CONSTRUCTORS Class Constructors

Section: Object Oriented Programming


When designing a constructor for a FreeMat class, you should design the constructor to take a certain form. The following is the code for the sample mat object
function p = mat(a)
  if (nargin == 0)
    p.c = [];
    p = class(p,'mat');
  elseif isa(a,'mat')
    p = a;
    p.c = a;
    p = class(p,'mat');

Generally speaking when it is provided with zero arguments, the constructor returns a default version of the class using a template structure with the right fields populated with default values. If the constructor is given a single argument that matches the class we are trying to construct, the constructor passes through the argument. This form of the constructor is used for type conversion. In particular,

   p = mat(a)

guarantees that p is an array of class mat. The last form of the constructor builds a class object given the input. The meaning of this form depends on what makes sense for your class. For example, for a polynomial class, you may want to pass in the coefficients of the polynomial.