Design Documents

Technical specifications and design documents for major features and algorithms.

Contents

Crate Boundary and Pruning Duality

Placement rule for future measures:

• why non-negative min-plus costs stay in liblevenshtein
• why gain-valued fzf scoring crosses through duallity to lling-llang
• the corrected unstarted local-alignment upper bound
• why the balanced prefix visitor is DFS rather than BFS

Class-A Alignment Presets

Exact configuration-based string measures:

• Hamming, insertion/deletion, and directional bounded-skip semantics
• public reference distances and generalized-grid conformance
• operation-set validation and resource ceiling
• rejected specialized-walker decision and formal/property evidence

True-Damerau Streaming

History-dependent string-automaton design:

• Lowrance–Wagner entry/extension/resolution refinement
• DamerauPending payload and kind-aware subsumption
• explicit representation/resource boundaries
• heterogeneous formal and empirical evidence

Elastic Kernels

Generic exact time-series retrieval design:

• ElasticKernel and ElasticTransducer<K,V> ownership boundary
• K1–K4 subtree, candidate, and exact-rescoring obligations
• additive and bottleneck cost-monoid support
• literate range/kNN algorithms, security boundaries, and multi-tool verification

PositionKind and AutomatonVariant

Monomorphized legacy-automaton seam:

• typed continuation languages in the unchanged 24-byte Position
• one runtime selection per dictionary edge
• variant-specific successor, epsilon, subsumption, finish, and window contracts
• property, formal, disassembly, and pre-registered zero-cost gates

Ordered Cost Monoid

Bounded dynamic-programming cost design:

• exact L1–L7 algebra and dominance argument
• unit, weighted, and bottleneck carriers
• checked decimal-to-integer CostScale
• IEEE-754 trust boundary and multi-tool verification

Generalized-Automaton Repair

Exact operation-driven acceptance:

• sparse alignment graph over arbitrary consuming operations
• exact cumulative fractional weights via CostScale
• correct Hamming, indel, bounded-skip, and empty-side semantics
• compatibility, resource, formal-proof, and behavior-change boundaries

Language Product

Generic distance-to-language product design:

• LanguageAutomaton<U> set-transition contract
• Cost-indexed frontier and merge proof
• Iterative dictionary intersection
• Resource policy and multi-tool formal evidence

Dynamic DAWG

Design specification for the dynamic directed acyclic word graph:

• Incremental construction algorithm
• Mutation operations
• Memory efficiency considerations
• Trade-offs vs. static DAWG

Hierarchical Correction

Design for hierarchical error correction in fuzzy matching:

• Multi-level correction strategies
• Priority-based candidate selection
• Performance optimization techniques

Prefix Matching

Prefix-based search optimization design:

• Trie-based prefix matching
• Early termination strategies
• Integration with Levenshtein automata

Protobuf Dictionary and Operation-Set Persistence

Protocol buffer serialization format specification:

• Schema design
• Backward compatibility guarantees
• Size optimization strategies
• Cross-language interoperability

Suffix Automaton

Suffix automaton implementation design:

• Construction algorithm
• Online building process
• Space-time trade-offs
• Use cases and applications

Contextual Completion Progress

Complete implementation history and status of the contextual code completion engine:

• Phase-by-phase implementation tracking (Phases 1-6)
• Architecture overview (ContextualCompletionEngine, draft state, finalized terms)
• Performance benchmarks and optimization results
• API documentation and usage examples
• Future enhancement roadmap

Zipper vs Node Performance

Comprehensive performance analysis of zipper-based vs node-based query iteration:

• Benchmark results (1.66-1.97× performance difference)
• Root cause analysis (indirection, locks, allocations, cache effects)
• Architectural trade-offs and benefits
• Use case recommendations (when to use each approach)
• Future optimization opportunities

Performance Characteristics

Contextual Completion Engine (Zipper-based):

• Insert character: ~4 µs (12 M chars/sec)
• Checkpoint: ~116 ns per operation
• Query (500 terms, distance 1): ~11.5 µs
• Query (distance 2): ~309 µs
• Thread-safe, hierarchical context support

Simple Fuzzy Matching (Node-based):

• Query (distance 1): ~53 µs (1.88× faster)
• Query (distance 2): ~156 µs (1.97× faster)
• Best for single-dictionary, high-throughput scenarios

Related Documentation

• Developer Guide - Implementation guidelines
• Research - Performance research and analysis