text: var f = function() { return 'a' }
  
  f()
  
  // Trace:
  //   1: before  f=/
  //   1: after   f=<function>
  //   3: before
  //     1: enter
  //     1: before
  //     1: after
  //     1: leave   return='a'
  //   3: after   f()='a'
  
  