You're correct in that special-case "like this other thing, except for this one particular thing that it does differently" objects happen all the time due to business rules.
But the Decorator pattern is not "inheritance without the syntactic sugar." Decorated objects, unlike subclass instances, are allowed to break the contract of the object they decorate: they don't have to claim to obey any of its interfaces, they can hide its methods, they can answer with arbitrarily different types to the same messages, etc.
If a language made defining decorators simple, I think it'd remove a lot of what people think of as the use-case for inheritance. (I mean, you aren't supposed to use inheritance for Decorator-pattern use-cases--it will likely break further and further as you try--but people will keep trying as long as the first steps are so much easier than the alternative.)
> If a language made defining decorators simple, I think it'd remove a lot of what people think of as the use-case for inheritance. (I mean, you aren't supposed to use inheritance for Decorator-pattern use-cases--it will likely break further and further as you try--but people will keep trying as long as the first steps are so much easier than the alternative.)
I actually agree with this, and I'd be interested to hear of language efforts in that direction. But until there's this easy way to do decorators, just telling people "don't use inheritance" isn't going to work.
But the Decorator pattern is not "inheritance without the syntactic sugar." Decorated objects, unlike subclass instances, are allowed to break the contract of the object they decorate: they don't have to claim to obey any of its interfaces, they can hide its methods, they can answer with arbitrarily different types to the same messages, etc.
If a language made defining decorators simple, I think it'd remove a lot of what people think of as the use-case for inheritance. (I mean, you aren't supposed to use inheritance for Decorator-pattern use-cases--it will likely break further and further as you try--but people will keep trying as long as the first steps are so much easier than the alternative.)