XSMP Link Base (.xsmplnk)

Link base files collect reusable links separately from assembly bodies.

They are useful when the same wiring should be applied to several assembly instances or when link topology should stay separate from instantiation logic.

Document comments and metadata

Link-base files use the shared document-comment rules described in Shared Syntax: Comments, Paths, Templates and Values.

Use a leading documentation comment with the shared root-level tags @title, @date, @creator and @version when you want to enrich exported SMP metadata.

Example:

/**
 * Orbital segment reusable links.
 * @title Orbital Links
 * @creator alice
 * @date 2026-03-27T08:00:00Z
 * @version 1.0
 */
link OrbitalLinks

Root structure

A Link Base groups reusable wiring rules that can later be attached to assembly instances.

Syntax

link <name> [for <assembly>]
    <component-link-base>*

Required:

• link
• the link-base name

Optional:

• for <assembly>
• any number of component link-base blocks

Behavior:

• for <assembly> states which assembly shape this link base is written for
• without for, the file still acts as a reusable link container, but path checking may be less precise

Example:

link OrbitalLinks for OrbitalSegment

Component link-base blocks

A Component Link-Base Block changes the current component context and groups links below one subtree.

Syntax

<path>
{
    (<link> | <component-link-base>)*
}

Required:

• one component path
• one block body

Behavior:

• an absolute path starts from the assembly root
• a relative path is resolved below the parent component link-base
• nested blocks let you organize links by subtree

Examples:

/
{
}

avionics
{
}

payload
{
    router
    {
    }
}

Link kinds

Link Kinds describe the three kinds of reusable wiring supported by a link base.

Link bases support three link kinds:

• event links
• field links
• interface links

Event link

An Event Link connects one event source to one compatible event sink.

Syntax

event link <owner-path> -> <client-path>

Required:

• event link
• one owner path
• ->
• one client path

Example:

event link publishedMode -> child.commandedMode

Field link

A Field Link connects one output field to one compatible input field.

Syntax

field link <owner-path> -> <client-path>

Required:

• field link
• one owner path
• ->
• one client path

Example:

field link power.lineVoltage -> router.incomingBus

Interface link

An Interface Link connects one published reference to one client instance, optionally with a back reference on the client side.

Syntax

interface link <source-path> -> <client-path> [ :<back-reference> ]

Required:

• interface link
• one source path
• ->
• one client path

Optional:

• :<back-reference>

Behavior:

• the last segment of source-path selects the published reference
• any earlier segments navigate to the owner component instance
• the optional back-reference selects one local reference on the client side

Examples:

interface link logger -> payload

interface link nested.logger -> payload:backLogger

Back references

A Back Reference names one local reference on the client side of an interface link.

Back references use a local named reference syntax:

[unsafe] <name>

Required:

• one local reference name

Optional:

• unsafe

Behavior:

• the back reference is resolved on the client side of the interface link
• unsafe keeps the local name exactly as written even when it cannot be checked safely

Example:

interface link nested.logger -> payload:backLogger

Paths

A Link-Base Path identifies the component context and the endpoints used by reusable links.

Link-base paths are used in:

• component link-base headers
• event links
• field links
• interface links

Link-base paths use the shared path model described in Shared Syntax: Comments, Paths, Templates and Values, the shared unsafe behavior documented in unsafe, and the shared placeholder forms described in Template parameters and placeholders.

Behavior:

• an absolute path starts from the link-base root context
• a relative path starts from the current component link-base block
• the last segment is interpreted according to the link kind that uses the path

Examples:

{BusMember}.power.lineVoltage

field link unsafe outValue -> unsafe child.inValue

interface link unsafe logger -> payload:unsafe backLogger

Minimal complete example

/**
 * @title Orbital Links
 * @creator alice
 * @date 2026-03-27T08:00:00Z
 * @version 1.0
 */
link OrbitalLinks for OrbitalSegment

/
{
    field link {BusMember}.power.lineVoltage -> {RouterMember}.incomingBus
    interface link {BusMember}.logger -> {LoggerMember}
    event link {BusMember}.publishedMode -> inboundMode
}