Callable function as variable

  // Execute the screen specific preprocess function.
  $preprocess_func = 'sample_module_preprocess_screen__' . $screen;
  if (is_callable($preprocess_func)) {
    $preprocess_func($variables);
  }

Magic Variables

These are the magic variables I used a lot in php coding.

Name Description
__LINE__ Good for debugging with var_dump().
__FILE__ The full path and filename.
__DIR__ The directory of the file.
__FUNCTION__ The function name.

Closures

Closures is the anonymous function in PHP. We can use it in the callback.

$greetings = array_map(function($name) {
  return 'Hello ' . $name;
}, ['John', 'Eric', 'Josh']);

print_r($greetings);