Seems pretty well designed. Though the decision to be able to refer to the properties of data in a pipe directly with their names might cause some confusion in

Seems pretty well designed. Though the decision to be able to refer to the properties of data in a pipe directly with their names might cause some confusion in the end (the 'size' in 'ls | where size > 1'). Ok it's succinct, but it's also a bit weird that the loop variable (what this basically is in a pipe) is treated different than all others. Not that e.g. PS' $_ is so great, but at least it's obvious: it's a variable just like all others.