This document discusses domain specific languages (DSLs) and provides examples of implementing validation DSLs in PHP. It shows how to create rule classes that implement interfaces, use a rule factory to instantiate rules, apply annotations to validate object properties, and put everything together into a validator class. The examples demonstrate filtering annotations from comments, creating rule instances from annotations, and validating objects by checking rules against properties. Other DSL examples mentioned include Behat, Composer, Phing, and DQL. The document discusses topics like the life cycle of a DSL, internal vs external DSLs, domain knowledge in DSLs, and ensuring DSLs communicate effectively for their intended users.

1. MELHORANDO
SUA API COM
DSLS@augustohp

2. DOMAIN SPECIFIC LANGUAGE

3. A SEGUIR,
UMA
DSL

4. VALIDAÇÃO

6. 1 <?php
2
3 use RespectValidationValidator as v;
4
5 v::stringType()
6 ->exactLength(8)
7 ->contains("-")
8 ->contains("/^[A-Z]{3}/")
9 ->contains("/[0-9]{4}$/")
10 ->assert($something);

7. 1 <?php
2
3 namespace EasyTaxiValidationRules;
4
5 use RespectValidationRules as BaseRules;
6
7 class CarPlate extends BaseRulesAllOf
8 {
9 public function __construct()
10 {
11 $this->name = 'Brazilian car plate';
12
13 parent::__construct(
14 new BaseRulesStringType(),
15 new ExactLength(8),
16 new BaseRuleContains("-")->setName('Separator'),
17 new BaseRuleContains("/^[A-Z]{3}/")->setName("Prefix")
18 new BaseRuleContains("/^[0-9]{4}/")->setName("Sufix")
19 );
20 }
21 }

8. 1 <?php
2
3 namespace EasyTaxiValidationRules;
4
5 use RespectValidationRules as BaseRules;
6
7 class CarPlate extends BaseRulesAllOf
8 {
9 public function __construct()
10 {
11 $this->name = 'Brazilian car plate';
12
13 parent::__construct(
14 new BaseRulesStringType(),
15 new ExactLength(8),
16 new BaseRuleContains("-")->setName('Separator'),
17 new BaseRuleContains("/^[A-Z]{3}/")->setName("Prefix")
18 new BaseRuleContains("/^[0-9]{4}/")->setName("Sufix")
19 );
20 }
21 }

9. 1 <?php
2
3 // ... dentro de algum método de um Controller ...
4
5 ValidationValidator::arrayType()
6 ->key('driver_name', v::driverName())
7 ->key('driver_birthdate', v::minimumAge(18))
8 ->key(
9 'driver_car', v::arrayType(
10 v::key("model", v::carModel($this->get('model.vehicle'))),
11 v::key("assembler", v::carAssembler()),
12 v::key("year", v::maximumAge(5)),
13 v::key("plate", v::carPlate())
14 )
15 )
16 ->key('license_number', v::driverLicense())
17 ->key('taxi_permission', v::taxiPermissionNumber())
18 ->key('address', v::address())
19 ->assert($_POST);

10. COMO
CRIAR
ISSO?

11. 1 <?php
2
3 namespace RespectValidation;
4
5 class Validator
6 {
7 public function stringType() {}
8 public function contains($search) {}
9 public function assert($mixed) {}
10 }

13. 1 <?php
2
3 namespace RespectValidation;
4
5 interface Rule
6 {
7 public function isValid($mixed): bool;
8 }

14. IMPLEMENTANDO
UMA
REGRA

15. 1 <?php
2
3 namespace RespectValidationRules;
4
5 use RespectValidation;
6
7 class StringType implements ValidationRule
8 {
9 public function isValid($mixed): bool
10 {
11 return is_string($mixed);
12 }
13 }

16. 3 namespace RespectValidationRules;
4
5 use RespectValidation;
6
7 class AllOf implements ValidationRule
8 {
9 protected $rules = [];
10
17 public function __construct(ValidationRule ...$rules)
18 {
19 $this->rules = $rules;
20 }
21
22 public function isValid($mixed): bool
23 {
24 foreach ($this->rules as $rule) {
25 if (false === $rule->isValid($mixed)) {
26 return false;
27 }
28 }
29
30 return true;
31 }
32 }

