• Easier to write,  far more difficult to maintain.
• Requires more time to read and comprehend.
• Inhibits code re-use.
• More difficult to test.
• Positive correlation to defective code.
• 
  

• Cyclomatic Complexity
• Npath Complexity

// 1 point for the function declaration
function foo($list) {
  // 1 point for any for, foreach, or while
  foreach ($list as $item) {
    // 1 point for any if, elseif, case
    if ($item == 'foo') {
      return 'bar';
    }
    else if ($item == 'bar') {
      return 'baz';
    }
    //no points given for else, this represents default execution path
    else {
      return 'default';
    }
  }
}

function complex_form_alter(&$form, &$form_state, $form_id) {
  switch ($form_id) {
    case 'search_form':
      if (user_is_logged_in()) {
        array_unshift($form['#submit'], 'complex_submit');
      }
      break;

    case 'article_node_form':
      drupal_set_title('This is an article form!');
      break;

    default:
      watchdog('complex', 'someone accessed a form!');
      break;
  }
}

function foo($foo, $bar) {
    // First conditional, two possible outcomes  
    if ($foo > 100) {
        echo 'path 1';
    } else {
        echo 'path 2';
    }
    // Second conditional, two possible outcomes
    if ($foo > $bar) {
        echo 'path 3';
    } else {
        echo 'path 4';
    }
}

function foo($foo, $bar) {
    // First conditional, two possible outcomes  
    if ($foo > 100) {
        echo 'path 1';
    } 
    else {
        echo 'path 2';
    }
    // Second conditional, two possible outcomes  
    if ($foo > 200) {
      echo 'path 3';
    } 
    else {
      echo 'path 4';
    }
    // Third conditional, two possible outcomes
    if ($foo > $bar) {
        echo 'path 5';
    } else {
        echo 'path 6';
    }
}

• Written by By Manuel Pichler
• FOSS
• Requires PHP >= 5.2.3

 composer global require 'phpmd/phpmd'

 phpmd [filename|directory] [report format] [ruleset file]

if ($something) {
  foreach ($list as $item) {
    if ($item == 'foo') {
      foreach ($other_list as $other_item) {
        while ($yet_another = get_another_thing()) {
          if ($yet_another == 'bar') {
            print 'AAAAAAAAHHHHH!!!!!!';
          }
        }
      }
    }
  }
}

function foo($words) {
  $contains_long_word = false;
  foreach ($words as $word) {
    if (strlen($item) >= 20) {
      $contains_long_word = true;
    }
  }
  if ($contains_long_word) {
    foreach ($words as $key => $word) {
      $words[$key] = strtolower($words[$key);
    }
  }
}

function array_some($arr, $fn) {
  foreach ($arr as $item) {
    if (!$fn($item)) {
      return false;
    }
    return true;
  }
}
function is_long_word($word) {
  return (strlen($word) >= 20);
}

function foo($words) {
  $has_long_word = array_some($words, 'is_long_word');
  if ($has_long_word) {
    return array_map('strtolower', $words);
  }
  return $words;
}

• If, else if, switch statements in hook_form_alter()
  
• Use hook_form_FORM_ID_alter() instead
• Conditionals inside theme overrides or templates
• Use theme hook and template suggestions
• block__module
• block__module__delta
• example.com/page/something
• page--something.tpl.php