mps-lang-core-xml

name	mps-lang-core-xml
description	Use when authoring XML documents as MPS root nodes or building XML-generating generator templates with jetbrains.mps.core.xml — covers XmlFile, XmlDocument, prolog (XML declaration, DOCTYPE, processing instructions, comments), elements, attributes, CDATA, entity references, and macro attachment via the smodelAttribute role for templates that emit XML output.
type	reference

jetbrains.mps.core.xml Language

jetbrains.mps.core.xml is an MPS language for authoring and generating XML documents inside MPS models. It is used either for direct XML authoring (an XmlFile root holds a complete document) or for generator templates (an XmlFile carries RootTemplateAnnotation and macros via smodelAttribute child roles).

Language reference: l:479c7a8c-02f9-43b5-9139-d910cb22f298:jetbrains.mps.core.xml

Critical Directives

• Wrap everything in XmlFile → XmlDocument. XmlFile is the only rootable concept. XmlDocument.rootElement has cardinality 1 — put the root there, not in content.
• XmlProlog is optional (0..1). Omit it entirely when no prolog is needed.
• Attribute values are lists of XmlValuePart. A plain string is a single XmlTextValue. An attribute with no value children renders as a valueless (boolean) attribute.
• Property name asymmetry: XmlText / XmlSingleLineText use the property value. XmlTextValue (attribute value part) uses the property text. Do not swap them.
• In generators, macros go in the smodelAttribute child role of the node they annotate — not as siblings in content or attributes.
• Subclass the base types. Extend XmlBaseAttribute (not XmlAttribute) and XmlBaseElement (not XmlElement) when defining custom concepts for derived languages.
• Do not hand-edit serialized .mps files. Use MPS MCP node tools for all changes.

Common-Path Workflow

1. Add jetbrains.mps.core.xml as a used language on the target model. For generator templates, also add jetbrains.mps.lang.generator.
2. Create an XmlFile root node with a name. The name is the template/document identifier, not the output filename.
3. Add an XmlDocument child in role document. Optionally add an XmlProlog for declarations/comments/PIs.
4. Build the document tree under XmlDocument.rootElement and the inner content lists.
5. For generator templates, attach RootTemplateAnnotation to the XmlFile via smodelAttribute, and attach macros (PropertyMacro, LoopMacro, CopySrcNodeMacro, …) to inner nodes via their smodelAttribute role.
6. Validate with mps_mcp_check_root_node_problems.

Related Skills

• mps-aspect-generator — for generator-side macro design that produces these XML templates.
• mps-aspect-textgen — for the text-serialization layer that turns these XML trees into output files.
• mps-node-editing — generic JSON-blueprint node creation/replacement workflow.

Reference Index

• Concept catalog — open when you need exact concept names, properties, cardinalities, or aliases for any document, prolog, element, attribute, or content node. See references/concept-catalog.md.
• JSON blueprint patterns — open when constructing or editing concrete XML trees as JSON for mps_mcp_insert_root_node_from_json, mps_mcp_update_node. Includes minimal files, prolog with declarations, DOCTYPE, comments, attributes, mixed values, CDATA, processing instructions, and a full generator-template example. See references/json-blueprints.md.
• Rules and pitfalls — open when a node validates but the rendered XML is wrong, when attribute/value naming feels inconsistent, or before subclassing element/attribute concepts. See references/rules-and-pitfalls.md.
• Language dependencies — open when setting up a new model that uses XML concepts, or when wiring generator templates that mix XML with generator macros. See references/language-dependencies.md.