在PHP中打破多个函数

I want to return multiple nested functions in PHP. It's possible to break out of multiple loops by adding a number after "break". Eg.

while(1)
  while(1)
    while(1)
      break 3;

Can I do the same thing with functions?

Not that I know of, it's also not very healthy of a design, as the parent and grandparent functions in question will never know of the break. You should throw an exception and catch it on the parent, which in turn will throw an exception and catch it on the grandparent etc.

To "break" out of functions, you can use the return.

function somefunction()
{
    return;

    echo 'This will never get displayed';
}

As the manual states break is for loop only.

Another solution would be to add a condition to each while.

while(1 && $isTrue)
  while(1 && $isTrue)
    while(1 && $isTrue)
      $isTrue = false;
      break;

Although I don't think this is a very clean approach.

What I do in such cases is that have an exception return value(or object) and do value check on return value at every function return point to make sure that the situation is propagated or handled appropriately, be careful while doing recursions though, you might completely fold up the tree by mistake....btw if it is a simple exit on error kind of situation you can also use exceptions.

It's possible to return a special result from child functions that indicates a specific condition has been met. WordPress uses WP_Error and is_wp_error() for this sort of operation. Any number of nested functions can check to see if a called function returned an error state, and opt to pass that error up the chain rather than continue with processing.

Example:

function outer() {
    $result = inner();

    // pass failure back to parent
    if( is_wp_error($result) ) {
        return $result;
    }

    // other processing

    return $final_result;
}

function inner() {
    if( some_condition() ) {
        // generate an error
        return new WP_Error( 'code', 'message' );
    }

    return $other_result;
}

$result = outer();

// did we get an error?
if( is_wp_error($result) ) {
    echo 'Something went wrong.';
} else {
    echo $result;
}