Expose extraction support APIs - #934
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📝 WalkthroughSummary by CodeRabbit
WalkthroughThe extraction system now uses layered cost-model traits and structured batched results. ChangesExtraction API refactor
Estimated code review effort: 4 (Complex) | ~45 minutes Merge Risk: 🔵 Low · up to The new batched extraction APIs may re-traverse shared subterms when processing many roots, adding bounded performance overhead for large shared DAGs. This does not affect correctness and is mergeable with explicit owner awareness or follow-up. Sequence Diagram(s)sequenceDiagram
participant ResolvedNCommand
participant EGraph
participant TreeExtractor
participant TermDag
ResolvedNCommand->>EGraph: evaluate roots and call extract_best or extract_variants
EGraph->>TreeExtractor: prepare total costs and extract terms
TreeExtractor->>TermDag: build shared extracted term DAG
TermDag-->>EGraph: return term IDs and shared DAG
EGraph-->>ResolvedNCommand: return structured extraction results
Possibly related PRs
Suggested reviewers: 🚥 Pre-merge checks | ✅ 5✅ Passed checks (5 passed)
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## main #934 +/- ##
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+ Coverage 86.65% 86.72% +0.06%
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Files 95 95
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+ Hits 25894 25959 +65
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Actionable comments posted: 3
🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Inline comments:
In `@src/extract/dag_extract.rs`:
- Around line 336-342: The hot path in discover_node is cloning the full
constructor list from extractable_funcs_by_output_sort just to drop the borrow
before mutating self. Change the builder/storage type for that map to
Arc<[String]> and convert the lists once in prepare so the lookup at
discover_node can keep using .cloned() but only performs a cheap Arc clone;
verify func_names.iter() still works unchanged in the downstream loop.
In `@src/lib.rs`:
- Around line 1692-1694: The variant-count check in the extraction path
currently panics on a negative value, which can abort the interpreter when a
user-supplied expression evaluates to a bad count. Update the logic in the
extraction routine that handles n so it returns an Error instead of calling
panic, and propagate that error through the surrounding extraction/evaluation
flow so malformed input is reported cleanly without crashing.
In `@src/proofs/proof_extraction.rs`:
- Around line 94-97: The proof-term extraction path in proof_extraction.rs drops
the underlying error by using unwrap_or_else(|_| ...), so the panic message
loses the failure cause. Update the extract_best_for_proofs handling in the
proof extraction logic to bind the error value and include it in the panic
message alongside func.name, so failures from extract_best_for_proofs report the
actual Error details.
🪄 Autofix (Beta)
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
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Cargo.lockis excluded by!**/*.locktests/greedy-dag-taylor.eggis excluded by!**/*.eggtests/greedy-dag-vec-extract.eggis excluded by!**/*.eggtests/snapshots/files__proof_unsupported_files.snapis excluded by!**/*.snap
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.agents/logs/2026-06-24-greedy-dag-extractor-perf.md.github/workflows/build.ymlCargo.tomlcore-relations/src/free_join/mod.rscore-relations/src/lib.rsegglog-bridge/src/lib.rssrc/ast/desugar.rssrc/ast/mod.rssrc/ast/parse.rssrc/extract.rssrc/extract/dag_extract.rssrc/extract/secondary_map.rssrc/lib.mdsrc/lib.rssrc/prelude.rssrc/proofs/proof_encoding.rssrc/proofs/proof_encoding_helpers.rssrc/proofs/proof_extraction.rssrc/typechecking.rstests/files.rstests/integration_test.rs
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📓 Path-based instructions (1)
**/*.{md,txt,rs}
📄 CodeRabbit inference engine (CLAUDE.md)
Keep documentation concise and avoid duplicate information
Files:
src/prelude.rssrc/ast/desugar.rscore-relations/src/lib.rssrc/typechecking.rssrc/lib.mdsrc/proofs/proof_encoding_helpers.rstests/files.rscore-relations/src/free_join/mod.rssrc/proofs/proof_encoding.rssrc/ast/mod.rssrc/extract/dag_extract.rsegglog-bridge/src/lib.rssrc/ast/parse.rstests/integration_test.rssrc/proofs/proof_extraction.rssrc/lib.rssrc/extract/secondary_map.rssrc/extract.rs
🔇 Additional comments (30)
tests/integration_test.rs (2)
10-115: LGTM!
578-710: LGTM!tests/files.rs (1)
271-280: LGTM!.agents/logs/2026-06-24-greedy-dag-extractor-perf.md (1)
1-1123: LGTM!.github/workflows/build.yml (1)
72-73: 🩺 Stability & AvailabilityBenchmark input files confirmed present.
Both
greedy-dag-vec-extract.eggandgreedy-dag-taylor.eggare checked in under thetestsdirectory. The build job will not fail due to missing inputs.src/extract/dag_extract.rs (3)
20-89: LGTM!
