sysmlpy — Project Status

Current version: v0.97.1 (2026-10-16)

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In Flight (on main, unreleased)

(Nothing staged.)

Recent Highlights (0.97.1)

• Boxes action-flow view: v2-native glyphs — chamfered octagons + the solid start diamond; named succession statements bind their keyword control ends; flow/succession edge dedupe.

Recent Highlights (v0.97.0)

• CI integrations (GitHub Actions / GitLab / pre-commit, new sysmlpy ci subcommand): parse gate blocking, semantics advisory (--semantic strict opt-in) — see docs/ci-integration.md. Dogfooded on this repo: the gate on the bundled library found and fixed two visitor crashes on named multiplicity bounds ([nCauses], [wallNumber]).

Recent Highlights (v0.96.4)

• doc_ids=True — source-carried explicit ids: doc /* @id: … */ inside an element's braces fixes its interchange @id (L3 identity, survives any edit); duplicate claims raise at export. Placement contract pinned by tests.

Recent Highlights (v0.96.3)

• Stable element identities (L2 + L3): content-addressed interchange @ids (to_interchange(stable_ids=True), CLI --stable-ids) survive insertion/reordering elsewhere; a registry sidecar (reconcile_ids / --reconcile-with model.json) keeps ids across ancestor renames and re-nesting — re-export with the previous file as registry and name-matched elements never lose identity.
• Documented in full: docs/stable-identities.md (L0-L3 levels, options, decisions); runnable demo examples/element_identity.py; README "Element Identity: Stable Interchange IDs".
• Gates: interchange 59/59, fast suite 654 passed / 1 skipped.

Recent Highlights (v0.96.2)

• Grammar upgraded to OMG release 2026-08: vendored grammar is now daltskin/sysml-v2-grammar v2026.08.1 (upstream #11 expression cascade

• 16 required import visibility). Bare import X; is a

  SysMLSyntaxError.
• Non-normative forms removed per the upstream review: bare qualified identification and connector-end trailing multiplicity. Normative forms (connect [1] a to b;, subject : Q::N;) round-trip.
• OMG XPect conformance: 123 passed / 3 skipped; grammar round-trip 168/168; fast suite 595 passed; KerML batteries 5/5.

Recent Highlights (v0.96.1)

• doc comments survive everywhere: doc /* ... */ on packages and on any usage/definition kind (previously dropped when shared with sibling body items; only Requirement kept it) is captured as .doc on the API object and re-emitted by dump()/classtree().
• interface ends captured: end <name>; and end <name> ::> part.port; in interface bodies parse into Interface.ends / Interface.iface_connections (previously grammar-layer only), and ::> targets survive the dump round-trip.
• Round-trip fix: interface usages no longer dump a spurious connect keyword (syntax error on re-parse).
• Flows verified end-to-end: flow a to b; → Flow child → dump → Interconnection View edge.

Recent Highlights (v0.96.0)

• KerML parser: OMG-KEBNF-generated ANTLR4 grammar + visitor-dict layer (sysmlpy.kerml); 130/130 .kerml corpus files parse.
• LibrarySymbolIndex now parses .kerml library files (2,986 symbols, was 1,604 regex-scraped).
• Zero correctness failures on the OMG release-repo corpus sweep (404 files); Annex A SimpleVehicleModel and all interface-connect forms parse.
• Community PRs merged: port-def rendering fix (#10), boundary ports (#13), interface-usage connection edges (#12), binding connector rendering (#11) in the Interconnection View.

Completed

Public API Classes

These classes are fully implemented, have programmatic construction, dump() serialization, and test coverage.

Class	SysML Keyword(s)	Notes
Package	package	Name, shortname, children, load_from_grammar
Model	(root)	Wraps packages; load from string
Part	part / part def	Typed by, children, load_from_grammar
Item	item / item def	Typed by, children
Attribute	attribute / attribute def	set_value/get_value with pint units
Port	port / port def	In/out/inout directed features, add attribute
Action	action / action def	Add in/out parameters, typed by, specializes
Reference	ref	Simple, typed, and redefinition (ref :>> name : Type;)
Requirement	requirement def / requirement	Subject, actor, doc, constraint, assume constraint
UseCase	use case def / use case	Subject, actor, include
Interface	interface def / interface	Add end, add connection
Message	message	From, to, of-type
State	state def / state	Transitions, entry/do/exit actions, .parent property
Transition	transition	Source, target, guard, trigger, effect
Constraint	constraint def / constraint	Assert constraint, derivation forms
AnalysisCase	analysis def / analysis	Subject, objective, result expression
VerificationCase	verification def / verification	Parse and load from grammar
Concern	concern def / concern	Parse and load from grammar
View	view def / view	Parse and load from grammar
Viewpoint	viewpoint def / viewpoint	Parse and load from grammar
Individual	individual def / individual	Parse and load from grammar
Metadata	metadata def / metadata	Parse and load from grammar
Rendering	rendering def / rendering	Parse and load from grammar
Allocation	allocation def / allocation	Parse and load from grammar
Flow	flow def / flow	Parse and load from grammar
Connection	connection def / connection	Parse and load from grammar
Calculation	calc def / calc	Parse and load from grammar
Enumeration	enum def / enum	Parse and load from grammar

