On Wed, August 2, 2006 5:30 am, Hartmut Holzgraefe wrote: > Ron Korving wrote: > >> So, my suggestion is this: why not support function overloading in >> PHP6, > > because in PHPs dynamicly typed world this would require runtime > checks *on every single function call* as things can't be resolved > at compile time?
Yes and no. The Lisp guys have dealt with this issue for DECADES and have several slick work-arounds to optimize this checking. First, you *CAN* check the number of args at compile time, and reduce your search-space considerably that way. Lisp also caches the inheritence order for which method to call "next" for multiple-inhertence classes. I believe that method signatures could also be cached on class definitions in such a way that it would NOT drastically affect performance to check which method to run. So while the checks would need to be done at run-time, the information to lookup which method to call could be reduced to a minimal lookup routine of O(1) or O(log N) or somewhere in that range, where N is the number of ancestors. There is no need to rule out using func_get_args() -- Once the method whose signature matches has been called, there's no reason why func_get_args() could not be utilized to process the args that "remain" for a matching signature. I.e., a method signature would "match" if the parameters list matches the corresponding arguments -- and any additional arguments need not be considered a failure to "match" This would probably best be done in PHP 7 rather than 6, I should think -- but it's a VERY good reason to not paint ourselves into a corner with OOP strictness today which will have to be violated with a BC-breaking change somewhere down the road when polymorphism is supported. If we want to condemn PHP to *never* support polymorphism, then enforcing the parameter lists to match seems less problematic -- But if there's a gleam in the eye for polymorphism "some day" this restriction seems a bit short-sighted to me. -- Like Music? http://l-i-e.com/artists.htm -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