389-660: LGTM!
662-870: LGTM!src/lib.rs (3)
49-49: LGTM!Also applies to: 1659-1690
1695-1720: LGTM!
1791-1803: LGTM!src/proofs/proof_extraction.rs (2)
1-6: LGTM!
98-109: LGTM!src/ast/desugar.rs (1)
167-169: LGTM!src/ast/mod.rs (1)
77-77: LGTM!Also applies to: 162-169, 276-283, 846-847, 962-967, 1754-1756, 1850-1855, 1975-1982
src/ast/parse.rs (1)
114-131: LGTM!Also applies to: 653-683
src/proofs/proof_encoding.rs (1)
1335-1335: LGTM!Also applies to: 1353-1353
Cargo.toml (1)
152-152: LGTM!src/lib.md (1)
41-41: LGTM!core-relations/src/lib.rs (1)
39-39: LGTM!src/typechecking.rs (1)
460-460: LGTM!Also applies to: 482-482
src/proofs/proof_encoding_helpers.rs (1)
564-564: LGTM!src/extract/secondary_map.rs (3)
27-225: LGTM!
227-530: LGTM!
532-650: LGTM!src/extract.rs (2)
6-54: LGTM!Also applies to: 56-94, 105-183, 200-314, 526-639, 647-677, 741-818, 848-879
148-156: 🚀 Performance & Scalability
find_canonicaldoes a full UF-table scan on every call; use the new indexed lookup.This iterates the entire UF parent table via
for_eachfor each invocation, even though the comment describes it as a one-hop "lookup". The greedy-DAG extractor callsfind_canonicalper node (compute_cost_node,discover_node,reconstruct_termdag_node_helper), so extraction becomes roughlyO(nodes × uf_table_size)— directly at odds with this PR's performance goal. Thefor_each_matching_colhelper added in this PR resolves matches via the lazy column index (with a scan fallback), and the single-parent invariant guarantees at most one matching row, so semantics are preserved.⚡ Proposed switch to indexed column lookup
let mut canonical = value; egraph .backend - .for_each(uf_func.backend_id, |row: egglog_bridge::ScanEntry<'_>| { - // UF table has (child, parent) as inputs - if row.vals[0] == value { - canonical = row.vals[1]; - } - }); + .for_each_matching_col(uf_func.backend_id, 0, value, |row| { + // UF table has (child, parent) as inputs + canonical = row.vals[1]; + }); canonicalsrc/prelude.rs (1)
93-93: LGTM!core-relations/src/free_join/mod.rs (1)
31-34: LGTM!Also applies to: 777-802
egglog-bridge/src/lib.rs (1)
475-520: LGTM!
Merging this PR will not alter performance
Comparing 
Footnotes
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saulshanabrook
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Things to look into from talking to @oflatt:
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Looks good to me (PR descriptions very out of date)
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One thing I'd love is to have extraction work inside a ReadState as well as on the EGraph. But not this PR's problem. |
| | Constraint::LtConst { .. } | ||
| | Constraint::GtConst { .. } | ||
| | Constraint::LeConst { .. } | ||
| | Constraint::GeConst { .. } => return true, |
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Should they be impossible cases?
| } | ||
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| impl TreeCostModel<DefaultCost> for TreeAdditiveCostModel { | ||
| fn total_enode_cost( |
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I remember we discussed this and decided to keep the existing enode_cost? The original one is also more natural to me.
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The existing enode_cost has the problem where its only ever used to produce total cost with the fold, so it seemed like odd to keep it. Like the functions were ever only called changed together, with enode_cost feeding into the total call.
So that it returned a "Cost" type was also a bit weird, really it could return anything that the fold took in, like I had to return odd stuff from it from Python to basically just pass data between them and do all the computation in total_enode_cost.
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Did you pass odd stuff because there was no DAG cost model and extractor, or do you still need to do it even with the new DAG extractor?
If we use enode_cost here, TreeCostModel exposes a superset of cost functions of DAG cost model's, which is nice and matches our (my) intuition. My mental model of the tree cost model is that the term is annotated with cost tags and the cost of a term is just a fold over these cost tags. So, for example, the proposed cost model forbids you from doing it if you want to visualize an e-graph with per-node cost annotation, or serialize an e-graph with a custom cost model.
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As I understand it, we should have the cost trait reflect what the underlying extraction algorithm needs. The fact that you can split this up into a fold and an e-node cost is an implementation choice of a particular cost model, not a requirement of the extractor.
So for example, you could have a cost model for the tree extractor which says "on this particular e-node multiply the child costs by ten and on this other one multiply the child costs by twenty. In the other interface, you would have to smuggle the e-node ID through the cost output of enode_cost and then interpret it in fold.
