Hi internals, I often have code dealing with plain old PHP objects with properties and no methods, either as a substitute for keyword arguments, or to represent a JSON or YAML document for a web service, configuration file or schemaless database.
At the moment, instantiating an object and setting public properties requires a temporary variable for each object in the structure: $obj1 = new Obj1(); $obj1->prop1 = ...; $obj1->prop2 = ...; $params = new FooParams(); $params->prop1 = ..; $params->prop2 = ...; $params->prop3 = $obj1; $this->fooMethod($arg1, $arg2, $params); For large structures, this gets verbose very quick. There is a good example of this here <https://github.com/jesseschalken/fail-whale/blob/72870b37c4c21d19f17324a966344ec476b432a7/src/FailWhale/Introspection.php#L22> involving 18 unnecessarily variables. I can remove the local variables by defining setters for all the properties: $this->fooMethod( $arg1, $arg2, (new FooParams()) ->setProp1(...) ->setProp2(...) ->setProp3((new Obj1()) ->setProp1(...) ->setProp2(...)) ); But now for each property I have to spend an extra 3-5 lines of code defining a setter, which is more code than it saved (unless the class is used heavily enough). I could define __construct() taking every property as a parameter, but then each property has to be mentioned another three times (four times with a doc comment), and the type twice: class FooParams { public int $prop1; // ... public function __construct( int $prop1 // ... ) { $this->prop1 = $prop1; // ... } } and where the object is constructed, it isn't immediately visible what the meaning of each positional parameter is without some IDE assistance (eg Ctrl+P in PhpStorm), and only specifying some parameters requires filling preceding ones with defaults. I could also define the __call() method to automatically expose setters, but then IDEs and static analysis can't understand what's going on (it can't see that those methods exist, what their parameters are and what they return). @method doc comments on the class help, but that's another line for every property which I have to manually keep in sync with the real properties. It would be great if there was a simple shorthand syntax for setting properties on an object in-line, without needing to extract a variable: $this->fooMethod( $arg1, $arg2, new FooParams() { prop1 = ..., prop2 = ..., prop3 = new Obj1() { prop1 = ..., prop2 = ..., }, } ); This way the structure can be written directly in the code as an expression and FooParams and Obj1 remain simple containers for properties. The grammar might look like (I haven't used bison/yacc before): expr_without_variable: /* ... */ | expr '{' inline_set_properties '}' ; inline_set_properties: /* empty */ | identifier '=' expr | identifier '=' expr ',' inline_set_properties ; (Although I think that would conflict with the alternative $var{8} syntax for array/string offset.) Has this been explored before? What problems can you foresee (or have been foreseen) with such a feature? Thanks