SYSML17 — ProxyPort property "matching"

[From email to sysml-rtf@omg.org 7-May-2019, and discussed at the SysML RTF meeting 9-May-2019.]

The situation of a proxy port's InterfaceBlock having multiple flow properties, and may be also multiple value properties, leads to the vexing question of how they all get paired up with [the] port's owning blocks' features. Putting aside behaviour ports (isBehavior=true), the most straightforward solution would be to use a binding connector between each feature in the proxy port and the actual features in the owning block. However, I find the public draft of SysML 1.6 to still not be completely clear on this matter, despite its improvements to the chapter on ports and flows.

The section on FlowPorperty (9.3.2.8) refers to property matching (2nd paragraph), but does not contextualise when property matching might occur. Most of what it states makes perfect sense in the context of connected proxy ports, especially when the ports have the same type (i.e. an InterfaceBlock) and one port is conjugated. However, it becomes remarkably unclear what it means when matching is applied to the proxy port and its owning block's flow properties.

The section on Proxy Ports (9.3.2.13), replaces the later part of the first paragraph with a subsequent paragraph to spell out how a proxy port relates to its owning block, but seems to do this in a weak way by stating "This can be achieved in several ways. For instance by...", which sounds informative, rather than normative. Nevertheless it does state "by binding it to a fully specified internal part or by having all its properties individually bound to internal parts."

If a proxy port is bound to an internal part, is there a need for the port's type to match that of the bound part? If not, what are the rules for feature matching?

If a proxy port's "properties [are] individually bound to internal parts", then dose the meaning of "part" extend to the block's value properties and flow properties? (I wouldn't ordinarily consider them to be parts.) If not then where does it state that these properties can be bound?