class DocParser

final class DocParser {
    
    /**
     * An array of all valid tokens for a class name.
     *
     * @var array
     */
    private static $classIdentifiers = array(
        DocLexer::T_IDENTIFIER,
        DocLexer::T_TRUE,
        DocLexer::T_FALSE,
        DocLexer::T_NULL,
    );
    
    /**
     * The lexer.
     *
     * @var \Doctrine\Common\Annotations\DocLexer
     */
    private $lexer;
    
    /**
     * Current target context.
     *
     * @var string
     */
    private $target;
    
    /**
     * Doc parser used to collect annotation target.
     *
     * @var \Doctrine\Common\Annotations\DocParser
     */
    private static $metadataParser;
    
    /**
     * Flag to control if the current annotation is nested or not.
     *
     * @var boolean
     */
    private $isNestedAnnotation = false;
    
    /**
     * Hashmap containing all use-statements that are to be used when parsing
     * the given doc block.
     *
     * @var array
     */
    private $imports = array();
    
    /**
     * This hashmap is used internally to cache results of class_exists()
     * look-ups.
     *
     * @var array
     */
    private $classExists = array();
    
    /**
     * Whether annotations that have not been imported should be ignored.
     *
     * @var boolean
     */
    private $ignoreNotImportedAnnotations = false;
    
    /**
     * An array of default namespaces if operating in simple mode.
     *
     * @var array
     */
    private $namespaces = array();
    
    /**
     * A list with annotations that are not causing exceptions when not resolved to an annotation class.
     *
     * The names must be the raw names as used in the class, not the fully qualified
     * class names.
     *
     * @var array
     */
    private $ignoredAnnotationNames = array();
    
    /**
     * @var string
     */
    private $context = '';
    
    /**
     * Hash-map for caching annotation metadata.
     *
     * @var array
     */
    private static $annotationMetadata = array(
        'Doctrine\\Common\\Annotations\\Annotation\\Target' => array(
            'is_annotation' => true,
            'has_constructor' => true,
            'properties' => array(),
            'targets_literal' => 'ANNOTATION_CLASS',
            'targets' => Target::TARGET_CLASS,
            'default_property' => 'value',
            'attribute_types' => array(
                'value' => array(
                    'required' => false,
                    'type' => 'array',
                    'array_type' => 'string',
                    'value' => 'array<string>',
                ),
            ),
        ),
        'Doctrine\\Common\\Annotations\\Annotation\\Attribute' => array(
            'is_annotation' => true,
            'has_constructor' => false,
            'targets_literal' => 'ANNOTATION_ANNOTATION',
            'targets' => Target::TARGET_ANNOTATION,
            'default_property' => 'name',
            'properties' => array(
                'name' => 'name',
                'type' => 'type',
                'required' => 'required',
            ),
            'attribute_types' => array(
                'value' => array(
                    'required' => true,
                    'type' => 'string',
                    'value' => 'string',
                ),
                'type' => array(
                    'required' => true,
                    'type' => 'string',
                    'value' => 'string',
                ),
                'required' => array(
                    'required' => false,
                    'type' => 'boolean',
                    'value' => 'boolean',
                ),
            ),
        ),
        'Doctrine\\Common\\Annotations\\Annotation\\Attributes' => array(
            'is_annotation' => true,
            'has_constructor' => false,
            'targets_literal' => 'ANNOTATION_CLASS',
            'targets' => Target::TARGET_CLASS,
            'default_property' => 'value',
            'properties' => array(
                'value' => 'value',
            ),
            'attribute_types' => array(
                'value' => array(
                    'type' => 'array',
                    'required' => true,
                    'array_type' => 'Doctrine\\Common\\Annotations\\Annotation\\Attribute',
                    'value' => 'array<Doctrine\\Common\\Annotations\\Annotation\\Attribute>',
                ),
            ),
        ),
        'Doctrine\\Common\\Annotations\\Annotation\\Enum' => array(
            'is_annotation' => true,
            'has_constructor' => true,
            'targets_literal' => 'ANNOTATION_PROPERTY',
            'targets' => Target::TARGET_PROPERTY,
            'default_property' => 'value',
            'properties' => array(
                'value' => 'value',
            ),
            'attribute_types' => array(
                'value' => array(
                    'type' => 'array',
                    'required' => true,
                ),
                'literal' => array(
                    'type' => 'array',
                    'required' => false,
                ),
            ),
        ),
    );
    
