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Show HN: Prela – Purely Algebraic Relation Combinators (github.com)

73 points by remywang ↗ HN
Prela is an embedded query language based on Tarski's Algebra of Relations. Its queries are concise, clear, and fast. It is implemented by shallow embedding in a host programming language: Prela operators are regular functions in the host. The implementation follows continuation-passing style which compiles to efficient columnar execution.

5 comments

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anentropic
> Prela queries are readable even to those new to the language

Not really, too many obscure symbols.

Certainly learnable but I wouldn't say immediately readable.

WorldMaker
It seems to be assuming a familiarity with logic algebras in general. It's main operator is just the common math symbol for logical conjunction (∧) [0] and how familiar it feels versus how obscure it feels depends on your mathematical background (and how long it has been). But yeah, most programming languages tend to prefer operators like & or && or `and` for logical conjunction, so Prela chose the mathematical choice over the programming language choice. Which is perhaps easily explainable by Prela starting as trying to be a pure syntax of Relational Algebra [1] which does usually prefer the mathematical symbols, given it is the mathematical theory (underpinning things like SQL) for academic/mathematical discussion more than a working programming language. Though we live in a time of Unicode where that distinction starts to get blurry again and mathematical symbols are easier to use than prior eras without dedicated APL keyboards or things like that.

[0] https://en.wikipedia.org/wiki/Logical_conjunction

[1] https://en.wikipedia.org/wiki/Relational_algebra

gavinray
Julian Hyde (Apache Calcite author) has a side project called Morel

Morel is an ML dialect that can compile set-producing expressions into bytecode that Calcite can execute against databases

Sort of like "If you could query anything with SQL but it's ML instead"

I bring this up because the example query looks very similar to Morel queries

Neat xample of solving a combinatorial optimization problem with a single query that he posted recently to Twitter:

https://x.com/i/status/2062066151841321370

http://blog.hydromatic.net/2026/06/02/package-queries.html

cpard
SQL, JS, Excel are really hard to substitute because of how widely used they are by people. Even if something new comes up that it's objectively better, so far has always failed gaining traction because of this reality.

I wonder though, is such a dialect better for agents? Have you tried to measure if an agent performs better expressing queries in such a language instead of SQL?

chowells
The heading saying "Simple (SPJ)" caught my eye, because I'm not sure SPJ has ever talked about simplicity in an especially referenceable way. Were you thinking of Rich Hickey's "Simple made Easy", or did SPJ do a presentation I missed out on?