Relationship Methods (on all Usage/Definition classes)

Method	Syntax
set_typed_by()	: TypeName
set_specializes()	:> SuperDef (definitions)
set_subsets()	:> superset (usages)
set_redefines()	:>> original
add_child()	fluent child builder

Parser

• CLI — sysmlpy console script with subcommands (v0.61.0): parse (repr/dump/grammar-JSON), analyze (semantic analysis with CI exit codes: 0 clean, 1 findings at --fail-on threshold, 2 parse error; text or --format json), view --view NAME (all 11 views, --focus, --element, --style, --direction, --format, -o), format (alias fmt, multiple files), trace (requirement traceability & verification coverage: --format text|markdown|json, --fail-on uncovered, -o; exit 0 clean, 1 uncovered, 2 parse error). repl (v0.93.x — interactive session: declarations accumulate with member-granularity merge; %eval/%set/%calc/%check/%values over the evaluator, %sim/%send/%step over the simulator, %view, %list/%show/%dump/%load/%save/%reset). Legacy flat invocation (sysmlpy FILE --dump) preserved with original exit codes.
• Requirement traceability — sysmlpy.traceability (extract_traceability() → TraceabilityReport with per-requirement traces, coverage queries, text/markdown/JSON output; as_traceability_matrix_view() in markdown/html/plantuml). Satisfy / verify / verification / subject relationships parse and round-trip (v0.62.0).
• JSON interchange — sysmlpy.interchange (to_interchange() / from_interchange()): JSON-LD-style partition documents (flat @graph, @id/@type elements, deterministic uuid5 ids) with lossless import back to a live model (v0.63.0).
• Expression evaluator — sysmlpy.evaluator (collect_values() / evaluate_expression() / evaluate_calculation() / check_constraints()): pint-bound evaluation of attribute defaults, calc results and constraint bodies, with what-if bindings; sysmlpy eval CLI (v0.64.0).
• LSP server — sysmlpy.lsp: dependency-free LSP 3.17 subset (diagnostics, documentSymbol, hover, definition, completion; FULL text sync) over stdio; sysmlpy-lsp console script + python -m sysmlpy.lsp; VS Code extension scaffold in editors/vscode/; Neovim recipes in docs/LSP.md (v0.65.0).
• Spreadsheet bridge — sysmlpy.spreadsheet: CSV export of the tabular views (--format csv), XLSX workbook export (sysmlpy xlsx, optional openpyxl extra), and spreadsheet value import into evaluator bindings (eval --set-file, import_values_csv()) (v0.66.0).
• Official SysML v2 notation fidelity — edge encodings aligned to the OMG pilot's PlantUML generator (thick plain connection lines, heaviest binding lines, distinct redefinition arrow, send/accept action edges, variant/objective/metadata edges); connection endpoints now parse (was a parse stub); stv renders composite states as nested blocks; gv renders connector edges (v0.67.0).
• Boxes-backed interconnection + action flow views — as_interconnection_view_boxes() (parts as boxes with boundary ports, connection usages as port-to-port Z-routed edges) and as_action_flow_view_boxes() (actions as boxes, parameters as in/out ports, flows as port-to-port edges, nested actions as composite children, successions as dashed ..> edges) against diagramboxes (renamed from boxes, its v0.4.0); braille + SVG render helpers for both (v0.68.0). Control nodes render in both: PlantUML afv uses hexagons (deployment syntax has no diamond), boxes afv uses true decision diamonds + start/done dots via diagramboxes 0.5.0, whose sugiyama port routing is obstacle-aware (v0.68.0+). The PlantUML interconnection view follows official iv notation (enclosure nesting, typed labels, flows/connections as the only edges — flows port-to-port; v0.68.0+), and the package view follows official package notation: package "Name" { members } enclosure, leaf definition boxes, typed member labels (v0.68.0+). State-machine simulation (v0.69.0): sysmlpy sim FILE runs a state def machine Cameo-style — triggers fire transitions, guards evaluate against model attribute values (pint-aware) with --set/set_value what-if overrides, completion transitions run to completion, effects are logged, and an interactive TUI shows the live state with the transitions available from it (--run "T1; T2" scripts sessions). Guards also appear in boxes-view edge labels (the shorthand-when extraction fix); transition do effects parse through to the simulator — references round-trip, send/assignment declarations surface as text (send Alert to logger, x := 5) — and composite regions simulate with qualified names: entering a composite lands in its initial substate, region transitions run inside it, and composite-level transitions apply from every substate. For color-vision accessibility, set_stereotype_palette("okabe-ito") switches the style="color" views to the Okabe-Ito palette (bw remains the default). Validator depth (Goal 9) starts with state-machine well-formedness: UNRESOLVED_TRANSITION_ENDPOINT (error), NO_INITIAL_STATE and UNREACHABLE_STATE (warnings) run inside analyze() on the simulator's expanded machine descriptor. Batch 2 (v0.69.1) adds UNRESOLVED_TRIGGER_PAYLOAD (bare and guarded accept payloads resolve or error) and REQUIREMENT_UNCOVERED (requirement usages with no satisfy/verify traces; defs exempt). Batch 3 (v0.70.0) adds UNRESOLVED_TRACE_TARGET / TRACE_TARGET_NOT_REQUIREMENT on satisfy targets — dangling edges no longer materialize phantom requirements in coverage reports un-flagged. Batch 4 (v0.71.0) adds UNRESOLVED_VERIFY_TARGET and CONNECTOR_DIRECTION_MISMATCH; batch 5 (v0.72.0) adds UNRESOLVED_SATISFY_PART and fixes nested satisfies silently reading as uncovered; batch 6 (v0.73.0) adds UNRESOLVED_CONNECTOR_END and SATISFY_SUBJECT_TYPE_MISMATCH and completes Goal 9 at 29 rule codes. Goal 8 (semantic model diff) starts at v0.74.0: sysmlpy.diff element-level diff with text / Markdown / JSON rendering and a CI-friendly sysmlpy diff CLI. Goal 10 opens at v0.75.0: *// unit-dimension derivation (UNIT_DIMENSION_DERIVATION_MISMATCH, 30 rule codes) and SLL error parity (sll_only stays in SLL prediction). v0.76.0 adds connector-end type compatibility (CONNECTOR_END_TYPE_MISMATCH, 31 rule codes) and lexer-based import extraction for dependency scanning (bare imports fixed, comment/string false positives gone). v0.77.0 closes Goal 10 with CayleyStore hardening + query parity, verified against a live podman Cayley v0.7 server (delete/clear/get/put/len/query fixes, label-namespaced subjects, NetworkX-identical glob query results).
• Relationship legends opt-in — include_legend=False by default everywhere; the built-in legends restated standard notation and are noise. Monochrome bw remains the default style for color-vision accessibility (v0.68.0).
• ANTLR4 parser — default parser, using OMG grammar v2026.03.0
• load(), loads(), parse(), load_grammar() (public API)
• load_antlr(), load_grammar_antlr() (explicit ANTLR4 path)
• Full ANTLR4 visitor (antlr_visitor.py, ~11K lines) converting parse tree to internal dict representation
• Supports comments, documentation blocks, and annotating elements
• Supports Case, AnalysisCase, VerificationCase, and TradeStudy definitions
• State machine support: entry/do/exit actions, accept/send/perform/assign nodes, transitions with guards
• Non-raising parse(text) variant: returns (Model, []) on success, (None, [errors]) on syntax error

