Learning common expressions and macros

[Rishabh Jain]

Hello CEL authors, 

I'm starting to use CEL-java for a rules management system, similar to how Google is using it for IAM. The language looks great so far with especially the ability to add variables and macros. I've gone through the CEL spec and am going through the code, especially some tests, to understand how to build more macros. Are there more tests than the join macro function and is there a suggested way to navigate the codebase. I'd also appreciate if you can point me to any literature you'd recommend in understanding expression languages as I'm finding it a bit hard to follow. 

Thanks, 
Rishabh

[BAKE ZQ]

Looking for tutorials on macros  too, and what's the difference between macros and functions, which one should I choose?

I extended the cel expression by adding functions/methods, there are detailed examples in ext module of cel-GO repo on how to register custom functions.