17. INSTANCIANDO
REGRAS

18. 1 <?php
2
3 $factory = new RespectValidationRuleFactory;
4 $rule = $factory->createInstance('StringType');

19. 1 <?php
2
3 namespace RespectValidation;
4
5 class RuleFactory
6 {
7 public function createInstance($ruleName, array $args = []): Rule
8 {
9 $ruleNamespace = 'RespectValidationRules';
10 $className = $ruleNamespace . $rule;
11 $reflection = new ReflectionClass($className);
12
13 return $reflection->newInstanceArgs($args);
14 }
15 }

20. PODEMOS
TER
MENOS
CÓDIGO ?

21. 1 <?php
2
3 namespace RespectValidation;
4
5 class RuleFactory
6 {
7 public function __call($methodName, $methodArguments)
8 {
9 return $this->createInstance($methodName, $methodArguments);
10 }
11
12 public function createInstance($ruleName, array $args = []): Rule
13 {
14 /* ... */
15 }
16 }

22. 1 <?php
2
3 $checkFor = new RespectValidationRuleFactory;
4
5 $isString = $checkFor->StringType();
6
7 $isTwitterUserName = $checkFor->AllOf(
8 $checkFor->AlNum(),
9 $checkFor->NoWhitespace(),
10 $checkFor->Length(1, 15)
11 );

23. PODEMOS
TER
MENOS
CÓDIGO ?

24. 3 namespace RespectValidation;
4
5 class RuleFactory
6 {
7 private static $factory = null;
8
9 public static function getInstance()
10 {
11 if (is_null(self::$factory)) {
12 self::$factory = new static;
13 }
14
15 return self::$factory;
16 }
17
18 public static function __callStatic($methodName, $methodArguments)
19 {
20 $factory = self::getFactory();
21
22 return $factory->createInstance($methodName, $methodArguments);
23 }
24
25 /* ... */
26 }

25. 1 <?php
2
3 use RespectValidationRuleFactory as v;
4
5 $isTwitterUserName = v::AllOf(
6 v::AlNum(),
7 v::NoWhitespace(),
8 v::Length(1, 15)
9 );

27. @ANNOTATION

28. O QUE TEMOS

29. 1 <?php
2
3 namespace EasyTaxiValidation;
4
5 interface Rule
6 {
7 public function isValid($mixed): bool;
8 }

30. 1 <?php
2
3 namespace EasyTaxiValidationRules;
4
5 use EasyTaxiValidation;
6 use RespectValidationValidator as v;
7
8 class PlateValidator implements Rule
9 {
10 public function isValid($mixed): bool
11 {
12 return v::stringType()
13 ->exactLength(8)
14 ->contains("-")
15 ->contains("/^[A-Z]{3}/")
16 ->contains("/[0-9]{4}$/")
17 ->setName('Car plate')
18 ->validate($mixed);
19 }
20 }

31. O QUE QUEREMOS

32. 1 <?php
2
3 namespace EasyTaxiDriver;
4
5 class Car
6 {
7 /**
8 * @PlateValidator
9 */
10 private $plate = '';
11
12 public function __construct($plate)
13 {
14 $this->plate = $plate;
15 }
16 }

33. 1 <?php
2
3 use EasyTaxiAnnotation;
4 use EasyTaxiValidation;
5
6 $filter = new AnnotationFilter();
7 $factory = new AnnotationFactory($filter);
8 $validator = new ValidationValidator($factory);
9 $fusca = new Car('AAA-1111');
10
11 $validator->annotations($fusca);

34. FILTRANDO
A PARTE
INTERESSANTE
DE UM
COMENTÁRIO

35. 1 <?php
2
3 namespace EasyTaxiAnnotation;
4
5 class Filter
6 {
7 public function firstAnnotation($doc): string {
8 foreach ($this->breakLines($doc) as $line) {
9 if (false === $this->hasAnnotation($line)) {
10 continue;
11 }
12
13 return $this->filterName($line);
14 }
15 }
16
17 private function breakLines($doc): array {
18 return explode(PHP_EOL, $doc);
19 }
20
21 private function hasAnnotation($line): bool {
22 return false !== strpos($line, '@');
23 }
24
25 private function filterName($line): string {
26 return trim(str_replace(['*', '/', '@'], '', $line));
27 }
28 }

