抽象类不能声明为public？ [关闭]

I am writing a code in drupal custom module

It throws error while adding public keyword before abstract

public abstract class testParent {
  public function abc() {
    return 1;
  }
}

// Class to extent abstract class property  
class testChild extends testParent {
  public function xyz() {
  //body of your function
  }
}


$a = new testChild();
print $a->abc();

The members of a class may be limited in visibility, but all classes are essentially 'public' in PHP.

http://php.net/manual/en/language.oop5.visibility.php

You will get a syntax error if you try to use the public keyword on a class (something like PHP Parse error: syntax error, unexpected 'public' (T_PUBLIC))