If we use enode_cost here, TreeCostModel exposes a superset of cost functions of DAG cost model's, which is nice and matches our (my) intuition.
We can already use any dag cost model as a tree cost model, do you mean something else?
So, for example, the proposed cost model forbids you from doing it if you want to visualize an e-graph with per-node cost annotation, or serialize an e-graph with a custom cost model.
This is already true with fold, which is more general than what is allowed in the visualizer or in serialization. Both of those in fact do not currently support the set-cost even, so if we want to somehow make those features aware of this, we would have to change things.
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To me this is not an implementation choice, but the definition of the tree cost model.
The idea is that enode_cost returns all e-graph specific cost information, and fold is an e-graph--agnostic way to combine such information. This gives a clear description of the tree extraction problem, which can be specified as an e-graph with per-node cost information, and a generic fold function. I believe you cannot do this with total_node_cost.
"On this particular e-node multiply the child costs by ten and on this other one multiply the child costs by twenty" is a combine function we can define, while I think smuggling e-node ID is a bad idea. If you want to return odd stuff from enode_cost (e.g., the constant folded result of the children as a loop count estimate), the user can define the cost as a pair (ActualCost, Option) and ignore the second part for comparison, or better, we can tweak the egglog interface to support that.
We can already use any dag cost model as a tree cost model, do you mean something else?
I meant you could convert a tree cost model into a DAG one by disregarding combine.
Both of those in fact do not currently support the set-cost even
But we can implement this, right? Again, a serialized e-graph with node costs + an e-graph--agnostic fold function gives a complete specification of the extraction problem. But committing to total_enode_cost would eliminate this possibility.
Maybe another way to think about this is that TreeAdditiveCostModel and SetCostModel are essentially the same cost model, besides how they obtain the per-node cost, but the new interface loses this connection.
| /// subterm should always lead to a non-worse superterm, to guarantee the extracted term | ||
| /// being optimal under the given cost model. | ||
| /// If this is not followed, the extractor may panic on reconstruction | ||
| pub struct Extractor<C: Cost + Ord + Eq + Clone + Debug> { |
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Why is Extractor no longer public?
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We dont need it. Every use case of it just extracted a few particular nodes, so I cleaned up the interface to just expose that to keep the details more private.
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I thought part of the point of the extractor interface is to provide a zoo of different extractor implementations (like extraction-gym for egglog). It would be weird if someone implemented a faster extractor but found they couldn't get a handle on the plain Extractor for comparison. I'm also in favor of minimizing interface changes unless it's a strict improvement.
Another potential use case of the extractor is if the user wants to interactively extract a series of terms, without building the Extractor every time
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We don't have an extractor interface. We just have a tree extractor and a dag extractor, and they expose different methods on the e-graph. Without anything that calls this interface, I am not sure what it would be for?
You can of course compare against the main extractor, you just call the methods on the e-graph.
Another potential use case of the extractor is if the user wants to interactively extract a series of terms, without building the Extractor every time
Yeah I just thought since I hadn't seen any use cases in experimental and main that exercised this pattern, we could remove it. That also frees us up to change how the extractor performs in the future. Like now it does this search at a sort level of the e-graph to trim, and does all extractions for that. But we could change it to do a more precise traversal of the e-graph and only build extractions for those expressions, instead of all pieces. By keeping the interface smaller then that doesn't have to be a breaking change.
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We will want an extractor interface, right? There are many DAG extractor implementations (ILP, branch and bound, ASP, etc.), and there's the Dijkstra algorithm for tree extraction. Just like we have an interface for extensible schedulers, we should do the same for extractors. I'm all in for standardizing the interfaces around DAG and tree extractors, just like what we did in extraction-gym.
Not in experimental and main does not mean users won't have this pattern? A user could import egglog, build an e-graph, and interactively extract terms from the Rust side.
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Sure but would that interface be? We dont define it in this PR and I would opt to defer it.
If we define that interface, then we want a way to actually use that interface in main somehow, like being able to switch extractors.
A user could import egglog, build an e-graph, and interactively extract terms from the Rust side.
Yeah you can do that today with the methods on the e-graph.
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Basically I think there are two related points here:
- There is a question about having a re-usable extractor interface. I like this idea, but I didn't implement it in this PR. There was no previous extractor trait, just a concrete implementation of extractor. That extractor happened to work in a way that traverses first the e-graph at a sort level first, prepares all of those items, then allows extractions. It's not clear that we would want to use this as "the" interface, because for example, the DAG extractor does not traverse the whole e-graph by sort. It does a depth first traversal based on the actual nodes you want to extract. I would prefer not to standardize an extractor interface in this PR and defer that to later work. If we do have an interface, we should have a way to use that in the e-graph in some way.