Grammar Round-Trip Coverage (parse → dump)

168 / 168 tests passing (100%) as of v0.90.0.

The suite grew from 96 to 165 cases (full-model round-trips drawn from the OMG spec corpus, including ActionTest / ControlNodeTest / DecisionTest action-body successions; v0.87.0 added view filter/expose members, guarded entry transitions, typed-nameless connections, and typed prefixed-usage round-trips; v0.88.0 added usage-body imports, satisfy valueparts, and accept-member name/typing/multiplicity round-trips; v0.88.1 added nested-definition and typed-transition round-trips). Earlier corpus-level fixes: implicit-package wrap vs trailing line comments, MetadataFeature / TextualRepresentation annotating elements, missing succession-member classes, WHEN triggers, and malformed interface ends.

All categories pass, including the 14 control flow node tests (IfNode, WhileLoopNode, ForLoopNode, ControlNode, SendNode, AcceptNode, TerminateNode).

Category	Pass	Total
Packages	3	3
Part definitions	1	1
Generalization / Subsetting / Redefinition	3	3
Enumerations	2	2
Parts	2	2
Items	1	1
Connections	1	1
Ports	2	2
Interfaces	2	2
Binding connectors	2	2
Flow connections	3	3
Actions	5	5
States	6	6
Expressions	4	4
Calculations	3	3
Constraints	7	7
Requirements	4	4
Analysis	3	3
Control flow	14	14
Lifecycle metadata	9	9
Corpus-driven full models	+17	+17
Total	96	96

Grammar Resilience (v0.27.0)

All 68+ raise NotImplementedError stubs in grammar/classes.py replaced with graceful handling. The parser no longer crashes on any edge-case input.