    /**
     * Hash-map for handle types declaration.
     *
     * @var array
     */
    private static $typeMap = array(
        'float' => 'double',
        'bool' => 'boolean',
        // allow uppercase Boolean in honor of George Boole
'Boolean' => 'boolean',
        'int' => 'integer',
    );
    
    /**
     * Constructs a new DocParser.
     */
    public function __construct() {
        $this->lexer = new DocLexer();
    }
    
    /**
     * Sets the annotation names that are ignored during the parsing process.
     *
     * The names are supposed to be the raw names as used in the class, not the
     * fully qualified class names.
     *
     * @param array $names
     *
     * @return void
     */
    public function setIgnoredAnnotationNames(array $names) {
        $this->ignoredAnnotationNames = $names;
    }
    
    /**
     * Sets ignore on not-imported annotations.
     *
     * @param boolean $bool
     *
     * @return void
     */
    public function setIgnoreNotImportedAnnotations($bool) {
        $this->ignoreNotImportedAnnotations = (bool) $bool;
    }
    
    /**
     * Sets the default namespaces.
     *
     * @param array $namespace
     *
     * @return void
     *
     * @throws \RuntimeException
     */
    public function addNamespace($namespace) {
        if ($this->imports) {
            throw new \RuntimeException('You must either use addNamespace(), or setImports(), but not both.');
        }
        $this->namespaces[] = $namespace;
    }
    
    /**
     * Sets the imports.
     *
     * @param array $imports
     *
     * @return void
     *
     * @throws \RuntimeException
     */
    public function setImports(array $imports) {
        if ($this->namespaces) {
            throw new \RuntimeException('You must either use addNamespace(), or setImports(), but not both.');
        }
        $this->imports = $imports;
    }
    
    /**
     * Sets current target context as bitmask.
     *
     * @param integer $target
     *
     * @return void
     */
    public function setTarget($target) {
        $this->target = $target;
    }
    
    /**
     * Parses the given docblock string for annotations.
     *
     * @param string $input   The docblock string to parse.
     * @param string $context The parsing context.
     *
     * @return array Array of annotations. If no annotations are found, an empty array is returned.
     */
    public function parse($input, $context = '') {
        $pos = $this->findInitialTokenPosition($input);
        if ($pos === null) {
            return array();
        }
        $this->context = $context;
        $this->lexer
            ->setInput(trim(substr($input, $pos), '* /'));
        $this->lexer
            ->moveNext();
        return $this->Annotations();
    }
    
    /**
     * Finds the first valid annotation
     *
     * @param string $input The docblock string to parse
     *
     * @return int|null
     */
    private function findInitialTokenPosition($input) {
        $pos = 0;
        // search for first valid annotation
        while (($pos = strpos($input, '@', $pos)) !== false) {
            // if the @ is preceded by a space or * it is valid
            if ($pos === 0 || $input[$pos - 1] === ' ' || $input[$pos - 1] === '*') {
                return $pos;
            }
            $pos++;
        }
        return null;
    }
    
    /**
     * Attempts to match the given token with the current lookahead token.
     * If they match, updates the lookahead token; otherwise raises a syntax error.
     *
     * @param integer $token Type of token.
     *
     * @return boolean True if tokens match; false otherwise.
     */
    private function match($token) {
        if (!$this->lexer
            ->isNextToken($token)) {
            $this->syntaxError($this->lexer
                ->getLiteral($token));
        }
        return $this->lexer
            ->moveNext();
    }
    