- There is the loss of functionality with this changes around the default extractor. Previously, you could do the work of creating costs for a subset of the e-graph based on a list of sorts and all their possible children. I have shrunk the API to simply providing a list of expressions and getting their extractions out. I didn't see any uses for this more flexible API. I decided to shrink the exposed syntax to make it easier in the future if we want to change out default tree based extractor to use a different design that might not require traversing the e-graph by sort first. By keeping this public API it keeps us locked into that syntax, so further performance improvements would need to conform to it as well. If there are actual use cases today for this interface that would be helpful to understand why it's important to preserve.
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Just talked to Yihong, will keep public and change to TreeExtractor
| /// | ||
| /// This is the normal user extraction path: it respects `:unextractable` | ||
| /// and hidden internal functions. | ||
| pub fn extract_best<C: Cost, M: TreeCostModel<C> + 'static>( |
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They seem to overlap with extract_value and extract_value_with_cost_model. Do we need all of them?
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Yeah extact_value and extract_value_with_cost_model were previous helpers, I can remove them.
| impl Cost for $cost { | ||
| impl CommutativeMonoid for $cost { | ||
| fn identity() -> Self { 0 } | ||
| fn unit() -> Self { 1 } |
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Why do we no longer have unit() for a cost? This provides a default for e.g., base values.
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You dont need it. It was only used in the default trait implementation and not used at all in the actual extractor, it was just used in the deafult trait implementation, but that wasn't really needed. so it seems cleaner to remove it. Like there is no reason for a cost to require it.
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It provides a default head cost for functions and values. For example, in your implementation of TreeAdditiveCostModel and CustomCostModel, you use the magic number 1. It does not need to be magic if we have unit(). Alternatively, consider how you would make a generic AstSizeCostModel<C> where C: Cost if without unit.
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Yeah it provides a default cost, but its not clear to me its worth having there, because if you define your own cost model, its not needed. I.e. cost should be about what the extraction/cost model needs, and its not required, its optional basically.
Like in the current implementation, this is how we implement the cost model for u64:
impl CostModel<DefaultCost> for TreeAdditiveCostModel {
fn fold(
&self,
_head: &str,
children_cost: &[DefaultCost],
head_cost: DefaultCost,
) -> DefaultCost {
children_cost.iter().fold(head_cost, |s, c| s.combine(c))
}
fn enode_cost(&self, egraph: &EGraph, func: &Function, _enode: &Enode<'_>) -> DefaultCost {
func.extraction_head_cost(egraph)
}
}It isn't clear to me how this is better than doing:
impl CostModel<DefaultCost> for TreeAdditiveCostModel {
fn fold(
&self,
_head: &str,
children_cost: &[DefaultCost],
head_cost: DefaultCost,
) -> DefaultCost {
children_cost.iter().fold(head_cost, |s, c| s.combine(c))
}
fn enode_cost(&self, egraph: &EGraph, func: &Function, _enode: &Enode<'_>) -> DefaultCost {
func.extraction_head_cost(egraph)
}
fn base_value_cost(&self, egraph: &EGraph, sort: &ArcSort, value: Value) -> C {
1
}
}There was a problem hiding this comment.
I updated it to make TreeAdditiveCostModel generic, so that you can parameterize it with different unit costs for different cost types.
| } | ||
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| /// Requirements for a type to be usable as a cost by a [`CostModel`]. | ||
| pub trait Cost { |
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Do we have to change the name?
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I can change it back
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Reverted, I think its clearer now
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Small nit: it seems some relatively big files are checked into the git history. Maybe worth doing a squash merge at the end. |
* Expose enough e-graph introspection to walk and rebuild a sub-e-graph Three additions to what a primitive body can see, none of them specific to any one extension. Together they are what an out-of-tree primitive needs to walk the term structure under an e-class and build a modified copy of it. Read::enodes_for_eclass(name, eclass, f) walks a constructor's rows by output e-class through the backend's lazy column index, instead of scanning the table and filtering. Cherry-picked from #934 along with the core-relations ExecutionState::for_each_matching_col and egglog-bridge TableAction::for_each_output_value it rests on. Read::table_schema(name) and Read::table_subtype(name) report a table's declared column sorts and its subtype. EGraph::functions_iter already exposes this from &EGraph, but a primitive body only ever sees a state wrapper, and those carried no sort information at all - so a primitive could read rows without being able to tell an e-class column from a base value. Backed by a FunctionSchemas map the e-graph shares with the wrappers exactly as it already shares ActionRegistry, and snapshot/restored across push/pop so a popped table stops resolving. table_subtype also replaces probing a subtype by starting a scan and reading the error, which egglog-experimental does today. Core::rebuild_container(type_id, value, remap) remaps a container value's contents and interns the result. Out-of-tree code cannot go through Core::register_container, which requires naming the container's Rust type. