Is defining a class method without visibility a shorthand of 'public'?

问题

I often see code a function defined without visibility keywords. e.g:

class Foo() {
  function bar() {
    // ...
  }
}

Is it a shorthand of public function? Is it a good practice to omit it?

class Foo() {
  public function bar() {
    //..
  }
}

回答1:

As written in the PHP Doc,

Methods declared without any explicit visibility keyword are defined as public.

So, yes, in

class Foo() { public function bar() { //.. } }

Foo::bar() is public, but omitting the visibility keyword is never a good practice. If it's a fast and ugly script why not, but in other cases you should specify it.

回答2:

Yes, you are right; when you omit the visibility modifier it means it's public.

It's a holdover from PHP 4 which did not support visibility operators. This feature is included for backward compatibility.

You can read more about it here.

来源：https://stackoverflow.com/questions/10987443/is-defining-a-class-method-without-visibility-a-shorthand-of-public