8.10: About Dependency Granularity
- Page ID
- 45281
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)We want to discuss the difference between depending on a package, depending on a project and the different ways to express it. Imagine the following baseline1.1 from Fame.
baseline11: spec
<version: '1.1-baseline'>
spec for: #'common' do: [
spec blessing: #'baseline'.
spec description: 'Baseline 1.1 first version on SmalltalkHub, copied from baseline
1.0 on SqueakSource'.
spec repository: 'http://www.smalltalkhub.com/mc/Moose/Fame/main'.
spec
package: 'Fame-Core';
package: 'Fame-Util';
package: 'Fame-ImportExport' with: [spec requires: #('Fame-Core' ) ];
package: 'Fame-SmalltalkBinding' with: [spec requires: #('Fame-Core' ) ];
package: 'Fame-Example';
package: 'Phexample' with: [spec repository: 'http://smalltalkhub.com/mc/
PharoExtras/Phexample/main' ];
package: 'Fame-Tests-Core' with: [spec requires: #('Fame-Core' 'Fame-
Example' 'Phexample' ) ].
spec
group: 'Core' with: #('Fame-Core' 'Fame-ImportExport' 'Fame-Util' 'Fame-
SmalltalkBinding' );
group: 'Tests' with: #('Fame-Tests-Core' ) ].
In this baseline, package: 'Phexample' with: [spec repository: 'http://smalltalkhub. com/mc/PharoExtras/Phexample/main' ]; expresses that there is one package that can be found in the specified repository. However, such an approach is not good because this way you are just downloading a package from a repository and Metacello is not involved. For example, if PhexampleCore has dependencies they will not be loaded.
In the following baseline1.2 we express dependencies between projects as presented above.
baseline12: spec
<version: '1.2-baseline'>
spec for: #'common' do: [
spec blessing: #'baseline'.
spec description: 'Baseline 1.2 to make explicit that Fame depends on HashTable
and Phexample (now on smalltalkHub and with working configurations'.
spec repository: 'http://www.smalltalkhub.com/mc/Moose/Fame/main'.
spec project: 'HashTable' with: [
spec
versionString: #stable;
repository: 'http://www.smalltalkhub.com/mc/Moose/HashTable/main' ].
spec project: 'Phexample' with: [
spec
versionString: #stable;
repository: 'http://www.smalltalkhub.com/mc/Phexample/main' ].
spec
package: 'Fame-Core' with: [spec requires: 'HashTable'];
package: 'Fame-Util';
package: 'Fame-ImportExport' with: [spec requires: #('Fame-Core' ) ];
package: 'Fame-SmalltalkBinding' with: [spec requires: #('Fame-Core' ) ];
package: 'Fame-Example';
package: 'Fame-Tests-Core' with: [spec requires: #('Fame-Core' 'Fame-
Example') ].
spec
group: 'Core' with: #('Fame-Core' 'Fame-ImportExport' 'Fame-Util' 'Fame-
SmalltalkBinding' );
group: 'Tests' with: #('Fame-Tests-Core' ) ].
Now when we express dependencies between projects we lose the fact that this is the package Fame-Tests-Core that depends on Phexample and this is a loss of information.
To keep such information we can simply define in our configuration a new project named for example, PhexampleCore and we will be able to express that Fame-Tests-Core is dependent on PhexampleCore as follows.
spec
project: 'PhexampleCore'
with: [ spec
versionString: #stable;
loads: #('Core');
repository: 'http://www.smalltalkhub.com/mc/Phexample/main' ].
....
'Fame-Tests-Core' with: [spec requires: #('Fame-Core' 'Fame-Example'
'PhexampleCore' ) ].