# Requirements Document

## Introduction

本機能は、tree-sitter-analyzerにYAML言語サポートを追加します。tree-sitter-yaml（v0.7.2）を使用して、YAMLファイル（設定ファイル、GitHub Actions、Kubernetes manifests、Docker Compose等）の構造解析を実現します。

既存の言語プラグイン（CSS、Markdown等）のアーキテクチャに従い、他の言語に影響を与えない独立したプラグインとして実装します。SQL言語サポートで得た教訓（クロスプラットフォーム互換性、エラーハンドリング）を活かし、堅牢な実装を目指します。

## Glossary

- **YAML**: YAML Ain't Markup Language - 人間が読みやすいデータシリアライゼーション形式
- **YAMLPlugin**: YAML言語解析を担当するプラグインクラス
- **YAMLElementExtractor**: YAML要素を抽出するクラス
- **YAMLElement**: YAML固有のコード要素データモデル
- **tree-sitter-yaml**: YAML用のtree-sitterパーサーライブラリ（v0.7.2）
- **Mapping**: YAMLのキー・バリューペア構造
- **Sequence**: YAMLのリスト/配列構造
- **Scalar**: YAMLの単一値（文字列、数値、真偽値等）
- **Anchor**: YAMLの参照定義（&anchor）
- **Alias**: YAMLの参照使用（*alias）
- **Document**: YAMLドキュメント（---で区切られる単位）

## Requirements

### Requirement 1

**User Story:** As a developer, I want to analyze YAML configuration files, so that I can understand the structure of my configuration and identify key-value pairs.

#### Acceptance Criteria

1. WHEN a user provides a YAML file path THEN the YAMLPlugin SHALL parse the file and return structured elements
2. WHEN the YAML file contains mappings THEN the YAMLPlugin SHALL extract all key-value pairs with their line numbers
3. WHEN the YAML file contains sequences THEN the YAMLPlugin SHALL extract all list items with their positions
4. WHEN the YAML file contains nested structures THEN the YAMLPlugin SHALL preserve the hierarchy information
5. WHEN the YAML file contains multiple documents THEN the YAMLPlugin SHALL extract each document separately

### Requirement 2

**User Story:** As a developer, I want to extract specific YAML elements, so that I can navigate and understand complex configuration files.

#### Acceptance Criteria

1. WHEN extracting YAML elements THEN the YAMLElementExtractor SHALL identify scalar values with their types (string, number, boolean, null)
2. WHEN extracting YAML elements THEN the YAMLElementExtractor SHALL identify anchors and aliases
3. WHEN extracting YAML elements THEN the YAMLElementExtractor SHALL identify comments and their associated elements
4. WHEN extracting YAML elements THEN the YAMLElementExtractor SHALL provide accurate start_line and end_line for each element
5. WHEN extracting YAML elements THEN the YAMLElementExtractor SHALL include raw_text for each element

### Requirement 3

**User Story:** As a developer, I want the YAML plugin to integrate seamlessly with the existing analyzer, so that I can use it alongside other language plugins.

#### Acceptance Criteria

1. WHEN the YAMLPlugin is loaded THEN the plugin manager SHALL register it automatically via entry points
2. WHEN analyzing a .yaml or .yml file THEN the analyzer SHALL automatically select the YAMLPlugin
3. WHEN the YAMLPlugin fails to parse a file THEN the analyzer SHALL continue processing other files without crashing
4. WHEN tree-sitter-yaml is not installed THEN the YAMLPlugin SHALL gracefully degrade and log a warning
5. WHEN the YAMLPlugin is used THEN other language plugins SHALL remain unaffected

### Requirement 4

**User Story:** As a developer, I want consistent output format for YAML analysis, so that I can process results uniformly with other languages.

#### Acceptance Criteria

1. WHEN returning analysis results THEN the YAMLPlugin SHALL use the standard AnalysisResult format
2. WHEN creating YAML elements THEN the YAMLPlugin SHALL use YAMLElement extending CodeElement
3. WHEN formatting output THEN the YAMLPlugin SHALL support text, json, and csv formats
4. WHEN displaying table output THEN the YAMLPlugin SHALL show element type, name, and line information
5. WHEN serializing YAML elements THEN the YAMLPlugin SHALL produce valid JSON output

### Requirement 5

**User Story:** As a developer, I want to query YAML structures, so that I can find specific configuration patterns.

#### Acceptance Criteria

1. WHEN executing tree-sitter queries THEN the YAMLPlugin SHALL support standard query syntax
2. WHEN querying for mappings THEN the YAMLPlugin SHALL return matching key-value pairs
3. WHEN querying for sequences THEN the YAMLPlugin SHALL return matching list structures
4. WHEN querying for specific keys THEN the YAMLPlugin SHALL return elements with matching names
5. WHEN no matches are found THEN the YAMLPlugin SHALL return an empty result set

### Requirement 6

**User Story:** As a developer, I want robust error handling for YAML parsing, so that malformed files do not crash the analyzer.

#### Acceptance Criteria

1. WHEN parsing invalid YAML syntax THEN the YAMLPlugin SHALL return an error result with descriptive message
2. WHEN encountering encoding issues THEN the YAMLPlugin SHALL attempt multiple encodings before failing
3. WHEN the YAML file is empty THEN the YAMLPlugin SHALL return a valid empty result
4. WHEN the YAML file contains only comments THEN the YAMLPlugin SHALL extract comment elements
5. WHEN parsing fails THEN the YAMLPlugin SHALL log detailed diagnostic information

### Requirement 7

**User Story:** As a developer, I want the YAML plugin to be well-tested, so that I can rely on its correctness.

#### Acceptance Criteria

1. WHEN testing the YAMLPlugin THEN property-based tests SHALL verify parsing consistency
2. WHEN testing the YAMLPlugin THEN unit tests SHALL cover all element types
3. WHEN testing the YAMLPlugin THEN integration tests SHALL verify MCP tool compatibility
4. WHEN testing the YAMLPlugin THEN golden master tests SHALL ensure output stability
5. WHEN testing the YAMLPlugin THEN cross-platform tests SHALL verify consistent behavior

