Files
Radixor/README.md
Leo Galambos 038514bad0 Refine stemmer core, compiled trie workflow, tests, and public documentation
feat: implement Compile CLI for building binary stemmer tables from source dictionaries
feat: add loading support for persisted compiled tries, including GZip-compressed binaries
feat: add a builder path for recreating a writable trie from a compiled trie
feat: expose read-only value/count access for compiled trie entries
feat: support deterministic NOOP patch encoding for identical source and target words

fix: make value selection deterministic for equal frequencies using length and lexical tie-breakers
fix: preserve valid alternative reductions during trie optimization and reduction
fix: correct patch command edge cases discovered in round-trip and malformed-input tests
fix: address persistence and compiled-trie handling defects found during implementation review
fix: resolve test failures and behavioral regressions uncovered by PMD and JUnit runs

refactor: reorganize trie-related support types into dedicated packages and classes
refactor: simplify the core FrequencyTrie design toward a cleaner practical architecture
refactor: improve compiled/read-only trie boundaries without restoring mutability
refactor: clean up internal reduction, serialization, and helper structure

test: add professional JUnit coverage for stemmer core classes
test: split trie tests into dedicated test classes per production type
test: improve parameterized tests for readability, diagnostics, and edge-case traceability
test: cover positive, negative, malformed, persistence, and round-trip scenarios
test: verify compiled dictionaries against source inputs using getAll semantics

docs: write public README and supplementary Markdown documentation for project publishing
docs: document architecture, reduction model, built-in languages, and operational guidance
docs: clarify reverse-word storage, mutable construction, and compiled-trie runtime behavior
docs: remove placeholders, vague buzzwords, and unexplained terminology from the documentation
docs: improve examples and wording for professional reader-facing project guidance

chore: align project materials with the practical Radix scope and Egothor/Stempel lineage
chore: raise overall project quality through documentation review and test hardening
2026-04-13 02:10:46 +02:00

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Radixor logo

Radixor

Fast algorithmic stemming with compact patch-command tries.

Radixor is a fast, algorithmic stemming toolkit for Java, built around compact patch-command tries in the tradition of the original Egothor stemmer.

It is designed for production search and text-processing systems that need stemming which is:

  • fast at runtime
  • compact in memory and on disk
  • deterministic in behavior
  • driven by dictionary data rather than hardcoded language rules
  • practical to maintain, extend, and test

Radixor keeps the valuable core of the original Egothor idea, modernizes the implementation, and adds capabilities that make it more useful in real software systems today.

Table of Contents

Why Radixor

The central idea behind Radixor is simple: learn how to transform a word form into its stem, encode that transformation as a compact patch command, store it in a trie, and make runtime lookup extremely fast.

This gives you a stemmer that is:

  • data-driven rather than rule-hardcoded
  • reusable across languages
  • compact enough for deployment-friendly binary artifacts
  • suitable for both offline compilation and runtime loading

Radixor is especially attractive when you want something more adaptable than simple suffix stripping, but much smaller and easier to operate than a full morphological analyzer.

Heritage

Radixor stands in the line of the original Egothor stemming work and its later Stempel packaging.

Historical Stempel documentation describes the stemmer code as taken virtually unchanged from the Egothor project, and Elasticsearch still documents the Stempel analysis plugin as integrating Lucenes Stempel module for Polish.

Useful historical references:

Radixor is not just a repackaging of legacy code. It is a practical modernization of the approach for current Java development and long-term maintainability.

What Radixor adds

Radixor keeps the patch-command trie model, but improves the engineering around it.

Compared with the historical baseline, Radixor emphasizes:

  • simplification to the most practical core
    The implementation focuses on the parts of the original approach that are most useful in production.

  • immutable compiled tries
    Runtime lookup uses compact read-only structures optimized for efficient access.

  • support for more than one stemming result
    Radixor can expose both a preferred result and multiple candidate results where the data is ambiguous.

  • frequency-aware deterministic ordering
    Candidate results are ordered consistently and reproducibly.

  • practical subtree reduction modes
    Reduction can be tuned toward stronger compression or more conservative behavioral preservation.

  • reconstruction of writable builders from compiled tables
    Existing compiled stemmer tables can be reopened, modified, and compiled again.

  • better tests and implementation stability
    Stronger coverage improves confidence during refactoring and further development.

Key features

  • Fast algorithmic stemming
  • Compact compiled binary artifacts
  • Patch-command based transformation model
  • Dictionary-driven language adaptation
  • Single-result and multi-result lookup
  • Deterministic result ordering
  • Compressed binary persistence
  • Programmatic compilation and loading
  • CLI compilation tool
  • Bundled language resources
  • Support for extending compiled stemmer tables

Documentation

The repository keeps the front page concise and places detailed documentation under docs/.

Start here:

Project philosophy

Radixor does not preserve historical complexity for its own sake.

It preserves the valuable idea:

  • compact learned transformations
  • trie-based lookup
  • language-data driven stemming
  • practical runtime speed

Then it improves the parts modern users care about:

  • maintainability
  • testability
  • modification workflows
  • persistence
  • determinism
  • clearer APIs

The goal is to keep the Egothor/Stempel lineage useful as a serious contemporary software component.

Historical note

Egothor showed that stemming could be both algorithmic and compact. Stempel proved that the approach was practical enough to survive inside major search ecosystems. Radixor continues that tradition with a modernized implementation focused on production use, maintainability, and controlled evolution.