Alias and diff books

An alias points to content instead of copying it; a diff adds a layer of changes on top of it. Both work on bits by their IDs, so they stay valid when the original is updated.

Alias books and bits

An alias book shows another book under its own properties: its own title, publisher or theme. A white-label edition or a co-published version needs no copy, and every update to the original reaches the alias.

[.book-alias]
[#Electrical installations — training edition]
[@publisher: Example Training Centre ]
[@theme: training ]
[@bookAlias: iec-60364-ed3 ]

An alias bit places a single bit of another book here, by its ID:

[.bit-alias][►p_4_1]

Diff books

A diff book is a layer of changes on a base book. Each change is a [.bit-diff] that names its target bit and the hash of that bit as it was when the change was written. If the base has changed since, applying the change raises a warning instead of silently writing over new content.

[.book-diff]
[#Swiss deviations]
[@bookDiff: iec-60364-ed3 ]

[.bit-diff]
[@diffRef: p_4_1 ]
[@diffBase: 7c21a9f0d2d0a206 ]
In Switzerland the limit is 0.2 seconds.
==== patch ====
[@diffOp:substitute][@diffAt:body][@diffFind:0.4 seconds]
--
0.2 seconds

• @diffRef is the target bit, @diffBase the hash it had.
• The body explains the change to a person.
• Each ==== patch ==== card is one operation: test, replace, remove, add or substitute, at a path inside the bit (@diffAt).

Typical layers:

• national deviations on an international norm;
• a training layer on a norm, with explanations and videos;
• a customer's annotations;
• translations;
• amendments.