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1 | | -# What is a DSL? |
| 1 | +# INI DSL Guide |
2 | 2 |
|
3 | | -DSLs are Domain Specific Languages, small languages implemented for specific |
4 | | -domains. Respect\Config is an **internal DSL** hosted on the INI format to |
5 | | -hold dependency injection containers. |
| 3 | +Respect\Config extends the standard INI format with a DSL for declaring dependency |
| 4 | +injection containers. Everything in this guide maps to the PHP API described in the |
| 5 | +[Feature Guide](README.md) — if you haven't read that first, start there. |
| 6 | + |
| 7 | +## Loading INI |
| 8 | + |
| 9 | +```php |
| 10 | +use Respect\Config\IniLoader; |
| 11 | + |
| 12 | +// From a file |
| 13 | +$container = IniLoader::load('services.ini'); |
| 14 | + |
| 15 | +// From a string |
| 16 | +$container = IniLoader::load('db_host = localhost'); |
| 17 | + |
| 18 | +// Onto an existing container |
| 19 | +IniLoader::load('overrides.ini', $container); |
| 20 | +``` |
| 21 | + |
| 22 | +## Simple Values |
| 23 | + |
| 24 | +```ini |
| 25 | +app_name = "My Application" |
| 26 | +per_page = 20 |
| 27 | +tax_rate = 0.075 |
| 28 | +error_mode = PDO::ERRMODE_EXCEPTION |
| 29 | +severity = E_USER_ERROR |
| 30 | +``` |
| 31 | + |
| 32 | +```php |
| 33 | +$container->get('per_page'); // 20 (int) |
| 34 | +$container->get('tax_rate'); // 0.075 (float) |
| 35 | +$container->get('error_mode'); // 2 (PDO::ERRMODE_EXCEPTION) |
| 36 | +``` |
| 37 | + |
| 38 | +## Sequences |
| 39 | + |
| 40 | +Comma-separated values inside brackets produce PHP arrays: |
| 41 | + |
| 42 | +```ini |
| 43 | +allowed_origins = [http://localhost:8000, http://localhost:3000] |
| 44 | +``` |
| 45 | + |
| 46 | +```php |
| 47 | +// ['http://localhost:8000', 'http://localhost:3000'] |
| 48 | +$container->get('allowed_origins'); |
| 49 | +``` |
| 50 | + |
| 51 | +## Instances |
| 52 | + |
| 53 | +Create instances using INI sections. The section name becomes the container key, |
| 54 | +the class name follows after a space: |
| 55 | + |
| 56 | +```ini |
| 57 | +[connection PDO] |
| 58 | +dsn = "sqlite:app.db" |
| 59 | +``` |
| 60 | + |
| 61 | +```php |
| 62 | +$container->get('connection'); // PDO instance |
| 63 | +``` |
| 64 | + |
| 65 | +The `instanceof` keyword uses the class name itself as the container key: |
| 66 | + |
| 67 | +```ini |
| 68 | +[instanceof PDO] |
| 69 | +dsn = "sqlite:app.db" |
| 70 | +``` |
| 71 | + |
| 72 | +```php |
| 73 | +$container->get(PDO::class); // PDO instance, keyed by class name |
| 74 | +``` |
| 75 | + |
| 76 | +## Constructor Parameters |
| 77 | + |
| 78 | +Parameter names under a section are matched to the class constructor via reflection: |
| 79 | + |
| 80 | +```ini |
| 81 | +[connection PDO] |
| 82 | +dsn = "sqlite:app.db" |
| 83 | +username = "root" |
| 84 | +password = "secret" |
| 85 | +``` |
| 86 | + |
| 87 | +You can also pass all constructor arguments as a positional list: |
| 88 | + |
| 89 | +```ini |
| 90 | +[connection PDO] |
| 91 | +__construct = ["sqlite:app.db", "root", "secret"] |
| 92 | +``` |
| 93 | + |
| 94 | + 1. Set only the parameters you need — unset parameters keep their defaults. |
| 95 | + 2. Trailing `null` parameters are automatically stripped so defaults apply. |
| 96 | + |
| 97 | +## References |
| 98 | + |
| 99 | +Use `[name]` as a parameter value to reference another container entry. This is |
| 100 | +the INI equivalent of passing an `Instantiator` object as a parameter in PHP: |
| 101 | + |
| 102 | +Given the class: |
| 103 | + |
| 104 | +```php |
| 105 | +class Mapper { |
| 106 | + public function __construct(public PDO $db) {} |
| 107 | +} |
| 108 | +``` |
| 109 | + |
| 110 | +Wire it with `[name]` references: |
| 111 | + |
| 112 | +```ini |
| 113 | +[connection PDO] |
| 114 | +dsn = "sqlite:app.db" |
| 115 | + |
| 116 | +[mapper Mapper] |
| 117 | +db = [connection] |
| 118 | +``` |
| 119 | + |
| 120 | +```php |
| 121 | +$container->get('mapper'); // Mapper instance with the PDO connection injected |
| 122 | +``` |
| 123 | + |
| 124 | +References also work inside sequences: |
| 125 | + |
| 126 | +```ini |
| 127 | +admin = admin@example.com |
| 128 | +notify = [[admin], ops@example.com] |
| 129 | +``` |
| 130 | + |
| 131 | +```php |
| 132 | +$container->get('notify'); // ['admin@example.com', 'ops@example.com'] |
| 133 | +``` |
| 134 | + |
| 135 | +## Method Calls |
| 136 | + |
| 137 | +Call methods on an instance after construction using `[]` syntax. |
| 138 | +Each `methodName[]` entry is one call: |
| 139 | + |
| 140 | +```ini |
| 141 | +[connection PDO] |
| 142 | +dsn = "sqlite:app.db" |
