AppleScript in a Nutshell

Subroutines with Labeled Parameters

These subroutine types are a slightly different animal than the subroutines with positional parameters, but they have some of the same rules. The keywords on or to are required in the labeled-subroutine definition, followed by the name of the subroutine, and optionally a nonlabeled parameter called a direct parameter. If the subroutine has a direct parameter (it does not have to), then the subroutine name has to be followed by the keyword of or in:

On Square of intOne...

Subroutines with labeled parameters are unwieldy to design compared with subroutines with positional parameters, but they make more subroutine calls resembling human language possible. The two different types of AppleScript subroutine designs are also a matter of personal taste, I suppose. Example 8-5 shows a labeled subroutine definition.

Example 8-5. Labeled Subroutine Definition

on Square of intOne above intLimit given Intclass:theClass
   if (intOne > intLimit) and (theClass is integer) then
      return intOne ^ 2
   else
      return 0
   end if
end Square
Square of myint above 0 given Intclass:(class of myint)

Example 8-6 redesigns the preceding subroutine using positional parameters instead.

Example 8-6. A Redesigned Subroutine Using Positional Parameters

on Square(intOne,intLimit,theClass)
   if (intLimit > 0) and (theClass is integer) then
      return intOne ^ 2
   else
      return 0
   end if
end Square

The rules on naming the subroutine (using local and global variables) and ending the subroutine definition ...