While function declarations in formulas are useful, you cannot access them from another formula. To be able to re-use code in multiple formulas, you need to use classes instead.

Classes are declared in formula files, or in plug-in library files with the .ulb file extension. A class looks a bit like a regular formula entry, but the entry identifier is preceded by the class keyword. Here is an example of a simple class that represents a point with integer coordinates:

class Point {
  func Point(int aX, int aY)
    x = aX
    y = aY

  float func distance(Point p)
  ; Returns the distance to the second point p.
    return sqrt(sqr(p.x - x) + sqr(p.y - y))

  int x
  int y

This class, named Point, contains a constructor, which is a special function that initializes an instance of the class. The constructor always has the same name as the class. Also, there is an additional method called distance, and two fields called x and y that store the coordinates of the point.

Next: Objects

See Also
Plug-in parameters