| 143 | +setAttribute[] = [PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION] |
| 144 | +setAttribute[] = [PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC] |
| 145 | +exec[] = "PRAGMA journal_mode=WAL" |
| 146 | +exec[] = "PRAGMA foreign_keys=ON" |
| 147 | +``` |
| 148 | + |
| 149 | +```php |
| 150 | +$container->get('connection'); // PDO with attributes set and PRAGMAs executed |
| 151 | +``` |
| 152 | + |
| 153 | +## Static Factory Methods |
| 154 | + |
| 155 | +Static methods use the same `[]` syntax. They are detected automatically via |
| 156 | +reflection: |
| 157 | + |
| 158 | +```ini |
| 159 | +[y2k DateTime] |
| 160 | +createFromFormat[] = [Y-m-d, 2000-01-01] |
| 161 | +``` |
| 162 | + |
| 163 | +```php |
| 164 | +$container->get('y2k'); // DateTime for 2000-01-01 |
| 165 | +``` |
| 166 | + |
| 167 | +The `Container` will skip the constructor and use the factory, same as the pure |
| 168 | +PHP version. |
| 169 | + |
| 170 | +## Properties |
| 171 | + |
| 172 | +Names that don't match a constructor parameter or method are set as public |
| 173 | +properties on the instance: |
| 174 | + |
| 175 | +```php |
| 176 | +class Request { |
| 177 | + public int $timeout = 10; |
| 178 | + public string $base_url = ''; |
| 179 | +} |
| 180 | +``` |
| 181 | + |
| 182 | +```ini |
| 183 | +[request Request] |
| 184 | +timeout = 30 |
| 185 | +base_url = "https://api.example.com" |
| 186 | +``` |
| 187 | + |
| 188 | +```php |
| 189 | +$container->get('request')->base_url; // 'https://api.example.com' |
| 190 | +``` |
| 191 | + |
| 192 | +The resolution order is: constructor parameter → static method → instance method → property. |
| 193 | + |
| 194 | +## Autowiring |
| 195 | + |
| 196 | +Use the `autowire` modifier to enable automatic type-hint resolution: |
| 197 | + |
| 198 | +```php |
| 199 | +class UserRepository { |
| 200 | + public bool $cacheEnabled = false; |
| 201 | + public function __construct(public PDO $db) {} |
| 202 | +} |
| 203 | +``` |
| 204 | + |
| 205 | +```ini |
| 206 | +[connection PDO] |
| 207 | +dsn = "sqlite:app.db" |
| 208 | + |
| 209 | +[repository autowire UserRepository] |
| 210 | +``` |
| 211 | + |
| 212 | +```php |
| 213 | +$container->get('repository'); // UserRepository with PDO auto-injected |
| 214 | +``` |
| 215 | + |
| 216 | +The `PDO` instance is injected automatically because the container has an |
| 217 | +entry keyed by `PDO`, matching the type hint on the constructor. |
| 218 | + |
| 219 | +Explicit parameters can be mixed in alongside autowiring: |
| 220 | + |
| 221 | +```ini |
| 222 | +[repository autowire UserRepository] |
| 223 | +cacheEnabled = true |
| 224 | +``` |
| 225 | + |
| 226 | +## Factory (Fresh Instances) |
| 227 | + |
| 228 | +Use the `new` modifier to create a fresh instance on every access: |
| 229 | + |
| 230 | +```php |
| 231 | +class PostController { |
| 232 | + public function __construct(public Mapper $mapper) {} |
| 233 | +} |
| 234 | +``` |
| 235 | + |
| 236 | +```ini |
| 237 | +[controller new PostController] |
| 238 | +mapper = [mapper] |
| 239 | +``` |
| 240 | + |
| 241 | +```php |
| 242 | +$a = $container->get('controller'); // new PostController |
| 243 | +$b = $container->get('controller'); // another new PostController |
| 244 | +assert($a !== $b); |
| 245 | +``` |
| 246 | +Dependencies like `[mapper]` are still resolved and cached normally. |
| 247 | + |
| 248 | +## String Interpolation |
| 249 | + |
| 250 | +The `[name]` placeholder syntax can also be used inline within a string to |
| 251 | +build composite values. This always produces a string: |
| 252 | + |
| 253 | +```ini |
| 254 | +db_driver = mysql |
| 255 | +db_host = localhost |
| 256 | +db_name = myapp |
| 257 | +db_dsn = "[db_driver]:host=[db_host];dbname=[db_name]" |
| 258 | +``` |
| 259 | + |
| 260 | +```php |
| 261 | +$container->get('db_dsn'); // "mysql:host=localhost;dbname=myapp" |
| 262 | +``` |
| 263 | + |
| 264 | +Only root-level simple scalars can be interpolated. |
| 265 | + |
| 266 | +## State Precedence |
| 267 | + |
| 268 | +When loading INI onto a pre-populated container, existing non-Instantiator |
| 269 | +values take precedence: |
| 270 | + |
| 271 | +```php |
| 272 | +$container = new Container(['env' => 'production']); |
| 273 | +IniLoader::load('config.ini', $container); |
| 274 | +// If config.ini has env = development, the existing 'production' value wins |
| 275 | +``` |
| 276 | + |
| 277 | +This allows environment-specific values to be set before loading the INI file, |
| 278 | +ensuring they are not overwritten. |
6 | 279 |
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7 | 280 | *** |
8 | 281 |
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