Since Scala has closures, you don't need special syntax for this. The
idea is, instead of the programmer writing down "val wr", they write
down the "wri" as a closure parameter, i.e. "wri =>" . Here's the
Notice that using is declared using a parameterized type, so that the
"wri" variable ends up being typed as a FileWriter. If you declared
using using "Closeable", instead of "T <: Closeable", then "wri"
would end up being a "Closeable".