scala> val a="42"
a: String = 42

scala> "a=\"$a\""
res33: String = a="$a"    // ok

scala> s"a=\"$a\""
<console>:1: error: ';' expected but string literal found.
       s"a=\"$a\""
                ^         // oops

scala> s"a=\'$a\'"
res34: String = a='42'    // ok with \'

scala> """a=\"$a\""""
res35: String = a=\"$a\"  // escape not interpreted, ok

scala> s"""a=\"$a\""""
res36: String = a="42"    // escape interpreted, should it ?