Our first Parsing Analysis diagram about leptons

The source «document» of the snippet is a page 'Lepton' from Wikipedia, named here 'Wikipedia:Lepton' and assigned as the mandatory tagged value 'source' of the «snippet». The 'url' tagged value has been set on the «document» along with the optional 'org' tagged value which has been set to the «organisation» 'Wikipedia'.

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The first thing you might notice is all those cobweb-like dashed-line "anchors" drawn from the snippet symbols to the elicited model element symbols and labels. Such visual clutter does not matter here because:

Webel Parsing Analysis «pa» diagrams are NOT intended as final presentation diagrams! They serve merely to traceably elicit model elements, which may then be shown in other (typically much tidier) presentation diagrams elsewhere.

There is clearly some kind of abstraction ElementaryParticle, of which a Lepton is a special case. So far, there are value properties for spin:Spin, isLepton:Boolean and a derived value property /calcIsLepton:Boolean. In the more specific Lepton class the spin:Spin has been redefined to be a readonly property with fixed default value 0.5, and the isLepton:Boolean is redefined to be a readonly property with fixed default value 'true'. These properties also have isLeaf set 'true' so they can't be further redefined.

The value property /calcIsLepton:Boolean is intended to be calculated in the context of any specific particle via a constraint declared on a constraint block IsLepton. We'll see next how this can be calculated using Magic Cyber-Systems Engineer ^® (Cameo Systems Modeler^®) or Magic Model Analyst^® (Cameo Simulation Toolkit^®) for an instance :Lepton.

Webel Best Practice: Computed category membership test values are sometimes adequate and can prevent Class/Block explosion. However, a dedicated Class/Block encapsulating a clear domain concept offers a clear documentation point and can carry other characterising features.

We are told that a lepton 'does not undergo strong interactions'. This important concept is encapsulated as a custom stereotype keyword «not undergoes» applied to a Dependency. This may remind some readers of semantic triples in OWL and RDF. It is also represented as a value property isInteractsStrong:Boolean, which is redefined in Lepton to always be 'false'.

Presumably there are other types of interactions, not just strong interactions. Let's pretend for the moment we don't know that. To more formally indicate elicited elements that are not explicitly mentioned in the text of a source one can use a custom stereotype with a keyword like «pa:implied», where the 'pa' stands for Parsing Analysis. Some other similar keywords might include «pa:assumed». If this is clarified by another snippet, these keywords can then be removed.

The Parsing Analysis diagram is itself also stereotyped with «pa». This helps remind us that it is NOT a final presentation diagram and only serves as a temporary "scratchpad" for traceable elicitation of model elements.

Up next

Calculate whether a specific particle is a lepton using SysML parametrics

Notes

[POLICY, STYLE]{STRICT} Webel Parsing Analysis «pa» diagrams are NOT intended as final presentation diagrams! They serve merely to traceably elicit model elements, which may then be shown in other (typically much tidier) presentation diagrams elsewhere.

[TIP]{EDITORIAL} In Webel Parsing Analysis every Package, Model, or Diagram used to perform Parsing Analysis MUST have the stereotype keyword «pa» applied, and MUST live under a top-level Model or Package 'source' separate from the rest of the project model.

[POLICY]{STRICT} Webel Parsing Analysis: A Snippet (keyword «snippet») MUST always have exactly one domain 'source' Document (keyword «document»).

Snippets (quotes/extracts)

In particle physics, a lepton is an elementary particle of half-integer spin (spin 1⁄2) that does not undergo strong interactions.