Postel's Law is bad. It directly contradicts with the Unix philosophy of building small and composable interfaces. Look how small and generic the interface of R

Postel's Law is bad. It directly contradicts with the Unix philosophy of building small and composable interfaces. Look how small and generic the interface of Reader in Go. It has one method with a simple signature and can be used widely. Otoh, when your software is not opinionated about what it accepts, that's when it tends to produce surprising behaviors. This whole argument made me lean on TOML even more. It's not perfect but certainly better than ini in many ways.