The two ways in which object inquiry built-in functions are most used during runtime are to base actions on the current attributes of an object, and to position objects.

 

Besides the object inquiry functions described below, you can also use the xcoord and ycoord response inquiry functions to inquire about an object's position. These functions return the position of a selection in the current object.

 

If you give an object inquiry function the name of an object that does not exist, an error message is produced.

 

Object inquiry functions do not return correct values when used in compile-time object definitions; for example:

 

# CORRECT:

response to start

    add graphical region RegionA

        size (xsize of TR_1) (ysize of TR_1)

 

# INCORRECT:

graphical region RegionA

    size (xsize of TR_1) (ysize of TR_1)