Constructors

Clipp can use both c++ constructors and free functions as basis to create a scripting constructor.

If we go back to our point example:

    //constructor
    point::point(double x,double y,double z);

    //function working like a constructor
    point* create_point(double x,double y,double z);	

We can then expose these to the scripting in the following way:

    //expose constructor
    cls.constructor(arguments<double,double,double>());
    //Optional syntax
    cls[constructor<double,double,double>()];

    //expose function working like a constructor
    cls.constructor(create_point); 

In javascript, a constructor can be used both in a new expression, and in a call expression

    var a=new point(5,6,7);	//new expression
    var b=point(5,6,7);		//call expression

This is the default behaviour for constructor registering today. If you want to change the constructor to be used only in new expressions, you have to add the argument construct_method  to the constructor exposing function:

    //Ensure that the constructor can only be used in new expressions
    cls.constructor(arguments<double,double,double>(),construct_method);

We can also expose create_point as a global function that will only be activated in call expressions:

    //expose function working like a constructor
    function(c,"point",create_point); 

Copyright © 2003-2005 Peder Holt

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