Introduce a logging API to GHC
I don't have a lot of mileage with the code base, but I do see that there is no standard logging API that the various components can use (or there is and it just needs to be used??).
At least, I would expect to see a standard API to generate log entries with the following minimal parts:
- Log level - for example, ERROR, WARN, INFO, DEBUG, TRACE (-v[1-3] could map to INFO, DEBUG and TRACE. Log levels are inclusive so INFO also means WARN and ERROR.
- Component name - so we know what is the source of the log message. At least I would expect to see (Desugarer, Typechecker, Parser, etc)
- the message
It would also mean a single back-end to collect the log messages and dump them to a file, stdout/stderr, etc. There are many other features beyond this point (customize log messages, colors, filtering, etc), but in terms of the API that is used throughout the code base, it should be simple.
Was this already discussed in the past? Is there already such an API in the codebase? Is there an existing library that we could use to achieve the same? Any other ideas?
This ticket is mostly to spawn a discussion about it.