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Revision as of 23:34, 1 October 2007 (edit) Sandman (Talk | contribs) m (→Example) ← Previous diff		Revision as of 23:20, 18 December 2007 (edit) (undo) Sandman (Talk | contribs) m (→Statement) Next diff →
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	=== Statement ===		=== Statement ===
-	'''Process''' <name>([<parameters>]);	+	'''Process''' <name>([<parameters>])<br>
		+	['''Public'''
		+	:<public variables>]
		+	['''Private'''
		+	:<private variables>]
		+	'''Begin'''
		+	:<main code>
		+	['''OnExit'''
		+	:<OnExit code>]
		+	'''End'''
-	Process is a reserved word used to start the code of a process.	+	Process is a reserved word used to start the code of a process.
	=== Concept ===		=== Concept ===

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Revision as of 23:20, 18 December 2007

Up to Basic Statements

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Contents 1 Definition 1.1 Statement 1.2 Concept 2 Example

Definition

Statement

Process <name>([<parameters>])
[Public

<public variables>]

[Private

<private variables>]

Begin

<main code>

[OnExit

<OnExit code>]

End

Process is a reserved word used to start the code of a process.

Concept

A process is a subroutine to which one or more of the following apply:

• it receives parameters
• it acts on the parameters
• it processes data located elsewhere

In addition to these possibilities, a process always has a frame; statement. The difference between a function and a process is a process is treated as a separate thread. This means one can't let a process return a value like a function, as the father process continues its code as well, as soon as the process hits a frame; statement or when the code is done. When that happens, the process 'returns' its ProcessID and continues the code (in the next frame).

In earlier Fenix versions (2005 and earlier) there is no difference in syntax, however, a process is treated like a function when there is no frame; statement in the code.

When the frame; statement is reached in the code, a number of other local variables are defined or updated not only of the new process, but also of related processes. These are:

• The father variable of the new process.
• The son variable of the father process (updated).
• The bigbro variable of the new process.
• The smallbro variable of the processes called by the father immediately before the new process was called (updated).
• The son and smallbro variables are also defined of the new process, but do not yet carry values.

Example

Process SpaceShip( int x, int y, int angle, int maxspeed, int maxturnspeed)
Public // Declare public variables here (Fenix 0.86 and up)
Private // Declare private variables here
    int speed;
Begin // Start the main processcode
    graph = new_map(20,20,8);
    map_clear(0,graph,rgb(0,255,255));
    Loop
        speed+=key(_up)*(speed<maxspeed)-key(_down)*(speed>-maxspeed);
        angle+=(key(_left)-key(_right))*maxturnspeed;
        advance(speed);
        frame;
    End
OnExit // Start the exit code (Fenix 0.90.2 and up)
    unload_map(0,graph);
End // End the main processcode

Now one can call this process for example by doing the following.

Program example;
Begin
    SpaceShip(100,100,0,20,5000);
    Loop
        frame;
    End
End

And when the SpaceShip process ends - because the code of it reached the End or something sent an s_kill signal - the OnExit code starts. In this example it will unload the memory used for the created graphic. If there is no OnExit code, the process will just end.

Used in example: key(), advance(), new_map(), map_clear(), angle

This will make a SpaceShip with a cyan coloured block, able to move around the screen.