true
  false

True and false are Boolean values that you can use to set or test the value of switch variables:

  set fred to true
  set barney item 3 to false

  do when fred = true

Note that switch variables return a true or false value directly so that do when fred = true and do when fred do the same thing. Similarly, do when fred = false does the same thing as do unless fred.

While all switches default to false, you should explicitly set the value of all variables before using them. This makes your programs easier to read and helps avoid errors.