# Changelog

All notable changes to Veritext will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [Unreleased]

### Added

- Project scaffold with pyproject.toml and development tooling
- Core exception hierarchy (`VeritextError` and subclasses)
- Core types: `ValidationContext`, `CheckResult`, `ValidationResult`
- Word tokeniser with Unicode normalisation support
- Configuration module with pydantic-settings
- Structured logging with structlog
- Metrics module with `Metric` protocol, `AggregateStats`, and `BatchResult` types
- BLEU metric implementation (BLEU-1 through BLEU-4 with brevity penalty)
- Lexical similarity metric (Jaccard similarity and token overlap)
- ROUGE metric (ROUGE-1, ROUGE-2, ROUGE-L with precision/recall/F-measure)
- Flesch-Kincaid readability metrics (grade level and reading ease)
- Batch scoring with aggregate statistics for all metrics
- Validators module with `Check` protocol for validation checks
- Metric-based validators: `BleuValidator`, `RougeValidator`, `LexicalValidator`
- Constraint validators: `LengthValidator`, `ReadabilityValidator`, `ContainsValidator`, `ExcludesValidator`
- Composite validators: `AllOf` (all checks must pass), `AnyOf` (any check must pass)
- Factory functions for clean validator API (`bleu()`, `rouge()`, `lexical()`, `length()`, `readability()`, `contains()`, `excludes()`, `all_of()`, `any_of()`)
- Semantic similarity module with embedding-based text comparison (requires `veritext[semantic]` extra)
- `SemanticSimilarity` metric using sentence-transformers for semantic relatedness
- `SemanticValidator` for threshold-based semantic similarity validation
- `semantic()` factory function for creating semantic validators
- Embedding caching for performance optimisation in repeated comparisons