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> * Split table_schema by subtype, and tidy the diff's docs table_schema returned a schema for either subtype, which reads past the fact that a constructor's last column is an e-class and a function's is an output. Splitting it matches how the rest of Read and Write already work - lookup / eclass_of, constructor_enodes / function_entries, set / add - so it is now constructor_schema and function_schema, each erroring with WrongSubtype on a mismatch. table_subtype stays as the error-free predicate to dispatch on when either subtype is acceptable, which is what retires the subtype probe in egglog-experimental. Also applies the tidy-diff-docs skill to the comments this branch adds, and records a new rule in that skill: import a type rather than naming it by an inline full path, which is what FunctionSchemas was doing with crate::util::HashMap. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> * Store a function's signature once, instead of adding a third copy The first cut of this branch added a FunctionSchemas registry so a primitive body could see column sorts. That was a third copy of data egglog already kept twice: TypeInfo::func_types holds a FuncType {name, subtype, input, output}, and Function holds the same content again as a ResolvedSchema plus decl.subtype (and a third time, unresolved, in decl.schema). What was actually missing was not the data but a way to reach it from a state wrapper. So there is now one store. TypeInfo::func_types becomes the shared cell - Arc<RwLock<HashMap<String, Arc<FuncType>>>> - and the state wrappers hold a handle to it, which is what backs constructor_schema / function_schema / table_subtype. FunctionSchemas is gone. Function points at the same Arc<FuncType> rather than storing its own copy, so Function::schema() -> &ResolvedSchema becomes Function::func_type() -> &FuncType and ResolvedSchema is removed, its get_by_pos moving to FuncType. declare_function reuses the signature typechecking already resolved instead of resolving the sorts a second time; it still resolves and records the functions desugaring generates (global bindings, proof tables), which never go through typechecking. Two things this had to get right. TypeInfo::clone deep-copies the map: a clone is an independent e-graph - a pushed copy, or the parallel typechecking the proof checker keeps - and declaring a function in one must not make it resolve in the other. And pop restores the pushed contents into the live cell the registered primitives already hold, rather than swapping in a cell they have no handle to. Also drops the second RwLock acquisition per primitive invocation the first cut introduced: the wrapper holds the unlocked handle and the schema accessors lock only when called, so a primitive that never asks pays nothing. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> * Shorten the changelog entry and fold it into the existing API entries The additions belong with the name-indexed e-graph access entry they extend, not as a standalone block longer than anything else on the list. The signature consolidation keeps a one-line breaking bullet next to the other breaking ones. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> * Let a primitive borrow the e-graph's signatures, instead of locking a handle The schema accessors read TypeInfo through an Arc<RwLock<_>> the primitive captured when it was registered. That lock was never guarding a race: declaring anything needs &mut EGraph, run_rules already holds that borrow for the whole execution, and nothing on Core/Read/Write can declare. It was there only because external functions are stored as Box<dyn ExternalFunction + 'static>, so a wrapper cannot hold a borrow of the e-graph. So change the route rather than the synchronization. ExecutionState now carries an ExternalContext - a borrowed value the caller of an operation makes visible to the external functions it reaches - and egglog passes &TypeInfo into run_rules and with_execution_state*. The state wrappers read it back with downcast_ref, so `constructor_schema` hands out a &FuncType borrowed from the e-graph itself. With that, the invariant is enforced by the borrow checker instead of stood in for by a lock: the &TypeInfo is live for exactly the operation that supplied it, so the e-graph cannot be mutably borrowed to declare a function while a rule is running. TypeInfo::func_types goes back to a plain owned map, so get_func_type keeps its original Option<&FuncType> signature and costs a map lookup again; TypeInfo::clone goes back to derive; and push/pop restore the map like every other field, with no cell to reattach. Rebuild paths pass None: they run generated rebuild rules whose actions evaluate in the Write context, which has no schema accessors. The one lock left on the invocation path is the pre-existing ActionRegistry read in RegistryPrimWrapper::invoke, which this does not touch. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> * Share the signature a function decl carries, and say why it carries one GenericFunctionDecl held both an untyped `schema: Schema` and a `resolved_schema: Head`, which for a resolved decl was a whole owned FuncType inside a ResolvedCall - a fourth copy of the signature - and for an unresolved one was a placeholder `String::new()` standing in for "not resolved yet". It is now `Option<Arc<FuncType>>`: no placeholder, and a typechecked decl points at the same FuncType TypeInfo holds rather than cloning it. Worth recording why the field survives at all, since it looks redundant next to TypeInfo. Proof encoding runs over decls that desugaring generates *after* typechecking - the functions global bindings lower to - which no TypeInfo knows about until they are executed. Deleting the field and looking signatures up by name works for every ordinary declaration and then panics on `$I`. The doc comment now says so, so the next reader does not have to rediscover it. Also drops ResolvedCall::view_types, whose only caller was one of the two readers this touches. