SysML v2 notation coverage

This page states which parts of the SysML v2 graphical notation longeron draws, and which parts it does not. The reference is the OMG Systems Modeling Language v2.0 specification: its per-clause notation tables and the clause 8.2.3 graphical-notation BNF. Every implemented glyph was verified against rendered spec figures, and the notation gallery shows each one beside its spec figure with a self-verifying assertion. The browser test tier re-checks the gallery on every CI run.

Legend: ✔ implemented per the spec figure · ◐ implemented with a stated approximation · ✖ not implemented (reason given).

Relationship edges and endpoints

Notation	Spec form	Status
Subclassification :> (def→def)	solid line, hollow triangle	✔
Subsetting :> (usage→usage)	solid line, hollow triangle	✔
Feature typing :	solid line, hollow triangle, colon dots on the shaft	✔
Redefinition :>>	solid line, hollow triangle, bar tick on the shaft	✔
Reference subsetting ::>	solid line, hollow triangle, 2×2 dots	✔
Composite membership	filled diamond at the whole end, end multiplicities	✔ (composition="defs")
Referential membership (ref)	hollow diamond at the whole end	✔
Owned membership edge	circle-plus at the owning end	✔ (membership="edges"; nesting stays the default presentation)
Alias membership	hollow circle at the referencing end, alias name	✔
Connection (undirected)	solid line, no endpoint	✔
Connection with direction	open-V head at the target end	✔ (direction comes from sourceEnd/targetEnd def-end names, the spec’s own model signal)
N-ary connection / dependency	junction dot, radiating links	✔ (links meet at the dot center)
Proxy connection (nested ends)	ball on the shallowest drawn ancestor, residual-path label	✔
Binding connection	= riding the line	✔
Dependency	dashed open-V, optional name label	✔
Satisfy requirement (longhand)	«satisfy requirement» box + reference-subsetting edge	✔ (printed p.133 form)
Satisfy (shorthand by)	keyword edge	✔
Allocation	«allocate» keyword edge + «allocation» box forms	✔
Flow connection	border pins, filled head at the target pin, payload labels	◐ pins are edge-end decorations, not ELK ports, to keep packed layouts stable; port-attached flows use the real port squares
Portion membership	notched ball at the whole-occurrence end	✔
Conjugation ~	textual only (no edge glyph in the spec)	✔ as text
Succession (action views)	dashed open-V	✔
Transition (state views)	solid open-V, trigger/guard/effect label	✔
Message/event lines	sequence view	✖ longeron has no sequence view

All arrowheads share the spec’s slender (~27°) geometry, derived from one set of constants in both render pipelines.

Nodes and adornments

Notation	Spec form	Status
Definition / usage boxes	square corners for defs, rounded for usages	✔
Package	folder tab	✔ (tab selects and hovers with the box)
Ports	boundary squares, direction arrows inside, ~ label for conjugates	✔ (direction derives from the port definition’s directed features; arrows point relative to the node interior)
Actor	stick figure, name below (default); «actor» keyword box	✔ (actor_style="box" for the alternative)
Stakeholder	«stakeholder» keyword box	✔
Compartments	left-aligned rows, «keyword» stereotypes	✔
Comment / documentation	folded-corner note, dashed anchor	✔ (annotations=True)
Metadata	«@Type» / «#keyword» adornments	✔ (annotations=True)
Individual / timeslice / snapshot	keyword adornments	✔
View usage	«view» keyword box	✔ (a saved diagram’s recipe is a model element; view persistence)

Behavior views

Notation	Spec form	Status
Start	filled circle	✔
Done / final	bullseye	✔
Terminate	circle with inscribed X	✔
Fork / join	filled bar	✔
Decision / merge	hollow rhombus	✔ (in/out links meet at single anchors)
Accept action	rounded box, notched-banner badge at top left	✔
Send action	rounded box, pointed-tag badge at top left	✔
Swim lanes	dashed «performer» lanes	◐ content-sized lane containers ordered by ELK partitioning, not full-height columns (lanes=)
Typed submachines	expanded in place	✔ (submachine_depth, cycle-protected)
State entry/exit points	border circles	✖ the language model has no border connection-point element to render; tracked as a model-layer gap

Interaction

Selection and hover treat a node and its adornments (tab, badges, ports) as one shape. Diagrams open fitted and centered. The toolbar provides search-that-highlights, edge-routing and layout-direction toggles, and fit/center/collapse controls. Edge routing offers orthogonal (default), polyline, and splines; endpoint symbols stay correctly oriented in all three.

How this page stays honest

The gallery notebook asserts every ✔ above against the built diagram, and executes on every CI run, headless and in a real browser. When a glyph changes, the gallery fails before this page can drift. Deferred items keep their reasons next to them; when a deferral lands, its row moves up and the gallery gains a section.