oop - Why is it possible to have an interface without a return type in PHP? -

why possible create interface without specifying return type? why doesn't make interface unusable?

this makes more clear:

interface run {     public function getinteger(); }  class mystring implements run {         public function mynumber()     {      }      public function getinteger()     {           return "not number";     }     } 

in java every interface has return type integer, string or void

i know php unfortunately loosely typed language isn't there solution problem?

is possible define interface return type integer?

type hinting function/method arguments or return values supported @ php7.0 or later

check details here: http://php.net/manual/en/migration70.new-features.php

if using php5 current accepted practice use phpdoc comments indicate "contract" present.

/**   * something.  * @return int  **/ public function getinteger() { return 1; } 

if code violates "contract," suggest finding original coder , having them fix and/or filing bug and/or fixing if it's in own codebase.