trustfall VS prql

Pleasantly surprised to see Predrag show up as a reviewer, but at the same time not at all surprised:

- The [Firebase technical screen](https://startupandrew.com/posts/how-firebase-interviewed-sof...) would have been much easier with something like this, as it was Just Another Optimization Problem™. Part of me wants to try it again with Picat!

- He's doing other very interesting things with programming languages, e.g.: https://github.com/obi1kenobi/trustfall

Email: [email protected]

Hi, I'm u9g. I'm looking for an internship for either this winter (in a few weeks) or a summer internship!

Some things I've done:

I integrated a [query engine for lints](https://github.com/obi1kenobi/trustfall) (and contributed optimizations) into [OXC](https://github.com/oxc-project/oxc) (a new Rust-based Javascript Linter).

I wrote [several](https://github.com/u9g/money-lens) [toy](https://github.com/u9g/quickquestion/tree/main/extension) languages and syntax highlighting for them.

I also wrote a [js-to-scheme transpiler](https://github.com/u9g/js2scheme/blob/main/example.js).

Happy to work on things compiler or database oriented, but also happy to learn something new!

If you'd like to dig deeper, here are some links:

- cargo-semver-checks: https://github.com/obi1kenobi/cargo-semver-checks

- Trustfall query engine, which powers cargo-semver-checks: https://github.com/obi1kenobi/trustfall

- Trustfall playground, where you can query Rust library APIs in your browser -- for example, "which structs in `itertools` are importable by more than one path": https://play.predr.ag/rustdoc#?f=2&q=*3-Structs-importable-f...

- 10min conference talk on Trustfall: https://www.hytradboi.com/2022/how-to-query-almost-everythin...

I'm also giving a talk at P99 CONF in a few months about how Trustfall's new optimizations API made cargo-semver-checks over 2300x faster: https://twitter.com/PredragGruevski/status/16893002495908003...

No worries!

Trustfall is even more general than semver actually, one can use it to query any data source -- even HN itself:

https://play.predr.ag/HackerNews

Here's a link to that project if you'd like to check it out:

https://github.com/obi1kenobi/trustfall

I gave a 10min conference talk on it last year titled "How to query (almost) everything"

https://www.hytradboi.com/2022/how-to-query-almost-everythin...

I've had my eye on Taxi for a while, and it's neat! I agree that the problems it aims to solve are real and painful in real life.

In my experience, I'm not sure people care about schemas or schema languages — they are just implementation details best left under the hood. This is why in my own work, I started on the query end of the spectrum instead.

This is why I built Trustfall, a query engine able to query any data source: DBs, APIs, files like PDF, CSV, or JSON, or any combination of those.

GitHub: https://github.com/obi1kenobi/trustfall

Playground showing the query "which GitHub/Twitter users comment on HackerNews stories about OpenAI?": https://play.predr.ag/hackernews#?f=1&q=IyBDcm9zcyBBUEkgcXVl...

Here's an example adapter for querying RSS/Atom feeds. Here's an example adapter for querying the HackerNews APIs. Both projects also include a schema and example queries which you can run.

> I completely attribute this to SQL being difficult or "backwards" to parse. I mean backwards in the way that in SQL you start with what you want first (the SELECT) rather than what you have and widdling it down.

> The turning point for me was to just accept SQL for what it is.

Or just write PRQL and compile it to SQL

https://github.com/PRQL/prql

Hey HN! We’ve built Pretzel, an open-source data exploration and visualization tool that runs fully in the browser and can handle large files (200 MB CSV on my 8gb MacBook air is snappy). It’s also reactive - so if, for example, you change a filter, all the data transform blocks after it re-evaluate automatically. You can try it here: https://pretzelai.github.io/ (static hosted webpage) or see a demo video here: https://www.youtube.com/watch?v=73wNEun_L7w

You can play with the demo CSV that’s pre-loaded (GitHub data of text-editor adjacent projects) or upload your own CSV/XLSX file. The tool runs fully in-browser—you can disconnect from the internet once the website loads—so feel free to use sensitive data if you like.

Here’s how it works: You upload a CSV file and then, explore your data as a series of successive data transforms and plots. For example, you might: (1) Remove some columns; (2) Apply some filters (remove nulls, remove outliers, restrict time range etc); (3) Do a pivot (i.e, a group-by but fancier); (4) Plot a chart; (5) Download the chart and the the transformed data. See screenshot: https://imgur.com/a/qO4yURI

In the UI, each transform step appears as a “Block”. You can always see the result of the full transform in a table on the right. The transform blocks are editable - for instance in the example above, you can go to step 2, change some filters and the reactivity will take care of re-computing all the cells that follow, including the charts.

We wanted Pretzel to run locally in the browser and be extremely performant on large files. So, we parse CSVs with the fastest CSV parser (uDSV: https://github.com/leeoniya/uDSV) and use DuckDB-Wasm (https://github.com/duckdb/duckdb-wasm) to do all the heavy lifting of processing the data. We also wanted to allow for chained data transformations where each new block operates on the result of the previous block. For this, we’re using PRQL (https://prql-lang.org/) since it maps 1-1 with chained data transform blocks - each block maps to a chunk of PRQL which when combined, describes the full data transform chain. (PRQL doesn’t support DuckDB’s Pivot statement though so we had to make some CTE based hacks).

There’s also an AI block: This is the only (optional) feature that requires an internet connection but we’re working on adding local model support via Ollama. For now, you can use your own OpenAI API key or use an AI server we provide (GPT4 proxy; it’s loaded with a few credits), specify a transform in plain english and get back the SQL for the transform which you can edit.

Our roadmap includes allowing API calls to create new columns; support for an SQL block with nice autocomplete features, and a Python block (using Pyodide to run Python in the browser) on the results of the data transforms, much like a jupyter notebook.

There’s two of us and we’ve only spent about a week coding this and fixing major bugs so there are still some bugs to iron out. We’d love for you to try this and to get your feedback!

> Looks like PRQL doesn't have a Go library so I guess they just really wanted something in Go?

There's some C bindings and the example in the README shows integration with Go:

https://github.com/PRQL/prql/tree/main/prqlc/bindings/prqlc-...

Can someone tell me why PRQL is better? I went here: https://github.com/PRQL/prql

It looks nice, but what's the strengths compared to SQL?

PRQL [1] is a compile-to-SQL relational querying language that puts FROM first.

[1] https://prql-lang.org

https://prql-lang.org/ might be an answer for this. As a cross-database pipelined language, it would allow RAG to be intermixed with the query, and the syntax may(?) be more reliable to generate