Support custom scalars

[mat-sop]

No description provided.

[lromanowicz]

Yes please! Any ETA on adding that? :D @mat-sop

[rafalp]

Hello @lromanowicz, we don't have an ETA for this. Currently non-standard scalars are typed as Any by codegen and returned in their serialized form.

We are experimenting with both simple approach to scalars where you will define them using a section in pyproject.toml:

[ariadne-codegen.scalar.datetime]
py_type = "datetime.datetime"
serialize = ".datetime_scalar.serialize"
parse = ".datetime_scalar.parse"

And you will just add the datetime_scalar to list of files to include in final build.

But we are also considering a plugin system (#67) and letting plugins do the scalars by modifying the generated code, so result types would use Pydantic's magic for scalar's logic.