readOnly

ReadOnly.cyan

package metaobjectTest


@doc{*
  Annotation 'readOnly' should be attached to a method. 
  It assures that there is no assignment to either
  shared or non-shared fields inside the method.
  Note that does not guarantee that the method does
  not change the receiver fields (self fields). These
  can be changed by methods called by the attached method:
        @readOnly
        func unary {
            // otherMethod can change a field
            self otherMethod;
            // can change a field
            // because it can keep a reference to
            // the current self
            aField set: 0;
            // self is passed as parameter and
            // a method that change a field can 
            // be called
            aField add: self;
        }
  
    
*}
open
object ReadOnly
    
    func run {
        at: 10;
    }

    @readOnly
    func at: Int n { 
        // error if uncommented
        //value = n; 
        
        // error if uncommented
        //sharedValue = n;
    }
    
    
    var Int value = 0; 
    shared var Int sharedValue = 0; 
end