# Data Structures

Triplet graphs similar to linked data fragments with envelopes. decoupling content addressing from versioning

- Merkel DAGs
- Envelopes
- Versioning
- Typed objects with formatting

(Containers)=
## Containers

```{important}
Ya this seems like the right set of ideas to build on

- https://www.w3.org/TR/json-ld11-framing/
- https://w3c.github.io/rdf-canon/spec/#introduction
```

- Packets of LD-triplets that contain
	- Hash of triplets
	- Encryption Info (if applicable)
	- Permissions scope
	- Signature
- Anything that can be directly referenced without local qualifier is a container. 
	- Triplets within a container can be referenced with the [query syntax](qlocation)
- Containers also behave like "feeds" 
	- Eg. one might put their blog posts in `@user:blog` or 
- The account identifier is the top-level container.
- Ordering: 
	- Every triple within a scope is ordered by default by the time it is declared
	- A container can declare its ordering (see {term}`Container`)
- Naming: 
	- Each container intended to be directly referenced SHOULD contain a `name` so it can be referenced w.r.t its parent: `@<ACCOUNT>:<name>`
	- Each container can also be indicated numerically
- Identity: Each container is uniquely identified by the hash of its contents and the hash of the account identifier. 
- Format: A container can specify one or several ways it can be displayed 
- Capabilities: A container can specify different capabilities that another account can take (eg. "Like", "Upvote", "Reply")
	- Capabilities should also contain a permissions scope, if none is present, the global scope is assumed.
	- Since Identities are just a special form of container, they too can advertise different actions that they support with capabilities.
- Basically a container is a merkle DAG with binary data at its leaves a la the {index}`Linked Data; Platform`
- Re: Ordering - https://github.com/ssbc/ssb-tangle

Re hashing a graph: the container always has one root node that is the container's identity from which a graph traversal starts. A {index}`Merkle DAG` is then constructed starting from the leaves. 



## Triplets

- Triplet format
	- Objects require a shortname that can be hierarchically indexed from 
- Types/Schema
- Including intrinsic notion of nesting
	- every object can have blank/positionally indexed children
	- every triple can have blank/positionally indexed "qualifiers" like RDF-star or wikidata's qualifiers.

## Schema


## Codecs

See IPLD Codecs and Linked Data Platform spec

Means of interacting with binary data. 

Describes

- Format
-  

## Versioning

- A given container has an identity hash from its first packing
- A given triple can be contained by

## Canonicalization

- https://w3c.github.io/rdf-canon/spec/#introduction
- https://json-ld.org/spec/ED/rdf-graph-normalization/20111016/
- https://www.w3.org/TR/json-ld11-framing/

## Compare to:

- {index}`CORAL` - https://github.com/jmchandonia/CORAL
	- Good idea, also making use of extended context. Very focused on scientific data - 'units' are a core part of the model. distinction between static and dynamic data types seems like sort of a hack. data bricks are similar to containers. the source is an absolute mess.