    /**
     * Attempts to match the current lookahead token with any of the given tokens.
     *
     * If any of them matches, this method updates the lookahead token; otherwise
     * a syntax error is raised.
     *
     * @param array $tokens
     *
     * @return boolean
     */
    private function matchAny(array $tokens) {
        if (!$this->lexer
            ->isNextTokenAny($tokens)) {
            $this->syntaxError(implode(' or ', array_map(array(
                $this->lexer,
                'getLiteral',
            ), $tokens)));
        }
        return $this->lexer
            ->moveNext();
    }
    
    /**
     * Generates a new syntax error.
     *
     * @param string     $expected Expected string.
     * @param array|null $token    Optional token.
     *
     * @return void
     *
     * @throws AnnotationException
     */
    private function syntaxError($expected, $token = null) {
        if ($token === null) {
            $token = $this->lexer->lookahead;
        }
        $message = sprintf('Expected %s, got ', $expected);
        $message .= $this->lexer->lookahead === null ? 'end of string' : sprintf("'%s' at position %s", $token['value'], $token['position']);
        if (strlen($this->context)) {
            $message .= ' in ' . $this->context;
        }
        $message .= '.';
        throw AnnotationException::syntaxError($message);
    }
    
    /**
     * Attempts to check if a class exists or not. This never goes through the PHP autoloading mechanism
     * but uses the {@link AnnotationRegistry} to load classes.
     *
     * @param string $fqcn
     *
     * @return boolean
     */
    private function classExists($fqcn) {
        if (isset($this->classExists[$fqcn])) {
            return $this->classExists[$fqcn];
        }
        // first check if the class already exists, maybe loaded through another AnnotationReader
        if (class_exists($fqcn, false)) {
            return $this->classExists[$fqcn] = true;
        }
        // final check, does this class exist?
        return $this->classExists[$fqcn] = AnnotationRegistry::loadAnnotationClass($fqcn);
    }
    
    /**
     * Collects parsing metadata for a given annotation class
     *
     * @param string $name The annotation name
     *
     * @return void
     */
    private function collectAnnotationMetadata($name) {
        if (self::$metadataParser === null) {
            self::$metadataParser = new self();
            self::$metadataParser->setIgnoreNotImportedAnnotations(true);
            self::$metadataParser->setIgnoredAnnotationNames($this->ignoredAnnotationNames);
            self::$metadataParser->setImports(array(
                'enum' => 'Doctrine\\Common\\Annotations\\Annotation\\Enum',
                'target' => 'Doctrine\\Common\\Annotations\\Annotation\\Target',
                'attribute' => 'Doctrine\\Common\\Annotations\\Annotation\\Attribute',
                'attributes' => 'Doctrine\\Common\\Annotations\\Annotation\\Attributes',
            ));
        }
        $class = new \ReflectionClass($name);
        $docComment = $class->getDocComment();
        // Sets default values for annotation metadata
        $metadata = array(
            'default_property' => null,
            'has_constructor' => null !== ($constructor = $class->getConstructor()) && $constructor->getNumberOfParameters() > 0,
            'properties' => array(),
            'property_types' => array(),
            'attribute_types' => array(),
            'targets_literal' => null,
            'targets' => Target::TARGET_ALL,
            'is_annotation' => false !== strpos($docComment, '@Annotation'),
        );
        // verify that the class is really meant to be an annotation
        if ($metadata['is_annotation']) {
            self::$metadataParser->setTarget(Target::TARGET_CLASS);
            foreach (self::$metadataParser->parse($docComment, 'class @' . $name) as $annotation) {
                if ($annotation instanceof Target) {
                    $metadata['targets'] = $annotation->targets;
                    $metadata['targets_literal'] = $annotation->literal;
                    continue;
                }
                if ($annotation instanceof Attributes) {
                    foreach ($annotation->value as $attribute) {
                        $this->collectAttributeTypeMetadata($metadata, $attribute);
                    }
                }
            }
            // if not has a constructor will inject values into public properties
            if (false === $metadata['has_constructor']) {
                // collect all public properties
                foreach ($class->getProperties(\ReflectionProperty::IS_PUBLIC) as $property) {
                    $metadata['properties'][$property->name] = $property->name;
                    if (false === ($propertyComment = $property->getDocComment())) {
                        continue;
                    }
                    $attribute = new Attribute();
                    $attribute->required = false !== strpos($propertyComment, '@Required');
                    $attribute->name = $property->name;
                    $attribute->type = false !== strpos($propertyComment, '@var') && preg_match('/@var\\s+([^\\s]+)/', $propertyComment, $matches) ? $matches[1] : 'mixed';
                    $this->collectAttributeTypeMetadata($metadata, $attribute);
                    // checks if the property has @Enum
                    if (false !== strpos($propertyComment, '@Enum')) {
                        $context = 'property ' . $class->name . "::\$" . $property->name;
                        self::$metadataParser->setTarget(Target::TARGET_PROPERTY);
                        foreach (self::$metadataParser->parse($propertyComment, $context) as $annotation) {
                            if (!$annotation instanceof Enum) {
                                continue;
                            }
                            $metadata['enum'][$property->name]['value'] = $annotation->value;
                            $metadata['enum'][$property->name]['literal'] = !empty($annotation->literal) ? $annotation->literal : $annotation->value;
                        }
                    }
                }
                // choose the first property as default property
                $metadata['default_property'] = reset($metadata['properties']);
            }
        }
        self::$annotationMetadata[$name] = $metadata;
    }
    
