geolog-zeta-fork/notes/006-missing-components.md
2026-03-20 11:30:19 +01:00

9.7 KiB

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

# 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())
# 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

// 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

// 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

// All errors are just strings
fn elaborate_theory(...) -> Result<Theory, String>

// Can only display, not handle programmatically
match result {
    Err(msg) => println!("{}", msg),  // That's all you can do
}

What's Needed

enum GeologError {
    Parse(ParseError),
    Type(TypeError),
    Chase(ChaseError),
    Solver(SolverError),
}

enum ParseError {
    UnexpectedToken { span: Span, found: Token, expected: Vec<Token> },
    UnterminatedString { span: Span },
    // ...
}

enum TypeError {
    UndefinedSort { name: String, span: Span, similar: Vec<String> },
    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

// 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