Design a global logging system for better error reporting

[JamieJQuinn]

Currently errors are reported throughout the codebase with regular print statements:

print *, "Error: something happened"

While this is generally fine, a more sophisticated system that looks something like...

logger.warn("This is just a warning")
> WARNING: This is just a warning

logger.error("This is a catastrophic error")
> ERROR: This is a catastrophic error

logger.info("Just reporting regular information")
> INFO: Just reporting regular information

would allow some nice benefits:

• flexible, global redirection of different types of errors to files & other output streams
• uniform hierarchy of messages (e.g. error, warn, info, debug, etc)

Mainly just adding this issue to discuss whether we want this & what it could look like.

Tasks:

• Integrate fypp into build system
• Write logger
• Migrate all existing print statements to logger
• Catch future uses of print with some static analysis

[slaizet]

yes please for this! You will know better than me what's best to do!

[pbartholomew08]

Something to maybe consider is whether to print regardless of rank or only on root, or atleast having the option to do so. Though this might run the risk of deadlocks, maybe a case only for the info class of messages.