preferences:set-default

This function must be called every time your application starts up, before any call to preferences:get.

• (preferences:set-default symbol value test) -> void
      symbol : symbol
      value : TST
      test : (TST -> boolean)

  This sets the default value of the preference symbol to value. If the user has chosen a different setting, the user's setting will take precedence over the default value.

  The last argument, test is used as a safeguard. That function is called to determine if a preference read in from a file is a valid preference. If test returns #t, then the preference is treated as valid. If test returns #f then the default is used.