Appendix — Processing Model

Appendix to: AEON Specification v1

Canonical topic owners: AEON Specification v1 and AEOS Specification v1.

This appendix is an orientation aid for the v1 processing pipeline. Canonical phase ownership lives in the top-level v1 specs and compliance documents. If this appendix conflicts with the canonical v1 spec set, the canonical v1 spec set wins.

This appendix illustrates AEON's conceptual processing phases, Assignment Events, processor selection boundaries, tuple/indexed-path support, and annotation stream emission.

1. Processing Phases

Implementations should read these phases as a conceptual pipeline. Normative phase ownership and conformance requirements live in the canonical v1 specs and compliance documents.

2. Assignment Events

2.1 Definition

AEON projects each represented value occurrence into the transport-neutral event model defined by aes.events.v1. Named bindings, anonymous structural children, attribute entries, and node heads can therefore each produce flat events.

2.2 Portable fields

Every portable body event has path and kind. Scalar and other valued kinds also have value. datatype, identity, origin, and span are optional under their AES rules. key, nested AST values, attached annotation maps, and raw source lexemes are not portable AES fields.

Attributes use ordinary flat descendant events below the owner's .@ address space. Structural children use indexed descendant events. Containers and node literals do not embed their descendants.

2.3 Example

p@{style = #FF0000}:point = { x = 23, y = 3 }

Portable body events include:

path=$.p
kind=ObjectNode
datatype=point

path=$.p.@.style
kind=HexLiteral
value=ff0000

path=$.p.x
kind=NumberLiteral
value=23

path=$.p.y
kind=NumberLiteral
value=3

2.4 Tuple Example (v1 baseline)

score:tuple<string,int32> = ("alice", 95)

path=$.score
kind=TupleLiteral
datatype=tuple<string,int32>

path=$.score[0]
kind=StringLiteral
value=alice

path=$.score[1]
kind=NumberLiteral
value=95

3. Uniqueness (Const Semantics)

AEON documents are immutable by construction:

• For any canonical path, there MUST be at most one Assignment Event

• Duplicate path bindings MUST raise an error

• No implicit override, merge, or replacement semantics

4. Annotation Stream Emission (v1 baseline)

Annotation stream records are emitted in Phase 4, in parallel with Assignment Events. They do NOT appear in the AES.

See Appendix: Annotation Stream for record format and binding rules.

Key invariants:

• Annotation stream emission MUST NOT affect AES contents

• AES with all comments stripped MUST equal AES with comments present

• Annotation stream records are source-ordered

5. Processor Registry

5.1 Definition

A Processor is a deterministic transformation function applied to Assignment Events.

5.2 Design Principles

1. No implicit execution — Documents cannot invoke processors directly

2. Profile-scoped authority — Only the active profile enables processors

3. Determinism — Same input produces identical output

4. No structural mutation — Processors cannot add/remove nodes

5. Explicit phase boundary — Processors run in Phase 5 only

5.3 Processor Binding

Profiles declare processors bound to:

• Datatype hints (e.g., point → geom.point)

• Annotation keys (e.g., style:color → core.hex)

• Canonical paths

5.4 Invocation

During Phase 5, for each Assignment Event:

1. Profile determines applicable processors

2. Processors invoked in deterministic order

3. Each processor receives the event and current value

4. Processor may validate, transform, or attach metadata

5.5 Processor Input

Processors receive:

• path — canonical path

• value — current value (may be ListNode or TupleLiteral in v1)

• datatype — if present

• annotations — if present

5.6 Processor Output

Processors MAY:

• Return a transformed value

• Return the same value unchanged

• Raise a validation error

Processors MUST NOT:

• Return multiple values

• Alter the canonical path

• Emit new Assignment Events

6. Reference Evaluation Phase

6.1 Binding Visibility Rule

A binding becomes eligible as a reference target only after its Assignment Event has been committed.

Self-references (e.g., a = ~a) are therefore invalid.

6.2 No Forward References

References MUST target paths already bound earlier in the document.

The no-forward rule applies independently per namespace (data and attribute).

6.3 Indexed Reference Targets (v1 baseline)

In v1 mode, references may target indexed paths:

items  = (10, 20, 30)
second = ~items[1]     // clone of element at $.items[1]

Resolution proceeds using the same no-forward rule (referenced indexed path must be already bound).

6.4 Resolution Semantics

6.5 Cycles

Because AEON forbids forward references, cycles are unrepresentable.

7. Error Reporting

Diagnostics should reference:

• Canonical path

• Span (when available)

• Phase where error occurred

Example:

Error: Unknown processor "geom.point"
Path: $.p
Phase: Profile Interpretation