Switch to new backend

[saulshanabrook]

Adds support for new backend in Egglog. A follow up PR can expose the new custom costs mechanism and extraction.

TODO:

• Diagnose performance slowdown (Large slowdown with new backend egglog#631)

[codspeed-hq]

CodSpeed Instrumentation Performance Report

Merging #291 will not alter performance

_{Comparing new-backend (55f94bc) with main (b8be084)}

Summary

✅ 7 untouched benchmarks

[codspeed-hq]

CodSpeed WallTime Performance Report

Merging #291 will degrade performances by 50.11%

_{Comparing new-backend (55f94bc) with main (b8be084)}

Summary

❌ 3 regressions
✅ 4 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
❌	test_jit[add]	366.3 ms	461.4 ms	-20.61%
❌	test_jit[lda]	8.4 s	16.8 s	-50.11%
❌	test_jit[tuple]	631.2 ms	1,003.7 ms	-37.11%

[saulshanabrook]

Blocked on egraphs-good/egglog#627 EDIT: resolved

[Copilot]

Pull Request Overview

This PR switches the Egglog Python extension to the new backend architecture by migrating the Python object sort, adapting EGraph bindings for the new add_primitive! interface, wrapping e-graph execution in thread-safe GIL calls, and updating the Python DSL to use unbound/let-ref declarations.

• Implements new PyObjectSort with BaseSort and add_primitive!
• Replaces ArcPyObjectSort with PyObjectSort and registers it via add_leaf_sort
• Migrates Python declaration types from VarDecl to UnboundVarDecl/LetRefDecl, removes simplify/QueryExtract APIs

Reviewed Changes

Copilot reviewed 20 out of 21 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/py_object_sort.rs	Redefines PyObjectSort, implements BaseSort, primitives, and term reconstruction
src/egraph.rs	Uses add_leaf_sort, wraps run_program and serialize in allow_threads
src/lib.rs	Binds new PyObjectSort into the Python module
src/conversions.rs	Fixes conversion for AddRuleset and Extract commands with spans
rust-toolchain.toml	Bumps toolchain channel to 1.87.0
Cargo.toml	Upgrades to 2024 edition and switches to egglog-backend dependencies
python/tests/	Updates tests for the new Extract API, removes simplify usage
python/egglog/runtime.py	Uses LetRefDecl for parameter defaults instead of VarDecl
python/egglog/pretty.py	Replaces VarDecl with UnboundVarDecl/LetRefDecl in pretty printer
python/egglog/egraph_state.py	Adds span() to AddRuleset/UnstableCombinedRuleset, uses unbound var types
python/egglog/egraph.py	Removes global simplify, adapts let binding to LetRefDecl
python/egglog/declarations.py	Introduces UnboundVarDecl and LetRefDecl types
python/egglog/bindings.pyi	Updates stubs for new commands (Extract, UserDefined, spans)
docs/reference/egglog-translation.md	Removes simplify example, updates code samples
docs/reference/contributing.md	Adds debugging guide, moves "Making changes" under debugging section
docs/changelog.md	Notes upgrade, breaking changes, removed simplify