    /**
     * Collects parsing metadata for a given attribute.
     *
     * @param array     $metadata
     * @param Attribute $attribute
     *
     * @return void
     */
    private function collectAttributeTypeMetadata(&$metadata, Attribute $attribute) {
        // handle internal type declaration
        $type = isset(self::$typeMap[$attribute->type]) ? self::$typeMap[$attribute->type] : $attribute->type;
        // handle the case if the property type is mixed
        if ('mixed' === $type) {
            return;
        }
        // Evaluate type
        switch (true) {
            // Checks if the property has array<type>
            case false !== ($pos = strpos($type, '<')):
                $arrayType = substr($type, $pos + 1, -1);
                $type = 'array';
                if (isset(self::$typeMap[$arrayType])) {
                    $arrayType = self::$typeMap[$arrayType];
                }
                $metadata['attribute_types'][$attribute->name]['array_type'] = $arrayType;
                break;
            // Checks if the property has type[]
            case false !== ($pos = strrpos($type, '[')):
                $arrayType = substr($type, 0, $pos);
                $type = 'array';
                if (isset(self::$typeMap[$arrayType])) {
                    $arrayType = self::$typeMap[$arrayType];
                }
                $metadata['attribute_types'][$attribute->name]['array_type'] = $arrayType;
                break;
        }
        $metadata['attribute_types'][$attribute->name]['type'] = $type;
        $metadata['attribute_types'][$attribute->name]['value'] = $attribute->type;
        $metadata['attribute_types'][$attribute->name]['required'] = $attribute->required;
    }
    
    /**
     * Annotations ::= Annotation {[ "*" ]* [Annotation]}*
     *
     * @return array
     */
    private function Annotations() {
        $annotations = array();
        while (null !== $this->lexer->lookahead) {
            if (DocLexer::T_AT !== $this->lexer->lookahead['type']) {
                $this->lexer
                    ->moveNext();
                continue;
            }
            // make sure the @ is preceded by non-catchable pattern
            if (null !== $this->lexer->token && $this->lexer->lookahead['position'] === $this->lexer->token['position'] + strlen($this->lexer->token['value'])) {
                $this->lexer
                    ->moveNext();
                continue;
            }
            // make sure the @ is followed by either a namespace separator, or
            // an identifier token
            if (null === ($peek = $this->lexer
                ->glimpse()) || DocLexer::T_NAMESPACE_SEPARATOR !== $peek['type'] && !in_array($peek['type'], self::$classIdentifiers, true) || $peek['position'] !== $this->lexer->lookahead['position'] + 1) {
                $this->lexer
                    ->moveNext();
                continue;
            }
            $this->isNestedAnnotation = false;
            if (false !== ($annot = $this->Annotation())) {
                $annotations[] = $annot;
            }
        }
        return $annotations;
    }
    
