Re: insteadof considered harmful

On Apr 9, 2012, at 7:15 AM, Szczepan Hołyszewski wrote: > > I must admit with embarrassment that after months of googling and posting > questions to various forums I still fail to understand the purpose of the > "insteadof" keyword and the insteadof clause. > > As I currently see it, the whole insteadof clause is completely redundant. In > a clause like this: > > Foo::tweak insteadof Bar; > > the "insteadof Bar" part does not specify any information that is not already > unambiguously specified by the "Foo::tweak" part. "Foo::tweak;" already > conveys the intention of using tweak from the trait Foo instead of any other > trait that has a member named tweak. What if we are using seven such traits? > Do we have to list them all after insteadof? Why do we have to explicitly > enumerate things that we DON'T want to use? > > I would like to see a small code example where the insteadof clause provides > information that is BOTH necessary to make the program unambiguous AND cannot > be conveyed with the simple "Foo::tweak;" syntax. Absent such example, I > consider "insteadof" harmful because it does nothing and adds a maintenance > chore. It should be made optional and deprecated ASAP, and removed at some > point in the future. See http://us.php.net/manual/en/language.oop5.traits.php and scroll down to conflict resolution to see simple example. It is used to resolve method naming conflicts when multiple traits are used to emulate multiple inheritance. Tom