Support defining scalar functions in php

[aszenz]

The duckdb c api allows for defining scalar functions, these can be useful for reusing existing php logic.

One can also define aggregate and table functions, although those aren't as useful for my usecase

[dhernandez]

Not sure if this is a good idea, since it will impact performance.

It is clearly documented in FFI

Although this works, this functionality [...] is not efficient and leaks resources by the end of request.
It is therefore recommended to minimize the usage of PHP callbacks.

But, apart from FFI, I would say this is an internal PHP issue related to switching context between C an PHP.

I would say it is doable but not in an optimal way due to PHP internal architecture so... Does it make sense?

[aszenz]

I would say it is doable but not in an optimal way due to PHP internal architecture so... Does it make sense?

So you think it's a limitation of the ffi interface or PHP internals?

Note:

sqlite extension also has user defined functions but they don't seem to have these issues documented, see:

https://www.php.net/manual/en/sqlite3.createfunction.php
https://www.php.net/manual/en/sqlite3.createaggregate.php