    /**
     * Annotation     ::= "@" AnnotationName MethodCall
     * AnnotationName ::= QualifiedName | SimpleName
     * QualifiedName  ::= NameSpacePart "\" {NameSpacePart "\"}* SimpleName
     * NameSpacePart  ::= identifier | null | false | true
     * SimpleName     ::= identifier | null | false | true
     *
     * @return mixed False if it is not a valid annotation.
     *
     * @throws AnnotationException
     */
    private function Annotation() {
        $this->match(DocLexer::T_AT);
        // check if we have an annotation
        $name = $this->Identifier();
        // only process names which are not fully qualified, yet
        // fully qualified names must start with a \
        $originalName = $name;
        if ('\\' !== $name[0]) {
            $alias = false === ($pos = strpos($name, '\\')) ? $name : substr($name, 0, $pos);
            $found = false;
            if ($this->namespaces) {
                if (isset($this->ignoredAnnotationNames[$name])) {
                    return false;
                }
                foreach ($this->namespaces as $namespace) {
                    if ($this->classExists($namespace . '\\' . $name)) {
                        $name = $namespace . '\\' . $name;
                        $found = true;
                        break;
                    }
                }
            }
            elseif (isset($this->imports[$loweredAlias = strtolower($alias)])) {
                $found = true;
                $name = false !== $pos ? $this->imports[$loweredAlias] . substr($name, $pos) : $this->imports[$loweredAlias];
            }
            elseif (!isset($this->ignoredAnnotationNames[$name]) && isset($this->imports['__NAMESPACE__']) && $this->classExists($this->imports['__NAMESPACE__'] . '\\' . $name)) {
                $name = $this->imports['__NAMESPACE__'] . '\\' . $name;
                $found = true;
            }
            elseif (!isset($this->ignoredAnnotationNames[$name]) && $this->classExists($name)) {
                $found = true;
            }
            if (!$found) {
                if ($this->ignoreNotImportedAnnotations || isset($this->ignoredAnnotationNames[$name])) {
                    return false;
                }
                throw AnnotationException::semanticalError(sprintf('The annotation "@%s" in %s was never imported. Did you maybe forget to add a "use" statement for this annotation?', $name, $this->context));
            }
        }
        if (!$this->classExists($name)) {
            throw AnnotationException::semanticalError(sprintf('The annotation "@%s" in %s does not exist, or could not be auto-loaded.', $name, $this->context));
        }
        // at this point, $name contains the fully qualified class name of the
        // annotation, and it is also guaranteed that this class exists, and
        // that it is loaded
        // collects the metadata annotation only if there is not yet
        if (!isset(self::$annotationMetadata[$name])) {
            $this->collectAnnotationMetadata($name);
        }
        // verify that the class is really meant to be an annotation and not just any ordinary class
        if (self::$annotationMetadata[$name]['is_annotation'] === false) {
            if (isset($this->ignoredAnnotationNames[$originalName])) {
                return false;
            }
            throw AnnotationException::semanticalError(sprintf('The class "%s" is not annotated with @Annotation. Are you sure this class can be used as annotation? If so, then you need to add @Annotation to the _class_ doc comment of "%s". If it is indeed no annotation, then you need to add @IgnoreAnnotation("%s") to the _class_ doc comment of %s.', $name, $name, $originalName, $this->context));
        }
        
        //if target is nested annotation
        $target = $this->isNestedAnnotation ? Target::TARGET_ANNOTATION : $this->target;
        // Next will be nested
        $this->isNestedAnnotation = true;
        