36. CRIANDO
REGRAS A PARTIR
DE UM
COMENTÁRIO

37. 3 namespace EasyTaxiAnnotation;
4
5 class Factory
6 {
7 private $filter = null;
8
9 public function __construct(Filter $annotationFilter)
10 {
11 $this->filter = $annotationFilter;
12 }
13
14 public function createFromProperty($instance, $propertyName)
15 {
16 $object = new ReflectionObject($instance);
17 $property = $object->getProperty($propertyName);
18
19 return $this->createInstanceFromComment($property->getDocComment());
20 }
21
22 private function createInstanceFromComment($doc)
23 {
24 $annotationClass = $this->filter->firstAnnotation($doc);
25 $class = new ReflectionClass($annotationClass);
26
27 return $class->newInstance();
28 }
29 }

38. JUNTANDO
TUDO
NUM
MONTINHO
SÓ

39. 3 namespace EasyTaxiValidation;
4
5 use EasyTaxiAnnotation;
6
7 class Validator
8 {
9 private $annotationFactory = null;
10
11 public function __construct(AnnotationFactory $factory) {
12 $this->annotationFactory = $factory;
13 }
14
15 public function annotations($object) {
16 $annotation = $this->annotationFactory;
17 $class = new ReflectionObject($object);
18 $properties = $class->getProperties();
19 foreach ($properties as $property) {
20 $propertyName = $property->getName();
21 $rule = $annotation->createFromProperty($object, $propertyName);
22 if ($rule->isValid($object)) {
23 continue;
24 }
25
26 throw new Exception("$propertyName is not valid.");
27 }
28 }
29 }

40. 1 <?php
2
3 use EasyTaxiAnnotation;
4 use EasyTaxiValidation;
5
6 $filter = new AnnotationFilter();
7 $factory = new AnnotationFactory($filter);
8 $validator = new ValidationValidator($factory);
9 $fusca = new Car('AAA-1111');
10
11 $validator->annotation($fusca);

41. OUTROS
EXEMPLOS

42. BEHAT

43. COMPOSER

44. PHING

45. DQL

46. PHPUNIT MOCK OBJECTS

47. A VIDA DE
UMA
DSL

49. DOMÍNIO

50. DSL
INTERNAO

51. DSL
EXTERNA

52. LIMITES DE
UMA
DSL

54. AUTOMATIZAR
TAREFAS
REPETITIVAS

55. <TARGET NAME=“TEST”>

56. <TARGET NAME=“DEPLOY”>

57. <TARGET NAME=“BUILD”>

58. <CONDITION>

59. <CONDITION>
FAIL

60. A SEGUIR,
UMA
MENSAGEM

61. 1 <?php
2
3 use RespectValidationValidator as v;
4
5 v::stringType()
6 ->exactLength(8)
7 ->contains("-")
8 ->contains("/^[A-Z]{3}/")
9 ->contains("/[0-9]{4}$/")
10 ->assert($something);

62. A VIDA DE
UMA
MENSAGEM

63. 99% JAPA
MAS
AQUELE 1%
É ITALIANO

64. PARA
QUEM
VOCÊ ESTÁ
FALANDO

65. PARA
QUEM
VOCÊ ESTÁ
CODANDO

66. UMA BOA
MENSAGEM
TEM LIMITES

68. FAZ USO
DE
CONHECIMENTO
PRÉVIO

69. FAZ USO
DE UM
VOCABULÁRIO
COMUM

70. DOMÍNIOS

71. QUE
#%$!*&
SÃO
DSLS
?

73. DSLS
SÃO
BOAS
MENSAGENS

74. DEPENDEM
DE BONS
DOMÍNIOS

75. SÃO MAIS
ESPECÍFICAS
DO QUE
LINGUAGENS
GENÉRICAS

76. POR ISSO
COMUNICAM
MAIS
COISAS

77. DESENVOLVIMENTO
É SOBRE
COMUNICAÇÃO

78. PERGUNTAS?

79. AGRADECIMENTOS
@NELSONSAR
@IVONASCIMENTO
@ALGANET @ITEASYTAXI

80. HTTP://BIT.LY/PHPX-DSLS