tom_som_rust_runtime — generic Rust SOM runtime

> Cross-references. > tom_specs_model/doc/som_multiplatform_spec_model.md > is the SOM authority: SOM §9 decides what a runtime must contain, SOM §6 > decides the split between the generic and the typed access path, SOM §11 and > SOM §12 decide the *.md and *.docspecs.yaml formats, and SOM §19 > decides the conformance corpus this port is measured against. > tom_specs_model/doc/som_toolchains.md > decides this language plane's build and verify toolchain. This README says how > to use this package's code; those documents own the model, the formats and > the rules, and nothing here restates them.

Generic TomSpecs object-model runtime (Rust port). Paths, model, reflection, document, validator, YAML/Markdown codecs; zero external dependencies (standard library only).

Where this fits

TomSpecs specifications are documents with a typed shape: a spec model describes which sections exist, what each may contain and how it serializes. The SOM makes that model usable from nine languages, and each language is a pair — a hand-written runtime (this crate) holding everything that is the same everywhere, and a generated tom_som_rust_v0 facade holding the typed structs for one model version. Without the split, every regeneration would rewrite the document store, the codecs and the validator; with it, the generator emits only what actually changes when the model changes.

This crate is a faithful transcription of the Dart reference, tom_som_dart_runtime, and of the Python, Java, JavaScript, TypeScript and Go ports — it invents nothing, and "faithful" is a measured claim rather than an intention: every port is validated against the same goldens, byte for byte (SOM §19). Reach for it directly when you drive the generic API by section path; otherwise depend on the typed facade, which pulls this in.

Overview

A SOM document is sparse and path-keyed: values live in three stores (content, form fields, list sequences) under the globally-unique section-ID path they belong to, and an absent key means "no value" rather than an empty one. SpecDocument is that store. Everything else in the crate is a layer over it — the meta-model (SpecModel, SpecReflection) that makes generic navigation possible without generated structs, the byte-stable YAML and Markdown codecs, the editing and validation tiers, and the Phase-4 CodeSpecs extractor.

It holds no document values of its own and contains no generated typed structs — those belong to the per-language tom_som_<lang>_v0 crates.

Installation

[dependencies]
tom_som_rust_runtime = { path = "../tom_som_rust_runtime", version = "1.1.0" }

The crate is publish = false (proprietary). The version tracks the TomSpecs model version, and tom_som_rust_v0 pins the same one — upgrade both together (SOM §4.2). See readme_howtointegrate.md for the crates.io / git / path routes, version pinning, and cargo package from source.

Features

Modules

File	Responsibility
`spec_paths.rs`	The section-path grammar (root / child / list-item segments).
`spec_model.rs`	The meta-data loader — the exported class graph ( `SpecModel` , `SpecRoot` , `SpecClass` , `SpecField` , …).
`spec_reflection.rs`	Value-free enumeration + path resolution ( `SpecReflection` , `SpecResolution` , node-kind constants).
`spec_document.rs`	A sparse in-memory document — values keyed by section path.
`spec_typed_values.rs`	Parse/format at the store boundary — the one place the text form of an `int` / `double` / `num` / `bool` / enum-name is decided.
`spec_editor.rs`	The generic meta-model-driven modification API ( `SpecEditor` , YRD7) — typed edits over any path, without a generated facade.
`spec_validator.rs`	Validates a document's values against the model.
`spec_text_pattern.rs`	The portable pattern subset ( `SomTextPattern` ) — a hand-written leftmost-first backtracker over UTF-16 code units, so match spans agree with every other runtime (std ships no regex, and the `regex` crate would be both a dependency this crate does not take and a different grammar).
`spec_query.rs`	The lexical/structural query surface ( `SpecQueryEngine` , `SpecQuery` , `SpecQueryCursor` ) plus the flat tier-1 node projection ( `SpecNodeProjection` ).
`spec_node_creation.rs`	The constrained node-creation gate ( `check_add_node` , `SpecNodeCreator` ) — a document may only grow in ways the model permits.
`spec_codespecs_extract.rs`	The Phase-4 CodeSpecs specification extract generator ( `CodeSpecsExtractor` , `CodeSpecsAreaCatalog` ) — one verbatim, provenance-carrying extract per CodeSpecs area. Walks one `@Document` root, resolved at construction from an optional root-type argument ( `codespecs_prompt.md` §5).
`spec_document_yaml.rs`	Byte-stable `*.docspecs.yaml` codec (`SOM §12`).
`spec_document_markdown.rs`	Meta-data-driven Markdown import/export codec (`SOM §11`).
`som_facade.rs`	Editing-facade base types ( `SomNode` , `SomScalar` , `SomList<T>` ) for the generated `tom_som_rust_v0` .
`yaml.rs`	Hand-rolled, dependency-free reader for the constrained docspecs YAML subset.
`json.rs`	Hand-rolled, dependency-free JSON reader/encoder (Rust std ships no JSON).

Quick start

use tom_som_rust_runtime as som;

let mut doc = som::SpecDocument::new();
doc.set_content("SBP/content", "A unifying order platform.");
println!("{}", doc.content_or("SBP/content"));
// A unifying order platform.