Stubs fully implemented (__init__, dump(), get_definition()): - PortionKind — stores kind field (snapshot/timeslice/individual) - PrefixMetadataMember — stores memberElement, dumps as @<name> - LifeClassMembership — stores memberElement, dumps as lifeClass <name>

Missing classes added: - DefinitionBody, DefinitionBodyItem - FeatureSpecializationPart, SubclassificationPart

Catch-all unknown branches → print warning instead of crashing (68 sites): - DefinitionElement, InterfaceBodyItem, OccurrenceUsageElement, NonOccurrenceUsageElement, PrimaryExpression, PackageBody, RelationshipBody, ConnectorPart, FeatureSpecialization, and more.

Expression chain classes — gracefully handle None child / non-empty operands: - ConditionalExpression, NullCoalescingExpression, ImpliesExpression, OrExpression, XorExpression, ClassificationExpression, ExponentiationExpression, UnaryExpression, ExtentExpression

Semantic Analysis Engine (v0.17.0 → v0.20.0)

Feature	Status	Details
Symbol table	✅ Complete	Hierarchical scopes with parent chain lookup
Import resolution	✅ Complete	Namespace (::*), membership, recursive (::*::**)
Import visibility	✅ Complete	private/public/protected enforcement
Library symbol index	✅ Complete	88 .kerml/.sysml files, ~1,417 symbols
Inheritance resolution	✅ Complete	Supertype chain traversal for subsetting/redefinition
OCL constraints	✅ 8 checks	See table below

Implemented OCL Well-Formness Checks

Code	Rule	Description
UNDEFINED_SYMBOL	—	Reference to non-existent type or feature
DUPLICATE_NAME	Namespace.duplicate_names	Two members with same name in a scope
CYCLIC_SPECIALIZATION	Type.no_cyclic_specialization	Type specializing itself (directly or indirectly)
INCOMPATIBLE_SUBSETTING	Feature.subsetting_compatible	Subsetting ref to undefined feature
INCOMPATIBLE_REDEFINITION	Feature.redefinition_compatible	Redefinition ref to undefined feature
INCOMPATIBLE_PART_DEFINITION	Part.definition_compatible	Part typed by non-PartDefinition
INCOMPATIBLE_PORT_DEFINITION	Port.definition_compatible	Port typed by non-PortDefinition
INCOMPATIBLE_FEATURE_CHAIN	Feature.chaining_compatible	Chained features with incompatible types
INVALID_MULTIPLICITY_BOUNDS	Multiplicity.bounds_valid	Lower bound > upper bound
UNRESOLVED_IMPORT	—	Import target does not exist

PlantUML View Generation (v0.25.2 → v0.27.0)

Function	SysML v2 View	Output	Notes
as_general_view()	General View (GV)	PlantUML	All element types, full filtering
as_package_view()	Package View	PlantUML	Package structure + import arrows
as_action_flow_view()	ActionFlowView (AFV)	PlantUML	Actions + flow connections
as_interconnection_view()	InterconnectionView (IV)	PlantUML	Parts, ports, connections
as_state_transition_view()	StateTransitionView (STV)	PlantUML	States + transitions
as_tabular_view()	Tabular View (GridView)	PlantUML / MD / HTML	Configurable columns
as_data_value_tabular_view()	Data Value Tabular View	PlantUML / MD / HTML	Attribute values + units
as_relationship_matrix_view()	Relationship Matrix View	PlantUML / MD / HTML	Cross-element relationship matrix

All views support: focus, elements, show_external, direction, B&W/color toggle, custom_style, and legend.

Nested Requirement Children (v0.36.1)

Requirement.load_from_grammar now populates self.children with nested requirement usages and requirement def definitions encountered in the body. Previously the body walk stubbed out DefinitionBodyItem with pass, so nested requirements were parsed by the grammar but dropped from the public object tree. Deep nesting recurses; .parent links are set on each child. Non-requirement nested elements are skipped for now. Grammar-object round-trip is unaffected.

Boxes-backed State-Machine Visualizer (v0.36.0)

Optional renderer that produces a boxes Diagram with native UML state shapes (rounded «state» boxes, filled-circle initial pseudostate, bullseye final state, orthogonal port-to-port routing). Alternative to as_state_transition_view() when you don't want a PlantUML/Java runtime.

