Crate energyml_cache 

What a package keeps of itself, layer by layer.

A face - the front end’s session, the command line, Python - holds one Cache per open store. Every layer is optional and lazy: Cache::off keeps nothing, and a function that can use a cache takes one rather than existing twice, so the fast answer and the slow one are the same code (ADR-0010).

This crate holds what a WebAssembly front end used to keep for itself alone:

layer	kept	module
index	the package’s links and property sheets, exact for the store’s revision	index
colours	the colour walks of the objects asked, and the set they read	colours
attachments	the listings of what is attached to an object	Cache::attachments_of

One implementation, a cache that keeps nothing

A layer that is off is not a second code path: the same function runs, over a slot that is thrown away when the call returns. A question to Cache::off therefore builds the index it needs and drops it - slower, never different. tests/ holds the proof: every answer, cache on and cache off, side by side.

The colours and the attachments are derived from the index (they read its links, and what its updates disturb is what they drop), so turning either on turns the index on (Layers::normalised).

What this crate does not hold yet

Identity is still the uuid and the uri the store gives (ObjKey is not there yet), and there is no dependency registry (Ledger). The creation pieces and the section view’s work are still held by that front end.

The tests of energyml-cache are one binary (one crate, one test binary, ADR-0016): a new file is a mod line in tests/main.rs, or it does not run.

Re-exports

pub use index::Consumer;

pub use index::Disturbed;

pub use index::IndexSlot;

Modules

colours

The colour of an object, one rule for every face - the walks that a WebAssembly front end used to keep for itself (the inheritance-resolution order), now held by the Cache.

index

The package index of a store, built when first asked for and kept exact by the store’s own revision (ADR-0010), moved here from a WebAssembly front end.

Structs

Cache

What a package keeps of itself: one per open store, with the layers it was made with.

Held

What a Cache holds right now - a count, so that a test can say “nothing” without a clock.

Layers

Which layers are on. Every one is off by default and turned on by name.

Enums

Error

What can go wrong asking a Cache a question.