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> * Store a function's signature once, everywhere Two copies were left after the last pass. GenericFunctionDecl::resolved_schema is gone. I had concluded it was load bearing, because deleting it and looking signatures up by name panics on `$I`: proof encoding runs over decls desugaring generates after typechecking, which no TypeInfo knows about yet. That was the wrong conclusion. The encoder never needed a FuncType - it needed the column *sorts*, and sorts resolve by name from TypeInfo like any other. Resolving them from the decl's own untyped schema drops the field, its ResolvedCall::view_types reader, and the placeholder `String::new()` an unresolved decl carried in it. (Populating TypeInfo with the generated signatures instead does not work: the desugared program is typechecked again afterwards, so recording early trips the already-bound check.) ResolvedCall::Func now holds an Arc<FuncType> rather than an owned one, so a resolved call site shares the signature instead of cloning it - and there are as many of those as there are calls in every rule. The patterns that matched `ResolvedCall::Func(FuncType { subtype: Custom, .. })` cannot look through an Arc, so they match the variant and test the subtype in a guard via a new ResolvedCall::is_custom_func. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> * Review pass: tidy the diff's docs, cover the new API, fix two defects Two reviews, one of them independent, converged on the same two defects: - Deleting `ResolvedCall::view_types` left its `///` block behind, so the public `from_resolution_func_types` was documented as a different function. - `func_type_of` reported `ApiError::MissingTable` for a table that exists whenever the execution carried no context, conflating "no declarations here" with "no such table". Now `ApiError::SchemasUnavailable`. Coverage: the codecov report on the PR put `src/exec_state.rs` at 0% for this patch - none of the new accessors were exercised in-tree, only from egglog-experimental. `tests/api_introspection.rs` covers them, pinning `enodes_for_eclass` against a filtered `constructor_enodes` scan (with a row-count assertion so the comparison cannot pass vacuously), the subtype split of the schema accessors, and `rebuild_container`'s three outcomes. `core-relations` covers the context mechanism itself: an external function reads back what the caller supplied, `None` when nothing was, and `None` rather than a misparse when the type does not match. Also from review: `record_signature` now debug-asserts a cached signature agrees with the declaration it is reused for, `enodes_for_eclass` documents that it matches the eclass column as stored, `is_custom_func` moved into the existing inherent impl, the `context` parameters are documented on the entry points that gained them, and `FuncType::get_by_pos` - carried over from the deleted `ResolvedSchema` with no callers in the workspace - is dropped. Doc tidy per the repo's tidy-diff-docs skill: five comments stated mechanism instead of contract (the lazy-column-index narration on `for_each_matching_col` and `for_each_output_value`, the rationale paragraph on `ExternalContext`, the borrow-checker explanation on `type_info`, and "shares rather than copies" on two `Arc` fields, which the type already says). Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> * Address review: fewer accessors, fewer strings, and a name that fits From @yihozhang's pass: - `func_type_arc` is gone; `get_func_type` returns `Option<&Arc<FuncType>>`, so the callers that keep a signature clone the `Arc` and the rest are unchanged. - `record_signature` is inlined into `declare_function`, its only caller. - `non_stale()` after a scan was compensating for a bug fixed in this release (`9369a702 Filter stale rows in constrained bounded scans`). The invariant is now written down on `Table::scan_generic_bounded` and the `scan_bounded` / `scan_project` wrappers, and the five vestigial filters over scan output are gone. The three in `table/mod.rs` stay: those read pending-insert queues, where rows really can be stale. - `for_each_matching_col` now prefers a sort the table already has, then a cacheable column's index, then the constraint during the scan - the order `Database::process_constraints` uses. It previously built and refreshed an index even when `split_fast_slow` had already answered by binary search. - `EGraph::with_execution_state{,_tracked}` always pass `&TypeInfo`, so no call site has to reason about whether a primitive it cannot see needs it. - `FunctionSubtype::label` and `TableKind::label` replace a free function and two inline matches, and `check_subtype` derives both labels instead of taking one as a string. `Display for FunctionSubtype` delegates to `label` rather than repeating it. - `rebuild_container` is `map_container`: it maps a container's contents and interns the result without touching the original, and "rebuild" collided with egglog's canonicalize-after-union sense. It returns `Option<Value>` now, so a `TypeId` that does not match the value is reported rather than looking like "nothing changed" - `ContainerEnv` already drew that distinction and only the outer wrapper discarded it. New test: a `ReadPrim` that resolves a signature from inside a `:naive` rule, covering the path that reaches its execution state through `run_rules` rather than `with_execution_state`. Verified it fails if that call site passes `None`. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> --------- Co-authored-by: Oliver Flatt <oflatt@gmail.com> Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
…-dag-extractor # Conflicts: # core-relations/src/action/mod.rs # egglog-bridge/src/lib.rs # src/exec_state.rs # src/extract.rs
…-dag-extractor # Conflicts: # CHANGELOG.md
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Inline comments:
In `@src/extract.rs`:
- Around line 676-698: Reuse the reconstruction memo across batched roots by
adding a variant of extract_best_with_sort that accepts a caller-owned mutable
HashMap<(Value, String), TermId>, and pass it to reconstruct_termdag_node_helper
instead of creating a fresh default cache per call. Update EGraph::extract_best
to create one cache for the batch and reuse it for each root, following the
existing pattern in extract_variants_with_sort while preserving output behavior.
