I'm not sure if it's due to the name not really conveying what it what sounds like they're trying to describe or my lack of familiarity with other parts of the language, but this page doesn't really give me any clue to what a "subscript" actually is. They're very explicit that it's not a function, but from both the syntax and the usage exactly, it seems to look and act pretty much just like a function. Given that it's supposed to help avoid needing references in the language, I assume that the reason they're making this distinction is to convey that it doesn't use call stack semantics like a function call normally does, so...is it just an inlined function, or a hygenic macro defined with essentially the same syntax as a normal one except for the "subscript" keyword? I want to give the benefit of the doubt about their being something "novel" about this feature, but the confusing name and the documentation being quite verbose without really giving much detail makes me feel like either the authors don't grasp that they're just giving a new name to something existing or that they purposely are trying to make it less obvious.