YamlInline::parseScalar PHP Method

    public static function parseScalar($scalar, $delimiters = null, $stringDelimiters = array('"', "'"), &$i = 0, $evaluate = true)
    {
        if (in_array($scalar[$i], $stringDelimiters)) {
            // quoted scalar
            $output = self::parseQuotedScalar($scalar, $i);
            // skip next delimiter
            ++$i;
        } else {
            // "normal" string
            if (!$delimiters) {
                $output = substr($scalar, $i);
                $i += strlen($output);
                // remove comments
                if (false !== ($strpos = strpos($output, ' #'))) {
                    $output = rtrim(substr($output, 0, $strpos));
                }
            } else {
                if (preg_match('/^(.+?)(' . implode('|', $delimiters) . ')/', substr($scalar, $i), $match)) {
                    $output = $match[1];
                    $i += strlen($output);
                } else {
                    throw new InvalidArgumentException(sprintf('Malformed inline YAML string (%s).', $scalar));
                }
            }
            $output = $evaluate ? self::evaluateScalar($output) : $output;
        }
        return $output;
    }

 /**
  * Parses a YAML string to a PHP value.
  *
  * @param  string A YAML string
  *
  * @return mixed  A PHP value
  */
 public function parse($value)
 {
     $this->value = $this->cleanup($value);
     $this->currentLineNb = -1;
     $this->currentLine = '';
     $this->lines = explode("\n", $this->value);
     $data = array();
     while ($this->moveToNextLine()) {
         if ($this->isCurrentLineEmpty()) {
             continue;
         }
         // tab?
         if (preg_match('#^\\t+#', $this->currentLine)) {
             throw new InvalidArgumentException(sprintf('A YAML file cannot contain tabs as indentation at line %d (%s).', $this->getRealCurrentLineNb() + 1, $this->currentLine));
         }
         $isRef = $isInPlace = $isProcessed = false;
         if (preg_match('#^\\-(\\s+(?P<value>.+?))?\\s*$#', $this->currentLine, $values)) {
             if (isset($values['value']) && preg_match('#^&(?P<ref>[^ ]+) *(?P<value>.*)#', $values['value'], $matches)) {
                 $isRef = $matches['ref'];
                 $values['value'] = $matches['value'];
             }
             // array
             if (!isset($values['value']) || '' == trim($values['value'], ' ') || 0 === strpos(ltrim($values['value'], ' '), '#')) {
                 $c = $this->getRealCurrentLineNb() + 1;
                 $parser = new YamlParser($c);
                 $parser->refs =& $this->refs;
                 $data[] = $parser->parse($this->getNextEmbedBlock());
             } else {
                 if (preg_match('/^([^ ]+)\\: +({.*?)$/', $values['value'], $matches)) {
                     $data[] = array($matches[1] => YamlInline::load($matches[2]));
                 } else {
                     $data[] = $this->parseValue($values['value']);
                 }
             }
         } else {
             if (preg_match('#^(?P<key>[^ ].*?) *\\:(\\s+(?P<value>.+?))?\\s*$#', $this->currentLine, $values)) {
                 $key = YamlInline::parseScalar($values['key']);
                 if ('<<' === $key) {
                     if (isset($values['value']) && '*' === substr($values['value'], 0, 1)) {
                         $isInPlace = substr($values['value'], 1);
                         if (!array_key_exists($isInPlace, $this->refs)) {
                             throw new InvalidArgumentException(sprintf('Reference "%s" does not exist at line %s (%s).', $isInPlace, $this->getRealCurrentLineNb() + 1, $this->currentLine));
                         }
                     } else {
                         if (isset($values['value']) && $values['value'] !== '') {
                             $value = $values['value'];
                         } else {
                             $value = $this->getNextEmbedBlock();
                         }
                         $c = $this->getRealCurrentLineNb() + 1;
                         $parser = new YamlParser($c);
                         $parser->refs =& $this->refs;
                         $parsed = $parser->parse($value);
                         $merged = array();
                         if (!is_array($parsed)) {
                             throw new InvalidArgumentException(sprintf("YAML merge keys used with a scalar value instead of an array at line %s (%s)", $this->getRealCurrentLineNb() + 1, $this->currentLine));
                         } else {
                             if (isset($parsed[0])) {
                                 // Numeric array, merge individual elements
                                 foreach (array_reverse($parsed) as $parsedItem) {
                                     if (!is_array($parsedItem)) {
                                         throw new InvalidArgumentException(sprintf("Merge items must be arrays at line %s (%s).", $this->getRealCurrentLineNb() + 1, $parsedItem));
                                     }
                                     $merged = array_merge($parsedItem, $merged);
                                 }
                             } else {
                                 // Associative array, merge
                                 $merged = array_merge($merge, $parsed);
                             }
                         }
                         $isProcessed = $merged;
                     }
                 } else {
                     if (isset($values['value']) && preg_match('#^&(?P<ref>[^ ]+) *(?P<value>.*)#', $values['value'], $matches)) {
                         $isRef = $matches['ref'];
                         $values['value'] = $matches['value'];
                     }
                 }
                 if ($isProcessed) {
                     // Merge keys
                     $data = $isProcessed;
                 } else {
                     if (!isset($values['value']) || '' == trim($values['value'], ' ') || 0 === strpos(ltrim($values['value'], ' '), '#')) {
                         // if next line is less indented or equal, then it means that the current value is null
                         if ($this->isNextLineIndented()) {
                             $data[$key] = null;
                         } else {
                             $c = $this->getRealCurrentLineNb() + 1;
                             $parser = new YamlParser($c);
                             $parser->refs =& $this->refs;
                             $data[$key] = $parser->parse($this->getNextEmbedBlock());
                         }
                     } else {
                         if ($isInPlace) {
                             $data = $this->refs[$isInPlace];
                         } else {
                             $data[$key] = $this->parseValue($values['value']);
                         }
                     }
                 }
             } else {
                 // one liner?
                 if (1 == count(explode("\n", rtrim($this->value, "\n")))) {
                     $value = YamlInline::load($this->lines[0]);
                     if (is_array($value)) {
                         $first = reset($value);
                         if ('*' === substr($first, 0, 1)) {
                             $data = array();
                             foreach ($value as $alias) {
                                 $data[] = $this->refs[substr($alias, 1)];
                             }
                             $value = $data;
                         }
                     }
                     return $value;
                 }
                 throw new InvalidArgumentException(sprintf('Unable to parse line %d (%s).', $this->getRealCurrentLineNb() + 1, $this->currentLine));
             }
         }
         if ($isRef) {
             $this->refs[$isRef] = end($data);
         }
     }
     return empty($data) ? null : $data;
 }