mps-language-inheritance

name	mps-language-inheritance
description	Investigate inheritance between MPS languages and between concepts — extended languages, superconcepts, implemented interfaces, sub-/assignable concepts, and cross-language specialization. Use when tracing language hierarchies, finding extension points, or checking concept assignability.
type	reference

MPS Language and Concept Inheritance

Two layers of inheritance matter in MPS: module-level (one language extends another) and concept-level (concepts inherit superconcepts and implement interface concepts).

Critical Directives

• Concept-level inheritance is realized through module-level extension — different languageReference on a concept and its superConcept indicates a cross-language specialization, which usually requires the consumer's language to extend the parent.
• GET_ALL_SUPERCONCEPTS gives the full transitive closure in a single call — prefer it over recursive walking of superConcept / superInterfaces.
• IS_SUBCONCEPT_OF is the fastest way to verify a single assignability question; do not enumerate GET_SUB_CONCEPTS and search by hand.

Module-Level Inheritance (Language Extension)

One language can inherit the structure and functionality of another via an "extends" relationship.

1. Tool: mps_mcp_get_project_structure (with includeDependencies: true).
2. Workflow: check the extendedLanguages field in the response for the target language. This lists direct parent languages.
3. Hierarchy tracing: recursively call this tool for each parent to build the full inheritance tree.

Concept-Level Inheritance

Upward Hierarchy (Ancestors)

• Direct ancestors: use mps_mcp_get_concept_details. The response includes:
  • superConcept: immediate parent concept.
  • superInterfaces: immediate implemented interface concepts.
  • superConceptContainingProject and superInterfaceDetails[*].containingProject when an ancestor comes from another open MPS project and is read-only from the selected project.
• Full closure: use mps_mcp_query_structure with GET_ALL_SUPERCONCEPTS to get the complete chain of ancestors and interfaces in one call.

Downward Hierarchy (Descendants)

• Specializations: use mps_mcp_query_structure with GET_SUB_CONCEPTS to find all concepts (direct and indirect) inheriting from a base.
• Implementations: use GET_ASSIGNABLE_CONCEPTS to retrieve only non-abstract subconcepts that can be instantiated.

Strategic Analysis

• Verification: use mps_mcp_query_structure with IS_SUBCONCEPT_OF to check if concept A inherits from concept B.
• Cross-language extension: compare the languageReference of a concept with that of its superConcept. Different references indicate a language boundary specialization; foreign-project ancestors are marked explicitly with the containing-project fields.
• Discovery: use mps_mcp_search_concepts to find base concepts (e.g. "Statement") for extension.
• Implicit dependencies: if a model uses a language without an explicit import, check if its used languages extend the missing language via mps_mcp_get_project_structure.

Best Practice

Identify extension points by first checking high-level extendedLanguages via mps_mcp_get_project_structure, then use mps_mcp_get_concept_details to pinpoint cross-language concept specializations.

Related Skills

• mps-language-analysis — start here when you need general language inspection, not just inheritance.
• mps-aspect-structure-concepts — when you intend to define new concepts (with their own super/interface lists).
• mps-aspect-accessories — for extendedLanguages vs usedLanguages semantics at module level.