > What I would like is some kind of function such that I can do
> > something like this:
> >
> > c = subsection.get_by_interpolation('foo')
> >
> > ...that would look for an option named foo, but would look in the same
> > places as the first operation.  Here's the reason why I want to do
> > this.  Using envbuilder, I want to write a config file like this:
> >
> > [project]
> > parcel = 'parcel1', 'parcel2'
> >
> >   [[DEFAULT]]
> >   branch = 'master'
> >
> >   [[parcel1]]
> >
> >   [[parcel2]]
> >   branch = 'someotherbranch'
> >
> > [commands]
> >   [[update]]
> >   default = 'git pull origin %branch'
> >
> > Essentially, I've written my own interpolation engine for commands
> > such that a variable beginning with % is to be on the parcel.  So when
> > I run "envb update", it should essentially run:
> >
> > # Get parcel1 using branch from default
> > $ git pull origin master
> >
> > # Get parcel2 using branch from parcel2
> > $ git pull origin someotherbranch
> >
> > However, parcel1 would throw an exception because it doesn't actually
> > have an option named "branch".  Of course, I could do something like
> > this:
> >
> > [project]
> > parcels = 'parcel1', 'parcel2'
> >
> >   [[DEFAULT]]
> >   default_branch = 'master'
> >
> >   [[parcel1]]
> >   branch = '$default_branch'
> >
> >   [[parcel2]]
> >   branch = 'someotherbranch'
> >
> > [commands]
> >   [[update]]
> >   default = 'git pull origin %branch'
> >
> > ...but that gets tedious when you start dealing with a nontrivial
> > amount of parcels.
> >
> > Does that make things more clear, or did I just confuse you even
> > more?  :-)
> >
> > ------------------------------------------------------------------------------
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> > proactively, and fine-tune applications for parallel performance.
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> > _______________________________________________ Configobj-develop mailing list Con...@li... https://lists.sourceforge.net/lists/listinfo/configobj-develop
>
> I as well am interested in this. Auto-interpolation of a tree of
> sections. Or rather, start from a specified branch, and then percolate
> towards the trunk until a valid variable is found.
>
> My Example: (IRC Bot)
> [servers]
>    nick = BarBaz
>    # ...
>    [[Freenode]]
>        nick = FooBar
>        # ...
>    [[EFNet]]
>        # ...
>
> config['servers']['EFNet'] (or some similar syntax) would return
> "BarBaz"
>
>
> ------------------------------------------------------------------------------
> Download Intel&#174; Parallel Studio Eval
> Try the new software tools for yourself. Speed compiling, find bugs
> proactively, and fine-tune applications for parallel performance.
> See why Intel Parallel Studio got high marks during beta.
> http://p.sf.net/sfu/intel-sw-dev
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