Looseleaf Release Control

For a looseleaf partition, TopLeaf maintains an essentially separate file system for each release. The data files generating the mainwork, or first release) form the basis of subsequent editing leading to the second issue (release 1). When typesetting release 1 TopLeaf compares the new pages with the corresponding pages of release 0, and selectively outputs only those pages that are new or different from release 0.

The life of a looseleaf publication proceeds in this way with a sequence of releases, each of which is controlled by comparison with the material published for the previous release.

Thus each partition contains a “Published” phase (the file system belonging to the release last published) and the "Update" phase (the release in preparation).

TopLeaf API commands for the Published phase are concerned with acquiring and printing output pages, and status information of the release, including details of the input data and how it was allocated to the leaves.

API commands for the Update phase are concerned with typesetting the new material and assessing the printed content of the new release. With third party applications it is most likely that the new data file will be processed outside TopLeaf and presented to TopLeaf for a trial typesetting run, at least in part to determine the size of the release output.

In addition to the above routine processing commands, the third party application needs commands to exercise the higher-level control of moving the publication from one phase to the next, that is, authorising the present Update phase to become the new Published phase, to initiate the output of the new Published release, and to authorise the initiation of the next Update phase. These functions are grouped under the heading “Release Processing” in “API Calls by Function”.