The question of "where do scripts go?" is an organizational one--and a philosophical one, too. A flash scriptor must think about the categories of his or her flash project. If one has actions that act upon buttons and they refer to code routines which act upon the flash movie (the whole project or scene), then where do the code routines or functions get placed?

In computer programming, the flash movie is like a specialized class file. A class file is a description, in computing code, that models a system, whether complex or simple. By class I mean type or category definition. For instance, if you had a summer cookout class, you might have a barbecue function and data objects like steaks, chicken, roasted vegetables, and beer. The barbecue function acts upon the steak, chicken, and roasted vegetables and it might use the beer data object for flavor on the grill.

The question of where do the functions go is answered by the notion of encapsulation. A class is like a container, or mixing bowl for ingredients. A set of ingredients cannot all act on the recipe or work toward the completion of a food item unless it is available to the mixing function, i.e. in the same bowl of ingredients. We encapsulate the mixing functions and the data objects or ingredients into the class and this is how we define the class type: creamed spinach. The name "creamed spinach" encapsulates the milk and spinach that go into the recipe along with a mixing procedure that acts upon those ingredients.

The question of where do functions go then appears to be answered by the fact that a Flash movie is like a code type definition for vector animation. Each flash file is a definition of vector animation AND the specific subject matter that it deals with, a factor also detailed in the naming scheme for the objects in the flash movie. Another thing is that flash movies contain other classes in the form of objects--symbols. When we make an object from a symbol, this is a type definition that we instantiate or make an instance of, and they define the project. So the flash file is a vector animation type definition that encapsulates the objects or symbols, object definitions that can be of any subject matter. The idea here is that a data object can also be a type definition differing solely in that it is a copy or instance of it. A Class can have subclasses.

With these distinct layers of components in Flash, you might ask when you are scripting, is this a general function applicable to a variety of objects that may use it, or is this a function that treats specifically an object in the flash movie, treats a button or movie clip? If it is a general function, then you want a flash movie (flash file) script. To create this, first create a separate script channel in the timeline and control-click on the first frame to place the script. When the movie plays frame one, it gets access to those generalized functions for acting on the objects.

Events and Buttons, and Encapsulation

How can encapsulation be used to explain button events or movie clip events? Well, it simply incorporates into objects the user in the data and procedural model. The user becomes an element that is accounted for by the programmer, in his or her code. So in the code, the user, thought of as a class uses buttons or movie clips. We have events which are modeled in the program. On Rollover is called when the mouse rolls over the button, this activates the stored procedures within the code snippet following the button event.

We say that the button is a type definition that has data (its look and visual characteristics) and procedures, functions, that act upon it. The button as a type definition encapsulates the data and procedures. In turn that type definition can be used as a data object in the Flash movie or class encapsulating the button objects.

So you have a bowl of ingredients with different properties, and because of what they are specifically coded to do, they resolve themselves in varying levels of encapsulation. Computer programming is both a mix or soup, and a definition of properties analogous to those in chemistry or physical science, that tells, when encapsulated, or mixed, the interaction between components.

Object Oriented Programming 101: type definitions or classes consist of data and procedures. The data can be other type definitions that have their own data and procedures which can have their own data and procedures. You want interaction between a button and a function that deals with the general movie? Make a movie script with a function. Put the function in the first frame to be available to the entire movie. Have the button event call that function. Encapsulation. The Soup. Mixing and defining properties for interaction. Computing is both a set of files or data, and procedures within that data that have varying orders of other data and procedures encapsulated. The programmer mixes, and distinguishes how interaction will emerge from the soup.