Feature request: Intercept method

[EotT123]

Currently, it is possible to add methods using manifold-ext. However, overriding the body of an existing method is not supported. This feature could be useful to inject custom logic before or after the original method call, or even to completely replace the method body.

At present, this is not possible because attempting to add an extension with the same method signature results in an exception.

I propose the following solution: adding an @Intercept annotation to an extension method would allow you to override the method’s body, potentially invoking the original method within the intercepted extension. For example:

package extensions.java.lang.Object;

import manifold.ext.rt.api.Extension;
import manifold.ext.rt.api.Intercept;
import manifold.ext.rt.api.This;

@Extension
public class MyObjectExt {
 
  @Intercept
  public static String toString( @This Object object )
  {
    return object == null ? return "null" : object.toString();
  }
}

[EotT123]

I've implemented this in #656

[EotT123]

This new feature could be integrated in PR #597, so StringUtils class could override all existing String methods, null checks integrated.