Standards: introduce prepareInstalledStandardsForDisplay() method

This commit introduces a new `Standards::prepareInstalledStandardsForDisplay()` method.
This new method only prepares the "list" into displayable phrases. It doesn't include output formatting with new lines, that's up to the actual display.

This new method allows for getting rid of some output buffering calls in select places.

Includes improving the readability of the "coding standard is not installed" error.
Includes deprecating the `Standards::printInstalledStandards()` method, which is now no longer used by PHPCS itself.

Author: jrfnl

src/Config.php

@@ -685,10 +685,7 @@ public function processShortArgument($arg, $pos)
             ob_end_clean();
             throw new DeepExitException($output, 0);
         case 'i' :
-            ob_start();
-            Standards::printInstalledStandards();
-            $output = ob_get_contents();
-            ob_end_clean();
+            $output = Standards::prepareInstalledStandardsForDisplay().PHP_EOL;
             throw new DeepExitException($output, 0);
         case 'v' :
             if ($this->quiet === true) {

src/Runner.php

@@ -258,11 +258,8 @@ public function init()
             if (Standards::isInstalledStandard($standard) === false) {
                 // They didn't select a valid coding standard, so help them
                 // out by letting them know which standards are installed.
-                $error = 'ERROR: the "'.$standard.'" coding standard is not installed. ';
-                ob_start();
-                Standards::printInstalledStandards();
-                $error .= ob_get_contents();
-                ob_end_clean();
+                $error  = 'ERROR: the "'.$standard.'" coding standard is not installed.'.PHP_EOL.PHP_EOL;
+                $error .= Standards::prepareInstalledStandardsForDisplay().PHP_EOL;
                 throw new DeepExitException($error, 3);
             }
         }

src/Util/Standards.php

@@ -312,28 +312,45 @@ public static function getInstalledStandardPath($standard)
 
 
     /**
-     * Prints out a list of installed coding standards.
+     * Prepares a list of installed coding standards for display.
      *
-     * @return void
+     * @return string
      */
-    public static function printInstalledStandards()
+    public static function prepareInstalledStandardsForDisplay()
     {
         $installedStandards = self::getInstalledStandards();
         $numStandards       = count($installedStandards);
 
+        $output = '';
         if ($numStandards === 0) {
-            echo 'No coding standards are installed.'.PHP_EOL;
+            $output .= 'No coding standards are installed.';
         } else {
             $lastStandard = array_pop($installedStandards);
             if ($numStandards === 1) {
-                echo "The only coding standard installed is $lastStandard".PHP_EOL;
+                $output .= "The only coding standard installed is $lastStandard";
             } else {
                 $standardList  = implode(', ', $installedStandards);
                 $standardList .= ' and '.$lastStandard;
-                echo 'The installed coding standards are '.$standardList.PHP_EOL;
+                $output       .= 'The installed coding standards are '.$standardList;
             }
         }
 
+        return $output;
+
+    }//end prepareInstalledStandardsForDisplay()
+
+
+    /**
+     * Prints out a list of installed coding standards.
+     *
+     * @deprecated 4.0.0 Use `echo Standards::prepareInstalledStandardsForDisplay()` instead.
+     *
+     * @return void
+     */
+    public static function printInstalledStandards()
+    {
+        echo self::prepareInstalledStandardsForDisplay(), PHP_EOL;
+
     }//end printInstalledStandards()