Disagree. Those are the super easy cases for me to create my own adapter that does that for me in a way that works for my use case, leaving others free to do it

Disagree. Those are the super easy cases for me to create my own adapter that does that for me in a way that works for my use case, leaving others free to do it / ignore it at their own discretion, depending on their use cases. Maybe one person creates various functional wrappers around the array structures to make composition of length or count work in their functional programming design. Someone else created mixins and their own derived classes that solve it with OOP designs, etc etc. Someone else only uses Jax and doesn’t care. Someone else uses infinite streams on top of these and so they never need length or count. Forcing the same call semantics on all these users doesn’t make sense. Let them build their own abstractions if they need to standardize semantics for their use cases.