From 38bccbfa3f185f37f3bd575212d9e7ddf5ed533b Mon Sep 17 00:00:00 2001 From: Hassan Abedi Date: Thu, 19 Mar 2026 16:39:20 +0100 Subject: [PATCH] Add notes on missing components --- notes/006-missing-components.md | 342 ++++++++++++++++++++++++++++++++ 1 file changed, 342 insertions(+) create mode 100644 notes/006-missing-components.md diff --git a/notes/006-missing-components.md b/notes/006-missing-components.md new file mode 100644 index 0000000..1d2c039 --- /dev/null +++ b/notes/006-missing-components.md @@ -0,0 +1,342 @@ +# Missing Components + +*Assuming Geolog's core is mature and stable, what would be needed to make it production-ready?* + +--- + +## Summary + +Geolog has a solid **core engine** (parser, type checker, chase, tensor algebra) but is missing everything around it: + +- **No way in** — no API, no language bindings +- **No way to scale** — no parallelism, no indexes, no query optimization +- **No way to operate** — no concurrency, no recovery, no monitoring +- **No way to debug** — no logging, no traces, no profiling + +It's a well-built engine without a car around it. + +--- + +## 1. Integration & APIs + +| Missing | Why It Matters | +|---------|----------------| +| **REST API** | Can't call Geolog from web apps, microservices, or other languages | +| **Language bindings** | No Python, JavaScript, or FFI — Rust-only | +| **LSP (Language Server)** | No IDE autocomplete, error squiggles, go-to-definition | +| **JSON/YAML serialization** | Only binary format (rkyv) — can't inspect data externally | +| **Async API** | All operations block — can't integrate with async runtimes | + +### What Integration Would Look Like + +```python +# This doesn't exist today +from geolog import Theory, Instance + +theory = Theory.parse(""" + theory Graph { + V : Sort; + E : Sort; + src : E -> V; + tgt : E -> V; + } +""") + +instance = Instance.create(theory) +instance.add_element("V", "alice") +instance.add_element("V", "bob") +instance.add_element("E", "edge1") +instance.set_function("edge1", "src", "alice") +instance.set_function("edge1", "tgt", "bob") + +# Run chase and get results as JSON +results = instance.chase() +print(results.to_json()) +``` + +```bash +# REST API that doesn't exist +curl -X POST http://localhost:8080/chase \ + -H "Content-Type: application/json" \ + -d '{"instance": "MyGraph", "max_iterations": 100}' +``` + +--- + +## 2. Performance & Scale + +| Missing | Why It Matters | +|---------|----------------| +| **Cost-based query optimizer** | No cardinality estimates — can't choose optimal join order | +| **Secondary indexes** | Only RoaringBitmaps — no B-trees for range queries | +| **Parallel execution** | Single-threaded only | +| **Benchmark suite** | No way to track performance regressions | +| **Memory profiling** | No visibility into allocation patterns | + +### What Would Struggle + +``` +Scenario: Theory with 10,000 elements and 50 axioms + +Problems: +→ No way to predict which axioms are expensive +→ No parallel chase execution +→ No index to speed up specific lookups +→ No benchmark to know if changes made it slower +``` + +### What's Needed + +```rust +// Cost-based optimizer (doesn't exist) +let plan = optimizer.compile(query); +println!("Estimated cost: {}", plan.estimated_cost()); +println!("Join order: {:?}", plan.join_order()); + +// Parallel chase (doesn't exist) +let results = chase_parallel(axioms, structure, num_threads=4); + +// Benchmarks (don't exist) +// benches/chase_benchmark.rs +// benches/tensor_benchmark.rs +``` + +--- + +## 3. Solver Intelligence + +| Missing | Why It Matters | +|---------|----------------| +| **Search heuristics** | Breadth-first only — no intelligent variable/value ordering | +| **Backtracking** | Can't explore branches — only refines single partial model | +| **Lemma learning** | No conflict-driven learning (CDCL) like modern SAT/SMT solvers | +| **External prover integration** | Can't delegate to Z3, Lean, or Coq | + +### Current Behavior + +``` +Solver tries everything in order: + x = 1? Try it. + x = 2? Try it. + x = 3? Try it. + ... + +No learning from failures. +No "this variable is most constrained, try it first." +``` + +### What Modern Solvers Do + +``` +CDCL (Conflict-Driven Clause Learning): + 1. Try x = 1 + 2. Conflict detected! + 3. Learn: "x ≠ 1" (add as constraint) + 4. Backtrack and never try x = 1 again + +Variable ordering: + 1. Count constraints on each variable + 2. Try most-constrained variable first + 3. Fail fast, prune search space early +``` + +--- + +## 4. Reliability & Operations + +| Missing | Why It Matters | +|---------|----------------| +| **Multi-user concurrency** | No locking — can't have multiple writers | +| **ACID transactions** | No rollback on failure | +| **Write-ahead log (WAL)** | No crash recovery | +| **Replication** | No distributed deployment | +| **Garbage collection** | Tombstoned elements accumulate forever | +| **Compression** | Data size grows unbounded | + +### Production Scenario That Fails + +``` +User A: :chase BigInstance (starts running) +User B: :add BigInstance x:V; (modifies while A is running) + +Result: Race condition, possible data corruption +No way to recover if either crashes mid-operation +No way to rollback User B's change if it breaks something +``` + +### What's