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🔇 Additional comments (21)
tests/integration_test.rs (8)
1-188: LGTM!
670-695: LGTM!
697-722: LGTM!
724-749: LGTM!
751-789: LGTM!
791-859: LGTM!
861-897: LGTM!
899-911: LGTM!tests/api_introspection.rs (2)
33-33: LGTM!
48-59: LGTM!src/extract.rs (4)
1-13: LGTM!Also applies to: 19-68, 70-192, 194-232, 234-271, 273-311, 352-354, 407-408, 434-434
463-472: LGTM!
729-760: LGTM!Also applies to: 782-782, 798-833
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CHANGELOG.md (1)
5-6: LGTM!src/lib.rs (3)
49-49: LGTM!Also applies to: 368-372
1735-1780: LGTM!
1843-1878: LGTM!Also applies to: 2339-2378
src/lib.md (1)
39-42: LGTM!src/prelude.rs (2)
88-96: LGTM!
113-114: 🎯 Functional CorrectnessNo change needed. The documented root uses visible, extractable
NumandAddconstructors, soextract_bestreturnsSomefor this example.> Likely an incorrect or invalid review comment.
yihozhang
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See comments! My main feedback is about trait naming and organization.
I also noticed some documents are sometimes repetitive about, say, optimal substructure property. Also, maybe we should only document these required properties at the cost model declaration site and not the extractor declaration site, since they are properties that make a cost model sound?
| /// | ||
| /// Repeated calls with the same arguments during one extraction must return | ||
| /// equal costs. | ||
| pub trait BaseCostModel<C: Cost> { |
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Can we collapse this into the other cost models? A cost model defines a function from a term to a cost, and base cost model alone does not define such a function. My understanding is this is for implementation reuse, but this does not seem to save much code I feel.
| /// Repeated calls with equivalent arguments during one extraction must return | ||
| /// equal costs. Greedy DAG extraction may recompute marginal costs while | ||
| /// reconciling producer choices. | ||
| pub trait MarginalCostModel<C: CombinableCost>: BaseCostModel<C> { |
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Similarly, I think we should bake in to this cost model the idea that we combine node costs with + and "DAG" cost. Otherwise, this trait alone does not tell us how to define a cost function. As a corollary of this, FoldCostModel should not require MarginalCostModel
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If we do that, I suggest we call MarginalCostModel "DagCostModel" and FoldCostModel "TreeCostModel", to align with the literature. If you want to distinguish them from TotalCostModel, maybe we can call them something like "TreeNodeCostModel" or "TreeMarginalCostModel"?
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Updated those and simplified the trait hierarchy
| /// Implementations must make `identity` a two-sided identity and `combine` | ||
| /// associative, commutative, deterministic, non-panicking, and monotone with | ||
| /// respect to [`Cost`]'s ordering. Rust cannot enforce these laws. | ||
| pub trait CombinableCost: Cost { |
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alt name idea: MonoidCost
| /// either fold for context-sensitive tree extraction. This opt-in is separate | ||
| /// from [`MarginalCostModel`] so custom models can choose between this derived | ||
| /// implementation and a direct [`TotalCostModel`] implementation. | ||
| pub trait FoldCostModel<C: CombinableCost>: MarginalCostModel<C> { |
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If you agree with the idea above, here we can duplicate the methods from MarginalCostModel.
| } | ||
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| /// The default, Bellman-Ford like extractor. This extractor is optimal for [`CostModel`]. | ||
| /// The default Bellman-Ford-like extractor. This extractor is optimal for a |
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There's some repetition in this doc currently
| /// assign lower costs to larger terms, but then the model is responsible for | ||
| /// avoiding negative-cost cycles and cyclic extracted terms. | ||
| pub struct TreeExtractor<'g, C: Cost> { | ||
| egraph: &'g EGraph, |
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Why do we need to store the EGraph?
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We could also pass it in on methods, but this way we know its the same e-graph which is required anyways for things to work, so seems better to store it on construction instead of requiring a new one to be passed in.
