@rune-langium/core

Parse .rosetta source into typed ASTs, build cross-file workspaces, and serialize models back to source text.

Use parse() for a single self-contained document, parseWorkspace() when files reference each other, and createRuneDslServices() when you need raw Langium services for custom tooling. The serializer exports are best for AST-driven workflows, tests, and code transformations that do not need to preserve original formatting.

When to Use

Use this skill when:

• Validating a single .rosetta file or snippet in memory → use parse
• Building a parse pipeline in a Node.js script → use parse
• Unit-testing grammar rules in isolation → use parse
• Generating code from a set of related .rosetta files → use parseWorkspace
• Validating a full namespace bundle where types reference each other → use parseWorkspace
• Running integration tests that span multiple Rosetta files → use parseWorkspace
• Parsing an expression body in isolation (editor previews, round-trip tests) → use parseExpression
• Validating user-typed expression text without a synthetic wrapper document → use parseExpression
• Building a Node.js script that parses or validates .rosetta files → use createRuneDslServices
• Writing unit tests for grammar rules or validators → use createRuneDslServices
• Constructing a parseWorkspace() pipeline outside of the LSP server → use createRuneDslServices
• This is used automatically by createRuneDslServices() → use RuneDslParser — you do not need to instantiate it directly.

Do NOT use when:

• Parsing files that have cross-references to other documents — unresolved references will have ref === undefined. Use parseWorkspace() instead. (parse)
• Running inside a Langium LSP server — the DocumentBuilder is already managed by the server lifecycle; calling parse() creates a second services instance and wastes memory. (parse)
• Parsing a single self-contained file — use the simpler parse() instead (parseWorkspace)
• Processing very large CDM workspaces incrementally — prefer the LSP server for streaming document updates (parseWorkspace)
• You need resolved cross-references — use parse()/parseWorkspace() with a full document instead. (parseExpression)
• Inside the LSP server — use createRuneLspServer() which provides the full LangiumServices (LSP providers) instead of core-only services. (createRuneDslServices)
• When you need to share a service instance across multiple requests in a long-running server — the returned instance is not thread-safe for concurrent DocumentBuilder.build() calls; serialize builds with a queue. (createRuneDslServices)
• Subclassing for grammar experiments — prefer creating a separate grammar variant and a new services container instead. (RuneDslParser)

API surface: 744 functions, 8 classes, 183 types, 86 constants

Configuration

2 configuration interfaces — see references/config.md for details.

Quick Reference

Key functions: parse (Parse a Rosetta DSL source string into a typed AST), parseWorkspace (Parse multiple Rosetta DSL source strings as a workspace), parseExpression (Synchronously parse a bare Rune DSL expression snippet (e), createRuneDslServices (Create the full set of services required for the Rune DSL language), createRuneDslParser (Factory function that creates and fully initializes a RuneDslParser), insertImplicitBrackets (Scans Rune DSL source text and inserts [ and ] around bare expressions that follow extract, filter, or reduce operators) Key classes: RuneDslParser (Custom Langium parser for the Rune DSL that normalizes lexer input to insert implicit [ and ] brackets around bare expressions after extract, filter, and reduce operators)

1021 exports total — see references/ for full API.

References

Load these on demand — do NOT read all at once:

• When calling any function → browse references/functions/ for grouped indexes, full signatures, parameters, and return types
• When using a class → browse references/classes/ for grouped indexes, properties, methods, and inheritance
• When defining typed variables or function parameters → read references/types.md
• When using exported constants → read references/variables.md
• When configuring options → read references/config.md for all settings and defaults

Links

• Author: Pradeep Mouli pmouli@mac.com (https://github.com/pradeepmouli)