mps-aspect-editor

name	mps-aspect-editor
description	Use when creating or changing MPS editor definitions — the overall workflow from scaffolding a `ConceptEditorDeclaration` through componentizing reusable `EditorComponentDeclaration`s, refining cell models and cell layouts, applying style sheets and indent-layout style items, wiring smart references, leveraging inheritance via super-concepts and interfaces, inspecting (`print_node_json`, `show_node_representation`) and validating (`check_root_node_problems`). Covers `jetbrains.mps.lang.editor` cell models (`CellModel_RefNode`/`CellModel_RefNodeList`/`CellModel_RefCell`/`CellModel_Property`/`CellModel_Constant`), layout choices, and JSON blueprints for common editor shapes. For the non-layout side (action maps, keymaps, transformation/substitute menus) use `mps-aspect-editor-menus-and-keymaps`.
type	reference

MPS Editor — Technical Reference

The jetbrains.mps.lang.editor language defines projectional editors as trees of cell models (display elements) with cell layouts and style items. This skill is the technical lookup: concept names, suffixes, style classes, and the rules that decide which cell model to use where.

Critical Directives

• Always use CellModel_RefNodeList for 0..n or 1..n children. CellModel_RefNode is for single cardinality only.
• Use IndentLayoutOnNewLineStyleClassItem (apply to the cell that should start on a new line) instead of the legacy IndentLayoutNewLineStyle (applied to the cell before the break) — the latter is easier to get wrong.
• : set the internal (e.g. ) inside an to so the referenced target cannot be accidentally renamed through the editor.