Class Precedence List:
synonym-stream, stream, t
A stream that is an alias for another stream, which is the value of a dynamic variable whose name is the synonym stream symbol of the synonym stream.
Any operations on a synonym stream will be performed on the stream that is then the value of the dynamic variable named by the synonym stream symbol. If the value of the variable should change, or if the variable should be bound, then the stream will operate on the new value of the variable.