Function	Returns	Notes
as_state_transition_view_boxes(model, focus=None)	boxes.Diagram	Build an in-memory diagram you can introspect / extend
render_state_transition_view(model, focus=None, routing=...)	braille terminal string	Quick terminal preview
render_state_transition_view_svg(model, focus=..., routing=..., scale=...)	SVG string	Vector output for embedding in docs

Handles entry; then X;, do/exit actions as state attributes, guarded transitions (if guard), shorthand accept X then Y;, the reserved done final-state target, dotted feature-chain targets (S2.S3), nested composite states, and parallel region composition. Lazy-loaded so import sysmlpy works without boxes installed. See docs/boxes_view.md for the full pseudostate landscape and worked examples.

Storage Backends

Backend	Dependencies	Persistence	Use Case
InMemoryStore	None	Volatile	Testing, small models
NetworkXStore	networkx	Volatile	Graph analysis, centrality, cycles
KuzuStore	kuzu	Disk (optional)	Embedded graph DB, Cypher queries
CayleyStore	requests	Server-managed	Remote graph DB, multi-tenant

Test Coverage

Counts from pytest --collect-only at v0.90.0 (1635 total).

Test file	Tests	Status
tests/grammar_test.py	165	✅ All pass (100%)
tests/semantic_test.py	179	✅ All pass
tests/plantuml_test.py	151	✅ All pass (incl. official-notation tests)
tests/store_test.py	121	Pass (optional deps skipped if not installed)
tests/class_test.py	84	✅ All pass
tests/traceability_test.py	46	✅ All pass
tests/interchange_test.py	38	✅ All pass
tests/evaluator_test.py	44	✅ All pass
tests/lsp_test.py	37	✅ All pass (batch 4: 36 more in tests/lsp_batch4_test.py)
tests/spreadsheet_test.py	37	✅ 35 pass, 2 skip (no openpyxl)
tests/navigate_test.py	42	✅ All pass
tests/cli_test.py	39	✅ All pass
tests/repl_test.py	28	✅ Interactive REPL: session merge, %commands, loop, CLI
tests/validator_test.py	84	✅ All pass
tests/repr_test.py	34	✅ All pass
tests/kuzu_store_test.py	32	Pass (skipped if kuzu not installed)
tests/import_test.py	31	✅ All pass
tests/cayley_store_test.py	39	Pass (skipped if cayley not installed)
tests/boxes_view_test.py	54	Pass (skipped if diagramboxes not installed)
tests/project_test.py	21	✅ All pass
tests/redefined_name_test.py	14	✅ All pass (100%)
tests/dfa_cache_test.py	14	✅ All pass
tests/resolve_test.py	12	✅ All pass
tests/reference_parse_test.py	12	✅ All pass
tests/constraint_text_test.py	12	✅ All pass
tests/two_stage_parse_test.py	12	✅ All pass
tests/main_test.py	7	✅ All pass
tests/partial_test.py	7	✅ All pass
tests/palette_test.py	6	✅ All pass
tests/conformance_test.py	123	✅ All pass (100%)
Total	1635	1510 fast + 123 conformance pass (2 skipped: optional deps)

Documentation

• README.md — installation, usage examples, view rendering docs
• AGENTS.md — AI agent onboarding guide
• docs/index.md — project overview
• docs/quickstart.md — step-by-step usage guide
• TUTORIAL.md — comprehensive guide with class mapping tables
• docs/PROJECT_SUMMARY.md — work summary for future agents/team members
• docs/plantuml-reference-analysis.md — PlantUML generator assessment
• docs/plantuml-examples/ — rendered diagram examples

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Completed Since v0.27.0

Dead-Code Removal + Lint Hygiene (v0.90.1)

• ~120 dead lines deleted — silently-shadowed duplicate methods (Action._get_definition, _evaluate_glued, two _get_child stubs), unused imports across 10 modules, the never-read sll_errors local, dead locals in Action.dump/_descend/ to_networkx_store.
• Bare except: → except Exception: in the example scripts; stale requirements.txt rewritten in sync with pyproject.toml.
• No behavior change: fast suite 1510 passed / 2 skipped and conformance 123/123 before and after; functional smoke over every touched module.

View Rendering Member Specializations (v0.90.0)

• render eng : Engine; / render eng2 : Engine :>> eng; / render eng3[2]; inside a view body no longer drop typing, redefinition and multiplicity on dump (the last live antlr_visitor.py TODO); _build_fsp_from_ctx() builds the FeatureSpecializationPart dict with proper group ordering.

Parallel Regions in the Simulator (v0.89.0)

• state def C parallel { ... } simulates: entering the composite activates all regions at their defaults, regions fire their own transitions independently (events dispatched per region in declaration order), run-to-completion applies per region, and transitions out of the composite exit all regions. sim.state is a tuple of active leaves while regions are co-active.
• Nested parallel composites (a parallel region inside a parallel region) activate and cascade on exit.
• Fixed: composites whose children were all composites were demoted to plain leaves (preventing these shapes from expanding at all).