Usage

The generic path

Load the exported class graph, then resolve paths against it — no generated structs involved:

let model = som::SpecModel::from_json_str(&meta_json).unwrap();
let reflection = som::SpecReflection::new(&model);

println!("{}", reflection.resolve("SBP/content").is_some());
// true
println!("{}", som::validate_document(&model, &doc).is_empty());
// true

Zero external dependencies

The crate depends only on the Rust standard library — no serde, serde_json, serde_yaml, or regex. JSON parsing uses the hand-rolled json module; YAML uses the hand-rolled yaml module (the constrained docspecs subset). Byte-stable *.docspecs.yaml output requires a js_json_string that matches JavaScript's JSON.stringify exactly — it delegates to json::encode_str, which emits the short escapes for " \ \b \f \n \r \t, control characters below 0x20 as lowercase \u00xx, and every other char (including < > & / and all non-ASCII) verbatim. The regex-driven Markdown anchors of the reference are replaced by hand-rolled scanners (heading_path, field_anchor, fence_open, item_seg).

Rust-specific surface

Rust has ownership, Result, and reserved keywords, so the facade differs from the other ports in idiomatic ways the emitter mirrors:

Shared document via Rc<RefCell<SpecDocument>> — aliased as DocRef. A

child facade clones the Rc (a cheap reference-count bump) and every read or write borrows the cell, so a mutation through the typed surface is immediately visible through the generic path and vice-versa. - No doc/path name guard — generated accessors reference the bound document explicitly through the embedded SomNode (self.node), so a method named doc or path cannot shadow anything. This is a deviation from the Go/TypeScript ports, which need a reserved-name guard. - Result instead of exceptions — the version check returns Result<(), SomVersionError>; SomVersionError implements std::error::Error. - Reserved-keyword collisions are resolved by the emitter with a trailing underscore (type_, match_, self_, move_, …).

Consumed by `tom_som_rust_v0`

The generated typed model depends on this crate via a relative path dependency in the v0 crate's Cargo.toml (tom_som_rust_runtime = { path = "../tom_som_rust_runtime" }), keeping the generated source path-free and golden-stable.

Building and running the tests

Correctness is defined by the shared, language-agnostic conformance corpus in tom_som_conformance/corpus, generated from the Dart reference. This port is validated against the exact same goldens every other port uses (SOM §19):

cargo build                                 # compile the runtime
cargo test                                  # the whole suite
cargo test --test conformance -- --nocapture # → "OK: N checks passed"
./run_tests.sh                              # conformance + the per-module suites

The conformance test reproduces every golden byte-for-byte and exercises the same cases as the Dart/Python/Java/JavaScript/TypeScript/Go runners: model meta-data load, state.json round-trip, YAML encode/decode, Markdown export/round-trip, the Markdown→memory landing check (the md.land.* shared contract — parsing expected.md lands the same memory as the YAML route), reflection resolution, validation, the imperative operations script, and the Phase-4 CodeSpecs tier (the routing diagnostic, the per-area extracts with their YAML/Markdown goldens, the "copied, never composed" guard and the ROUTE-TOTAL error cases).

Architecture

        typed path                          generic path
   tom_som_rust_v0        ─────▶   SomNode / SomScalar / SomList<T>
            │                                   │
            └───────────────┬───────────────────┘
                            ▼
                      SpecDocument         sparse, path-keyed value stores
                            │
        ┌───────────────────┼────────────────────┐
        ▼                   ▼                    ▼
  SpecReflection       SpecEditor          spec_document_yaml.rs
  SpecQueryEngine      validate_document   spec_document_markdown.rs
        │
        ▼
     SpecModel  ◀── meta/spec_model.meta.json

Type	Responsibility
`SpecDocument`	The sparse, path-keyed store of a document's content, form and list values.
`SpecModel`	The exported class graph — roots, classes, fields, annotations.
`SpecReflection`	Resolves and enumerates paths against the model without reading values.
`SpecEditor`	Typed edits over any path, driven by the meta-model rather than by generated structs.
`SpecNodeCreator`	The creation gate — a document may only grow in ways the model permits.
`validate_document`	The instance tier: a filled document's values checked against the model.
`spec_document_yaml`	Byte-stable `*.docspecs.yaml` encode/decode.
`spec_document_markdown`	DocSpecs-conform Markdown export, parse and round-trip.
`SpecQueryEngine`	Lexical/structural search over a document, matching with `SomTextPattern`.
`CodeSpecsExtractor`	The Phase-4 extract generator — one verbatim, cited extract per CodeSpecs area.
`SomNode` / `SomScalar` / `SomList<T>`	The editing-facade base types the generated `tom_som_rust_v0` structs embed.

Ecosystem

  tom_specs_model ──▶ tom_specs_clitool ──generate_som──▶ tom_som_rust_v0
   (the model)          (the generator)                     (typed facade)
                                                                  │ depends on
                                                                  ▼
                                                     tom_som_rust_runtime  ← this crate
                                                                  │ validated against
                                                                  ▼
                                                         tom_som_conformance
                                                          (shared corpus)

Further documentation

TomSpecs subject matter — the authorities this crate implements:

Document	Authority for
index.md	The catalogue of every TomSpecs subject-matter document, and the `§` citation convention.
som_multiplatform_spec_model.md	What a SOM runtime must contain, the two access paths, the `.md` and `.docspecs.yaml` formats, the validator, and the conformance corpus.
som_toolchains.md	This language plane's build and verify toolchain, and the reference host.
tom_specs_model_meta_schema.md	The on-disk schema of `meta/spec_model.meta.json`, which `SpecModel` loads.

This crate — its own guides:

Guide	Covers
readme_howtointegrate.md	Every dependency route and how to pin the version.

Siblings — packages you will reach for next:

Package	What it is
tom_som_rust_v0	The generated typed facade over this runtime — the normal path.
tom_som_dart_runtime	The Dart reference this port transcribes.
tom_som_conformance	The shared corpus and the cross-language drivers that run every port against it.

Status

Version 1.1.0, tracking the TomSpecs model version. Covered by 8 test files; the conformance runner reports OK: 3150 checks passed and ./run_tests.sh is green.