IPLD Patch

IPLD Patch is a system for declaratively specifying patches to a document, which can then be applied to produce a new, modified document.

IPLD Patch is roughly based on the JSON Patch (RFC 6902) specification -- it should feel very familiar.

For the full details, see the Fixtures -- the test fixture material is both for implementers, but also for end users, and provides rich examples and explanatory notes.

In brief highlights:

• There are six operations -- add, replace, remove, copy, move, test.
  • (This is the same as RFC 6902.)
• Operations are supplied in a list, and applied linearly. Any operation erroring results in the entire patch not being applied.
  • (This is the same as RFC 6902.)
• Operations do not create parent paths automatically.
  • (This is the same as RFC 6902.)
• Because this is IPLD, both the subject data, as well as the patch instructions themselves, can be communicated in any codec. (e.g. you can easily serialize a patch in CBOR, and apply it to a document encoded in dag-pb, and so on).
• Furthermore: because the Patch system is specified over the IPLD Data Model, you can expect it to work over other layers as well -- for example, Patches can be applied over data processed with Schemas or ADLs.
• The Patch system in IPLD is expected to maintain order whenever possible. Wherever this is ambiguous (e.g. operations adding data to a map under a key that didn't previously exist), operations are defined as appending to the end of the relevant node.

See the Fixtures for more details.