Dead-Code Removal + Nested-Definition Fidelity (v0.88.1)

• 410 dead lines deleted — _visit_nested_usage and 11 more zero-reference visitor helpers; the remaining specialization: None node-declaration slots verified unreachable (grammar rejects typed declarations there).
• Nested definitions round-trip — part p { state def X; } and 16 sibling kinds were silently dropped even at the grammar-dump level; the nested dispatcher now covers all package-level kinds.
• Nested usages in state bodies surface — state s1 { action a1 : A; } now yields an Action child with name + typed_by_name; nested states keep their children.
• Typed transitions — transition t1 : T first e1; keeps : T (round-trips, typed_by_name on the Transition object).
• Satisfy typing — members carry typed_by_name; semantic finding: ors is the requirement reference, not the member name (anonymous by design).

Control-Flow Member Fidelity + Usage-Body Imports (v0.88.0)

• Usage-body imports — part p1 { private import Q::*; } (and public/protected/recursive forms) round-trip; the visitor now dispatches importRule in every body and DefinitionBodyItem handles the Import relationship.
• satisfy valueparts — satisfy s1 : R = 3; keeps = 3 (the emitter now uses the shared _visit_value_part helper; the expression sat one level below where it probed).
• accept members — accept msg : M; keeps name + typing (was accept ;); multiplicities render in re-parsable source order (: M[1]).
• Metadata usages navigable — metadata m1 : MD; / @m1 : MD; / about forms surface as Metadata children with name + typed_by_name (find('m1') works).
• Nested rendering usages — part w { rendering r2 : E; } creates a Rendering child with name + typed_by_name.

Round-Trip Fidelity Close-Out + View Body Members (v0.87.0)

• View filter / expose members — the last known silent-drop TODOs in the visitor: view v { filter @e1; expose e1; } now parses into grammar classes and dumps back losslessly (was view v ;). Grammar classes ElementFilterMember / Expose / MembershipExpose / NamespaceExpose implemented.
• Guarded entry transitions — entry a1; if x > 0 then s2; round-trips (the visitor handler probed nonexistent ctx attributes and the dict shape crashed the grammar class).
• Typing round-trip on prefixed usages — view v : Engine, viewpoint, concern, allocation, rendering, connection, individual usages keep their typing on dump (visitor emitters previously hardcoded specialization: None).
• typed_by_name for all dispatch kinds — viewpoint, concern, allocation, rendering, metadata, individual, constraint, calculation, connection, flow, satisfy, dependency now populate typing names (post-pass over Package.load_from_grammar children; extraction made idempotent).
• ConnectionUsage.dump() canonicalization — bare connect a to b; no longer renders connection connect\n…; typed-nameless connections keep the connection keyword + typing.
• RootNamespace — KerML roots load members; root-level ElementFilterMember warns + skips (no UnboundLocalError).

Storage Query Parity Across Backends (v0.86.0)

• NetworkXStore gains siblings / hub_elements / shortest_path_between_named; KuzuStore gains all_paths / in-out degree centrality / descendants_depth_limited / neighborhood / impact_analysis (client-side, mirroring Cayley) plus hub direction validation and deterministic tie-breaking.
• TestBackendParity: 14 analytics queries must return identical results on NetworkX, Kùzu and a live Cayley server — the three graph stores now expose the same query surface. Goal 10 fully closed.

Interchange & Evaluator: Conditional Expressions, Calc Parameters, JSON-LD Context (v0.85.0)

• Conditional expressions: if <cond> ? <then> else <else> evaluate in attribute defaults, constraints, and calc bodies; boolean condition enforced, nested else-chains, embedded ternaries via fragment substitution, unit suffixes on branches; dump respaces glued ternary text so models round-trip.
• Calc invocation: positional in parameter binding with declared defaults, recursion supported (depth 32), constraints can call calcs with what-if bindings.
• JSON-LD context: :func:build_jsonld_context produces explicit term definitions (<vocab>#<name>); vocabulary IRI configurable (no normative OMG context file exists to bundle); import normalizes IRI-keyed properties.

Performance: Persistent DFA Cache + Profiling Harness (v0.84.0)

• sysmlpy.dfa_cache — warmed parser/lexer ATN+DFA graphs pickled to ~/.cache/sysmlpy/, reinstated on cold start (3.7x faster first parse on the benchmark model); SYSSMLPY_DFA_CACHE env + set_dfa_cache() control; cache failures never break parsing.
• benchmarks/bench_parse.py (cold/cached/warm timing) and benchmarks/profile_parse.py (cProfile harness; parse dominates ~80 %, no visitor hotspot).

