Pretty printing relations

[ydewit]

I am wondering if there is a technique that other people have used to pretty print relations.

Ideally, I would like to see a simple template language that could generate syntax text out of AST relations (think: Source -> AST -> Facts -> Outputs -> Annotated AST). But I am sure that is asking too much.

I guess using the API to traverse through the output facts?

[quentin]

Can you give an example of pretty-printing you would like to have? Is this for the stdout output?

You might want to write and register your own WriteStreamFactory in souffle::IOSystem, and then .output relation(IO="registered_name"). Although currently that is only possible with a compiled souffle program that you instanciate manually from your own c++ code.

Note that you need set --output-dir to anything but - otherwise the default stdout printer is selected regardless of the IO= value.

We could probably extend souffle to be able to call arbitrary write stream factories from a dynamically linked library (same way as functors).