objective c - Make NSDate mutable -

is there way change value of nsdate without creating new instance of nsdate? i'd keep pointer same , replace underlying data.

first idea sublass nsdate , adding property keeps nsdate value...

i understand reasoning, yet think idea of mutable subclass dangerous:

the problem frameworks don't expect nsdate instances change. thus, don't copy them in case of nsstring or other classes conforming nsmutablecopying.

also, nsdate implements copy retaining same instance , returning it. you'd have override behavior which, again, might unexpected.

the idea of nsdate (similar nsnumber) represent immutable value. it's difficult imagine how , frameworks rely on fact.