A software-development system or versioning system has a collection of modules for performing individual development functions such as document editing, keyword processing, and private-copy management. Each module has an interface compatible with that of the others, so that modules can be added to or substituted for the original modules, if the new modules conform to the interface. The architecture of this system supports the performance of development actions such as document merging and keyword expansion at any location within the system. The system operates upon documents and files as objects in an object space, rather than in name spaces.