O'Reilly logo
  • Subin Velleringatt thinks this is interesting:

However, if a dynamic variable already exists with the same name, let will instead, temporarily, override the value of the dynamic variable to the new value. *standard-output* is such a dynamic variable. This means that we can temporarily override the value of *standard-output* to a new value by passing it into our with-open-file command .

From

Cover of Land of Lisp

Note

Didnt quite understand.