Re: optional object arguments to a function

On 13 February 2010 10:07, Jochem Maas <jochem@iamjochem.com> wrote: > Op 2/13/10 8:05 AM, Michael A. Peters schreef: >> I've started working on a class using DOMDocument to assemble MathML in >> php. The class, assuming I actually succeed, will eventually be used for >> parsing LaTeX math equations to MathML without the need to have TeX >> installed. I probably won't be able to support all the possibilities for >> equations that LaTeX does w/o a TeX install (and definitely not user >> defined macros) but I suspect I can (hopefully) cover most of the common >> stuff. >> >> One thing I don't know how to do, though, is write a function where >> arguments are optional object. >> >> IE for a function to generate an integral, the limits are optional but >> if specified must be an object (since they may be an equation >> themselves). I want the default to be some kind of a null object so I >> know to do nothing with it if it is null. >> >> With string/integer you just do >> >> function foo($a='',$b='',$c=false) { >>   } >> >> How do I specify a default null object, or otherwise make the argument >> argument optional? > > this first one doesn't work: > > <? > > class Foo > { >        function dobar(stdObject $o = null) { /* ... */ } > } > > $e = new Foo; > $f = new Foo; > > $f->dobar();                    // works > $f->dobar($e);                  // catchable fatal > $f->dobar((object)array());     // catchable fatal - check the error msg!?!? > > ?> > > ... but if you're able/willing to specify a user defined class then you > have this option: > > <?php > > class Bar {} > > class Foo > { >        function dobar(Bar $o = null) { /* ... */ } > } > > $b = new Bar; > $f = new Foo; > > $f->dobar($b); > $f->dobar(); > > ?> > >> > > > -- > PHP General Mailing List (http://www.php.net/) > To unsubscribe, visit: http://www.php.net/unsub.php > > Try stdClass. If you know the class type, then that can be the type hint. You can also use func_get_args() to read all the parameters and type check them if there are MANY optional parameters. -- ----- Richard Quadling "Standing on the shoulders of some very clever giants!" EE : http://www.experts-exchange.com/M_248814.html EE4Free : http://www.experts-exchange.com/becomeAnExpert.jsp Zend Certified Engineer : http://zend.com/zce.php?c=ZEND002498&r=213474731 ZOPA : http://uk.zopa.com/member/RQuadling