The way nginx handles requests and responses in an implicit event loop reminds me of a recent talk by Brian Kernighan, in which he mentions the ubiquity of the “pattern–action” model in many domains. I think it’s a very useful architectural pattern to have in mind when you’re designing a configuration system or a DSL.
I also liked this quote:
> …it is worth avoiding the dilution of development efforts on something that is neither the developer’s core competence or the target application.