        //if annotation does not support current target
        if (0 === (self::$annotationMetadata[$name]['targets'] & $target) && $target) {
            throw AnnotationException::semanticalError(sprintf('Annotation @%s is not allowed to be declared on %s. You may only use this annotation on these code elements: %s.', $originalName, $this->context, self::$annotationMetadata[$name]['targets_literal']));
        }
        $values = $this->MethodCall();
        if (isset(self::$annotationMetadata[$name]['enum'])) {
            // checks all declared attributes
            foreach (self::$annotationMetadata[$name]['enum'] as $property => $enum) {
                // checks if the attribute is a valid enumerator
                if (isset($values[$property]) && !in_array($values[$property], $enum['value'])) {
                    throw AnnotationException::enumeratorError($property, $name, $this->context, $enum['literal'], $values[$property]);
                }
            }
        }
        // checks all declared attributes
        foreach (self::$annotationMetadata[$name]['attribute_types'] as $property => $type) {
            if ($property === self::$annotationMetadata[$name]['default_property'] && !isset($values[$property]) && isset($values['value'])) {
                $property = 'value';
            }
            // handle a not given attribute or null value
            if (!isset($values[$property])) {
                if ($type['required']) {
                    throw AnnotationException::requiredError($property, $originalName, $this->context, 'a(n) ' . $type['value']);
                }
                continue;
            }
            if ($type['type'] === 'array') {
                // handle the case of a single value
                if (!is_array($values[$property])) {
                    $values[$property] = array(
                        $values[$property],
                    );
                }
                // checks if the attribute has array type declaration, such as "array<string>"
                if (isset($type['array_type'])) {
                    foreach ($values[$property] as $item) {
                        if (gettype($item) !== $type['array_type'] && !$item instanceof $type['array_type']) {
                            throw AnnotationException::attributeTypeError($property, $originalName, $this->context, 'either a(n) ' . $type['array_type'] . ', or an array of ' . $type['array_type'] . 's', $item);
                        }
                    }
                }
            }
            elseif (gettype($values[$property]) !== $type['type'] && !$values[$property] instanceof $type['type']) {
                throw AnnotationException::attributeTypeError($property, $originalName, $this->context, 'a(n) ' . $type['value'], $values[$property]);
            }
        }
        // check if the annotation expects values via the constructor,
        // or directly injected into public properties
        if (self::$annotationMetadata[$name]['has_constructor'] === true) {
            return new $name($values);
        }
        $instance = new $name();
        foreach ($values as $property => $value) {
            if (!isset(self::$annotationMetadata[$name]['properties'][$property])) {
                if ('value' !== $property) {
                    throw AnnotationException::creationError(sprintf('The annotation @%s declared on %s does not have a property named "%s". Available properties: %s', $originalName, $this->context, $property, implode(', ', self::$annotationMetadata[$name]['properties'])));
                }
                // handle the case if the property has no annotations
                if (!($property = self::$annotationMetadata[$name]['default_property'])) {
                    throw AnnotationException::creationError(sprintf('The annotation @%s declared on %s does not accept any values, but got %s.', $originalName, $this->context, json_encode($values)));
                }
            }
            $instance->{$property} = $value;
        }
        return $instance;
    }
    
    /**
     * MethodCall ::= ["(" [Values] ")"]
     *
     * @return array
     */
    private function MethodCall() {
        $values = array();
        if (!$this->lexer
            ->isNextToken(DocLexer::T_OPEN_PARENTHESIS)) {
            return $values;
        }
        $this->match(DocLexer::T_OPEN_PARENTHESIS);
        if (!$this->lexer
            ->isNextToken(DocLexer::T_CLOSE_PARENTHESIS)) {
            $values = $this->Values();
        }
        $this->match(DocLexer::T_CLOSE_PARENTHESIS);
        return $values;
    }
    
