8.2: One Tool for Each Job

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Pharo provides three tools for managing software packages; they are closely related, but each has its own purpose. The tools are Monticello, which manages versions of source code, Gofer, which is a scripting interface for Monticello, and Metacello, which is a package management system.

Monticello: source code versioning. Source code versioning is the process of assigning unique versions to particular software states. It lets you commit a new version, update to a new version committed by someone else, merge changes, look at the differences between versions, revert to an older version, etc.

Pharo uses the Monticello source code versioning system, which manages Monticello packages. Monticello lets us do all of the above operations on individual packages, but Monticello does not provide a good way to easily specify dependencies between packages, identify stable versions of a package, or group packages into meaningful units. Chapter 7 describes it.

Gofer: Monticello's scripting interface. Gofer is a small tool that sits on top of Monticello: it is used to load, update, merge, difference, revert, commit, recompile and unload groups of Monticello packages. Gofer also makes sure that these operations are performed as cleanly as possible. For more information, see Chapter 8.

Metacello: package management. Metacello introduces the notion of project, as a set of related Monticello packages. It is used to manage projects, their dependencies, and their metadata. Metacello also manages dependencies between packages.