herrera-io/annotations

A tokenizer for Doctrine annotations.

Monday, February 3, 2014
by kherge
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The README.md

Annotations

The Annotations library is for tokenizing and converting Doctrine-styled annotations. Unlike the Doctrine Annotations library, this one does not require that classes or constants exist, nor are they evaluated., _(*2)

The [DocLexer][] class from the Doctrine Annotations library is used to generate the tokens from the annotated docblocks. This library handles the filtering, validation, and conversion of those tokens., _(*3)

Example

use Herrera\Annotations\Tokenizer;

$tokenizer = new Tokenizer();

$tokens = $tokenizer->parse(
    <<<DOCBLOCK
/**
 * @My\Annotation(
 *     a="string value",
 *     @Nested,
 *     {"a list"},
 *     A_CONSTANT
 * )
 */
DOCBLOCK
);

/*
 * array(
 *     array(DocLexer::T_AT),
 *     array(DocLexer::T_IDENTIFIER, 'My\\Annotation'),
 *     array(DocLexer::T_OPEN_PARENTHESIS),
 *     array(DocLexer::T_IDENTIFIER, 'a'),
 *     array(DocLexer::T_EQUALS),
 *     array(DocLexer::T_STRING, 'string value'),
 *     array(DocLexer::T_COMMA),
 *     array(DocLexer::T_AT),
 *     array(DocLexer::T_IDENTIFIER, 'Nested'),
 *     array(DocLexer::T_OPEN_CURLY_BRACES),
 *     array(DocLexer::T_STRING, 'a list'),
 *     array(DocLexer::T_COMMA),
 *     array(DocLexer::T_IDENTIFIER, 'A_CONSTANT'),
 *     array(DocLexer::T_CLOSE_CURLY_BRACES),
 *     array(DocLexer::T_CLOSE_PARENTHESIS)
 * )
 */

Installation

Add it as a Composer dependency:, _(*4)

$ composer require herrera-io/annotations=~1.0

Tokenizing

To tokenize a docblock comment, you will first need to create an instance of Tokenizer. The object can be re-used to parse as many docblocks as needed:, _(*5)

use Herrera\Annotations\Tokenizer;

$tokenizer = new Tokenizer();

$tokenizer->ignore(
    array(
        'author',
        'package'
    )
);

$aliases = array('ORM' => 'Doctrine\\ORM\\Mapping');

$parsed = $tokenizer->parse($docblock, $aliases);

The ignore() method allows you to specify a list of annotations to ignore. By default, none are ignored, so it may be beneficial to register the default list provided by Doctrine:, _(*6)

array(
  'Annotation', 'Attribute', 'Attributes', 'Required', 'SuppressWarnings',
  'TODO', 'Target', 'abstract', 'access', 'api', 'author', 'category', 'code',
  'codeCoverageIgnore', 'codeCoverageIgnoreEnd', 'codeCoverageIgnoreStart',
  'copyright', 'deprec', 'deprecated', 'endcode', 'example', 'exception',
  'filesource', 'final', 'fixme', 'global', 'ignore', 'ingroup', 'inheritDoc',
  'inheritdoc', 'internal', 'license', 'link', 'magic', 'method', 'name',
  'override', 'package', 'package_version', 'param', 'private', 'property',
  'return', 'see', 'since', 'static', 'staticVar', 'staticvar', 'subpackage',
  'throw', 'throws', 'todo', 'tutorial', 'usedby', 'uses', 'var', 'version',
)

The $aliases argument allows you to specify a list of aliases that may have been used for the name of the annotation. For example. it is common practice to shorten the name of Doctrine ORM annotations using the following:, _(*7)

use Doctrine\ORM\Mapping as ORM;

The $aliases example demonstrates how only the ORM namespace alias will be mapped to Doctrine\ORM\Mapping. Additional aliases can be specified at the same time:, _(*8)

$aliases = array(
    'Assert' => 'Symfony\Component\Validator\Constraints',
    'ORM' => 'Doctrine\ORM\Mapping',
    'Route' => 'Sensio\Bundle\FrameworkExtraBundle\Configuration\Route',
);

The value of $parsed is an array of tokens. Each token will contain the token's numeric identifier, followed by the value parsed from the docblock (if applicable)., _(*9)

You can find a reference of the token identifiers here., _(*10)

This example docblock:, _(*11)

/**
 * @author Some Author <some@author.com>
 *
 * @package MyPackage
 *
 * @ORM\Column(name="MyColumn")
 */

will yield the following tokens in $tokens:, _(*12)

$parsed = array(
    array(DocLexer::T_AT),
    array(DocLexer::T_IDENTIFIER, 'Doctrine\\ORM\\Mapping\\Column'),
    array(DocLexer::T_OPEN_PARENTHESIS),
    array(DocLexer::T_IDENTIFIER, 'name'),
    array(DocLexer::T_EQUALS),
    array(DocLexer::T_STRING, 'MyColumn'),
    array(DocLexer::T_CLOSE_PARENTHESIS)
);

Converting

Once you have parsed a docblock for its tokens, you may find the need to convert the list of tokens into another format. Before I cover the available converters, I need to show you how to create an instance of Tokens and Sequence which are consumed by the converters., _(*13)