    /**
     * Values ::= Array | Value {"," Value}* [","]
     *
     * @return array
     */
    private function Values() {
        $values = array(
            $this->Value(),
        );
        while ($this->lexer
            ->isNextToken(DocLexer::T_COMMA)) {
            $this->match(DocLexer::T_COMMA);
            if ($this->lexer
                ->isNextToken(DocLexer::T_CLOSE_PARENTHESIS)) {
                break;
            }
            $token = $this->lexer->lookahead;
            $value = $this->Value();
            if (!is_object($value) && !is_array($value)) {
                $this->syntaxError('Value', $token);
            }
            $values[] = $value;
        }
        foreach ($values as $k => $value) {
            if (is_object($value) && $value instanceof \stdClass) {
                $values[$value->name] = $value->value;
            }
            else {
                if (!isset($values['value'])) {
                    $values['value'] = $value;
                }
                else {
                    if (!is_array($values['value'])) {
                        $values['value'] = array(
                            $values['value'],
                        );
                    }
                    $values['value'][] = $value;
                }
            }
            unset($values[$k]);
        }
        return $values;
    }
    
    /**
     * Constant ::= integer | string | float | boolean
     *
     * @return mixed
     *
     * @throws AnnotationException
     */
    private function Constant() {
        $identifier = $this->Identifier();
        if (!defined($identifier) && false !== strpos($identifier, '::') && '\\' !== $identifier[0]) {
            list($className, $const) = explode('::', $identifier);
            $alias = false === ($pos = strpos($className, '\\')) ? $className : substr($className, 0, $pos);
            $found = false;
            switch (true) {
                case !empty($this->namespaces):
                    foreach ($this->namespaces as $ns) {
                        if (class_exists($ns . '\\' . $className) || interface_exists($ns . '\\' . $className)) {
                            $className = $ns . '\\' . $className;
                            $found = true;
                            break;
                        }
                    }
                    break;
                case isset($this->imports[$loweredAlias = strtolower($alias)]):
                    $found = true;
                    $className = false !== $pos ? $this->imports[$loweredAlias] . substr($className, $pos) : $this->imports[$loweredAlias];
                    break;
                default:
                    if (isset($this->imports['__NAMESPACE__'])) {
                        $ns = $this->imports['__NAMESPACE__'];
                        if (class_exists($ns . '\\' . $className) || interface_exists($ns . '\\' . $className)) {
                            $className = $ns . '\\' . $className;
                            $found = true;
                        }
                    }
                    break;
            }
            if ($found) {
                $identifier = $className . '::' . $const;
            }
        }
        // checks if identifier ends with ::class, \strlen('::class') === 7
        $classPos = stripos($identifier, '::class');
        if ($classPos === strlen($identifier) - 7) {
            return substr($identifier, 0, $classPos);
        }
        if (!defined($identifier)) {
            throw AnnotationException::semanticalErrorConstants($identifier, $this->context);
        }
        return constant($identifier);
    }
    
    /**
     * Identifier ::= string
     *
     * @return string
     */
    private function Identifier() {
        // check if we have an annotation
        if (!$this->lexer
            ->isNextTokenAny(self::$classIdentifiers)) {
            $this->syntaxError('namespace separator or identifier');
        }
        $this->lexer
            ->moveNext();
        $className = $this->lexer->token['value'];
        while (null !== $this->lexer->lookahead && $this->lexer->lookahead['position'] === $this->lexer->token['position'] + strlen($this->lexer->token['value']) && $this->lexer
            ->isNextToken(DocLexer::T_NAMESPACE_SEPARATOR)) {
            $this->match(DocLexer::T_NAMESPACE_SEPARATOR);
            $this->matchAny(self::$classIdentifiers);
            $className .= '\\' . $this->lexer->token['value'];
        }
        return $className;
    }
    
    /**
     * Value ::= PlainValue | FieldAssignment
     *
     * @return mixed
     */
    private function Value() {
        $peek = $this->lexer
            ->glimpse();
        if (DocLexer::T_EQUALS === $peek['type']) {
            return $this->FieldAssignment();
        }
        return $this->PlainValue();
    }
    
