Working With Unit Type Value Classes

This section provides sample script statements for working with Unit Type value classes.

The following statements calculate the area of a circle with a radius of 7 yards, then coerce the area to square feet (pi is an AppleScript-defined constant).



 
set circleArea to (pi * 7) as square yards

    --result: square yards 21.991148575129

circleArea as square feet

    --result: square feet 197.920337176157

The following statements set a variable to a value of 5.0 square kilometers, then coerce it to various other units of area:



 
set theArea to square kilometers 5.0

    --result: square kilometers 5.0

theArea as square miles

    --result: square miles 1.930510798581

theArea as square meters

    --result: square meters 5.0E+6

You can also coerce a value from square meters to a real number or an integer:



 
set theArea to square meters 5.0

    --result: square meters 5.0

theArea as real

    --result: 5.0

theArea as integer

    --result: 5

However, you cannot coerce an area measurement to a Unit Type in a different category:



 
set theArea to square meters 5.0

    --result: square meters 5.0

theArea as cubic meters

    --result: error

theArea as degrees Celsius

    --result: error

The following statements demonstrate coercion of a Unit Type to a String, and from a String to a Unit Type:



 
set myValue to pounds 2.2   --result: pounds 2.2

myValue as string           --result: "2.2"

"2.2" as kilograms          --result: kilograms 2.2