Tokens and Sequence

Converters use either the Tokens or Sequence class when converting a list of tokens into an alternative format. The Tokens class acts like an array, but it will also validate the tokens as they are being used. The Sequence class is an extension of Tokens, but it also validates the order in which the tokens are used., _(*14)

The converters only require that you use Tokens, but they are compatible with the Sequence class as well. The only time you may find need for the Sequence class is for debugging annotation issues, or if you are accepting tokens from anything besides the Tokenizer class., _(*15)

Creating an instance of either class is very simple:, _(*16)

use Herrera\Annotations\Sequence;
use Herrera\Annotations\Tokens;

$tokens = new Tokens($parsed);
$sequence = new Sequence($parsed);
$sequence = new Sequence($tokens); // also accepts a Tokens object

To Array

An instance of ToArray is used to convert tokens to a simple array., _(*17)

use Herrera\Annotations\Convert\ToArray;

$toArray = new ToArray();

$array = $toArray->convert($tokens);

The value of $array is an array of objects. Each object represents a single annotation in the docblock. Each object will have two properties: name and values. Any values contained in () will be in values, including nested annotations., _(*18)

The following example:, _(*19)

$array = $toArray->convert(
    new Tokens (
        $tokenizer->parse(
        <<<DOCBLOCK
/**
 * @Annotation\A("Just a simple value.")
 * @Annotation\B(
 *     name="SomeName",
 *     nested=@Annotation(),
 *     {
 *         "an array",
 *         {
 *             "within an array"
 *         }
 *     }
 * )
 */
DOCBLOCK
        )
    )
);

will result with the following array:, _(*20)

$array = array(
    (object) array(
        'name' => 'Annotation\\A',
        'values' => array(
            'Just a simple value.'
        )
    ),
    (object) array(
        'name' => 'Annotations\\B',
        'values' => array(
            'name' => 'SomeName',
            'nested' => (object) array(
                'name' => 'Annotation',
                'values' => array()
            ),
            array(
                'an array',
                array(
                    'within an array'
                )
            )
        )
    ),
);

echo $array[0]->name;  // "Annotation\A"
echo $array[0]->values[0]; // "Just a simple value."
echo $array[1]->values['nested']->name; // "Annotation"

To String

An instance of ToString is used to convert tokens to their string representation., _(*21)

use Herrera\Annotations\Convert\ToString;

$toString = new ToString();

$string = $toString->convert($tokens);

Using this example:, _(*22)

$string = $toString->convert(
    new Tokens(
        $tokenizer->parse(
        <<<DOCBLOCK
/**
 * @Annotation\A("Just a simple value.")
 * @Annotation\B(
 *     name="SomeName",
 *     nested=@Annotation(),
 *     {
 *         "an array",
 *         {
 *             "within an array"
 *         }
 *     }
 * )
 */
DOCBLOCK
        )
    )
);

The result will be similar, but without any of the formatting:, _(*23)

$string = <<<STRING
@Annotation\A("Just a simple value.")
@Annotation\B(name="SomeName",nested=@Annotation(),{"an array",{"within an array"}})';
STRING;

While formatting is supported by the string converter, it is very limited in the number of options it provides:, _(*24)

setBreakChar($char) — Sets the line break character. (default: \n)
setIndentChar($char) — Sets the indentation character. (default: (space))
setIndentSize($size) — Sets the indentation size. (default: 0 (zero))
useColonSpace($bool) — Toggles whether a space should be added after a colon that is used for assignment. (default: false) (example: @Name({key: "value"}))

With a minor modification:, _(*25)

$toString->setIndentSize(4);

We can get a formatted string returned back to us:, _(*26)

$string = <<<STRUNG
@Annotation\A(
    "Just a simple value."
)
@Annotation\B(
    name="SomeName",
    nested=@Annotation(),
    {
        "an array",
        {
            "within an array"
        }
    }
)
STRUNG;

To XML

An instance of ToXml is used to convert tokens to an XML document., _(*27)

use Herrera\Annotations\Convert\ToXml;

$toXml = new ToXml();

$doc = $toXml->convert($tokens);

Using this example:, _(*28)

$doc = $toXml->convert(
    new Tokens(
        $tokenizer->parse(
        <<<DOCBLOCK
/**
 * @Annotation\A("Just a simple value.")
 * @Annotation\B(
 *     name="SomeName",
 *     nested=@Annotation(),
 *     {
 *         "an array",
 *         {
 *             "within an array"
 *         }
 *     }
 * )
 */
DOCBLOCK
        )
    )
);

echo $doc->saveXML();

will result in the following XML:, _(*29)


<annotations>
  <annotation name="Annotation\A">
    <value type="string">Just a simple value.</value>
  </annotation>
  <annotation name="Annotation\B">
    <value key="name" type="string">SomeName</value>
    <annotation key="nested" name="Annotation"/>
    <values>
      <value type="string">an array</value>
      <values>
        <value type="string">within an array</value>
      </values>
    </values>
  </annotation>
</annotations>

You can also validate annotation XML using ToXml::validate($input), where $input can be an XML string or an instance of DOMDocument. If you only need access to the XML schema, you can get the file path using the class constant ToXml::SCHEMA., _(*30)

While you may be able to get the schema path using the HERRERA_ANNOTATIONS_SCHEMA constant, I don't recommend it. It isn't available until the ToXml class is loaded, and the the name is not guaranteed to be consistent., _(*31)