Model plugin

Instantiates a metamodel: named objects with property values, linked together. A model is the starting point of an optimisation and the form every solution comes back in.

At a glance

Plugin id	model-service
Display name	Model
Description	Language support for model definitions (.m and .m_gen files)
Default URL	/plugin/model
Source	app/packages/service-model, app/packages/language-model, app/packages/editor-model
Depends on	The Metamodel plugin, since every model imports a metamodel

Languages contributed

Language id	Name	Extension	Textual editor	Graphical editor	Generated
model	Model	.m	✅	✅	❌
model_gen	Generated Model	.m_gen	❌	✅	✅

The model language

A .m file starts by naming its metamodel, then declares objects and the links between them.

using "./shapes.mm"

board : Canvas {
    title = "Poster"
    revision = 3
}

background : Layer {
    index = 0
}

foreground : Layer {
    index = 1
}

frame : Rectangle {
    name = "Frame"
    visible = true
    colour = Colour.BLUE
    tags = ["decoration", "border"]
    width = 210.0
    height = 297.0
}

dot : Circle {
    name = "Dot"
    visible = false
    colour = Colour.RED
    tags = []
    radius = 2.5
}

note : Annotation {
    text = "Keep the frame aligned with the page."
}

board.layers -- background
board.layers -- foreground
background.shapes -- frame
foreground.shapes -- dot
frame.annotations -- note

Creating a .m file in the workbench opens a dialog first, because the file cannot be written until its metamodel is known.

Objects

frame : Rectangle {
    name = "Frame"
    visible = true
    colour = Colour.BLUE
    tags = ["decoration", "border"]
    width = 210.0
}

An object is name : Class { ... }. The name is unique within the file and is what links refer to. Inside the braces, each line assigns a property declared by the class or one of its supertypes, and each property may be assigned at most once.

Values may be:

Kind	Example
String	"Frame"
Number	3, 210.0
Boolean	true, false
Enum entry	Colour.BLUE
List	["a", "b"], []

Links

board.layers -- background
frame.annotations -- note

A link connects two objects. Naming the property on an end says which association is meant; for an association that is navigable from only one side, that is the side you name. Both ends may be named when the association is bidirectional and the file benefits from being explicit.

The generated model language

.m_gen files are produced by the platform, not written by hand — an optimisation run emits one per solution on its Pareto front. They carry a serialised model rather than the textual syntax above, which is why the language has no textual editor.

They do open in the same diagram editor as hand-written models, so a solution can be inspected exactly like the model it came from.

Contribution plugins contributed

None. The model plugin does not extend any other language.

Contributions the model language accepts

The model language takes import contributions: a plugin can register a grammar for the content of an import <Name> { … } block, and answer a request for the objects and links that block stands for. The Model CSV plugin is the one bundled example, adding

import CSV {
    Task from "./tasks.csv"
}

so that the rows of a CSV file become objects of the named metamodel class. Imported objects are merged with the hand-written ones before the model is handed to the execution services, and are drawn in the diagram next to them.

Nothing in this plugin knows what CSV is. An import contribution supplies its own grammar for the block's contents, its own answer to "what objects does this stand for", and — optionally — its own diagram nodes; the model language matches the block to whichever plugin registered its keyword and asks that plugin. A second import format would need no change here.

Server-side capabilities

File data key	Contents
ast	The serialised AST, for both model and model_gen
model-data	The model in the form the execution services consume

The plugin has no execution handler of its own: models are executed by transformations and optimisations, not on their own.

Graphical editor

The model diagram editor shows objects as nodes and links as edges, with the palette populated from the metamodel the file imports — only classes that are not abstract can be created, and only associations declared between the relevant classes can be drawn. Copy and paste work within and between model diagrams.