Also this prevents using the extractor after the e-graph has been mutated which could cause errors.
| /// For convenience, if the rootsorts is `None`, it defaults to extract all extractable rootsorts. | ||
| /// Later calls to [`TreeExtractor::extract_best_with_sort`] and | ||
| /// [`TreeExtractor::extract_variants_with_sort`] reuse the prepared best | ||
| /// costs and producer choices for reachable eq-sort values. Primitive and |
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"Primitive and container ... enodes" - I find this sentence hard to parse. Similarly for the last paragraph "The cost model must remain ... extractor"
| /// Returns the extraction head cost for this table, falling back to `default`. | ||
| /// View tables inherit the cost of their referenced hidden term constructor. | ||
| pub(crate) fn extraction_head_cost(&self, egraph: &EGraph) -> DefaultCost { | ||
| pub(crate) fn extraction_head_cost( |
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nit: let this return Option<DefaultCost> and the caller does extraction_header_cost(..).unwrap_or(..)
| /// This is the normal user extraction path: it respects `:unextractable` | ||
| /// and hidden internal functions. The cost model must satisfy the | ||
| /// optimal-substructure and convergence requirements on [`TreeExtractor`]. | ||
| pub fn extract_best<C: Cost, M: TotalCostModel<C>>( |
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Maybe name this as extract_best_with_cost_model (similarly for the next function) and bring back extract_value that defaults TreeAdditiveCostModel?
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| /// Computes intrinsic costs that exclude selected child and element costs. | ||
| /// | ||
| /// Repeated calls with equivalent arguments during one extraction must return |
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Why greedy dag needs to recompute marginal cost? Can't it just cache that?
One of the reasons why I preferred FoldCM over TotalCM was because you only need to call marginal_enode_cost once to pin down the cost of each e-node. So that nothing stops us if later we want to export/serialize an extraction problem. Does our extractor implementation have to get the cost multiple times?
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Fixed so we cache it in experimental
…-dag-extractor # Conflicts: # CHANGELOG.md # tests/api_introspection.rs
4 participants
Extraction cost model and support APIs
This is the core half of the greedy-DAG extraction split. It does not add
:extractor greedy-dagto core egglog; that syntax and heuristic live in thedownstream experimental PR:
Related context:
greedy_dag_cost_modelegglog-python#387Changes
Costis the ordered, cloneable value needed to rank tree candidates.TreeCostModelcomputes enode/container annotations and folds them withselected child costs. Its cost type does not need an addition operation.
MonoidCostadds a lawful identity and associative, commutative,monotone combination operation.
DagCostModelreturns intrinsic enode, container, and base-value costssuitable for once-paid DAG accounting.
TreeCostModelFromDagexplicitly adapts a DAG model to tree extraction bycombining each intrinsic cost with its selected child costs.
AdditiveCostModel { node_cost }. Itsdefault
u64configuration preserves unit-node costs and constructor:costdeclarations.TreeExtractor<'g, C>. Callers can prepare costs for selected root sorts andrepeatedly extract individual values while its borrow keeps the e-graph
immutable.
EGraph::extract_best_with_cost_modelandEGraph::extract_variants_with_cost_modelmethods with named result structsand one shared
TermDag.EGraph::extract_value(&sort, value).NoneinExtractedTerms; strictcommand paths convert that case to
ExtractErrorwhere required.refactored tree extractor. Batched best extraction reuses one reconstruction
memo across roots.
container traversal/reconstruction and
Function::is_unextractable.Downstream combines these with the already-landed
Read::enodes_for_eclasslookup.Public Interfaces
Extraction:
Cost,MonoidCostTreeCostModel<C>,DagCostModel<C>,TreeCostModelFromDag<M>AdditiveCostModel,DefaultCostExtractedTerm<C>,ExtractedTerms<C>,ExtractedTermVariants<C>TreeExtractor<'g, C>compute_costs_from_rootsorts(rootsorts, egraph, cost_model)extract_best_with_sort(termdag, value, sort)extract_variants_with_sort(termdag, value, nvariants, sort)EGraph:extract_best_with_cost_model(roots, cost_model)extract_variants_with_cost_model(roots, nvariants, cost_model)extract_value(sort, value)container_inner_values(sort, value)reconstruct_base_value(sort, value, termdag)reconstruct_container_value(sort, value, termdag, element_terms)Function:Function::is_unextractable()Review Notes
The normal
(extract ...)command remains tree extraction. Proof extractionis root-directed and separate after
#941; this PR does not modify that
path.
MonoidCostlaws are semantic contracts that Rust cannot enforce. Built-inimplementations are limited to unsigned saturating integers and exact
BigInt/BigRationaladdition; arbitrary tree costs need only implementCost.Validation
cargo clippy --all-targets --all-features -- -D warningsRUSTDOCFLAGS='-D warnings' cargo doc --no-deps --all-featurescargo fmt --all -- --checkgit diff --check691.2 ms +/- 21.5 ms680.3 ms +/- 8.9 ms-1.59%, 95% CI[-3.10%, -0.04%]