# documents - Functional Specification

**Version**: v1.2.3 | **Status**: Active | **Last Updated**: March 2026

## Purpose

Provides robust, abstractable methods for reading and writing various document formats. The Documents module handles the mechanics of document I/O operations, distinct from the `documentation` module which focuses on the semantics of technical documentation.

## Design Principles

- **Format Abstraction**: Unified interface for all document formats
- **Encoding Safety**: Automatic encoding detection and handling
- **Metadata Preservation**: Maintain document metadata during operations
- **Extensible Design**: Easy addition of new formats and operations
- **Error Handling**: Clear error messages with context

## Functional Requirements

1. **Document Reading**: Read documents from files with format and encoding detection
2. **Document Writing**: Write documents to files with format validation
3. **Format Conversion**: Convert documents between supported formats
4. **Document Merging**: Merge multiple documents into a single document
5. **Document Splitting**: Split documents based on various criteria
6. **Metadata Operations**: Extract, update, and manage document metadata
7. **Document Validation**: Validate documents against schemas and format rules
8. **Search and Indexing**: Index documents and perform search operations

## Interface Contracts

### Core Classes

- `DocumentReader`: Unified document reading interface
- `DocumentWriter`: Unified document writing interface
- `DocumentParser`: Format-specific parsing
- `DocumentValidator`: Validation and schema checking
- `Document`: Document model with content and metadata

### Format Handlers

- `MarkdownHandler`: Markdown read/write
- `JSONHandler`: JSON read/write with schema validation
- `YAMLHandler`: YAML read/write
- `PDFHandler`: PDF read/write
- `TextHandler`: Plain text read/write

### Transformation

- `DocumentConverter`: Format conversion
- `DocumentMerger`: Document merging
- `DocumentSplitter`: Document splitting

### Metadata

- `MetadataExtractor`: Extract metadata from documents
- `MetadataManager`: Update and manage metadata
- `VersionManager`: Document versioning

## Supported Formats

- Markdown (.md, .markdown)
- JSON (.json)
- PDF (.pdf)
- YAML (.yaml, .yml)
- XML (.xml)
- CSV (.csv)
- HTML (.html, .htm)
- Plain Text (.txt, .text)
- RTF (.rtf)
- Office Formats (.docx, .xlsx) - via libraries

## Error Handling

All operations raise module-specific exceptions:

- `DocumentsError`: Base exception
- `DocumentReadError`: Reading failures
- `DocumentWriteError`: Writing failures
- `DocumentParseError`: Parsing failures
- `DocumentValidationError`: Validation failures
- `DocumentConversionError`: Conversion failures
- `UnsupportedFormatError`: Unsupported format requests
- `EncodingError`: Encoding detection/conversion failures
- `MetadataError`: Metadata operation failures

## Configuration

Module configuration via `DocumentsConfig`:

- Default encoding (default: utf-8)
- Maximum file size (default: 100MB)
- Caching enabled/disabled
- Cache directory location
- Strict validation mode

## Navigation

- **Human Documentation**: [README.md](README.md)
- **Technical Documentation**: [AGENTS.md](AGENTS.md)
- **Parent**: [../SPEC.md](../SPEC.md)

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## Testing

```bash
uv run python -m pytest src/codomyrmex/tests/ -k documents -v
```
