Re: Union `&` operator

2020-11-07 15:12 GMT, Eugene Sidelnyk <zsidelnik@gmail.com>: > When you follow ISP, you probably would have a lot of interfaces. > Thus, client code may require an object to implement a bunch of interfaces > depending on functionality needed. > > Consider class Bar: > > ```php > > interface A {} > > interface B {} > > interface C {} > > interface D {} > > interface E {} > > class Bar implements A, B, C, D, E { > // > } > ``` > > > And some code, which uses Bar, but depends rather on > interfaces, which > functionality is actually needed: > > ```php > function foo(A & B & E $object) { > // some work > > var_dump($object); > } > ``` > > It is currently feasable like this (ugly): > > ```php > function foo(A $object) { > (function(B $object) { > > (function(E $object) { > > // some work > > var_dump($object); > > })($object); > > })($object); > } > ``` > > Or like this (more readable, but still): > > ```php > function foo(A | B | E $object) { > > if (!$object instanceof A) { > throw new \RuntimeException(); > } > > if (!$object instanceof B) { > throw new \RuntimeException(); > } > > if (!$object instanceof E) { > throw new \RuntimeException(); > } > > // some work > > var_dump($object); > } > ``` > > Another possible option is to create interface, which combines A^ > ���bV���nf��, B, > E, but in some cases it would lead us to interfaces explosion. > > This idea proposes to eliminate instanceof checks by > introducing & > union operator. > You mean intersections? Psalm supports this notation.