Arbitrary character for array expansion
@split($(command) "\n") syntax is too verbose for expansion, and is quite common.
It would be better if Ion had a shorthand notation.
This could cause confusion with methods, where
@"\n"(command), where "\n" can be any arbitrary separator.
@"join"(command) behave fairly differently. Further more, this would not allow expansion and/or would make it awkward (ex: