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egraphs-good
egglog
Rust2023–2026
egraphs-good / egglog

egglog

egraphs + datalog!

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3Distinct people
5Mentions
0Explicit recommenders
882GitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

egraphs + datalog!

GitHub

Where it is used

No documented product use has been verified yet.

What people are saying

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Also in these discussions

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This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:03:16 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year5 dated mentions

Observed mentions: 2023-04-18 13:06:51 UTC to 2026-04-14 18:01:28 UTC.

01232023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 3 mentions; 0 submissions, 3 comments20232024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments20242025-01-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2026-01-01 00:00:00 UTC to 2027-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments. Incomplete calendar period.2026*

* An incomplete calendar period is marked with an outlined bar. Its count is not directly comparable with a full period.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC303
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC101
20252025-01-01 00:00:00 UTC2026-01-01 00:00:00 UTC000
2026 (partial)2026-01-01 00:00:00 UTC2027-01-01 00:00:00 UTC101

What Hacker News says

5 sources
mbid·Apr 14, 2026
I believe these ideas are much more mature and better explored for code gen, but similar techniques are useful also in the frontend of compilers, in the type checker. There's a blog post [1] by Niko Matsakis where he writes about adding equalities to Datalog so that Rust's trait solver can be encoded in Datalog. Instead of desugaring equality into a special binary predicate to normal Datalog as Niko suggests, it can be also be implemented by keeping track of equality with union-find and then propagating equality through relations, eliminating now-duplicate rows recursively. The resulting system generalizes both Datalog and e-graphs, since the functionality axiom ("if f(x) = y and f(x) = z, then y = z") is a Datalog rule with equality if you phrase it in terms of the graph of functions. Systems implementing this are egglog [2] (related to
Read the rest
egg mentioned in the article) and (self-plug, I'm the author) eqlog [3]. I've written about implementing Hindley-Milner type systems here: [4]. But I suspect that Datalog-based static analysis tools like CodeQL would also benefit from equalities/e-graphs. [1] https://smallcultfollowing.com/babysteps/blog/2017/01/26/low... [2] https://github.com/egraphs-good/egglog [3] https://github.com/eqlog/eqlog [4] https://www.mbid.me/posts/type-checking-with-eqlog-polymorph...
In The acyclic e-graph: Cranelift's mid-end optimizer
mbid·Nov 20, 2024
The post mentions the idea that querying a database D can be understood algebraically as enumerating all morphisms Q -> D, where Q is the "classifying" database of the query, i.e. a minimal database instance that admits a single "generic" result of the query. You can use this to give a neat formulation of Datalog evaluation. A Datalog rule then corresponds a morphism P -> H, where P is the classifying database instance of the rule body and H is the classifying database instance for matches of both body and head. For example, for the the transitivity rule edge(x, z) :- edge(x, y), edge(y, z). you'd take for P the database instance containing two rows (a_1, a_2) and (a_2, a_3), and the database instance H contains additionally (a_1, a_3). Now saying that a Database D satisfies this rule means that every morphism P -> D (i.e., every match
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of the premise of the rule) can be completed to a commuting diagram P --> D | ^ | / ⌄ / Q where the additional map is the arrow Q -> D, which corresponds to a match of both body and head. This kind of phenomenon is known in category theory as a "lifting property", and there's rich theory around it. For example, you can show in great generality that there's always a "free" way to add data to a database D so that it satisfies the lifting property (the orthogonal reflection construction/the small object argument). Those are the theoretical underpinnings of the Datalog engine I'm sometimes working on [1], and there they allow you to prove that Datalog evaluation is also well-defined if you allow adjoining new elements during evaluation in a controlled way. I believe the author of this post is involved in the egglog project [2], which might have similar features as well. [1] https://github.com/eqlog/eqlog [2] https://github.com/egraphs-good/egglog
In SQL, Homomorphisms and Constraint Satisfaction Problems
aseipp·May 10, 2023
The recent work on relational, datalog-inspired egraphs in PLDI this year ("Unifying Datalog and Equality Saturation") is actually interesting because it can solve cases like the y/x*x -> y identity example, by the power of an interval analysis on x (among other things.) Sort of like adding a postulate to a rewrite term and then proving it. But instead it's by adding relations between terms in the graph. See section 6.2 of the paper. https://github.com/egraphs-good/egglog https://arxiv.org/pdf/2304.04332.pdf
In Ask HN: What is new in algorithms and data structures these days?
philzook·Apr 18, 2023
A more direct link to a list of applications of egraphs is https://egraphs-good.github.io/ Largely optimizing rewrites in compilers/synthesizers/query optimizer and theorem proving applications. The egglog repo is here https://github.com/mwillsey/egg-smol with a wasm compiled web demo with examples here https://www.mwillsey.com/egg-smol/ It is still in pre-release, so there are no guarantees of stability and not necessarily ready for people to pile in. This system is related to ones Yihong Zhang and I gave separate talks on at last year EGRAPHS 2022 workshop https://effect.systems/doc/pldi-2022-egraphs/abstract.pdf http://www.philipzucker.com/egglog/
In Better Together: Unifying Datalog and Equality Saturation

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