    /**
     * PlainValue ::= integer | string | float | boolean | Array | Annotation
     *
     * @return mixed
     */
    private function PlainValue() {
        if ($this->lexer
            ->isNextToken(DocLexer::T_OPEN_CURLY_BRACES)) {
            return $this->Arrayx();
        }
        if ($this->lexer
            ->isNextToken(DocLexer::T_AT)) {
            return $this->Annotation();
        }
        if ($this->lexer
            ->isNextToken(DocLexer::T_IDENTIFIER)) {
            return $this->Constant();
        }
        switch ($this->lexer->lookahead['type']) {
            case DocLexer::T_STRING:
                $this->match(DocLexer::T_STRING);
                return $this->lexer->token['value'];
            case DocLexer::T_INTEGER:
                $this->match(DocLexer::T_INTEGER);
                return (int) $this->lexer->token['value'];
            case DocLexer::T_FLOAT:
                $this->match(DocLexer::T_FLOAT);
                return (double) $this->lexer->token['value'];
            case DocLexer::T_TRUE:
                $this->match(DocLexer::T_TRUE);
                return true;
            case DocLexer::T_FALSE:
                $this->match(DocLexer::T_FALSE);
                return false;
            case DocLexer::T_NULL:
                $this->match(DocLexer::T_NULL);
                return null;
            default:
                $this->syntaxError('PlainValue');
        }
    }
    
    /**
     * FieldAssignment ::= FieldName "=" PlainValue
     * FieldName ::= identifier
     *
     * @return array
     */
    private function FieldAssignment() {
        $this->match(DocLexer::T_IDENTIFIER);
        $fieldName = $this->lexer->token['value'];
        $this->match(DocLexer::T_EQUALS);
        $item = new \stdClass();
        $item->name = $fieldName;
        $item->value = $this->PlainValue();
        return $item;
    }
    
    /**
     * Array ::= "{" ArrayEntry {"," ArrayEntry}* [","] "}"
     *
     * @return array
     */
    private function Arrayx() {
        $array = $values = array();
        $this->match(DocLexer::T_OPEN_CURLY_BRACES);
        // If the array is empty, stop parsing and return.
        if ($this->lexer
            ->isNextToken(DocLexer::T_CLOSE_CURLY_BRACES)) {
            $this->match(DocLexer::T_CLOSE_CURLY_BRACES);
            return $array;
        }
        $values[] = $this->ArrayEntry();
        while ($this->lexer
            ->isNextToken(DocLexer::T_COMMA)) {
            $this->match(DocLexer::T_COMMA);
            // optional trailing comma
            if ($this->lexer
                ->isNextToken(DocLexer::T_CLOSE_CURLY_BRACES)) {
                break;
            }
            $values[] = $this->ArrayEntry();
        }
        $this->match(DocLexer::T_CLOSE_CURLY_BRACES);
        foreach ($values as $value) {
            list($key, $val) = $value;
            if ($key !== null) {
                $array[$key] = $val;
            }
            else {
                $array[] = $val;
            }
        }
        return $array;
    }
    
    /**
     * ArrayEntry ::= Value | KeyValuePair
     * KeyValuePair ::= Key ("=" | ":") PlainValue | Constant
     * Key ::= string | integer | Constant
     *
     * @return array
     */
    private function ArrayEntry() {
        $peek = $this->lexer
            ->glimpse();
        if (DocLexer::T_EQUALS === $peek['type'] || DocLexer::T_COLON === $peek['type']) {
            if ($this->lexer
                ->isNextToken(DocLexer::T_IDENTIFIER)) {
                $key = $this->Constant();
            }
            else {
                $this->matchAny(array(
                    DocLexer::T_INTEGER,
                    DocLexer::T_STRING,
                ));
                $key = $this->lexer->token['value'];
            }
            $this->matchAny(array(
                DocLexer::T_EQUALS,
                DocLexer::T_COLON,
            ));
            return array(
                $key,
                $this->PlainValue(),
            );
        }
        return array(
            null,
            $this->Value(),
        );
    }

}