@liendev/parser

AST parsing, complexity analysis, and semantic chunking for Lien.

This package is Lien's analysis engine: it turns source files into chunks with AST metadata, resolves dependency edges and test associations across 11 languages, computes complexity, and answers the deterministic review signals lien review runs. It has no server, no database and no network dependency — every answer is computed from the files you hand it.

Features

• AST parsing: Tree-sitter-based parsing for TypeScript, JavaScript, Python, PHP, Rust, Go, Java, C#, Ruby, Kotlin, and Swift
• Semantic chunking: split code into meaningful chunks respecting function/class boundaries
• Complexity analysis: cyclomatic, cognitive, and Halstead complexity metrics
• Dependency analysis: import/export tracking with transitive dependent resolution
• Symbol extraction: extract functions, classes, interfaces, and call sites from AST
• Test association detection: convention-based and import-based test file detection
• Codebase scanning: file discovery with gitignore support and ecosystem presets
• Deterministic review signals: structural questions about a change ("does this literal still appear unconditionally elsewhere?", "did this change add a variant to some but not all of a family's switch statements?") answered as pure functions over a diff plus parser output — no LLM, no network, no persisted index

Supported languages

| Language | AST Parsing | Complexity Metrics | Import/Export Tracking | |----------|:-----------:|:------------------:|:---------------------:| | TypeScript | Yes | Yes | Yes | | JavaScript | Yes | Yes | Yes | | Python | Yes | Yes | Yes | | PHP | Yes | Yes | Yes | | Rust | Yes | Yes | Yes | | Go | Yes | Yes | Yes | | Java | Yes | Yes | Yes | | C# | Yes | Yes | Yes | | Ruby | Yes | Yes | Yes | | Kotlin | Yes | Yes | Yes | | Swift | Yes | Yes | Yes |

Line-based chunking and symbol extraction are available for additional languages including Vue, Liquid, C/C++, Scala, and Markdown.

Usage

import {
  parseAST,
  chunkByAST,
  detectLanguage,
  analyzeComplexityFromChunks,
  scanCodebase,
  chunkFile,
} from '@liendev/parser';

// Parse a file into an AST
const language = detectLanguage('example.ts');
const result = parseAST(sourceCode, language);

// Chunk a file using AST-aware boundaries
const chunks = await chunkByAST('src/auth.ts', sourceCode, {
  chunkSize: 75,
  chunkOverlap: 10,
});

// Analyze complexity from chunks
const report = analyzeComplexityFromChunks(chunks, files, {
  cyclomatic: 15,
  cognitive: 15,
  halstead_effort: 60,
  halstead_bugs: 1.5,
});

Architecture

This package is part of the Lien monorepo. See CLAUDE.md for the current package dependency chain.

License

AGPL-3.0. See LICENSE for details.