Replace Data noun with save! and load verbs

[Affie]

Data noun to be replaced by save! and load, i.e. replace addData with save!.
As an example, we can have saveBlob[Variable]!, saveBlob[Graph]!, saveBlob[Model]!, saveBlob[Agent]!
Then also convenience functions such as saveDFG!, saveFeatures! etc.

See definitions for load and save:

• https://github.com/JuliaRobotics/DistributedFactorGraphs.jl/wiki/Standard-Definitions-of-API-via-verbNoun-structure

xref discussion

[dehann]

Examples:

• save or load images to blob

Locked in

verbs: save, load, ?delete/remove
Nouns: Variable, Agent, Factorgraph

Must Decide

Are these Nouns or Adjectives, Image, Json, Pointcloud, because either:

• verbNounAdj or
• verbNounNoun or
• verNounNounAdj

First reactions

Dehann likes:

# same aliases
  saveImage(::Variable)
  saveImageVariable()
  # bad, see below saveVariableImage(),

# similarly 
loadAgentJson()

Affie likes:
saveImage is high level for something like:

packBlob(of_mine_type_image)_addBlob!_addAgentBlobentry!

To avoid holding a full Variable object,

# Brainstorming idea
struct Node{AbstractDFGNode}
    label::Symbol
end

# to save an image to a variable blob entry something like
on_node = Node{VariableDFG}(:x1)
saveImage(::DFG, on_node::Node{<:Variable}, entry_label::Symbol, ...)
# to save an image to a agent blob entry something like
on_node = Node{Agent}()
saveImage(::DFG, on_node::Node{<:Agent}, entry_label::Symbol, ...)

# or if we want to use NounNoun, mabye
saveImage_Variable(::DFG, variable_label, entry_label,....)
saveImage_Agent(::DFG, entry_label,....)

[Affie]

We can consider using something similar to NvaNode that represents a reference to what Noun [Variable, Agent, Graph, etc.] the Blobentry should/is attached to.

[dehann]

so what about data levels, why not have for data lavel 0 something like (Node{T::Variable/Factor/...} is Skeleton{T})? Vs what we currently have as VariableSkeleton -- why not Skeleton{<:Variable}

Concern is VariableSkeleton and FactorSkeleton have different fields?

[Affie]

Variable and Factor skeletons have different fields, with Factor having the list of neighbours to rebuild the full graph skeleton (structure).

[dehann]

I dont like that the second Noun is divorced down to the second argument. Also don't like that the second argument is unlike all the rest of DFG.

saveImage(::DFG, on_node::Node{<:Agent},...)

[dehann]

I like the idea of reducing the full verbose function name by replacement:

packBlobMime_addBlob!_addAgentBlobentry!

Reduces like algebra via:

• save = pack + add + add
• Image = Blob + Mime + Blobentry
• Agent = Agent

So it seems natural to have the reduced signature be:

saveImageAgent(::DFG, aglb, imlb, ...)

I still don't think the underscores are necessary, since the user is just asking DFG/SDK/Accelerator to do thing. Knowing high vs low level API is more an internal thing to me.