Needed + +```rust +// Transactions (don't exist) +let tx = store.begin_transaction(); +tx.add_element("V", "new_vertex")?; +tx.chase("MyInstance")?; +tx.commit()?; // Or tx.rollback() on error + +// Concurrency control (doesn't exist) +let lock = store.write_lock("MyInstance"); +// ... safe modifications ... +drop(lock); + +// Crash recovery (doesn't exist) +// WAL ensures operations are durable before acknowledging +``` + +--- + +## 5. Developer Experience + +| Missing | Why It Matters | +|---------|----------------| +| **Logging framework** | No structured logs for debugging | +| **Interactive debugger** | Can't step through solver decisions | +| **Execution traces** | Can't replay what happened | +| **IDE plugin** | No syntax highlighting, no error squiggles | +| **Tutorials** | Only reference docs, no guided learning | + +### Debugging Today + +``` +> :chase MyInstance +// Something went wrong... but what? +// No logs, no trace, just the final state +// Which axiom fired? Which elements were created? Unknown. +``` + +### What's Needed + +``` +// Structured logging (doesn't exist) +[2026-03-19 10:30:01] INFO chase: Starting chase on MyInstance +[2026-03-19 10:30:01] DEBUG chase: Axiom ax/trans fired with {x: v1, y: v2, z: v3} +[2026-03-19 10:30:01] DEBUG chase: Added relation [x:v1, y:v3] leq +[2026-03-19 10:30:02] INFO chase: Fixpoint reached after 3 iterations + +// Interactive debugger (doesn't exist) +> :debug chase MyInstance +Breakpoint at axiom ax/trans + Variables: x=v1, y=v2, z=v3 + Action: Add [x:v1, y:v3] leq +(debug) step +(debug) inspect structure +(debug) continue +``` + +--- + +## 6. Error Handling + +| Missing | Why It Matters | +|---------|----------------| +| **Typed error enums** | All errors are strings — can't handle programmatically | +| **Error recovery suggestions** | "Did you mean X?" doesn't exist | +| **Partial results** | If 90% succeeds, you get nothing | +| **Stack traces** | Limited context for where errors occur | + +### Current State + +```rust +// All errors are just strings +fn elaborate_theory(...) -> Result + +// Can only display, not handle programmatically +match result { + Err(msg) => println!("{}", msg), // That's all you can do +} +``` + +### What's Needed + +```rust +enum GeologError { + Parse(ParseError), + Type(TypeError), + Chase(ChaseError), + Solver(SolverError), +} + +enum ParseError { + UnexpectedToken { span: Span, found: Token, expected: Vec }, + UnterminatedString { span: Span }, + // ... +} + +enum TypeError { + UndefinedSort { name: String, span: Span, similar: Vec }, + TypeMismatch { expected: Type, found: Type, span: Span }, + // ... +} + +// Now you can handle errors programmatically +match result { + Err(GeologError::Type(TypeError::UndefinedSort { name, similar, .. })) => { + println!("Unknown sort '{}'. Did you mean '{}'?", name, similar[0]); + } + // ... +} +``` + +--- + +## 7. Missing Language Features + +| Missing | Why It Matters | +|---------|----------------| +| **Modules/imports** | Can't organize large theories into files | +| **Parameterized axioms** | Can't write generic rules that work across sorts | +| **Arithmetic** | No `x + 1 = y` or `count > 0` | +| **Aggregation** | No `count`, `sum`, `max` over relations | +| **Stratified negation** | No "if NOT X" even in limited safe form | + +### What You Can't Express + +```geolog +// Modules (don't exist) +import std/graph; +import std/preorder; + +// Arithmetic (doesn't exist) +ax/increment : forall x : Nat. |- successor(x) = x + 1; + +// Aggregation (doesn't exist) +ax/has_friends : forall p : Person. + count([f: f] friend_of(p, f)) > 0 |- popular(p); + +// Stratified negation (doesn't exist) +ax/lonely : forall p : Person. + not exists f : Person. friend_of(p, f) |- lonely(p); +``` + +--- + +## Priority Ranking + +If making Geolog production-ready: + +| Priority | Component | Effort | Impact | +|----------|-----------|--------|--------| +| 1 | REST API | Medium | Unlocks all integrations | +| 2 | LSP server | Medium | Makes language usable in IDEs | +| 3 | Structured errors | Low | Enables better tooling | +| 4 | Benchmark suite | Low | Enables performance work | +| 5 | Logging/tracing | Low | Enables debugging | +| 6 | Concurrency/locking | High | Required for multi-user | +| 7 | Solver heuristics | High | Makes solver practical | +| 8 | Cost-based optimizer | High | Enables scale | +| 9 | Language bindings | Medium | Broader adoption | +| 10 | Modules/imports | Medium | Enables large projects | + +--- + +## Maturity by Area + +| Area | Maturity | What Exists | Critical Gap | +|------|----------|-------------|--------------| +| **Query** | 70% | Chase, optimization, temporal ops | No cost-based optimization | +| **Solver** | 65% | Explicit tree, tactics framework | No heuristics, no backtracking | +| **Storage** | 75% | Append-only, versioning | No concurrency, no recovery | +| **API** | 45% | Clean Rust library | No REST, no LSP, no FFI | +| **Performance** | 40% | Fuzzing, property tests | No benchmarks, no profiling | +| **Debugging** | 50% | Error formatting, query plans | No logging, no debugger | +| **Errors** | 60% | Recoverable, source spans | String-only, limited context | +| **Docs** | 65% | Architecture, inline comments | No IDE support, no tutorials |