Re: why interfaces ?

On Wed, Apr 30, 2008 at 12:06 PM, Jeremy Privett <jeremy@omegavortex.net> wrote: > Nathan Nobbe wrote: > >> all, >> >> in recent weeks there has been a lot of arguing about what interfaces are, >> arent (on php-general and now on the internals list as well) etc. etc. >> >> i am quite curious, why interfaces were added to the language in the first >> place. note, i am not criticizing them, i am overjoyed that the language >> has them, however i am curious about the history. is this something php >> borrowed from java? does it have anything to do with 'entirely virtual >> classes' in c++ ? i think that the history behind the addition of >> interfaces to php, would shed a lot of light on their intended purpose for >> use by php developers. >> >> thanks, >> >> -nathan >> >> >> > > "Interfaces" exist in different OO-enabled languages. PHP strengthened its > object model in PHP 5, and thus the introduction of interfaces. I'm pretty > sure the intended purpose of interfaces was just like pretty much every > other language. You implement interfaces in order to provide a consistent > API. As long as class A implements interface B, I can be for certain that > it's going to contain methods C and D. Interfaces also give you the ability > to "type hint" against them, requiring objects that implement that > interface, thus ensuring you know what methods are on that object. > > Interfaces are a very powerful feature, when implemented properly. thank you for you response Jeremy. i understand what interfaces are and i have stressed their importance and power on php-general more than once. im just curious more about what influenced the addition of them to php. im not as old as many of them members in the community, so i know there are many people who have dealt with more languages than i on a daily basis during their careers. from my limited base of knowledge, i think java was the first language to add the keyword 'interface'. and my presumption is that that grew from the convention of creating 'interfaces' in c++ by writing entirely virtual classes (as mentioned in gang of four). i have heard different perspectives on this, but i figured, what better place to get to the bottom of it than to ask the people who decided to add the interface construct to php in the first place. -nathan