LSP: Incremental Sync, Position Tracking, Workspace Symbols, .-Completion (v0.83.0)

• Incremental text sync (ranged didChange edits; full-text changes still accepted); UTF-16 position math with clamping.
• Position-tracked semantic diagnostics via source-order pairing (duplicate names map to their own declaration).
• workspace/symbol over open documents + workspace root *.sysml scan (cached, capped).
• .-member completion resolved through type names, surviving transiently unparsable documents via the last good parse.

Semantic Diff: Renames, Grammar Fields, State Machines, Trace Gate (v0.82.0)

• Rename detection: removed+added pairs with equal kind and structural signature match as renamed (unique candidate only; ambiguous stays removed+added); ElementChange.old_name/old_qualified_name.
• Grammar-level signature fields: value, multiplicity, direction, abstract (canonical-dump heuristics); requirement traces edges.
• diff_state_machines() — state-machine diff via the simulator's MachineDescriptor.
• sysmlpy diff --threshold FRAC change-rate CI gate; ModelDiff.change_rate / elements_old / elements_new.

State-Machine Simulation: Assignment Effects & History (v0.81.0)

• do x := <expr> effects are evaluated (evaluate_expression) and applied via StateSimulator.set_value, so later guards see the new value; applied pairs surface on StepRecord.assignments.
• History pseudostates (state h : HistoryUsage;, h : HistoryUsage;, or bare h;/history; references) are recognized by boxes_view._collect_state_machine (new per-region pseudostates), excluded from the state list, and transitions targeting them resume the region's last active substate (default entry when unvisited). Deep history via deep_history=True / sysmlpy sim --deep-history.

Action Control-Flow Node Classes (v0.28.0–v0.29.0)

All 14 control flow grammar classes are now ported to grammar/classes.py:

• IfNode, WhileLoopNode, ForLoopNode, ControlNode, InitialNode, InitialNodeMember, SendNode, AcceptNode, TerminateNode, ActionTargetSuccession, ActionTargetSuccessionMember, GuardedSuccession, GuardedSuccessionMember, SourceSuccession, SourceSuccessionMember

Mutation API Stabilization (v0.30.2)

All private underscore-prefixed mutation methods given public aliases: - _set_child() → add_child(); _set_name() → set_name(); _set_typed_by() → set_typed_by() - _set_specializes() → set_specializes(); _set_subsets() → set_subsets() - _set_redefines() → set_redefines(); _get_child() → get_child() - Private names kept as backward-compatible aliases.

Model Navigation Enhancements (v0.30.2–v0.31.0)

• find_one() — single-match find with LookupError on ambiguity
• __iter__, __len__, __contains__ — container protocol on all model elements
• __str__ — returns SysML text (delegates to dump())
• find() uses sysml_type= keyword (legacy type= still works with deprecation)
• Typed property accessors (model.parts, model.actions, etc.)

Semantic Analysis Enhancements (v0.30.2)

• AnalysisResult class with .errors, .warnings, .raise_on_errors(), bool()
• analyze(model, strict=True) raises immediately on errors
• SysMLSyntaxError exported from package root
• Non-raising parse() variant: model, errors = parse(text)

Jupyter Integration (v0.30.2)

• _repr_html_() on all model elements — collapsible HTML tree in notebooks

Grammar Round-Trip (v0.31.0)

• All 97 grammar tests pass (100%) — control flow, successions, lifecycle metadata complete. New tests/redefined_name_test.py (8 tests) for re-declaration name resolution and References (:>, references) handling.
• No deferred tests remaining

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Known Issues

Location	Description
antlr_visitor.py	~~Top-level attribute multiplicity not captured~~ Resolved — bounds since v0.40.0, ordered/nonunique flags since v0.59.0 (note: nonunique ordered canonicalizes to ordered nonunique on dump; grammatically identical).
definition.py (RootNamespace)	~~load_package_body() raises NotImplementedError for AliasMember and Import nodes~~ Resolved in v0.58.0 — node types were already dispatched; the real gap (imports/aliases moved to the end of the package body on public-API dump) is fixed. KerML NamespaceBodyElement roots load their members since v0.87.0.
usage.py	~~Type relationships (: TypeName) not preserved in load_from_grammar()~~ Fixed in v0.57.0 — _extract_specialization_info() hoisted to base Usage; typed_by_name now populates on all usage kinds, including the prefixed kinds (view, viewpoint, concern, allocation, rendering, constraint, connection) whose dispatch branches skipped it — wired via a post-pass in v0.87.0. typedby object resolution is a follow-up.
semantic.py	*// dimension derivation (mass * speed → ForceValue inference) not yet implemented (future); +/- dimension equality and operand-category checks are complete (v0.55.0).
antlr_parser.py	SLL error wording may differ from LL wording (missing '}' at '<EOF>' vs extraneous input '<EOF>' ...); source position always matches (v0.56.0).

