Scalar Functions

[lmangani]

Thanks for this amazing 🔥 firestarter @samansmink & team 🦆
The example registers a table function - is there a scalar function analogy?

error[E0599]: no method named `duckdb_register_scalar_function` found for struct `Connection` in the current scope

[samansmink]

@lmangani Not yet, see duckdb/duckdb-rs#407

[martin-conur]

any guidance on how to register a scalar function?

[yutannihilation]

There's no guidance, but these test code in duckdb-rs might help.

https://github.com/duckdb/duckdb-rs/blob/de4b777fc04442e8f568f4c28b88b3fe9ec11235/crates/duckdb/src/vscalar/mod.rs#L240-L274

To be honest, I feel the interface is not very matured yet, so I'm not sure if I can recommend you to implement it at the moment. But, I succeeded to implement a tiny extension using a scalar function.

https://github.com/yutannihilation/duckdb-ext-file-dialog

[martin-conur]

thank you! I was looking for some other extensions like yours!

[martin-conur]

I end up doing a basic stemmer: https://github.com/martin-conur/quacking-quack
Thank you again!

[benjamintli]

Related to this...has anyone had any success having a scalar function return an array/list? I'm having lots of trouble getting that to work unfortunately 😕. Seems to crash when I run the SQL function

[lmangani]

@benjamintli perhaps sharing a link to your code would make it easier to try with suggestions

[benjamintli]

https://gist.github.com/benjamintli/f266fee786a90cc3127f5f56ae1da42d

Sure! I create a gist of what I've been trying to do

[martin-conur]

@benjamintli did you manage to do it? I have a function that returns a List/array: https://github.com/martin-conur/quackformers/blob/main/src/lib.rs hope it helps

[nakagami]

I added the ScalarFunction code to the template, using this code as a reference.
https://github.com/duckdb/duckdb-rs/blob/1096461ea9d6a9632e5cb079860ea47b2de0257b/crates/duckdb/src/vscalar/mod.rs#L196-L238

I would like to merge #34 .