Module history 

The resource’s history as actions every framework app answers, so the people, scripts and agents working on it can look back, compare and take back through the same door they edit through:

• undo / redo: the caller’s own last steps (an agent’s are those of its run), or a named agent run’s;
• restore: a past version, whole or only some items, as a new step;
• review-restore / restore-reviewed: pin a causal review and restore exact differing paths only if the live frontier still matches;
• checkpoint: name the current version;
• history: every step with what it was given, who made it, in which run, and which are undone or checkpointed;
• diff: the items that differ between two versions.

Versions are change ids from history or checkpoint names. The verbs are ui_core::history_source::steps; an app with a richer comparison of its own (a picture of what changed) publishes its own diff, which takes the place of this one.

Structs

HistoryVersion

One version of the resource as an in-app history list shows it: what was done, by whom, and whether it was taken back or named.

Functions

version_name

A version’s name in an answer: its change id, or several for a version with concurrent heads.