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Remaining Work

High Priority

Feature	Description
~Typed-by preservation~	Done in v0.57.0, extended in v0.87.0 — _typed_by_name / typed_by_name preserved for all usage kinds loaded from grammar. v0.57.0 covered Part, Attribute, Item, Port, Action, Interface, UseCase, Requirement, State, behavior children; v0.87.0 wired the prefixed kinds (view, viewpoint, concern, allocation, rendering, constraint, connection, individual, metadata, satisfy) whose dispatch branches assigned grammar manually, and made the visitor emit specialization for view/viewpoint/concern/allocation/rendering/connection/individual so view v : Engine round-trips its typing. Resolving typedby to the definition object via a model pass remains a follow-up.
~Fix top-level attribute multiplicity~	Verified fixed (v0.40.0) + flags bug fixed in v0.59.0 — bounds ([N], [N..M], [*]) already survived since v0.40.0 (docs were stale); the real remaining bug was ordered/nonunique hardcoded False in the visitor extractors plus a MultiplicityPart.dump() XOR-guard that dropped ordered. All fixed.
~AliasMember / Import handling~	Done in v0.58.0 — nodes were already parsed and held on Package.imports (definition.py); the gap was _ensure_body() reordering imports/aliases to the end of the body on dump. Source-order interleaving now preserved in both Model and Package rebuild paths.

Medium Priority

Feature	Description
~Feature chain type resolution~	Done in v0.60.0 — ReferenceCollector tags reference kind (typing/subsetting/redefinition/subclassification); chain check applies only to genuine feature chains (fixes false INCOMPATIBLE_FEATURE_CHAIN on every qualified type name like ScalarValues::Real). Dotted expression chains (wheels.hub.mass) resolve through the declared type of each feature, following :> inheritance; members of an enclosing usage's declared type (part myCar : Car { attribute x :> engine::power; }) resolve for ::, ., and single-member references (_resolve_through_context); inherited chain features advance to their declared type in the compatibility check. 17 tests.
~Connection multiplicity ends~	Verified fixed (v0.87.0) — connect c1[0..1] to c2[1]; parses and the multiplicity ends survive the round-trip (round-trip test test_bare_connect_dump_canonical).
~Nested :>> redefines in return~	Verified working (v0.87.0) — return attribute X : Type { :>> feature = expr; } parses and round-trips.
~Connector end compatibility~	Done in v0.76.0 — full type-assignability check in _check_connector_ends_compatible() flags CONNECTOR_END_TYPE_MISMATCH (warning).

Low Priority

Feature	Description
Grammar auto-update pipeline	Automated refresh from the OMG KEBNF spec when new releases drop
Full OCL constraint library	Machine-readable OCL constraints extendable without code changes
Parse library files (not regex)	Replace LibrarySymbolIndex._extract_from_file() with actual parsing

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Conformance Test Suite

Source: SysML-v2-Pilot-Implementation-2026-03 (org.omg.sysml.xpect.tests) Library: 88 files bundled at src/sysmlpy/library/ (kernel/ systems/ domain/) Test files: 123 .sysml files under tests/sysmlv2/, each with a .error sidecar

Run with: poetry run pytest -m conformance

Current results (2026-05-27)

123 / 123 passing (100%)

Category	Files	Pass	Fail	Pass %
simpletests/	37	37	0	100%
validation/valid/	34	34	0	100%
validation/invalid/	47	47	0	100%
expression/	4	4	0	100%
linking/	1	1	0	100%
Total	123	123	0	100%

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Summary Counts

Category	Count
Public API classes (complete)	28
Grammar classes with get_definition()	358 of 358 (100%, reflection-audited)
Grammar classes with graceful fallback	All 358 (no more NotImplementedError crashes)
Unit + grammar + integration tests	809 passing
Grammar round-trip tests passing	143 / 143 (100%)
Helper-property tests	8 / 8
Grammar-side References dispatch	✅
PlantUML rendering tests	108 passing
Conformance tests (2026-03 XPect suite)	123 / 123 (100%)
Semantic analysis tests	153 passing
Storage backend tests	97 passing (optional deps skipped if missing)
Bundled standard library files	88 (kernel .kerml + systems .sysml + domain .sysml)
Library symbols indexed	~1,604 (incl. library function declarations, v0.54.0)
PlantUML view functions	10 (GV, PV, AFV, IV, STV, SV, CV, Tabular, DataValue, RelMatrix)