Re: [RFC] Custom Casting

Hi! > Not quite. The proposed is a syntactic sugar which is thought to handle > any transformation of a value, not necessarily or limited to type or > class conversion. It is of course possible to limit the usage to just > that, with any user defined convention or "best practice". In fact it's > pretty distinct from primitive casting, I just had in mind that reusing > the casting syntax could be an advantage due to similarity of the behavior. > > In simple words the statements of /$var = (ClassName)$var/ or > /function(ClassName $var){}/ would not be read as "Cast to", but "Cast > with". But currently this syntax already means "convert value to a value of this type" in the first case and "allow only value of this type" in the second case. Overloading this syntax IMHO will lead to a singificant confusion, and you would not know what exactly foo(ClassName $var) means - would it only accept ClassName or would it instead convert $var using transformation ClassName? My point is exactly that these are different things with different results. > The example suggestion with wrapping the value in an object just for > handling value validation/sanitization is not just overkill, but also is > excess, since there is no any need to have the value wrapped after the > function input processing. In fact, the closest construct to the > mentioned is: > > function foo(/* to be casted with PositiveInteger */ $i) { > $i = PositiveInteger::cast($i); > return 2*sqrt($i); > } Yes, I know. These are two different approaches - the difference is where the casting responsibility lies. You can define a type PositiveInteger and assign it the responsibility or you can define that each client is responsible for its own casting, however it wants to do it. I understood that you were going for the former. I think the idea of custom casting might be useful, but overloading existing syntax with it will lead to serious confusion. -- Stanislav Malyshev, Software Architect SugarCRM: http://www.sugarcrm.com/ (408)454-6900 ext. 227